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View Full Version : Severe Wx Possible across the SE Sunday


sparky
03-13-2005, 07:58 AM
http://www.spc.noaa.gov/products/outlook/day1otlk.html#topimage




DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0627 AM CST SUN MAR 13 2005

VALID 131300Z - 141200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 WNW
POE 30 ESE GGG 25 W ELD 25 W GWO 35 SW CHA 40 NNW AND 35 SSE SPA 30
WNW AGS CSG 55 SSW SEM 45 SW LUL 30 WNW POE.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SE DUG 50 NW SAD
35 W PRC 40 W GCN 35 SE FMN 20 NNE SAF 15 NNW 4CR 10 S ELP.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 E CHS 30 WSW DHN
30 S MOB ...CONT... 30 N BVE 15 NNW 7R4 20 NW LCH 15 S LFK 25 S TYR
50 WSW TXK 20 ESE LIT 30 NE BNA 15 SSE BLF 25 E ORF.

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE GULF CST
STATES AND CAROLINAS...

...SYNOPSIS...
HUDSON BAY POLAR VORTEX WILL CONTINUE TO RETROGRESS THIS PERIOD...IN
TANDEM WITH BAFFIN BAY BLOCK NOSING SWD INTO QUEBEC. UPSHOT OF THIS
PATTERN CHANGE WILL BE FURTHER LOWERING OF HEIGHTS FROM THE GRT
BASIN INTO THE CNTRL PLNS...AND CONTINUATION OF BROADLY CONFLUENT
WSWLY FLOW FROM THE SRN PLNS TO THE S ATLANTIC CST.

AT LWR LEVELS...WRN PART OF COLD FRONT NOW EXTENDING FROM E TN TO NW
TX SHOULD CONTINUE SURGING SWD TODAY...WHILE ERN PORTION /ROUGHLY E
OF THE MISSISSIPPI/ SETTLES MORE SLOWLY SWD INTO NRN LA/NRN AL AND
NRN SC BY EARLY TONIGHT.

...LA/SRN AR INTO SRN APLCNS/CAROLINAS...
AFOREMENTIONED COLD FRONT WILL SERVE AS FOCUS FOR THUNDERSTORM
DEVELOPMENT LATE TODAY THROUGH TONIGHT ACROSS PARTS OF THE GULF CST
AND SERN STATES THIS PERIOD. DEEP WSWLY FLOW OVER REGION HAS
CARRIED ELEVATED MIXED LAYER /EML/ PLUME EWD FROM TX TO THE S
ATLANTIC CST. THIS FEATURE LIKELY TO REMAIN IN PLACE THROUGH THE
PERIOD. COUPLED WITH THE FACT THAT SUBSTANTIAL BOUNDARY LAYER
MOISTURE RETURN IS ONLY JUST NOW GETTING UNDERWAY OVER THE WRN
GULF/LWR MS VLY...AND THE FACT THAT SHORTWAVE FORCING FOR ASCENT
WILL BE WEAK /PER SATELLITE AND MODEL DATA/...BELIEVE THAT MOST OF
THE STORMS WILL OCCUR JUST BEHIND FRONT

NEVERTHELESS...WHILE THE ACTIVITY MAY BE FOR THE MOST PART SLIGHTLY
ELEVATED...PRESENCE OF EML AND INCREASING MOISTURE RETURN SHOULD
FOSTER DEVELOPMENT OF SIGNIFICANT MUCAPE. VALUES MAY EXCEED 2000
J/KG IN LA THIS AFTERNOON...AND VALUES AOA 1000 J/KG COULD REACH E
INTO N GA/ UPSTATE SC BY THE END OF THE DAY. COUPLED WITH 40+ KT
CLOUD LAYER WSWLY SHEAR...SETUP WILL LIKELY PROVE FAVORABLE FOR
BANDS OF SUSTAINED STORMS/SUPERCELLS WITH HAIL AND POSSIBLY LOCALLY
DAMAGING WIND AS FRONT SLOWLY UNDERCUTS AXIS OF INSTABILITY. THE
ACTIVITY SHOULD WEAKEN LATER TONIGHT AS BOUNDARY CONTINUES
S/SEWD...AND AS NOCTURNAL STABILIZATION OF UPSTREAM ENVIRONMENT
LESSENS DEGREE OF ELEVATED INSTABILITY.

jeffl
03-13-2005, 01:28 PM
Weather Watch box.. likely severe thunderstorm is possible across N LA into MS within the next 1-2 hours.

Atmosphere continues to destabilize with dewpoints in the low to mid 60's and surface temps pushing to upper 70's and low 80's. Cold front currently over EC TX will move into W LA within the next 2-3 hours with strong convergence along boundary. Thunderstorms should fire within band of enhanced cumulus field over NW LA into NW MS. Severe threat will be mainly large hail, although a few damaging gust will be possible. Storms will become much more active overnight as a line or band moves ESE across MS, AL, and GA and SSW low level jet increases.


West over TX temps. have warmed to 90 at San Antonio, 83 at Hou, and 95 at Laredo this afternoon. Dry line currently along a line from KCLL to KVCT with the cold front from KCLL to KSHV. Visible satellite images show enhanced but capped Cu field from near CLL to NW LA along and just ahead of surface frontal boundary. Degree of heating is resulting in CAPE of 2500 J/kg over a large part of E and SE TX, however this air mass is strongly capped with over 100 J/kg of CIHN. Moisture is also extremely limited to below 950mb so I do not expect anything to fire over TX. However, given the degree of instability if something were to get going it would go severe quickly.

Jeff L