Its Gon' Feel Like Fall

The weather system that caused the rain and cloud cover the past two days is finally clearing out and much drier air is on its way in. Thursday morning we should be seeing temperatures in the lower and middle 50s. Be careful if your driving early as there could be some dense patches of fog. During the day, sun will be the rule with highs barely reaching 80. The air will have a cool feel to it due to the lowering of the dewpoints.

For Friday, morning lows should again be in the lower to middle 50s. A backdoor cold front ( cold front from the north) will have passed through the state early friday morning. This should help to keep temperatures on Friday only in the lower 70s. Also, due to a persistant northeast flow off the Atlantic, partly sunny skies are possible helping to possibly keep the temperatures even lower.

For the weekend, expect much of the same. Lows in the lower to middle 50s each morning and highs in the middle 70s. There will be a developing low pressure area off the coast that could add some moisture on Sunday but right now precipitation should not occur. Any additional cloud cover could keep temperatures lower during the day. I also do not want to forget to mention that there is some indication that there will be light flow from the SW in the middle levels of the atmosphere which could also add moisture for cloud development.

Outlook for next week: Continued seasonable with temperatures near normal...or in the upper 70s to around 80 with lows in the middle to upper 50s. The pattern we are seeing now seems to persist well into next week with a reinforcing high to our north that will keep a cool, dry flow into our region! It appears like fall has arrived!!

What Drought?

You probably noticed how much rain we have gotten the last several weeks, and even months. Here is a look at some precipitation statistics at RDU


Current September 2008 Precip: 7.76 inches (Including Today's 1.38 inches ; 5.45 above the normal month to date of 2.31 inches)
August 2008 Precip: 5.92 inches (Normal August Precip: 3.78 inches)
July 2008 Precip: 5.96 inches (Normal July Precip: 4.29 inches)
June 2008 Precip: 4.08 inches (Normal June Precip 3.42 inches)

We have gotten 23.72 inches of rain in the last three and a half months with the normal for the same period being 13.8 inches meaning we have gotten 9.92 inches of surplus rainfall.. in just the last 3.5 months. So how does our year to date rainfall stand?

Since January 1, 2008, RDU has received 40.71 inches. The normal value is 31.91 inches meaning we are 8.80 inches above the norm. Also if u notice, the year to date total was 40.71 inches and we received 23.72 inches of the total 40.71 inches in the last three and a half months. IMPRESSIVE!!

I am sure everyone knows 2007 was a dry year! Well get this.. Last year at this time since January 1, 2007, RDU only got 25.91 inches of rain meaning we were 6 inches below normal. BUT, the big thing to me is how again in the last three and a half months we have gotten 23.72 inches of rain.. almost the same amount of rain we received last year from January 1 through September 16.

Lets dive a little deeper. 2007 ended with 35.81 inches of rain, the normal value being 43.05 inches. Interesting how we already have received 4.9 inches more than we received all last year and there is still three and a half months left in the year. We ended the year 7.24 inches below normal.. so how much of the deficit have we really made up? Again, we have received 40.71 inches so far this year and 35.81 inches all last year. The normal yearly rain is 43.05 and the normal to date from Jan 1 to now is 31.91 inches totaling 74.96 inches. Our actual from January 1 to now is 76.52 inches. So in fact we have made up the last years deficit if my calculation is correct. We are 1.56 inches above the normal rainfall since January 1, 2007. Hopefully we will be able to get at least normal rainfall now until the end of the year so we can keep the surplus we have and not fall into another serious drought.


Here is a look at the last 3 weeks. We had the remnants of Tropical Storm Fay effect the area on August 26- 28. We received 3.71 inches of rain during this event. Then August 30-31, several rounds of thunderstorms effected the area totaling 0.96 inches of rain. Next came the big event, Tropical Storm Hanna, September 5-6, receiving 5.19 inches of rain. Finally, two widespread rainfall events, one on September 10 and one today, September 16, dumped a total of 2.57 inches of rain. SINCE AUGUST 26, RDU HAS RECEIVED 12.43 INCHES OF RAIN!

There is no doubt in my mind we are making up the deficit that we built last year. Last weeks drought monitor shows the decay of the drought region across south central NC, but the drought lingers across western NC and even northern and northeastern NC as shown below. The reason why the drought across our area is not completely gone is because of the water table. Precipitation amounts are only half of the puzzle. The water table was severely hurt last year and its still catching up.



The new drought monitor will come out Thursday morning and I will post it here. It will be interesting to see what changes as it will include the rainfall event that occurred on Wednesday, September 10. It will not include today's rain since the cutoff for their data analysis is 7am every Tuesday and most of the rain occurred from 11am to 4pm.

Heat Leaving Fast

There is no real indication that I can see that shows that we will not have another spell of some heat before we head into October, but it is looking less and less likely. Monday will be a transition day for us here in NC. A cold front that picked up Ike yesterday and raced him into the Great Lakes and now Canada is west of the Appalachian mountains currently. Behind this front is a cool fall-like surface high pressure. Under this high, temperatures are ranging from the 50s to the lower 70s. This air will not fully get here thanks to the strong upper level ridge sitting off the east coast. The ridge will actually slow the upper level pattern down somewhat meaning there will still be plenty of moisture advecting into the region from southwesterly flow aloft. A trough will be setting up just west of the mountains due to this trough, areas of rising motion will be moving in overhead. At the surface, cool, moist northeasterly flow off the Atlantic from the cool Canadian High will help bring in a fall like overrunning event with low clouds and areas of light rain and drizzle Tuesday - Wednesday. It will be somewhat similar to last weeks overcast regime, but the air will certainly be cooler and you will notice it.

In summary:

Monday will be a transition day with the cold front coming across the state. The cold front will be lying somewhere from the eastern Piedmont to the Coastal Plain tomorrow afternoon. Rain should be hard to come by with this passage, but cloud cover should prevent temperatures from getting into the 90s like they did this weekend. In fact, new data out tonight suggests the temperatures may not get above 85. The cooler air will begin to arrive towards evening with temperatures dropping into the 70s with dew points lowering into the low 60s possibly upper 50s.

By Tuesday morning, rain, mainly light should be across the area with temperatures in the lower to middle 60s. These temperatures may in fact not budge throughout the day if rain is more widespread.

By Wednesday morning, chances of light rain continue. Low overcast or fog could also be present. If clouds to break up slightly before sunrise temperatures could drop into the upper 50s.

Rest of the week: The trough should begin to lift out allowing for drier air to move in aloft. The question remains how much quickly does the lower level moisture leave the area. There are many cases where models erode the low cloud deck to quick. Since this is 3 days away, specifics will have to wait until we get closer but cooler temperatures during the day and night can be expected through Friday even if there is some sun as the airmass across much of the nation will be cooler.

Some climate information:
RDU normal high and low for Monday: 82, 62
RDU normal high and low for Tuesday - Thursday: 81, 60
RDU normal high and low for Friday: 81, 60

The point I am trying to make above is the next week should have average temperatures close to normal if not below and also shows that very hot weather will become less and less likely other than the typical anomaly that will always occur due to temporary changes in the jet stream.

I am taking the GRE in two weeks so my posting has been rather lack luster lately. I will try to keep updating take myself sane as I will be studying a lot more over the coming weeks.

Ike Landfall Iminent

Here is a radar image of Category 2 Hurricane Ike close to landfall. Official landfall does not occur until the actual center of the eye makes heads over land. IKE IS A BEAST. Just look at the size of the radar echoes..

Wrapping up Hanna; Ike Update

Hanna was really nothing more than a big rain event for most, but along the coast winds were definitely observed stronger as shown below.




Just to reiterate the point that Hanna was a big rain producer for NC.. here is an observed precipitation map for the event.



