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August 2013 Pattern & Discussion


LithiaWx

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Well dang; it looks like RAH is now backing off the CAD in favor of more tropical moisture influx. GFS still shows the wedge but the Euro is what RAH is hugging. This afternoon's Long range discussion. LOTS OF RAIN:

.LONG TERM /WEDNESDAY THROUGH MONDAY/...

AS OF 200 PM MONDAY...

THE LONG TERM SETS UP TO BE AN EXTENDED PERIOD OF UNSETTLED WEATHER.

THAT BEING SAID...THE LATEST RUN OF THE GFS HAS COME IN A BIT

DRIER...ESPECIALLY FOR FOLKS IN THE TRIAD AS THE MAIN FRONTAL

BOUNDARY IS DEPICTED TO BE SOUTH OF MOST OF THE FORECAST AREA

THROUGH THE END OF THE WORK WEEK. BY THE WEEKEND...THE DEVELOPMENT

OF AN UPPER LEVEL LOW TO THE WEST AND A WAVE COMING OUT OF THE GULF

OF MEXICO HELP TO TRANSPORT COPIOUS AMOUNTS OF MOISTURE INTO THE

CAROLINAS FOR THE WEEKEND. GIVEN THAT CLIMATOLOGY AND THE ECMWF

SUGGEST THAT PERHAPS THE FRONT WILL NOT BE ABLE TO MAKE IT AS FAR

SOUTH AS SHOWN...THERE IS A GOOD CHANCE THE FRONT WILL SET UP

SOMEWHERE OVER OUR SOUTHERN TIER WITH HIGHEST QPF AMOUNTS SOUTH AND

EAST AND A LARGE GRADIENT WITH MUCH LESS TO THE NORTHWEST.

THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT WEDNESDAY WILL BEGIN

WITH THE FRONT SOMEWHERE IN THE VICINITY OF US HIGHWAY 64 OR

SLIGHTLY SOUTH. FROM HERE THE GFS IS VERY PROGRESSIVE BRINGING THE

FRONT THROUGH THE CWA BY WEDNESDAY AFTERNOON WHEREAS THE ECMWF IS

ALMOST STATIONARY WITH IT. BY EVENING...PRECIPITATION SHOULD BE

LIMITED TO EAST OF I-95. THIS SOLUTION HOLDS THROUGH THURSDAY

KEEPING MOST PRECIP CONFINED TO THE SANDHILLS AND COASTAL PLAIN.

ON FRIDAY SOLUTIONS START TO DIFFER WITH THE GFS PRODUCING A VERY

WIDE WEDGE WHICH PUSHES PRECIP BACK OUT OF THE STATE TO THE SOUTH.

THE ECMWF SEEMS MORE REALISTIC WITH SOME OVERRUNNING PRECIP COVERING

AT LEAST SOME OF THE FORECAST AREA FOR MOST OF THE DAY ON FRIDAY.

SATURDAY IS WHEN A REINFORCEMENT OF MOISTURE OCCURS WITH A

SHORTWAVE MOVING UP FROM THE GULF OF MEXICO. WHILE THE GFS IS

FORMING THIS INTO AN ORGANIZED TROPICAL SYSTEM AS IT APPROACHES THE

FLORIDA PANHANDLE...THIS APPEARS UNLIKELY DUE TO UNFAVORABLE UPPER

LEVEL CONDITIONS FOR TROPICAL DEVELOPMENT. A MORE REALISTIC SOLUTION

IS THAT OF THE ECMWF WHICH HAS A MORE UNORGANIZED WAVE MOVING UP

THROUGH GA AND SC. EITHER WAY THE OUTCOME IS THE SAME...A VERY WET

WEEKEND FOR CENTRAL NC. THE 7 DAY QPF FORECAST FROM WPC REMAINS

LARGELY UNCHANGED WITH 5-6 INCHES EXPECTED ON THE COAST WITH 3-4

BACK OVER CENTRAL NC. GFS FORECAST SOUNDINGS SHOW VERY WET TROPICAL

SOUNDINGS FOR SATURDAY WITH HIGH SHEAR BUT NO INSTABILITY. IT WOULD

NOT TAKE MUCH INSOLATION THOUGH TO BREAK OUT AND CAUSE SOME TALL

SKINNY CAPE PROFILES. THIS WOULD SET UP A POTENTIAL HIGH SHEAR

LOW CAPE SEVERE WX SCENARIO. THIS THREAT IS EVEN MORE PRONOUNCED ON

SUNDAY WHEN AT LEAST 500 J/KG OF INSTABILITY IS FORECASTED WITH

30-50 KNOTS OF SHEAR AVAILABLE. IN ADDITION...THE STRONGEST SHEAR ON

SUNDAY IS IN THE LOWEST FEW KM OF THE ATMOSPHERE...INDICATING THAT

THE POTENTIAL FOR ROTATING STORMS AND AN ISOLATED TORNADO COULD BE

THERE.

