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Fall 2015 Pattern Discussion


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Here's the event write-up for Aug 12th (should be the same event):

http://www4.ncsu.edu/~nwsfo/storage/cases/20040812/

 

That is what I was talking about. I just saw the part about the one F1 tornado. I missed the other three on the map at the coast. I guess that is what they are talking about. Maybe just had the date off. 

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In the medium range, the12z GFS does have dew points dropping into the 40s for western portions of the SE; including most of GA. Easter parts of the SE will battle on low the dew points can drop.

http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2015&model_mm=09&model_dd=08&model_init_hh=12&fhour=150&parameter=DPTF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

Yep Sunday we are expecting low 70s with nearly clear skies and a dp in the 40s. also possible we drop down into the 40s for lows in some spots.

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THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

A SURFACE LOW PRESSURE SYSTEM WILL DEVELOP OVER THE CAROLINAS
FRIDAY NIGHT AS A POTENT UPPER LEVEL DISTURBANCE DIGS SOUTHEAST
TOWARD THE CENTRAL APPALACHIANS. THE LOW WILL STRENGTHEN OVER
CENTRAL NORTH CAROLINA SATURDAY AFTERNOON...THEN TRACK NORTHWARD
INTO VIRGINIA SATURDAY EVENING. SEVERE THUNDERSTORMS WILL BE
POSSIBLE AS THE SURFACE LOW GATHERS STRENGTH...PARTICULARLY ACROSS
CENTRAL AND EASTERN PORTIONS OF NORTH CAROLINA DURING THE LATE
AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED ON SATURDAY.

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Open windows are just a few days away:

 

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 PM WEDNESDAY...

DEEP UPPER TROUGH STILL APPEARS TO BE PROGRESSIVE ENOUGH SUCH
THAT SURFACE FRONT LIKELY TO BE EAST OF RAH FCST AREA BY SUNDAY
MORNING...ALONG WITH DEEPER CONVECTION AND HIGHER CHANCES FOR
PRECIP. 12Z GFS ESPECIALLY FAST WITH THIS. HOWEVER AS THE UPPER
TROUGH LIFTS NORTHEAST...COOLER TEMPS ALOFT WILL RESULT IN MID
LEVEL LAPSE RATES THAT COULD SUPPORT VERY SHALLOW CONVECTIVE
SHOWERS... VERY UNLIKELY TO BE ANY THUNDER...MAINLY FOR THE
NORTHERN AND EASTERN PORTIONS OF THE AREA. IF MORE PROGRESSIVE
TRENDS CONTINUE MAY EVENTUALLY DROP PRECIP CHANCES ALTOGETHER FOR
SUNDAY. MAIN STORY SUNDAY WILL BE MUCH COOLER AIR MASS AND WITH AN
ABUNDANCE OF CLOUDS HIGH TEMPS SHOULD BE AT LEAST 5F BELOW NORMAL.
70S FOR MOST LOCATIONS.


FOR THE EARLY PART OF NEXT WEEK THE UPPER TROUGH LIFTS WELL
NORTHEAST OVER NEW ENGLAND AND IS REPLACED BY A SHALLOW UPPER RIDGE
WITH AN ASSOCIATED LARGE AREA OF SURFACE HIGH PRESSURE. THIS WILL
KEEP DEEPER MOISTURE WELL TO THE SOUTH OF THE AREA WITH LOWER
HUMIDITIES AND COOL OVERNIGHTS
BUT SLOWLY RECOVERING MAX TEMPS BACK
INTO THE LOWER 80S BY MID WEEK.

 

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Indeed, I like what RAH has to say:

 

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 405 AM THURSDAY...

HEIGHTS ALOFT WILL RISE BEHIND THE UPPER LOW THROUGH EARLY NEXT
WEEK...WHICH WILL SUPPORT THE MAINTENANCE OF THE FIRST NOTICEABLY
CONTINENTAL POLAR AREA OF SURFACE HIGH PRESSURE INTO THE MIDDLE
ATLANTIC STATES EARLY-MID WEEK.

