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!!
Wednesday, September 17, 2008
Tuesday, September 16, 2008
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.
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.
Sunday, September 14, 2008
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.
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.
Saturday, September 13, 2008
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..
Monday, September 8, 2008
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
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
Sunday, September 7, 2008
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.
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.
Tuesday, September 2, 2008
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
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
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