FORECASTS FOR MONDAY OF NEXT WEEK ARE LOW CONFIDENCE AT THIS POINT

BUT MODELS STILL SHOW PLENTY OF MOISTURE IN THE AREA...ESPECIALLY

FROM HIGHWAY 1 EASTWARD. EXPECT YET ANOTHER DAY OF UNSETTLED WEATHER.

TEMPERATURES WILL START OUT IN THE LOW TO MID 80S ON WEDNESDAY

BEFORE GENERALLY FALLING INTO THE UPPER 70S IN THE NW TO LOW 80S SE

FOR MUCH OF THE PERIOD. A WARMING TREND IN THE EAST AT THE END OF

THE PERIOD WILL BRING HIGHS BACK INTO THE MIDDLE 80S. LOWS WILL

GENERALLY BE LOW TO MID 60S EARLY IN THE PERIOD WITH MID TO UPPER

60S FORECAST BY EARLY NEXT WEEK.

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^ Good write-up from Raleigh.  I've been a bit leery all along about how far south the wedge boundary would move.  Heaviest rains should be along and south of the frontal boundary...but the boundary is going to work back north toward the end of the week in response to the building trough / lowering heights to our west.

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Any mets have any model data as far as DP is forecasted to be Thursday? I know CAD are hard to forecast and ect.... but FWIW I know meteostar should be taken with a grain of salt. But in the Favored typical CAD regions..... Danville, Roxboro, Triad to Charlotte its indicating DP temps going from the 60s Wednesday crashing into the upper 40s to near 55 degree range. I've lived long enough in the region to know what CADs can do. Maybe RAH is underplaying the CAD some? With DPs that low.... Some places may do good to even break 60 for the day Thursday.

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Any mets have any model data as far as DP is forecasted to be Thursday? I know CAD are hard to forecast and ect.... but FWIW I know meteostar should be taken with a grain of salt. But in the Favored typical CAD regions..... Danville, Roxboro, Triad to Charlotte its indicating DP temps going from the 60s Wednesday crashing into the upper 40s to near 55 degree range. I've lived long enough in the region to know what CADs can do. Maybe RAH is underplaying the CAD some? With DPs that low.... Some places may do good to even break 60 for the day Thursday.

I would be a little skeptical of a cold front blasting through the area in August. It can happen, but it's not normal. The latest RAH disco is probably pretty close to what reality will likely be.

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Cold Air Damming…in August?! Yeap.

http://wp.me/p3Mr6T-2C

Will be interesting to see.

Did somebody mention CAD.....That's my kind of music! Bring it on....

The 12z NAM is painting a picture of spectacular weather for wednesday and thursday.

CAD signature still there at 12Z. I think it will now depend on precip rates to truly bring a CAD to full potential.http://itg1.meteor.wisc.edu/wxp_images/avn/avn_crhlia_h72.gif

Welcome wxgarrett! You had a very nice write up!

The CAD looks to barrell right down into metro Atlanta as well. Latest GFS shows spectacularly cool weather for mid August. Saturday doesn't get out of the 60's on the latest run with Thursday and Friday very cool as well!

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I'm in Durham until Friday :) I passed threw your city (I think) on the way here and waved to you as I passed by :hug: Where are the good places around here to eat? ^_^

Yes it is :wub:

. If you can make it to Roxboro, just outside of Durham , there is a great restaurant called: Clarksville train station! Very good food and people!!
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I would be a little skeptical of a cold front blasting through the area in August. It can happen, but it's not normal. The latest RAH disco is probably pretty close to what reality will likely be.

 

Nothing really has been normal this year compare to years past. Really after Sandy anything is possible. This summer there has been no problems with fronts coming and going well off the coast and eventually transit back towards the coast. No person or model is superior to get it 100% right but you can be skeptical but ya also cant deny there are strong signs of a CAD. Unless the models are bluffing then this is liable to be a big waste of CAD this early in the season. All we can do is wait and see but there has been a good push of dryer air in MN, ND, SD, WI, IA.

. If you can make it to Roxboro, just outside of Durham , there is a great restaurant called: Clarksville train station! Very good food and people!!

 

Agree, one spoiler though if you decide to come. Tell the waitress you want either end of the train cars. No more info shall be given...

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Nothing really has been normal this year compare to years past. Really after Sandy anything is possible. This summer there has been no problems with fronts coming and going well off the coast and eventually transit back towards the coast. No person or model is superior to get it 100% right but you can be skeptical but ya also cant deny there are strong signs of a CAD. Unless the models are bluffing then this is liable to be a big waste of CAD this early in the season. All we can do is wait and see but there has been a good push of dryer air in MN, ND, SD, WI, IA.

Agree, one spoiler though if you decide to come. Tell the waitress you want either end of the train cars. No more info shall be given...

Oh, I agree, anything is possible. You could be right; we could have a massive, anomalous CAD. I was just saying that climo doesn't favor it and RAH's thoughts made sense to me. But, yeah, it can happen.