WHILE THE ASSOCIATED DAYTIME HIGHS WILL MODERATE FROM THE MIDDLE 70S
ON AVG SUN-MON...TO AROUND 80 DEGREES OR SO THROUGH THE MIDDLE OF
THE WEEK...THE LOWEST OVERNIGHT LOWS WILL LAG BY ABOUT A DAY...WITH
THE COOLEST LOWS...AND NEAR OPTIMAL RADIATIONAL COOLING...MON NIGHT.
LOWS AT THAT TIME IN THE UPPER 40S TO LOWER 50S ARE PROBABLE - A
CONTINENTAL POLAR AIR MASS INDEED.

 

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RAH still talking about a severe threat for Saturday night, but sounds like it should be for a small area.

 

WHILE THE OVERALL KINEMATICS AND THERMODYNAMICS STILL APPEAR
FAVORABLE FOR A SEVERE WEATHER EPISODE...PARTICULARLY GIVEN THE
PROBABLE PRESENCE OF A SUB-TROPICAL JET EXIT REGION EMERGING ACROSS
THE SOUTHEAST AND COUPLING WITH THE POLAR JET ENTRANCE REGION OVER
THE CAROLINAS...THE CHARACTER OF THE ASSOCIATED SHEAR WILL BE
SENSITIVE TO SUBTLE CHANGES IN THE CONFIGURATION/STRENGTH AND TIMING
OF THE TROUGH ALOFT --AND-- THE MOST OPTIMUM SHEAR IS FORECAST TO
LAG THE WARM SECTOR AND NOT SPREAD EAST OF THE APPALACHIANS UNTIL
SAT NIGHT. IN ADDITION...IT APPEARS AT THIS TIME THAT SHEAR VECTORS
WILL BE ORIENTED LARGELY PARALLEL TO THE LOW LEVEL BOUNDARIES...
WHICH WOULD FAVOR A QUASI-LINEAR CONVECTIVE MODE...WITH POSSIBLE
EMBEDDED SUPERCELLS AS THE SHEAR INCREASES BY SAT EVENING.
ASSOCIATED FORECAST HODOGRAPHS ARE RELATIVELY STRAIGHT...ALBEIT
INCREASINGLY ELONGATED EARLY SAT NIGHT...SO ENHANCED LOW LEVEL SHEAR
--AND ANY CONSEQUENT TORNADO THREAT-- WOULD BE MOST LIKELY CONFINED
TO A SMALL AREA IMMEDIATELY NE OF THE ADVANCING SURFACE LOW WHERE
SURFACE FLOW WOULD BE LOCALLY BACKED. DAMAGING STRAIGHT LINE WINDS
WOULD OTHERWISE BE THE PRIMARY HAZARD.

ALTHOUGH ANY SEVERE THREAT SHOULD END WITH THE SLOW PASSAGE OF THE
MERGED FRONT OVERNIGHT SAT...SMALL HAIL WILL BE POSSIBLE WITH
SCATTERED INSTABILITY/COLD POOL ALOFT-DRIVEN SHOWERS AND STORMS ON
SUNDAY...MAINLY EAST OF THE SOUTHERN AND WESTERN PIEDMONT...WHERE
LOW LEVEL MOISTURE WILL BE RESIDUALLY HIGHER AND THE LOW LEVEL FLOW
LESS VEERED.

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Even though it won't last for long, Sunday is going to be a true fall day. Highs in the low to mid 70s. Lows near 50. Bright sunny skies and low humidity.  Perfect football weather this weekend.

It will get warm again but we'll also start seeing more and more of this type of weather in the coming weeks. Fall will not be denied.   

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Indeed, I like what RAH has to say:

 

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...

AS OF 405 AM THURSDAY...