This is very surprising in that the right quadrant of the storm actually contained less rain then did the left. The eye passed up the I-95 corridor. Hanna was thoroughly disrupted in the Bahamas due to strong shear. She never really regained organization true to what a hurricane would be so apart of me feels she continued to struggle even just before landfall when some signs of organization were found from recon aircraft. The west side of the storm typically has weaker winds and that was definitely what occurred with Hanna. After landfall, whatever core there was collapsed fairly rapidly and the winds weakened.


Ike is now becoming a concern to the western Gulf Coast of the United States specifically for Texas. Below are some of the more sophisticated tropical models and their tracks that were recently just run with data current as of 8pm.



One must not focus on the specific lines, but focus on the consensus of where they are tracking Ike...somewhere into Texas or northwest Louisiana. Intensity will also remain a concern as most models show an environment in the Gulf of Mexico that will be conducive to strengthening regardless of how what condition he is in once he emerges in the Gulf. Take the 8 am model run of the European Global Model. It has an extremely intense storm crashing into the Gulf Coast of Texas near or south of Houston. Note that global models often have trouble with tropical cyclones and usually miss how low the pressure is by a large margin. Interesting times are ahead yet again, but the good news is that the rest of the Tropical Atlantic is quiet and it may stay that way for quite some time.

8am European Global Model Valid 8am Saturday 9/13/08

Hanna Rainfall...and Ike a Category 4

Rainfall was the big story with Hanna. Winds were not terrible at all here in the Raleigh area 15-25 sustained at times with gusts to 35 ..maybe 45 mph in spots, but the rain was impressive. If you were out driving around the Raleigh area after midnight you will know what I mean. Some of the heaviest rain I have ever driven in... Flooding was the big story with Hanna and not the winds. The good thing is we definitely need the rain since we are still having moderate to severe drought issues across the state. Tomorrow if I have time I will try to do an analysis of what happened with Hanna including why we got the heaviest rain here on the west side of the eye path and why the winds were relatively weak here but for now the image below is from the National Weather Service in Raleigh showing rainfall estimates across the area from Doppler Radar.



Here is an update on Ike... He is a dangerous category 4 hurricane for the second time in his lifetime. He is headed to the Bahamas and will affect them overnight. Cuba is next in his sights. The big question remains whether or not he will spend several hours over Cuba or will he stay over water longer. Of course if he is over Cuba for an extended period of time he will of course weaken considerably so we do not know how strong he will be when he emerges in the Gulf of Mexico. Yes we have another storm that is possibly going to be in the Gulf later this week. For now check out an impressive infrared satellite image taken at 12:01 am. Incredible eye feature that is very large. You can see there is an area that still has cold clouds in it but it would appear that its trying to clear that out. Ike may in fact be slightly stronger than the 135 mph the NHC has him at currently.

Hanna, Ike, and Josephine

The focus of this post is to update the status on Hanna due to its threat to the United States. In passing just want to mention Tropical Storm Ike is getting better organized and is moving rapidly westward across the Atlantic Ocean. He is expected to be a hurricane as early as tomorrow and could approach category 3 status by the weekend. Right now the consensus is for him to hit the Bahamas. From there it could hit Cuba, Florida, the SE US, or even the Gulf States if it were to travel through the Florida Straits.

Now onto Hanna....
She is definitely in a hostile environment right now with strong northwesterly shear tearing apart any convection that tries to form. This is shown below by all the colder cloud tops being shunted to the east. The National Hurricane Center notes this is expected to change soon with shear relaxing and upper environmental conditions should become more favorable for better organization and could regain hurricane status Wednesday night or Thursday. Hanna has plenty of warm water including the Gulf Stream to go over so how strong she gets if she gets to hurricane status is still up in the air.

Today she has been drifting around north of Haiti. Air Force Reconnaissance found that the center of circulation was drifting east at times. It could be possible that the center is completing a loop as a NW motion is expected to begin on Wednesday. A new Air Force Reconnaissance plane will be in Hanna after 1 am so we should know more then but of course I will be sleeping.

Computer model forecasts have a general idea of hitting the SE US somewhere from Jacksonville, Florida to Wilmington, North Carolina. It should be noted that any slight deviation in track could make a huge difference in its landfall location. From there she is expected to race NNW or N through the Carolina's and up into the NE by Saturday Night.

11 pm September 2 NHC OFFICIAL FORECAST TRACK. (NOTE DO NOT PAY ATTENTION TO THE EXACT POINT BUT THE CONE OF UNCERTAINTY)



Infrared Satellite Image Taken at 10:45 PM

Gustav, Hanna, and Ike

The 2008 Atlantic Hurricane Season is about as active as it gets in my opinion. We have Gustav over land with still hurricane force wind gusts, but now it has weakened to a Tropical Storm. lashing areas of Louisiana. New Orleans appeared to have gotten through this better than Katrina but by no means am I saying it was a dud. Gustav made landfall as a strong category 2 hurricane with winds at 110 mph.

Now onto the next tropical cyclone to possibly effect the U.S. Earlier this morning, Tropical Storm Hanna was not very organized and was not expected to become a hurricane until Wednesday. She got much better organized despite being in an environment not conducive for strengthening. Hurricane Hunters flew in and found a much stronger Hanna and she was designated a hurricane at 1:30 pm. Hanna has since stalled in the Bahamas and is expected to meander for the next day or so as the steering environment is weak. As of 11pm, Hanna has 80 mph winds and a minimum central pressure of 978mb. One of the issues Hanna has been facing is northerly shear which tends to blow off most of the clouds and convection to the south and prevents the storm from really venting itself the way a strong hurricane can. The National Hurricane Center says this shear should relax as an upper level anticyclone will move overhead. This should help to help outflow in all quadrants which acts as exhaust. I am not going to get into specifics with the exact track right now because no discernible movement is being made by Hanna. I will just say this.. Anyone from Flordia to the North Carolina coast could see this landfall there. Because of the way the east coast is shaped, any 20-50 mile deviation could affect the landfall point. Below is the New 11pm 5-day track and intensity from The National Hurricane Center shown on Wunderground color maps.



More on Hanna tomorrow evening.

Quickly onto Tropical Storm Ike which was designated this afternoon at 5pm. Not much to say here except this is another tropical cyclone that needs to be watched closely. Here is the new 11pm 5-day track again from the National Hurricane Center on Wunderground maps.




And for your viewing enjoyment, you can see Tropical Storm Gustav over the Gulf States, Hurricane Hanna over the Bahamas and Tropical Storm Ike over the middle of the Atlantic Ocean.

Gustav Weakening Slightly.. Reintensification Likely

Gustav has weakening slightly as he interacted with Cuba Saturday Night. Max winds are 135 mph and the pressure is up to 958 mb but is still a category 4. Latest satellite imagery show the eye has been covered by clouds and the eyewall appears to have weakened. I also think an eye wall replacement cycle has occured and this might be why it looks a little ragged. Cloud tops are still extremely cold so i feel strengthening is inevitable. All indications point to Gustav regaining strength during his treck over the warm gulf waters and the loop current. Its anyones guess if he becomes a 5 or stays a 4, but as was seen on Saturday anything is possible.

August 30, 2008 5PM GUSTAV ADVISORY

Latest Info as 5pm on Gustav:

MAX WINDS: 150 mph... 6 away from being a category 5
Pressure: 942 mb

The Hurricane Center feels that Gustav could become a category 5 hurricane tonight with a landfall in the US as a category 4 hurricane. I will have more later tonight and tomorrow as I will not be able to post this evening. One thing I will say is hopefully Gustav will be peaking early and start to level off and come back down to a lower major hurricane status before landfall. Storm surge will be a big issue for Louisiana and if it makes landfall west of New Orleans, they may have to contend with 20-30ft storm surge...

UNBELIEVABLE IMAGE.. taken about 4:10pm




and at 5:01 pm.. Gustav is a monster!!!

Gustav Now A DANGEROUS CATEGORY 4 HURRICANE

Air Force Reconnaissance recently reported a much more intense Gustav.. with max winds near 145 mph and a pressure of 935 mb. Lets put this in perspective here.. Last night at 11pm.. he had a pressure of 974 mb, 5am today a pressure of 965 mb and 11am a pressure of 954 mb. He is now at 945 mb.. a rapidly deepening hurricane. Scary images below...




