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

Pics From Tonights AWESOME SKY

Well, most of us in Wake County did not see anything significant, the sky was amazing and there was some decent wind gusts. The storms that moved through the area this evening developed west of Charlotte in response to an upper atmospheric impulse which may have come from old storms that occurred in the midwest yesterday. There was also a disturbance that moved through northern NC early this afternoon which sparked off severe storms across NE NC. There was a good number of severe weather reports this afternoon and evening across NC.

Here are the pics I took:

Whoa Bertha

I have not posted about Bertha since last Thursday. Well this morning at 5am, Tropical Storm Bertha was classified as a hurricane, the first of the 2008 season. 12 hours later, Hurricane Bertha is now classified as a Major Category 3 hurricane.. wow. Here is a satellite image of Bertha and you will notice a well organized hurricane.



The Hurricane Center has Bertha weakening in the coming days as it heads Northwestward over open waters of the Atlantic. Bertha may have in fact topped out already, but that is not a sure bet as Bertha was not forecast to strengthen as much as she did. Here is the predicted 5 day track as of 5pm today. If I find other cool imagery I will post it here later.

Some Hail In Cary & Beneficial Rains Continue

This evening I finally made my first Skywarn Spotter Report to the National Weather Service. For about 2-3 minutes there was dime to close to penny sized hail falling in my backyard. It didnt last long and it was sporadic but there was definitely hail. I was also scanning the Skywarn frequency for this region and there was pea to dime sized hail near Crossroads Plaza and Tryon and Piney Plains Rd in Cary. There was some severe weather reported all across the region. The lightning was incredibly vivid during these storms. Sunday made the third day in row of significant rains across the Triangle especially at the official reporting site of RDU International Airport. Here are the totals for the last three days and some other stats:

Friday July 4: 0.62 in.
Saturday July 5: 0.86 in.
Sunday July 6: 0.85 in.
3-day Total: 2.33 in.
2008 Total Through July 6: 23.40 in.
2007 Total Through July 6: 18.15 in.
Normal Through July 6: 22.33 in.

That makes precipitaiton for 2008 above normal levels at RDU. Last year at this time we were close to 4 inches below normal. This type of rain does help the drought but you got to remember that some of this rain from thunderstorms runs off and does not really play a role in the drought categories. Any rain helps though as long as we do not go into some long dry period again as we head into the rest of July and August.

We have a chance of showers and storms tomorrow again. I am not quite as positive on the chances as I was for Saturday and Sunday, but there will definately be activity going on in the afternoon and evening with heavy downpours/ lightning/ possibly some hail and strong winds. The chance becomes less middle of the week but its not zero so that is always a positive! Can we make it 4 days in a row of significant rain in the Triangle area?

Yes, I was WAYYYY OFF

Yeah I mentioned a "Slight" chance of storms July 4th in the evening.... "There is just a slight chance of a shower/storm across the mountains and then again towards the coast. Through the Triangle, it should stay dry through the whole day but an isolated shower could occur so do not be surprised if you get under one." But I was off by alot... because the storms tonight were not isolated thunderstorms. This is an accumulated rainfall map estimated from Doppler Radar.. There is a large area that saw precipitation especially from a line from Charlotte to Raleigh. Some areas saw 2-3 inches of rain. Some areas saw nothing.. but this kind of coverage to me is no slight chance especially from Raleigh westward. Areas to the east saw nothing.. explanation as to what I think happened below.


Also the lightning was nearly continuous around western Wake County just when the time fireworks displays were going to begin.. delaying them until Saturday night.. but im afraid it will be tough to get those in as well.

It appeared to me that low level wind convergence increasing in the evening at the same time when low level moisture was beginning to increase. This convergence lifts this moist air and as long as there is no cap or lid stopping the air from rising( Warmer air aloft,, colder air is much more unstable) then thunderstorms can form. As the map of precip shows above.. areas where the best ingredients were mainly from Raleigh west. Places east still seemed to be capped or just not enough lift to sustain storm development. The activity in Cary,Apex, west Raleigh struggled to move east the southeastern part of the county and I feel difference in atmospheric conditions was definately apparent by storms barely moving past this point.

So yes I was wrong. There were mixed signals all day long on whether or not storms were going to be able to form. Most computer model guidance played catch up on the developing conditions, but there was one thats has been horrible of late that actually seemed to generate precipitation and it appeared to be on to something. It was one of those days where even us Meteorologists have kinda take the wait and see approach as there is not a clear cut indication as to whether or not storms will fire. Tomorrow, more moisture, lift and instability should be present and showers and storms should develop in the afternoon and evening. I think alot more people will see showers/storms. Who will see them first, or late and how much.. well thats always a question that will be difficult to answer.

Independence Day/ Weekend Forecast

Independence Day:

July 4th will be partly cloudy, hot and slightly more humid with temperatures mainly in the lower 90s all across the state. I expect a high of 92 around the Triangle area. There is just a slight chance of a shower/storm across the mountains and then again towards the coast. Through the Triangle, it should stay dry through the whole day but an isolated shower could occur so do not be surprised if you get under one. There could be some periods where there will be more clouds then sun but it should not ruin the day. Temperatures during the evening for fireworks etc will be in the lower 80s. Humidity will be on the rise throughout the evening so it may begin to become uncomfortable as the evening wears on.

Weekend:

There appears to be a very good chance of seeing showers and thunderstorms Saturday and then again on Sunday. Ingredients appear to be coming to together for beneficial rains across the entire southeast. It will not be raining every hour of both these days, but the afternoons and evenings should see very good coverage of showers and storms across the state. Temperatures will stay shy of the 90 degree mark due to hefty amounts of moisture and increased cloud cover. It will also be very humid both days as I expect dew points in the upper 60s and lower 70s.

Bertha Is Born

Tropical Storm Bertha was born at 11am this morning. It was a Tropical Depression this morning at 5am, but was shown to have characteristics of a weak Tropical Storm so the National Hurricane Center Upgraded it. Right now it is expected to trek across the open waters of the Atlantic. Below is a image from satellite. It is not well organized but it does have the definitive shape of a tropical cyclone.


Right now she has maximum winds at 40mph which is the minimal strength for a tropical storm. An update comes out in about an hour from the National Hurricane Center so if anything significant changes I will post it here. This is very early in the Hurricane Season to have a classified system this far east in the Atlantic. What is known as the Cape Verde Season does not normally begin until mid August. Back in 1996, Hurricane Bertha came through eastern NC in the middle of July. Bertha 1996 also formed from a Tropical Wave that came off the coast of Africa but did not get its act together until much further west then Bertha 2008. Very cool to see development out there this early in the season!

Oh What A BBBBUUUTIFUL DAY!

Today was about as nice as it can get in NC on July 1. The temperature barely got over the 80 degree mark with a high of 81. Temperatures will range from 56-59 across the area tomorrow morning. I am so tempted to not call for 90 tomorrow as statistical model guidance was way to warm today, but the fact that this cooler air mass is already going to be moving out combined with a high sun angle will probably make it close to 90. It will be very comfortable though with no humidity.

A few other topics to discuss:

July 4th forecast has not changed much. 93-95 temperature range with lots of sun and a slight increase in humidity. 10% chance of a storm.

According to the National Weather Service:
Warmest June ever recorded at RDU since records kept (1944).

Lastly, there is a tropical disturbance near the Cape Verde Islands off the coast of Africa. Some computer models develop this system into a tropical storm as it head westward across the Atlantic. Something to keep an eye on!