HEIGHTS ALOFT WILL RISE BEHIND THE UPPER LOW THROUGH EARLY NEXT

WEEK...WHICH WILL SUPPORT THE MAINTENANCE OF THE FIRST NOTICEABLY

CONTINENTAL POLAR AREA OF SURFACE HIGH PRESSURE INTO THE MIDDLE

ATLANTIC STATES EARLY-MID WEEK.

WHILE THE ASSOCIATED DAYTIME HIGHS WILL MODERATE FROM THE MIDDLE 70S

ON AVG SUN-MON...TO AROUND 80 DEGREES OR SO THROUGH THE MIDDLE OF

THE WEEK...THE LOWEST OVERNIGHT LOWS WILL LAG BY ABOUT A DAY...WITH

THE COOLEST LOWS...AND NEAR OPTIMAL RADIATIONAL COOLING...MON NIGHT.

LOWS AT THAT TIME IN THE UPPER 40S TO LOWER 50S ARE PROBABLE - A

CONTINENTAL POLAR AIR MASS INDEED.

 

I like it!

 

GFS 12z  hit 50/51 for Mon/Tue, GEFS mean 51/53...

 

GFS 2mT min for Boone, NC has been harping on  37 Tues morning for a while now but just picked up 37 for Mon as well...pretty polar.

 

K7Ohboq.png

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It will get warm again but we'll also start seeing more and more of this type of weather in the coming weeks. Fall will not be denied.

Soooooooo looking forward to this cool down this weekend!!!! Only problem is indeed the big warm up right back to where we are now. GSP looking at mid 80s over the next 2 weeks after that with lows in 60s. That is going to be absolutely torturous after this weekend, and not fallish in the least. Looking for that permanent cool down!!

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Soooooooo looking forward to this cool down this weekend!!!! Only problem is indeed the big warm up right back to where we are now. GSP looking at mid 80s over the next 2 weeks after that with lows in 60s. That is going to be absolutely torturous after this weekend, and not fallish in the least. Looking for that permanent cool down!!

At least our averages are dropping and our days are getting shorter. The heat can't last forever.

Also, I don't think heat in September is all that unusual. If we can get cold in March, I don't see why we can't get hot in September.

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Long discussion from RAH overnight about the severe storm threat tomorrow. The threat is still there, but of course there is model disagreement.

 

 

SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 420 AM FRIDAY...

THE MODELS OVERALL REMAIN IN RELATIVELY GOOD AGREEMENT THAT A MID-
UPPER TROUGH WILL SHARPEN FROM THE GREAT LAKES TO THE MID-MS VALLEY
BY EARLY SAT...BEFORE CLOSING OFF OVER THE OH VALLEY THROUGH
SUNDAY...THOUGH TIMING AND AMPLITUDE DIFFERENCES REMAIN. TO ACCOUNT
FOR THESE DIFFERENCES AND STILL RELATIVELY LARGE MODEL SPREAD FOR A
DAY 2 FORECAST...THE 00Z ECMWF SOLUTION IS PREFERRED AND OFFERS A
COMPROMISE SOLUTION BETWEEN THE FASTER AMERICAN MODELS AND SLOWER
CMC AND UKMET. HEIGHT FALLS ALOFT/FORCING FOR ASCENT WILL GRADUALLY
INCREASE WITH THE APPROACH OF BOTH THE AMPLIFYING UPPER TROUGH AND A
COUPLED SUB-TROPICAL JET EXIT REGION EMERGING ACROSS THE CAROLINAS
ON SAT. MULTIPLE WEAK AREAS OF LOW PRESSURE WILL CONSEQUENTLY
DEVELOP/DEEPEN IN THE LEE OF THE APPALACHIANS - ONE ALONG A WEAK
WARM FRONT/LEE TROUGH OVER NORTH-CENTRAL NC...AND ANOTHER ALONG A
SECONDARY COLD FRONT INVOF THE NC FOOTHILLS EARLY SAT. LOW PRESSURE
WILL THEN CONSOLIDATE AND TRACK NE THROUGH THE MIDDLE ATLANTIC
STATES THROUGH SAT NIGHT.