WOW!




UPDATE: 2:20pm

The National Hurricane Center now feels it is definitely possible that Gustav becomes a category 5 hurricane before it hits Cuba. It only needs 11 more mph added to wind speed for this to occur. They are still flying into the storm and I will be able to update until about 6 pm tonight.. thereafter.. I will not be able to update until at the earliest midnight Sunday when Gustav will be emerging into the southern Gulf. Here is an updated forecast track with new intensity updated. Note the category 4 point right before landfall with New Orleans to its right..




UPDATE: 3:17 PM

New satellite images show Gustav glancing the Isle of Youth.

Visible image as of 3:02pm



Infrared image as of 3:02pm

Gustav a Major Category 3 Hurricane

Gustav is now a major Category 3 hurricane with 125 mph winds! His pressure was reported earlier this morning by the Hurricane Hunters to be 954 mb. A new plane surveying the storm right now so we should have a good idea if Gustav continues to strengthen or level off. Forecast track has not changed much and it is still possible Gustav becomes a major category 4 hurricane in the south Gulf Of Mexico on Sunday. .. he could even be a 4 before making landfall in Cuba.. Breathtaking images below.. yet quite scary.

Visible Image @ 12:45pm



Infrared Image @ 12:45pm (Bright colors indicate deep cold cloud tops)

Gustav a Category 2 Hurricane

Gustav became a hurricane again early Friday afternoon. He is now a category 2 hurricane with 100 mph winds.. Here is the latest statement from the National Hurricane Center..

HURRICANE GUSTAV TROPICAL CYCLONE UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072008
210 AM EDT SAT AUG 30 2008


DATA FROM AN AIR FORCE RECONNAISSANCE AIRCRAFT INDICATE THAT
GUSTAV CONTINUES TO STRENGTHEN AND NOW HAS MAXIMUM WINDS NEAR 100
MPH...155 KM/HR WITH HIGHER GUSTS. THIS MAKES GUSTAV A CATEGORY TWO
HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE.

$$
FORECASTER BLAKE/AVILA

He appears to be continuing to intensify as of this post and is now only 10 mph in wind speed away from being a major category 3 hurricane on the Saffir Simpson scale. This may very well be the case when we all wake up in the morning. Gustav is still expected to make a landfall on the western tip of Cuba. This landmass may serve to temporary halt intensification or even weaken him, but once over the Southern Gulf, Gustav has a chance at becoming a category 4 hurricane (131-155 mph). The consensus is then for Gustav to move NW towards the central Gulf Coast west of New Orleans making landfall possibly as a category 3. The reason for the possible weakening is cooler waters in the northern Gulf Of Mexico. One needs to note that hurricanes go through cycles that can serve to weaken them even though conditions are ripe for intensification. These cannot be predicted! For now here is a satellite image of Gustav.. the eye is hard to pick out but Hurricane Hunters have found a 30nm closed eyewall. More on Gustav and tropical storm hanna later today/

Brother and Sister in the Atlantic Basin

Just wanted to update on Gustav and Hanna. Gustav is packing winds of near 70 mph which is very close to hurricane strength (74 mph or greater). He is moving very close to the shores of Jamaica. Hanna is north of the Leeward Islands and she is packing 50 mph winds. The potential track and strength of Gustav is troubling as he will likely strengthen rapidly once he moves away from Jamaica. He is forecast to move into the Gulf of Mexico and threaten the Gulf coast states. Lets hope it does not hit the main oil rig region but right now that looks possible that it will threaten that area. Please note in the images below, the track forecast of each storm after day 3 have very little skill and could easily change by hundreds of miles in later forecasts. Hanna is expected to meander near the Bahamas in the coming days and it appears she could also strengthen rapidly as well. Both storms do have the potential to become major hurricanes (Category 3 or greater) in the coming days. The NHC does mention this about Hanna even though it is not show on the track forecast.


Gustav 5-Day Projected Track



Hanna 5-Day Projected Track



Gustav middle and Hanna right(Infrared Satellite Image..Brighter colors mean strong convection and cold cloud tops)

August 26-28, 2008 Remnant Fay Analysis & Summary

The focus of this analysis is with what happened across North Carolina...

Beginning during the early morning hours on Tuesday, August 26 rain began to overspread western North Carolina from the southwest from the remnants of Tropical Storm Fay with only light rain and drizzle across central NC. The reason why the heaviest precipitation was focused in the western part of the state was because of an upslope component to the wind. By this I mean the wind was blowing up the higher terrain as the wind was blowing from the SE to NW. This aids in lifting necessary to get precipitation. Combine this process with abundant tropical moisture and the remnant circulation from Fay, you get very very heavy rainfall.

The heavy rains continued to affect the mountains, foothills, western Piedmont and southwest sandhills of NC. Drizzle and light rain continued across the Triangle. The large area of heavy rains finally began to shift NE through the early morning hours on Wednesday, August 27 with some of this rain getting as far east as Johnston county. By 7am, a trailing squall line of heavy rain and thunderstorms was crawling across eastward across the state. The line had rainfall rates of 2-4 inches an hour in spots. It finally reached the Triangle with 1.57 inches of rain falling in one hour at RDU.

Tornadoes then became a major threat as there were several boundaries draped across the state. Whenever a remnant circulation from a tropical storm exists, isolated tornadoes are a possibility. There was also a good amount of wind shear as well as a parameter called helicity which takes into account the wind shear and the possibility of a storm to ingest horizontal spin into its updraft. Wind shear is the change of wind with height. We had southeasterly winds at the surface and southwesterly winds in the middle and upper levels. There was also a increase in the speed of these winds as you go up. Due to the copius amounts of moisture, getting a quick tornado to spin up and touch down was certainly possible. Tornadoes are much more likely to occur when saturation of the air is occurring very low to the surface of the earth. Even if all the parameters necessary for tornadoes exist, if the low level air is dry a tornado may not be as much of a threat.

Below are the damage survey results from the tornadoes that touched down. If you were listening to the news, radio, or are a weather hobbyist you know the Raleigh National Weather Service had issued many warnings in the afternoon.

RANDOLPH COUNTY TORNADO NEAR RANDLEMAN...
TORNADO: EF-0
PEAK WIND: 60 MPH
PATH LENGTH: 500 YARDS
PATH WIDTH: 50 YARDS
TIME/DATE: 1230 PM WEDNESDAY, AUGUST 27, 2008
INJURIES: NONE NONE
FATALITIES: NONE


CHATHAM COUNTY TORNADO NEAR SILK HOPE...
TORNADO: EF-0
PEAK WIND: 75 MPH
PATH LENGTH: ONE AND A HALF MILE
PATH WIDTH: 100 YARDS
TIME/DATE: 415 PM WEDNESDAY, AUGUST 27, 2008
INJURIES: NONE NONE
FATALITIES: NONE

WAYNE AND WILSON COUNTY TORNADO SURVEY...

FIRST TOUCHDOWN AT AYCOCK CHURCH ROAD
TORNADO: EF-0
PEAK WIND: 75 MPH
PATH LENGTH: ONE HALF MILE
PATH WIDTH: 50 YARDS
TIME/DATE: 1258 AM THURSDAY, AUGUST 28, 2008
INJURIES: NONE NONE
FATALITIES: NONE

SECOND TOUCHDOWN AT BEAVER DAM ROAD
TORNADO: EF-0
PEAK WIND: 65 MPH
PATH LENGTH: 150 YARDS
PATH WIDTH: 25-50
TIME/DATE: 102 AM THURSDAY, AUGUST 28, 2008
INJURIES: NONE NONE
FATALITIES: NONE

Now back to the heavy rainfall..