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Some positive trends for the mountains and foothills. Seems like this system from the Gulf if develops with track further south which looks to put most of GA and SC under the gun which would cause major flooding in that part of the SE but does not look to be such a wide path of heavy rainfall across the south. Also with the front passing through is looks as if there is a bit of a CAD sign in the foothills but the mountains look to stay very cool for this time of the year also. Still a lot can change but encouraging not to see a large swath of 3-6 inch totals across the SE.

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One thing is for sure here in the mountains we are really going to cool down. Highs in the lower 70s and lows right around 50 and even some 40s sprinkled in. Going to be very nice. As for the rain looks like right know the GFS keeps pushing the heaviest stuff south but the Euro looks pretty wet here in the Carolinas also.

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. If you can make it to Roxboro, just outside of Durham , there is a great restaurant called: Clarksville train station! Very good food and people!!

Thanks! :) 

 

Southpoint Mall area. and no PM? :)

I just got the work lappy up and running last night. I believe the Southpoint Mall is just down the road from me? I'm on Hillsborough Rd....lol  PM is coming tonight once I know my schedule  :hug:  

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Our possible tropical system in the NW Caribbean and Gulf for this weekend may not look as strong as previous model runs but there is still a respectable reflection at both 500 and 850 mb. The big question in regards to who gets the most rain will depend on the speed of the next upcoming trough that will develop this weekend. If the trough can come in slow enough or try to cutoff a contour (which will in itself slow the progression), then the result regardless of how Gulf storm strength will allow the precip to make it up to the Appalachians. A faster progression of the trough would shunt the moisture more towards the Midlands and Coastal Region.

 

 

I still think Western North Carolina down to the Florida Panhandle still needs to watch this system...

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Our possible tropical system in the NW Caribbean and Gulf for this weekend may not look as strong as previous model runs but there is still a respectable reflection at both 500 and 850 mb. The big question in regards to who gets the most rain will depend on the speed of the next upcoming trough that will develop this weekend. If the trough can come in slow enough or try to cutoff a contour (which will in itself slow the progression), then the result regardless of how Gulf storm strength will allow the precip to make it up to the Appalachians. A faster progression of the trough would shunt the moisture more towards the Midlands and Coastal Region.

 

 

I still think Western North Carolina down to the Florida Panhandle still needs to watch this system...

I think with the troughiness of the next couple of weeks the whole of the SE will be wet. But, this may push any tropical systems too far east or south. Worse case situation; we get lots of rain from the upcoming pattern then it breaks and we get a tropical system. For us in NC that could be another Floid type of flooding.  

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Our possible tropical system in the NW Caribbean and Gulf for this weekend may not look as strong as previous model runs but there is still a respectable reflection at both 500 and 850 mb. The big question in regards to who gets the most rain will depend on the speed of the next upcoming trough that will develop this weekend. If the trough can come in slow enough or try to cutoff a contour (which will in itself slow the progression), then the result regardless of how Gulf storm strength will allow the precip to make it up to the Appalachians. A faster progression of the trough would shunt the moisture more towards the Midlands and Coastal Region.

I still think Western North Carolina down to the Florida Panhandle still needs to watch this system...

Lol look at the 18z GFS.
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A steady stream of moisture will move north out of the Gulf of Mexico this weekend, causing very heavy rain to fall across a large area. This storm will produce very heavy rain across may locations (NC, VA, GA, SC, FL) of 1-3 inches.

The "storm" or weak low pressure center track will be crucial, as that will add additional dynamics needed to provide heavy rain. I think these locations where the storm tracks will see 3-6 inches of rain. It is impossible to nail down the track of the "storm" or "upper air disturbance" at this time. Models do not do well when storms are weak.

I have a feeling we will have something to talk about Monday morning on the first day of classes at UNC-Asheville in the Atmospheric Science department. I am moving in on Saturday, so I hope the rain will subside for 30 minutes so I can move back in for my final semester of undergraduate studies at UNC-Asheville.

But, I do think flooding will be a concern with this weather event this weekend.

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It will be interesting to see just how much invest 92l develops.

I know it's too early to say, but do you think there will be a decent tornado threat with this one?

 

 

Not sure about that as of yet...as you said its early in the game. Plenty of variables that would affect things. Seems like in the past if you can get some mid level dry air intrusion as a storm comes ashore, it helps in providing additional instability especially with any outer bands. It may all be a moot point if 92L does not become a well developed cyclone.

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First I want to say there is a lot that can change the next 3 to 4 days but as of right know the GFS seems to be moving back in the direction of this affecting a lot of the SE with flooding type rains. Looks like right up through AL,Ga, and WNC, and Easter TN will see some very heavy rainfall with totals coming up from 3 to 6 inches possible which again if this plays out will lead to major flooding; no if ands of buts about it. But again a lot can change and will change.

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And right on queue, as we get closer to the event, the NWS starts backing off of significant impacts for central NC. Same with severe and wintry weather, usually. What looks to be a significant event (heavy rains, severe outbreak, snow/ice, tropical system), diminishes as we get closer. Parts of GA and SC look to get blasted though.

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