Equus
Member
Aaaaand here we go again. Big ol enhanced hatched for east Dixie on the D3 likely to go Moderate on the D2...
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT TUE APR 21 2020
VALID 231200Z - 241200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY OVER
ALABAMA...GEORGIA...AND NORTHERN FLORIDA INCLUDING THE PANHANDLE...
..SUMMARY
SIGNIFICANT SEVERE STORMS ARE EXPECTED OVER PARTS OF THE SOUTHEAST
ON THURSDAY, INCLUDING THE POTENTIAL FOR STRONG TORNADOES.
..SYNOPSIS
A POSITIVE-TILT UPPER TROUGH WITH 70-80 KT MIDLEVEL SPEED MAX WILL
MOVE FROM THE LOWER MS VALLEY THURSDAY MORNING TOWARD THE
APPALACHIANS BY 00Z, WITH A 50-60 KT LOW-LEVEL JET CORE SHIFTING
FROM AL TO THE MID ATLANTIC DURING THE DAY.
AT THE SURFACE, LOW PRESSURE WILL MOVE FROM NORTHEAST AR INTO KY
THROUGH 00Z, AND TOWARD THE DELMARVA BY 12Z FRIDAY. A DRYLINE WILL
EXTEND SOUTHWESTWARD FROM THE LOW, AND WILL MOVE ACROSS AL, MS AND
LA DURING THE PEAK HEATING HOURS. EAST OF THIS BOUNDARY, 65-70 F
DEWPOINTS WILL BE COMMON, BENEATH COOLING TEMPERATURES ALOFT.
MODELS DIFFER WITH HOW QUICKLY THE DRYLINE WILL MOVE, AND EARLY DAY
STORMS MAY DICTATE WHERE THE QUASI-STATIONARY WARM FRONT SETS UP
LATITUDINALLY. REGARDLESS, THE WARM SECTOR WILL BECOME VERY
UNSTABLE, WITH SHEAR FAVORING TORNADIC SUPERCELLS ALONG THE DRYLINE
AND WARM FRONT/OUTFLOW BOUNDARY. AT THIS TIME, IT APPEARS THE BULK
OF THE ACTIVITY WILL OCCUR OVER AL, GA, AND THE FL PANHANDLE INTO
NORTHERN FL.
THE NAM SOLUTION, IF TAKEN LITERALLY, SUGGESTS STRONG AND PERHAPS
VIOLENT TORNADOES WILL BE POSSIBLE OVER PARTS OF MS, AL, AND GA.
HOWEVER, THIS SOLUTION IS MUCH SLOWER WITH THE DRYLINE THAN OTHER
MODELS, AND MAY BE OVERDONE WITH INSTABILITY AND LOW-LEVEL SHEAR.
USING THE PREFERRED ECWMF SOLUTION, THE DRYLINE WILL EXTEND FROM
SOUTHERN MS INTO CENTRAL AL THURSDAY AFTERNOON, WITH EARLY DAY
STORMS REINFORCING A WARM FRONT ROUGHLY FROM BIRMINGHAM AL TO
ATLANTA GA. OUTFLOW COULD POTENTIALLY PUSH THE WARM FRONT FARTHER
SOUTH. SUPERCELLS WILL BE POSSIBLE BOTH ALONG THE DRYLINE AND ALONG
THE WARM FRONT, WITH STRONG TORNADOES POSSIBLE. THE STRONGEST LIFT
WILL OCCUR EARLY IN THE PERIOD RELATED TO WARM ADVECTION, AND THIS
WILL LIFT NORTHEAST DURING THE DAY. HOWEVER, SUBTLE LIFT ALONG THE
DRYLINE WILL FAVOR SUPERCELLS, AS OPPOSED TO A LINEAR STORM MODE.
MUCAPE OF 2000-3000 J/KG IS POSSIBLE, WITH MIDLEVEL LAPSE RATES OF
6.5 TO 7.0 C/KM AIDING UPDRAFT VIGOR. REGARDLESS OF PREFERRED MODEL,
THIS EVENT WILL BE ADJUSTED WITH TIME AS PREDICTABILITY INCREASES,
WITH CATEGORICAL UPGRADES POSSIBLE.
ELSEWHERE, LIFT ASSOCIATED WITH A LOW-AMPLITUDE SHORTWAVE TROUGH
MOVING INTO THE CENTRAL PLAINS MAY SUPPORT ISOLATED STRONG STORMS
ALONG A COLD FRONT OVER NE, KS AND OK WHERE WEAK INSTABILITY WILL
DEVELOP BENEATH A NORTHWEST FLOW REGIME.
..JEWELL.. 04/21/2020
So yeah. Surprisingly strong wording for a D3.
Large area of severe on Wednesday (Slight thus far) from Texas to Mississippi on Wednesday; main show in AL into GA/FL Panhandle on Thursday the 23rd into early Friday perhaps. Models had downtrended but now seem to be slowing the system down a bit putting E AL into play during peak heating. The NAM is really aggressive with this, no doubt overdoing it, with 4,000 j/kg SBCAPE across SE AL on Thursday evening and a dryline erupting plains-eqsue supercells in a favorable parameter space for intense tornadoes; Euro while trending up is showing more reasonable but still increasingly impressive values. GFS not convinced yet but seems to also be slowing the system down, and still shows a tornado risk along the Gulf Coast region from MS east to GA. Previously questionable wind fields also seem to be trending towards a more significant event. One to watch... yet again.