Heavy rain and thunderstorm bands continued through the night across central and eastern NC. Wake county got in on torrential rains and embedded lightning from around 10 through 2am. Here are some totals from around the region reported by the NWS. Note: I had to change the RDU report as I believe they made an error. I also highlighted some notable amounts including one in Greensboro with 10.99" and added Charlotte to the list also as they were not in the report sent out by the Raleigh office. The report totals go from 8am Tuesday the 26th to 8am Thursday the 28th.

LOCATION 48-HR RAINFALL TOTAL
----------------------------------------------------

...ALAMANCE COUNTY...

HAW RIVER 7.23"
GRAHAM 6.58"
BURLINGTON 0.8SE 4.70"
BURLINGTON AIRPORT 4.69"

...CHATHAM COUNTY...

PITTSBORO 6.5W 8.07"
PITTSBORO 5.4NW 7.81"
CHATHAM WATER TREATMENT PLANT 4.83"
SILER CITY 5.5ENE 4.58"
GOLDSTON 4N 3.91"

...CUMBERLAND COUNTY...

FAYETTEVILLE AIRPORT 3.36"
FORT BRAGG 3.26"
FAYETTEVILLE 3.00"

...DAVIDSON COUNTY...

LEXINGTON 4.70"
WINSTON SALEM 7.7S 3.47"

...DURHAM COUNTY...

DURHAM 9.5N 6.32"
DURHAM 7.4 NNW 5.20"
DURHAM 5.15"
DURHAM 1.2NW 3.42"
DURHAM 6.2S 2.96"

...EDGECOMBE COUNTY...

TARBORO 0.50"

...FRANKLIN COUNTY...

YOUNGSVILLE 1.2E 2.62"
YOUNGSVILLE 4.1SE 1.80"
LOUISBURG 8.2ESE 1.53"
LOUISBURG 1.05"

...FORSYTH COUNTY...

LEWISVILLE 4.2N 6.73
RURAL HALL 4.22"
PFAFFTOWN 3.24"
WINSTON-SALEM 0.6S 3.22
SMITH-REYNOLDS AIRPORT 3.15"

...GUILFORD COUNTY...

GREENSBORO 6.5SSE 10.99"
GREENSBORO 1SE 6.74"
PTI AIRPORT 5.79"
BROWNS SUMMIT 3NW 5.29"
GREENSBORO 5.07"
OAK RIDGE 2.3SSW 4.30"

...HALIFAX COUNTY...

ROANOKE RAPIDS 0.73"
HALIFAX CO AIRPORT 0.57"
SCOTLAND NECK 0.26"

...HARNETT COUNTY...

ERWIN-DUNN 3.12"
COATS 0.7W 1.69"

...HOKE COUNTY...

RAEFORD 2.59"

...JOHNSTON COUNTY...

SMITHFIELD 2.8SE 2.09"
CLAYTON 2.1W 2.07"
SMITHFIELD 1.98"
KENLY 6.6NW 1.27"
CLAYTON 5.8S 1.23"
CLAYTON 0.71"

...MECKLENBURG COUNTY...
CHARLOTTE INTERNATIONAL AIRPORT 8.54"

...MONTGOMERY COUNTY...

JACKSON SPRINGS 2.65"
TILLERY DAM 2.48"

...NASH COUNTY...

NASHVILLE 3.2W 1.19"
ROCKY MOUNT-WILSON AIRPORT 0.63"

...ORANGE COUNTY...

CHAPEL HILL 5.32"
CHAPEL HILL AIRPORT 5.02"
HILLSBOROUGH 7.4NW 4.88"
HILLSBOROUGH 4.9SW 4.02"
MEBANE 7.4SSE 2.99"

...RANDOLPH COUNTY...

RANDLEMAN 7.24"
ASHEBORO 1.2SW 4.91"
ASHEBORO 2.2SSE 4.58"
ARCHDALE 1.3SE 6.72"

...RICHMOND COUNTY...

BLEWETT 1.25"

...SAMPSON COUNTY...

CLINTON 1.16"

...SCOTLAND COUNTY...

LAURINBURG-MAXTON AIRPORT 1.58"
LAURINBURG 0.99"

...STANLY COUNTY...

STANFIELD 4.42"
ALBEMARLE 3.60"

...VANCE COUNTY...

HENDERSON NNE 3.09"

...WAKE COUNTY...

WAKE FOREST 4.6SW 4.45"
WILLOW SPRINGS 4.5SE 3.94"
RALEIGH 10.3N 3.90"
HOLLY SPRINGS 3.76"
APEX 6.1ESE 3.72"
RALEIGH-DURHAM AIRPORT 3.65"
RALEIGH 8.4N 3.43"
HOLLY SPRINGS 1.8ESE 3.35"
HOLLY SPRINGS 2ESE 3.33"
HOLLY SPRINGS 3.6SSE 3.24"
HOLLY SPRINGS 1.1ESE 3.16"
RALEIGH 1.5WNW 2.75"
GARNER 3W 2.65"
CARY 0.4NNW 2.53"
CARY 2.48"
CARY 2.6ESE 2.47"
APEX 2.47"
APEX 3.5W 2.29"
KNIGHTDALE 1.9WSW 2.19"

...WARREN COUNTY...

ARCOLA 1.44"

...WILSON COUNTY...

WILSON 1.95"
WILSON 2.1NNW 1.31"

...WAYNE COUNTY...

GOLDSBORO 1.5NE 3.35"
GOLDSBORO 4.4E 2.36"
GOLDSBORO 2.12"
GOLDSBORO AIRPORT 1.01"

Finally, The map below is showing the event total from the Raleigh NWS radar. This really puts in perspective just how much rainfall fell.

DROUGHT BUSTING RAINS

Western NC, SC, and Georgia got much much needed rainfall.. most areas way to much in a short period of time. Today, central NC got in on the action with RDU receiving 2.37 so far and more looks to come shortly. Chapel Hill has seen over 4.5 inches. There were also tornadoes that were spun up in some locations with some strong storms early today. A much more in depth post will be made tomorrow. Check back then for images and some analysis. Also where will Gustav go and how strong?

Rainfall "Potential" The Next 5 Days

An unsettled weather pattern is setting up for the upcoming week. The upper level ridging that we have seen keep our weather fairly tranquil the last week is beginning to shift away and weaken slightly allowing for a more southwesterly flow of air off the Gulf Of Mexico to take shape. We also will have to watch where the remnant circulation of Tropical Storm Fay moves to this week as it gets caught in this southwesterly flow. Currently the remnants of Fay are over southwestern Alabama and eastern Louisiana. On Monday evening, a cold front from the north will also be entering the state. Combine this front and the increase in moisture from the south there should be a scattering of showers and possible thunderstorms tomorrow afternoon and evening. Then this front will settle across the state with a weak high pressure at the surface moving into a warm-season Cold air damming location with northeasterly flow at the surface and warm moist air overriding this "cooler" shallow air mass. The big question that I see that could really affect the amount of rain we see here is how much dry surface air moves in with this high. There is no doubt in my mind that the air above the shallow "cool" dome will be very moist, but if the surface layer is too dry then precipitation may be hard to come by Tuesday. As we head into Wednesday and the end of the week, whatever is left of Fay will move NE into the Ohio Valley and low level moisture should increase again off the Gulf and Atlantic provided for more widespread showers and storms.

Here is a 5-day total Precipitation Forecast from the Hydrometeorological Prediction Center. It is obvious that the potential exists for significant rainfall this week especially across western NC, SC, and GA where exceptional and extreme droughts exist(The highest drought categories.)



Temperatures this week will average below the normals due to increased cloud cover and the potential for widespread precipitation. I am going to again do a temperature forecast for the week and update the blog with the actual observed temperatures. I will also update on the precipitation but feel it is not necessary to predict amounts, just let you know significant precipitation is possible.