ONGOING MORNING CONVECTION WILL BE POSSIBLE IN ASSOCIATION WITH THE
CLOSE APPROACH OF A LEAD DISTURBANCE/MCV NOW OVER THE MID-MS
VALLEY...AHEAD OF BROADER HEIGHT FALLS IN ADVANCE OF THE SYNOPTIC
TROUGH...AND INVOF A DIFFUSE WARM FRONT LIKELY TO STRETCH NEAR THE
VA/NC BORDER EARLY SAT. OTHERWISE...STORMS WILL INCREASE IN COVERAGE
--SCATTERED TO NUMEROUS AND IN THE FORM OF BROKEN CLUSTERS/SEMI-
DISCRETE MODES-- AHEAD OF AND ALONG THE COLD FRONT DURING THE
AFTERNOON AND EVENING...BENEATH STRENGTHENING BACKGROUND FORCING
OUTLINED ABOVE.

WHILE THE OVERALL KINEMATICS AND THERMODYNAMICS STILL APPEAR
FAVORABLE FOR A SEVERE WEATHER EPISODE...CONTINUED LARGER THAN AVG
MODEL SPREAD REGARDING THE TIMING AND AMPLITUDE OF THE UPPER
TROUGH...AS WELL AS QUESTIONS REGARDING THE DEGREE OF WARM SECTOR
DESTABILIZATION OWING TO EARLY DAY MULTI-LAYERED CLOUD COVER...LEND
HIGHER THAN AVG FORECAST UNCERTAINTY TO THE TIMING/EVOLUTION OF
CONVECTION SAT AFT-EVE.

IT STILL APPEARS THAT SHEAR VECTORS WILL BE ORIENTED LARGELY
PARALLEL TO THE PRIMARY LOW LEVEL BOUNDARIES...WHICH WOULD FAVOR
QUASI-LINEAR/BROKEN LINE CLUSTER(S) AND SOME SEMI-DISCRETE MODES
OWING TO STRENGTHENING DEEP LAYER FLOW...WITH BULK SHEAR VALUES IN
THE 35-45 KT RANGE SAT INCREASING WITH TIME INTO THE 40-60 KT RANGE
EARLY SAT NIGHT...THOUGH THAT INCREASE MAY BE RENDERED MOOT SINCE
THE CONVECTION IS LIKELY TO LARGELY OUTPACE THE STRONGER FLOW ALOFT.
ASSOCIATED FORECAST HODOGRAPHS ARE RELATIVELY STRAIGHT...ALBEIT
LONG...SO ENHANCED LOW LEVEL SHEAR AND ANY CONSEQUENT TORNADO THREAT
WOULD BE MOST LIKELY INVOF THE WARM FRONT/TRIPLE POINT RETREATING
NORTH THROUGH THE MIDDLE ATLANTIC...WITH AN OTHERWISE PRIMARY THREAT
OF DAMAGING STRAIGHT LINE WINDS...AND HAIL IN SEMI-DISCRETE
(ROTATING) STORMS.

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Long discussion from RAH overnight about the severe storm threat tomorrow. The threat is still there, but of course there is model disagreement.

 

 

SHORT TERM /SATURDAY AND SATURDAY NIGHT/...

AS OF 420 AM FRIDAY...

THE MODELS OVERALL REMAIN IN RELATIVELY GOOD AGREEMENT THAT A MID-

UPPER TROUGH WILL SHARPEN FROM THE GREAT LAKES TO THE MID-MS VALLEY

BY EARLY SAT...BEFORE CLOSING OFF OVER THE OH VALLEY THROUGH

SUNDAY...THOUGH TIMING AND AMPLITUDE DIFFERENCES REMAIN. TO ACCOUNT

FOR THESE DIFFERENCES AND STILL RELATIVELY LARGE MODEL SPREAD FOR A

DAY 2 FORECAST...THE 00Z ECMWF[/url

 

LOL. Brick is a trollbot.

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