Not that I trust its aggressive solution at all unless GFS/Euro come more into line but just for what it's worth, here's the NAM over-enthusiastically throwing violent tornadoes across the Clanton-Prattville corridor Thursday afternoon
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT TUE APR 21 2020
VALID 231200Z - 241200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY OVER
ALABAMA...GEORGIA...AND NORTHERN FLORIDA INCLUDING THE PANHANDLE...
..SUMMARY
SIGNIFICANT SEVERE STORMS ARE EXPECTED OVER PARTS OF THE SOUTHEAST
ON THURSDAY, INCLUDING THE POTENTIAL FOR STRONG TORNADOES.
..SYNOPSIS
A POSITIVE-TILT UPPER TROUGH WITH 70-80 KT MIDLEVEL SPEED MAX WILL
MOVE FROM THE LOWER MS VALLEY THURSDAY MORNING TOWARD THE
APPALACHIANS BY 00Z, WITH A 50-60 KT LOW-LEVEL JET CORE SHIFTING
FROM AL TO THE MID ATLANTIC DURING THE DAY.
AT THE SURFACE, LOW PRESSURE WILL MOVE FROM NORTHEAST AR INTO KY
THROUGH 00Z, AND TOWARD THE DELMARVA BY 12Z FRIDAY. A DRYLINE WILL
EXTEND SOUTHWESTWARD FROM THE LOW, AND WILL MOVE ACROSS AL, MS AND
LA DURING THE PEAK HEATING HOURS. EAST OF THIS BOUNDARY, 65-70 F
DEWPOINTS WILL BE COMMON, BENEATH COOLING TEMPERATURES ALOFT.
MODELS DIFFER WITH HOW QUICKLY THE DRYLINE WILL MOVE, AND EARLY DAY
STORMS MAY DICTATE WHERE THE QUASI-STATIONARY WARM FRONT SETS UP
LATITUDINALLY. REGARDLESS, THE WARM SECTOR WILL BECOME VERY
UNSTABLE, WITH SHEAR FAVORING TORNADIC SUPERCELLS ALONG THE DRYLINE
AND WARM FRONT/OUTFLOW BOUNDARY. AT THIS TIME, IT APPEARS THE BULK
OF THE ACTIVITY WILL OCCUR OVER AL, GA, AND THE FL PANHANDLE INTO
NORTHERN FL.
THE NAM SOLUTION, IF TAKEN LITERALLY, SUGGESTS STRONG AND PERHAPS
VIOLENT TORNADOES WILL BE POSSIBLE OVER PARTS OF MS, AL, AND GA.
HOWEVER, THIS SOLUTION IS MUCH SLOWER WITH THE DRYLINE THAN OTHER
MODELS, AND MAY BE OVERDONE WITH INSTABILITY AND LOW-LEVEL SHEAR.
USING THE PREFERRED ECWMF SOLUTION, THE DRYLINE WILL EXTEND FROM
SOUTHERN MS INTO CENTRAL AL THURSDAY AFTERNOON, WITH EARLY DAY
STORMS REINFORCING A WARM FRONT ROUGHLY FROM BIRMINGHAM AL TO
ATLANTA GA. OUTFLOW COULD POTENTIALLY PUSH THE WARM FRONT FARTHER
SOUTH. SUPERCELLS WILL BE POSSIBLE BOTH ALONG THE DRYLINE AND ALONG
THE WARM FRONT, WITH STRONG TORNADOES POSSIBLE. THE STRONGEST LIFT
WILL OCCUR EARLY IN THE PERIOD RELATED TO WARM ADVECTION, AND THIS
WILL LIFT NORTHEAST DURING THE DAY. HOWEVER, SUBTLE LIFT ALONG THE
DRYLINE WILL FAVOR SUPERCELLS, AS OPPOSED TO A LINEAR STORM MODE.
MUCAPE OF 2000-3000 J/KG IS POSSIBLE, WITH MIDLEVEL LAPSE RATES OF
6.5 TO 7.0 C/KM AIDING UPDRAFT VIGOR. REGARDLESS OF PREFERRED MODEL,
THIS EVENT WILL BE ADJUSTED WITH TIME AS PREDICTABILITY INCREASES,
WITH CATEGORICAL UPGRADES POSSIBLE.
ELSEWHERE, LIFT ASSOCIATED WITH A LOW-AMPLITUDE SHORTWAVE TROUGH
MOVING INTO THE CENTRAL PLAINS MAY SUPPORT ISOLATED STRONG STORMS
ALONG A COLD FRONT OVER NE, KS AND OK WHERE WEAK INSTABILITY WILL
DEVELOP BENEATH A NORTHWEST FLOW REGIME.
..JEWELL.. 04/21/2020
So yeah. Surprisingly strong wording for a D3.
Large area of severe on Wednesday (Slight thus far) from Texas to Mississippi on Wednesday; main show in AL into GA/FL Panhandle on Thursday the 23rd into early Friday perhaps. Models had downtrended but now seem to be slowing the system down a bit putting E AL into play during peak heating. The NAM is really aggressive with this, no doubt overdoing it, with 4,000 j/kg SBCAPE across SE AL on Thursday evening and a dryline erupting plains-eqsue supercells in a favorable parameter space for intense tornadoes; Euro while trending up is showing more reasonable but still increasingly impressive values. GFS not convinced yet but seems to also be slowing the system down, and still shows a tornado risk along the Gulf Coast region from MS east to GA. Previously questionable wind fields also seem to be trending towards a more significant event. One to watch... yet again.
Not that I trust its aggressive solution at all unless GFS/Euro come more into line but just for what it's worth, here's the NAM over-enthusiastically throwing violent tornadoes across the Clanton-Prattville corridor Thursday afternoon
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