Predicted RDU Temperatures for the next 3 days:
(Normal High is 86)

Monday: 86
Tuesday: 82
Wednesday: 78

Catching Up

It has been since Sunday when I posted last here and it was to discuss the many possibilities of Fay. Well it is almost Friday as I write this and Fay is still an issue. The models that had Fay stalling and drifting back west across Florida were correct. To put in perspective, Fay has dropped rainfall amounts over 2 feet locally in east central Florida Fay is currently sitting along the coast of Florida and will begin to track westward across Florida into the panhandle. Eventually the remnants will move back into the SE states of Alabama, Georgia, and parts of Louisiana and Mississippi. The question then becomes does her remnant circulation and moisture move NE towards the drought stricken areas of North Carolina, South Carolina, and North Georgia. Stay Tuned..

Closer to home, we have had relatively quiet weather, except a few showers/storms that formed on Wednesday evening dropping close to a half inch of rain at RDU. Temperatures have been normal to slightly above normal as well since last Friday. (Normal high is 87 now). I expect temperatures to be near 63 in the morning with a low overcast developing to a the low level easterly flow. This should burn off quickly though and temperatures should reach the middle 80s tomorrow with a high near 86. A very similar day is in store for Saturday and a little bit warmer on Sunday with a high closer to 88. Friday and Saturday evenings look to be extremely comfortable for this time of year with temperatures hovering near 70 early dropping to the low and middle 60s overnight.

Fay Going Where?

Tropical Storm has been a disorganized tropical cyclone since Friday as it passed through the Dominican Republic and Haiti. Fay is now just south of Cuba and is projected to begin turning west north west and northwest towards Florida. The big question then becomes how strong does Fay get after it re-emerges in the Gulf of Mexico and where does she eventually make U.S. landfall. Computer model forecasts have been extremely unstable where one day they are pushing Fay up into the Appalachians after landfall near Tampa Florida. The next day they are showing a landfall on the panhandle of Florida then slowing down as Fay meanders up into the southeast. Oh and not to mention there are models showing Fay turning NE back into the Atlantic and then making a second landfall on the east coast of the U.S near South Carolina or Georgia.

If the remnants of Fay do in fact move up into GA, SC, and NC, and her remnant circulation is west or south west of NC, then a much needed rainfall event will set up for several days as the flow regime will remain slow due to a a strong surface high setting up off the NE coast of the US. So whatever is left of Fay will meander somewhere over the SE US. Let it be known rain her in NC is by no means guaranteed.
Ill have more on Fay this week as hopefully things become a little clearer but right now expect a lot of chaos is the coming days with regards to what exactly we will feel here in NC.

Record Setting August 13

For a record low maximum temperature. In fact it tied the old record for low maximum for this day. Here is the report from the National Weather Service in Raleigh...

... Record low Max temperature tied at Raleigh-Durham international
Airport today...

As 500 PM EDT... a record low Max temperature of 74 degrees was set
at the Raleigh-Durham international Airport today. This ties the
previous record for August 13th for the coolest high temperature...
last set in 1996.

The normal high temperature for the Raleigh-Durham international
Airport for August 13th is 88 degrees

...

As far as the rainfall, my hunch on more rainfall further northwest was true but amounts were relatively light except in isolated spots that got under some slow moving showers or locations down south such as Fayetteville.

On August 13, 2007, RDU hit a temperature of 98. This was during the stretch of very warm temperatures that we had that included two 104 readings as well as a 105 on August 21. One of the meteorological fields I look at to get a feel for the general atmospheric flow is a 500mb height chart. The lines on the chart show the general wind flow as at this height winds blow parallel to the contours. These contours represent lines of equal 500 mb pressure level height. The barbs are showing the wind direction and speed and the color fill is where the strongest winds are located.

Below is last August 13, 2007 8am 500 mb chart.. Notice how the majority of the lines are to the north across the northern US and southern Canada. This means the majority of the country was under a ridge with very warm temperatures. The ridge is indicated by the large closed contour labeled 5940. This is a large anticyclone meaning high pressure and sinking air.



And here is this morning at 8am. Wow what a difference as the ridge is placed over the SW part of the country and is weaker than last year and there is a deep trough for August standards across the eastern US. This has allowed the cooler air to filter towards our region and because we had little sun today and rain most of the day temperatures were held down. This trough was also responsible for the cool Tuesday morning when we hit 56, and for the development of the low pressure that caused a gloomy, cool fall like day here in NC.




Oh and if your out driving tomorrow morning around sunrise, please be careful of dense fog. There are very light winds, moisture left over from today's rain and dry air on top of the moisture that has allowed for the development of fog. Visibilities have decreased to as little as 3 miles at RDU and 2.5 miles at Chapel Hill. We could also see the mercury drop to 58 or 59 in the morning coming short of the record low for August 14 of 55 set back in 1964.

UPDATE 12:05 AM AUG 14:
RDU does not seem to be sending out its observation for midnight but at Chapel Hill visibilities are down to a half a mile. The fog is getting denser out there and I would not be surprised if Dense Fog Advisories are hoisted for the early morning commute.

Unseasonable Storm System Approaching

First, I just want to mention that this mornings low temperature hit 56 degrees. Another gorgeous day also!...Now onto more important issues, and if your not Meteorologically(Is this even a word) savvy, this post may not be for you.

There is a cool-season like low pressure system that is developing across the southeast bringing widespreads with it to MS,AL, and GA. Forecast models are predicting this low pressure to move south of central NC and off the coast on Wednesday. With this will come increased mid and upper level moisture as well as the chance for rain. Forecast models are predicting widespread 2-4 inch rain amounts across parts of GA,SC, and coastal NC. Areas further north are forecast to receive much less in the range just a trace to .50 with higher amounts in spots. There is a stationary boundary draped across SC and GA as well and it appears that the low will track across wherever this boundary lies. Heres the problem.. this is summertime.. why wouldnt the boundary start to move north once the warm air advection off the coast kicks in overnight. In the wintertime, stalled out boundaries to the south have a very hard time moving northward and a Cold Air Damming event sets up where warm air overrides the cool (or cold) air at the surface. A situation like this may occur tomorrow if precipitation begins to fall into the relatively dry air we have right now at the surface. But is it really going to stop the boundary from moving further north than staying over the coast? Something just does not make sense to me with the scenarios the models show. I realize there is a large vortex over the NE part of North America but its also retreating further north now also.

I learned last year that sometimes model over develop precipitation bulleyes forcing other issues to occur in its grids allowing for misplaced features. Could this be happening? One short-term model that has better resolution(NAM) does have some of these features moving further north than the model that does not have better resolution (GFS) but which will be right?? Normally CAD events have surface pressures 1025mb or higher... right now surface pressure are running 1010-1013 mb.. not that strong.. so that could also be a factor.

I guess what I am trying to say is that I am in no way confident that there will be these huge amounts confined to a region in GA,SC, and coastal NC. This could be totally wrong and be to high, or it can simply be correct and then we here in central and northern NC will not see much at all. I am no way confident in any of these scenarios and apart of me wants to believe there will be more significant rains across a larger area with this type of system. Oh and one more thing, the NAM is much slower with the progress of the low and its track than the GFS and this to me seems more reasonable as the flow right now in the jet stream is for slow progression.

Well thats that. we will see whos right. a computer or human knowledge of the meteorological setup. We will soon find out

Cannot Get Any Better Than Today

For the middle of August. Today's high temperature was 86, 2 degrees below the normal high of 88. Add the mild temperature to extremely low dewpoints, you get a glorious fall-like (or spring-like) day. So how about tonight.. with continued clear, dry and relatively calm conditions, I expect to see lows in the middle to upper 50s. Take note that the record low for August 12 is 54 set back in 1954 at RDU. We will probably not reach 54, but we could come very close if the winds go completely calm. This would allow the heat from the day to totally escape into space and the temperature drop towards the dewpoint as long as the sky is clear.

Tomorrow looks to be another glorious day with high temperatures around 87. There will be an increase in high cirrus clouds in the afternoon and evening with the approach of a storm system that should affect some folks in the SE Tuesday night into Wednesday. Right now it appears that the most widespread precipitation will occur along the NC/SC border area but this is not set in stone so stay tuned! I will have an update on this tomorrow evening as new data, current observations, and trends are assessed. Regardless, Wednesday may struggle to get above 80 with cloud cover from this system even if it does not rain.

2008 Atlantic Hurricane Season Heating Up

Indications are that the next few weeks there will be an increase in tropical cyclone activity in the Atlantic Basin. The Intertropical Convergence Zone (ITCZ) has become quite active with wave after wave coming off the coast of Africa. This time of year also marks when systems, disturbances, or tropical waves (whatever you might want to call them) come off of Africa can make a full track across the Atlantic ocean and affect the Caribbean Islands, the Gulf of Mexico or even the U.S. mainland. The weather pattern is being predicted by several global computer models to begin shifting this week to a more favorable pattern for Atlantic tropical cyclones to develop and make this track across the Atlantic. It is impossible for computer models to predict exact tracks of these storms this far out in advance, but when 3 different computer models (American, European, UK) all hint at several waves becoming tropical cyclones its time to start paying attention. Computer models generally do a good job at sensing larger scale patterns and pattern shifts and the one being predicted is definitely one that supports hurricane development.

The National Hurricane Center already is keeping an eye of 2 of these waves over open waters of the Atlantic.

So Now What?

Not much occurred today across the northern portion of the state, but south of Wake County there has been several rounds of showers and thunderstorms. The first few rounds were severe with large hail and damaging winds. Golf ball (1.75 inch diameter) hail occurred in Fayetteville with nickel to quarter sized hail (.88 - 1.00 inch) in other areas including Harnett County and Pope AFB. Several trees fell on homes in Fayetteville. The radar shown below shows this nasty thunderstorm cell. Apart of me believes it was a supercell and some of the parameters necessary for supercells were there across the southern part of the state. Supercell thunderstorms are capable of producing large damaging hail, damaging winds, and the stronger tornadoes. Image courtesy of WRAL's Fayetteville Doppler. The purple and black colors indicate hail being detected by the radar(High intensity signal).



Here is an picture of some the hail and a tree that hit a house. WRAL says this house was up for sale. Images courtesy of WRAL.






So how come we did not see any thunderstorms with such a big weather change coming? Our winds were coming from the NW direction which is down slope of the higher terrain of the Appalachian mountains. This wind flow tends to dry out the air so it is harder for storms to develop in such an environment. The southern part of the state was in a much more favorable environment with higher low level moisture and was also in a region of high instability.

Now.. the next several days should stay away from the 90 degree mark. Last August, we had one day that did not hit 90. It appears like the next several days (maybe even into the middle of next week) will stay below 90. That is significant because our normal high temperature is 88 for the next several days meaning we will actually have more normal or even below normal weather if we stay below 88 which is certainly possible. There are other variables to discuss that might play a role in sensible weather but I will not get into details. Oh and one more thing..Saturday mornings low temperature should be near 60 and just as a note.. the record low for August 9 is 58.. could come close!

Wednesday Results

Wednesday Temperature Predictions and Actual Observations: I did well with Raleigh and Greensboro, but Charlotte and Fayetteville baked in full sun all day when Raleigh and Greensboro had to deal with high cirrus off and on which held temperatures back some.

Raleigh-Durham: Wednesday 96; Actual 96
Greensboro: Wednesday 94; Actual 94
Fayetteville: Wednesday 97; Actual 100
Charlotte: Wednesday 96; Actual 99

More tomorrow on any thunderstorm activity and the incredible weather for August this weekend.

Something For The Weather Weenie's

Lets discuss something absolutely incredible that happened near Chicago last night. If your not well informed about meteorological terminology then this post may not be for you. Last night there was a nasty severe weather complex that raced through Chicago. There was a game at Wrigley Field and the had to evacuate due to a tornado warning. The only actual report I have seen that may indicate a tornado was a report of a funnel cloud. Most damage reports were from straight-line winds. In order to get any type of convection, you need instability, moisture, and lift. All three were in doubt present last night, and the amounts of some of them are insane.

Below are 00z August 5 (8pm August 4)soundings in the Chicago region.

00z Sounding out of Davenport, Iowa



00z Sounding out of Lincoln, Illinois.



One of the things that sticks out at me is how positively buoyant surface parcels are if they are lifted. The Convective Available Potential Energy (CAPE) was through the roof. This shows how much an air parcel can rise and also how quickly it can rise if it is lifted. Surface-based CAPE (SBCAPE) was 6,600 J/kg and Most Unstable Cape (MUCAPE) was nearly 7,000 J/kg. Lifted Indexes (LI's) was -13 and Precipitable Water was 1.93 inches. If you notice the the temperature profile (red) and dew-point profile (green), they are not together meaning there is some dry-air to overcome in the storms. This adds to the downward momentum from severe convection. There is even a parameter for this called DCAPE or downward CAPE. This was also through the roof on the Davenport sounding with a value of 1610 J/kg. You think these values are high.. just wait. The Lincoln sounding showed even more instability. SBCAPE and MUCAPE was nearly 8,500 J/kg.. I have no words for this.. that is just INSANE. To put it in perspective, we see SBCAPE and MUCAPE more towards 1500-3000 J/kg over the summer with occasional times where these values can get close to 4,000 J/kg. DCAPE at Lincoln was almost 2,000 Jkg. Still INSANE. Precipitable water was also 1.93 inches at Lincoln. So there is no question there was instability and moisture. What about lift? There was a surface front across the region, and even a minor shortwave in the middle levels that provided for necessary lift. Here is a 700mb analysis map at 00z. Pay attention to the minor dip in the lines near the Great Lakes. To the right of the dip is usually where lift is located..



Now for some video footage.... first one taken in Chicago looking towards Wrigley field.. with the eery tornado siren in the backgroud.. Notice how the stadium basically dissappears with the rain and strong winds ( reports of winds near 90 mph). The second is some footage from someone who went to the game. The third is some amazing footage of lightning I believe after the worst of the storm moved through.

Tuesday Temperature Recap

Well my initial thoughts last week on this current heat wave were current. NOTHING spectacular. No one saw a 100 degree reading today and it is very unlikely anyone will Wednesday either. Here are my predicted temperatures and actual observations for Tuesday, August 5. If anything I was slightly too high on my predictions. A high of 96 is nothing uncommon in the summertime in the Triangle area. I did horrible for Charlotte, and was a degree or two off at the rest of the locations. All my predictions were too high.

Raleigh-Durham: Tuesday 98; Actual 96
Greensboro: Tuesday 97; Actual 96
Fayetteville: Tuesday 99; Actual 98
Charlotte: Tuesday 99; Actual 95

To continue what I have been doing during this current heat wave I will make one more set of forecasts for Wednesday. Thursday should be around 90 and could even be slightly lower if there is more cloud cover and precipitation. Big changes appear to be coming with a pattern shift from upper level ridging to a deep upper level trough. As long as all surface features, such as the projected cold front, do not stall over NC we should have delightful summer weather Friday through the weekend. Temperatures will be in the middle to upper 80s during the day and middle 60s at night!

Wednesday Temperature Predictions:

Raleigh-Durham: Wednesday 96
Greensboro: Wednesday 94
Fayetteville: Wednesday 97
Charlotte: Wednesday 96

I will post the actual observations tomorrow night. One note again is that the record high for August 6 at RDU and Greensboro is 97. If tomorrow does in fact decide to be the hottest day of the heat wave, then these records could be in jeopardy, but I think debris clouds from thunderstorm activity to our NW and the chance for some showers and storms to make there way into the state later in the day could put a halt to the mercury rise.

Monday's Actual Highs; Tuesday and Wednesday Predictions

The actual numbers are in for the cities I predicted for yesterday. Here are the predicted numbers and actual numbers.

Raleigh-Durham: Monday 94; Actual 94
Greensboro: Monday 93; Actual 92
Fayetteville: Monday 96; Actual 93
Charlotte: Monday 95; Actual 94

I did very well for Raleigh, Greensboro and Charlotte, but was too high in Fayetteville. The reason for the lower high temperature due to a thunderstorm that hit the area middle of the afternoon.
Tuesday will be much hotter and more humid across the entire area as the ridge of high pressure tries to nose into the state.

Below are my Tuesday and Wednesday predictions for Highs:
Raleigh-Durham: Tuesday 98; Wednesday 96
Greensboro: Tuesday 97; Wednesday 93
Fayetteville: Tuesday 99; Wednesday 97
Charlotte: Tuesday 99; Wednesday 96

I made some minor changes to Tuesday. I have a pretty good idea that these locations will not reach 100. Wednesday will be slightly lower due to more moisture, clouds, possible showers and the retreat of the upper ridge. Then, exactly how much the weather changes after Wednesday? Right now, it appears a nice push of cooler more Canadian summer air will make its way into the eastern United States by the end of the week!

Tropical Storm Edouard Develops; Monday Forecast

Tropical Depression 5 formed this afternoon at 5pm and one hour later was classified as Tropical Storm Edouard with 45 mph winds. Edouard is disorganized currently and is not forecast to become a hurricane, but is over the warm waters of the Gulf and vertical wind shear is almost nonexistent so this one needs to be watched. Edouard appears to have no chance of moving northward into Louisana and the SE US as the ridge of high pressure will force Edourd to the W-SW over the next day or so. Landfall is projected to be somewhere near Houston/Galveston Texas region. Click the image for a Track Map and Infrared Satellite map using google maps from WeatherUnderground.



Closer to home, the heat becomes the major concern over the next three days. Monday should not be too extreme with low dewpoints leading to a more "comfortable" heat meaning heat indexes should not be over the actual temperatures by more than 3-5 degrees. Tuesday's heat will be more extreme with dewpoints in the upper 60s leading which will make it feel terrible and I would not be surprised if heat advisories are hoisted for Tuesday. Wednesday could be very similar as Tuesday. I still do not expect to see temperatures reach 100 either Tuesday or Wednesday. Again, like has been the case the last several weeks, the models are predicting too high of temperatures than what is actually being observed. Below are my predictions for Monday and Tuesday for select locations in NC. I will update tomorrow on Edouard (unless he rapidly strenghtens this evening), and refine the numbers for Tuesday as new data becomes available. Note that the record at RDU for Tuesday is 100 and for Wednesday is 97.


Raleigh-Durham: Monday 94; Tuesday 99
Greensboro: Monday 93; Tuesday 98
Fayetteville: Monday 96; Tuesday 99
Charlotte: Monday 95; Tuesday 100

August Has Arrived

I posted on Tuesday about the potential for extreme heat the end of this weekend into next week. Well that looks like it is on hold until maybe Tuesday and Wednesday. The keyword here is maybe as again I am not confident in the model solutions and how high the temperatures are forecast to be in the coming days. Saturday will be no doubt be hot, but not as hot as the GFS (global model) says it will be (98). I predict a high of 95 (more in line with past two week trends and other guidance). That could be held down if there is more clouds and more showers and storms. Right now, it appears that another disturbance in the northwest flow aloft will come through during peak heating. Moisture should be on the rise again as currently the atmosphere is too dry to support precipitation. It is uncertain whether or not coverage will be isolated or more widespread.

Here are some statistics from the record breaking August 2007

90 degree days: 30
100+ degree days: 6 with 105 second hottest day recorded at RDU.
Precip: 0.91 inches ; normal August total: 3.78 inches

The big thing to note is 30 of the 31 days last August were above 90 with six of those being about 100. It was also extremely dry that month. Will we see another hot August? Luckily, we are heading into August with a bit more rainfall then we did last year heading into August, but the ground water is still low and could play a role in any hot spell that occurs including the one possible this coming week.

Extreme Heat To Return?

I am still not totally convinced that extreme heat will return late this weekend into next week. You may have heard from several radio and TV outlets that triple digit heat may make a return. Model predictions show a massive heat ridge somewhere over the eastern United States starting this weekend and then heading into next week. I am in no way saying that this will definitely not happen, but the exact location of this ridge and exactly where the surface high pressure ends up sitting will make all the difference. I posted about this last week how model guidance for temperature forecast have been higher than what is actually occurring. Today was no different with RDU reaching 92 and some guidance yesterday showing highs in the mid to upper 90s. The same holds true for Wednesday through Friday. I feel most guidance is slightly to warm.
Here is a look at extended range temperature statistical guidance from the GFS(global forecast system model) for RDU.

WED: 95
THURS: 94
FRI: 98
SAT: 97
SUN: 99
MON: 102
TUES: 100

As you can see, the heat is predicting to get extreme by next week. Will this happen? Its possible given the pattern that appears to be coming, but this model has also been several degrees above the actual observed readings.

For Wednesday, with higher moisture in the air I would expect that there would be a good amount of cumulus clouds with some of them becoming storms. This should help to keep temperatures from getting higher than 93. Thursday will be very similar with perhaps more showers and storms. Then from there, it all depends on how the ridge at the surface and aloft align themselves into the weekend. Stay tuned.

All Aboard The NC Rollercoaster Ride

Before I get into today's post, I want to post a satellite image of Hurricane Dolly making landfall on the south eastern coast of Texas yesterday. Sorry I did not post yesterday but it was my bday and there was enough severe going on in NC that I did not have a chance to post...



She made landfall packing maximum sustained winds close to 100 mph, a solid category 2 hurricane.

Just too recap, we had highs of 97 on both Monday and Tuesday with humid conditions. Due to storms and more clouds we only reached 90 on Wednesday but still with high humidity. Today we much cooler and more pleasant conditions with a high only 87 and we had dew points crash into the lower 50's earlier today. The days before the dew points were in the lower 70s. That is what makes the air feel more soupy and we basically cut the amount of water in the air in half today. As I write this, it is currently 73 degrees in my backyard under clear skies. We have a very real chance of seeing lows Friday morning in the upper 50s, a few degrees above the record 56 for a low set back in 1947. Friday will again be pleasant with a few more degrees added on to the high. Expect a high around 89 and a low of 59. This weekend the heat and humidity will make a return but will there be storms?

So How Hot Today?; Dolly Update; Severe Weather..

Lots to discuss tonight..and I am gonna try to make this as brief as possible.

First, here are my forecasted Highs for today for select cities with the actual next to them

Raleigh-Durham : 98; actual 97
Fayetteville: 99; actual 98
Greensboro: 96; actual 95
Winston-Sale: 96; actual 95
Charlotte: 98; actual 97

So as you can see, I was one degree too high at each city. If you remember what I posted yesterday about increased moisture, more cloud cover, and potential for storms.. well this seemed to hold the mercury just short of my predicted highs everywhere. There was not one 100 degree reading anywhere officially across NC today. Whats incredible is that we are in the middle of summer with stronger sun, and we couldnt top the heat wave of early June.

As far as Dolly goes, She became a hurricane this evening at 5pm and now is packing 80 mph winds as of 11pm. She is expected to make landfall just south of the US border tomorrow morning. Here is a nice Infrared Satellite capture of the 'Cane...



Now.. of more interest closer to home was the amount of severe weather across the state today. The atmosphere was quite unstable today and sure enough there was low-level triggers all over the place in the form of a surface trough, old outflow boundaries from storm complexes over the mid-west yesterday and more recent outflow from new storms. Outflow boundaries are like mini cold fronts in that they form from rain cooled thunderstorm air. The atmosphere largely supported what is known as pulse severe storms where the storms rapidly develop, become severe with hail, and damaging winds, and then die off. This occurred all over the place ( But not in Cary.. we missed.. hopefully we can get some storms on my BDAY tomorrow) including just NW of Charlotte where one of my friends witnessed a pulse severe storm. Stanton Lanham witnessed strong winds probably close to 60mph that snapped trees near a golf course he was at, then got penny sized hail with lots of lightning and heavy rain, and then more strong winds. When he got home to his house 2 miles from the course, he saw trees down everywhere. One of these trees fell on his friends roof. In Raleigh, we largely missed severe weather although at I-540 and US-64 Bypass there was a report of penny sized hail and also at RDU there was a 47 mph wind gust reported (Not severe.. needs to be 58 mph or greater) with .48 inches of rainfall. RDU got a pulse storm as well that formed and dissipated about 15 minutes later.

As for Wednesday, more storms are a definte possibility. Severe weather is still up in the air but with the amplyfication of an upper lever trough and approach of a cold front, I think more folks will at least see thunderstorms. These storms should begin in the afternoon and last through the evening.

HOT For One More Day; More on Dolly

Here are the High Temperatures around central NC for Monday July 21, 2008.

CHARLOTTE : 96
FAYETTEVILLE : 97
GREENSBORO : 97
WINSTON-SALEM : INT 97
LUMBERTON : 97
RALEIGH-DURHAM : 97
ROCKY MT-WILSON : 95
ROANOKE RAPIDS : 95

Definately one of the hottest day of actual summer, but not the hottest day during the June, July, August period as one should remember the early season 100+ spell we had in early June. Not so much at Greensboro and Winston-Salem as they have not seen as much rain as we have here in the Raleigh area, but recent rainfall and much wetter grounds than what we have seen here in a very long time may have played a role in stopping the temperatures short of 100 today. The suns energy went in to evaporating this moisture and helped hold temperatures down slightly from what was being forecast by many TV stations, agencies, and computer models. They were all slightly too warm, but computer models were several degrees too warm.

Here are some forecasted highs for RDU for Tuesday from local TV, The Weather Channel, and the National Weather Service as well as from Computer Model Guidance.

WRAL (CBS): 100
WNCN (NBC): 99
WTVD: (ABC): 99
TWC: (Weather Channel): 99
AccuWeather: 100
NWS (National Weather Service): 99
GFS( Global Forecast Model): 101

Pretty close forecasts by all above with a few at 100 and of course a computer model being the warmest of them all. My hunch is that we will come short of hitting 100 once again on Tuesday for very similar reasons as today except there will slightly increased cloud cover. Across the western parts of the Piedmont of Winston-Salem and Greensboro, there is a chance of storms that could hold temps down also. Storms wont be possible to after max heating across our area here in Raleigh. I do not expect to see the humidity drop at all tomorrow which is being predicted by the GFS so it will stay very very humid making heat indices above close to 105 at times. I would not be surpised if eastern NC is put in an Heat Advisory for this reason by the NWS in the morning. I am going with these predictions for the following select cities

Raleigh-Durham : 98 (yes I gonna be lower than everyone and am willing to be wrong )
Fayetteville: 99
Greensboro: 96
Winston-Sale: 96
Charlotte: 98

I will post the actual highs tomorrow evening to see how accurate I am.

Real Quick on Dolly. She is slowly intensifying in the Gulf of Mexico and is currently packing winds at 50 mph. She is predicted to become a hurricane tomorrow and make landfall somewhere near the US/Mexico border near Texas. More tomorrow as well.

Cristobal and Dolly. Mini heat wave upon us.

Tropical Storm Cristobal became official Saturday afternoon and has not been very impressive at all off the coast of NC. He will be moving off to the NE tomorrow and Tuesday, but will leave behind a west northwest flow that will usher in a dry atmosphere and a mini heat wave.

Tropical Storm Dolly became official this afternoon and is churning in the warm waters of the Caribbean Sea just west of Jamaica and is threatening the Yucatan Peninsula of Mexico where Cozumel and Cancun are located. The official 5pm Advisory on Dolly has her at .. I have posted the 5 day track positions as well as a Satellite image of Dolly. Notice the wide expanse of cloud cover with Dolly, but the actual center of circulation is located towards the southwest part of the cloud shield. Also notice the 5-day track forecast has Dolly re-emerging over open waters in the Gulf of Mexico and strengthening to a category 1 hurricane.. Conditions appear favorable for strengthening as long as Dolly can survive the trip over land. If Dolly glances the Yucatan, she will have a much better chance of getting stronger as conditions are very favorable for strengthening in the southwestern Gulf of Mexico. One thing that is noted by the National Hurricane Center is that final landfall is not certain so the point near the US/Mexico border could change in the next few days.






Now onto the mini heat wave.. Due to northwest flow around the departing Cristobal and sinking air that accompanies the passage of a tropical cyclone, it will be very hot Monday and Tuesday. Northwest flow has a downslope component which in turn drys out the air and compresses it which will warm the air also. We should see highs on Monday 96-98 and Tuesday 95-97. I lowered the range on Tuesday due to the potential for more cloud cover in the afternoon. Showers and thunderstorms are possible late Tuesday. One thing that I think will save us from triple digit heat in the Triangle is the fact the ground is wetter since we had rain this weekend and have been above normal for the last 2 months. This should help to hold temperatures just under 100 while when the ground is drier it is easier to heat up quicker due to less evaporation. Some hot spots in central NC could still see a 100 degree reading though but I think Raleigh should just miss.

Disturbed Weather Off The Coast Of Florida/Georgia

I have not posted since Sunday since I have been extremely busy and had to buy a new laptop battery and charger. Most importantly, nothing has changed since Sunday. There still remains a great deal of uncertainty in what will play out this weekend. There is a well defined circulation just off the coast of Georgia and Florida. It is over the gulf stream so it need to be watched closely as it appears possible that it could become a Tropical Depression or Tropical Storm by this weekend. Regardless, the track of this circulation will be key to sensible weather in central NC this weekend.
If the circulation tracks up the coast then we may see a scattered shower or thunderstorm here but will mainly stay hot. If the circulation tracks more inland, then we stand a good chance of getting wet this weekend. Of course this would be a welcome scenario but right now model forecasts do not predict the circulation to come inland, rather move along the coast taking most of its precipitation and keeping it along and east of I-95. A stronger storm will of course change these scenarios but right now it does not appear that it will get too strong. In sum, we are a day away from the weekend and there are still major questions that need to be answered regarding sensible weather this weekend. In looking at a radar loop of the circulation, it looks to me that it actually is moving westward towards the coast instead on a more north track. Interesting to see if this continues or not.

So What To Expect...

Easier said then done! Thats correct. .. Currently, a line of showers and thunderstorms stretching from east of Charlotte northeast to Greensboro is slowly moving east. I would expect to see this line to slowly make its way eastward into our area sometime later tonight, but it may not be as organized as it looks now. The cold front is currently west of the Appalachians and is expected to move into the state later tonight and into Monday bringing with it a continued chance of showers and thunderstorms.

For Tuesday, the front should be just off the coast of NC with slightly drier air behind it making it more bearable outside with temperatures in the middle and upper 80s. There should be a mix of sun and clouds.

The rest of the week: Much uncertainty exists as computer model guidance is very inconsistent in its many solutions, one of which may bring back a good a chance of showers/storms the end of the week and the other which stays dry with temperatures near 90. Gonna be interesting to see what plays out.

The storms tonight reeked of AWESOMENESS

Wow! Just Wow! The storms tonight were incredible with some of the most phenomenal lightning I have seen. It was nearly continuous with a cloud-to-ground strike every 2-5 seconds. It was loud out there. Heavy rain, strong winds and possibly some small hail also occurred in spots. Anywhere from .50 to 1 inch of rain fell across Wake County with RDU getting one of the top spots at .97 inches and NWS on NCSU campus getting 0.61 inches. I was only able to take one picture as I was too focused on following the situation on radar as I was seeing signs of intensifying storms as they approached Wake county. However, Jay Melbourne took some pictures for me while he was at work. My picture, his pictures and some radar captions from a program I use are below. All pictures taken in Cary. ENJOY!

My picture



Photos by Jay Melbourne..






2 radar captions using Gibson Ridge Level 2 Analyst Edition.

7:00pm


7:09pm