SPC Day 2 Thunderstorm Outlook Issued 0830Z 20040131

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ZCZC SPCSWODY2 ALL
ACUS02 KWNS 310748
SPC AC 310748

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0148 AM CST SAT JAN 31 2004

VALID 011200Z - 021200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 10 NW
GLS 10 ENE CLL 35 NE ACT 35 N DAL 45 ENE DUA 40 SE FSM 50 ENE LIT 20
NE GLH 30 SE HEZ 15 SE 7R4.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 WSW GLS 10 NNW CLL
25 NNW ACT 10 E SPS 45 W OKC 25 NNE END 10 SE EMP 10 ENE MKC 50 SSW
IRK 25 WSW STL 25 W MDH 25 E DYR 20 NE TUP 40 S GPT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 NW AQQ 20 SSW MGR
35 NNE SSI.

...THERE IS A SLGT RISK OF SVR TSTMS ERN TX/FAR SERN OK INTO THE
LOWER MS RIVER VALLEY...

MID/UPPER LEVEL PATTERN WILL REMAIN RATHER ACTIVE SUNDAY.
PROGRESSIVE LONG WAVE TROUGH WILL EXTEND SWD FROM UPPER LOW OVER THE
CANADIAN PRAIRIES INTO THE SRN PLAINS...WHERE A STRONG SHORTWAVE
TROUGH AND ASSOCIATED MID LEVEL JET DEVELOP ESEWD TOWARDS THE LOWER
MS RIVER VALLEY SUNDAY NIGHT.  STRONG SYSTEM WILL ALSO APPROACH THE
WEST COAST WITH WEAKENING SRN STREAM SYSTEM EJECTING NEWD ACROSS THE
SRN ATLANTIC STATES EARLY IN THE PERIOD.

...SRN PLAINS INTO THE LOWER MS RIVER VALLEY...
STRONG IMPULSE NOW DIGGING SEWD INTO CA WILL CONTINUE TO STRENGTHEN
AS IT MOVES INTO THE SRN ROCKIES BY SUNDAY MORNING.  IN
RESPONSE...LOW LEVEL WINDS WILL STRENGTHEN AND BECOME SSELY BY THE
BEGINNING OF THE PERIOD OVER MUCH ERN TX INTO OK.  ETA AND GFS
SOLUTIONS DIFFER IN RESPECT TO PLACEMENT OF SURFACE LOW/COLD FRONT
AND IN OVERALL SEVERE THREAT SUNDAY AFTERNOON AND NIGHT...WITH GFS
BEING SLOWER AND GENERALLY COOLER/MORE STABLE IN ITS BOUNDARY LAYER
AHEAD OF THE COLD FRONT.  ETA AND NGM FORECAST AFTERNOON MAX TEMPS
ALMOST 10 DEGREES HIGHER THAN THE GFS. THOUGH ETA MAY BE A BIT FAST
WITH ITS FRONTAL LOCATIONS AND LOW TRACK ACROSS MO DURING THE LATTER
HALF OF THE PERIOD...WILL TREND THIS FORECAST MORE TOWARDS A SLOWER
ETA SOLUTION.

NARROW AXIS OF MODIFIED GULF MOISTURE IS EXPECTED INTO NRN TX AND
THE ARKLATEX REGION BY LATE SUNDAY AFTERNOON WITH SURFACE DEW POINTS
LIKELY IN THE LOWER TO MID 50S.  THIS SHOULD SUPPORT MARGINAL TO
MODERATE INSTABILITY WITH ETA FORECAST SOUNDINGS YIELDING NEAR 1000
J/KG SBCAPES AROUND TYR AND 700 J/KG SBCAPE AT PRX BY 21Z.  SHEAR
WILL BE QUITE STRONG ALONG NOSE OF 80-90 KT MID LEVEL JET AND UNDER
40-50 KT SLY LLJ.  AS LARGE SCALE ASCENT OVERSPREADS COLD FRONT/DRY
LINE SHIFTING EWD ACROSS CENTRAL OK/TX DURING THE MID TO LATE
AFTERNOON...THUNDERSTORMS SHOULD INCREASE IN COVERAGE AND INTENSITY
FROM THE RED RIVER VALLEY INTO E-CENTRAL TX. DEEP LAYER SHEAR
VECTORS ARE FORECAST TO REMAIN WLY ENOUGH TO SUPPORT DISCRETE
UPDRAFTS...AND SUPPORT LARGE HAIL AND TORNADO POTENTIAL INITIALLY.
HOWEVER...STORMS WILL LIKELY EVOLVE INTO A MORE LINEAR MODE BY THE
EARLY EVENING AND DEVELOP SWD TOWARDS THE TX/LA COAST AS STRONG N-S
ORIENTED COLD FRONT MOVES RAPIDLY EWD INTO AR/LA OVERNIGHT. DESPITE
DIMINISHING INSTABILITY AFTER DARK...EXTREME LOW LEVEL SHEAR WILL
MAINTAIN A THREAT OF ISOLATED WIND DAMAGE/TORNADOES OVERNIGHT
TOWARDS THE MS RIVER AS STRONG/DEEP LIFTING OCCASIONALLY OVERCOME
SLIGHTLY STABLE BOUNDARY LAYER.

...FL...
EARLY IN THE PERIOD...CONVECTION WILL LIKELY REMAIN WIDESPREAD
ACROSS MUCH OF FL AS SRN STREAM SHORTWAVE TROUGH EJECTS NEWD. 
PRESENCE OF E-W SURFACE FRONT...LOW LCLS AND MODERATE TO STRONG
SHEAR WARRANT CONTINUING LOW PROBABILITIES OF SEVERE FOR THE FIRST 6
HRS OF THE PERIOD.  HOWEVER...WEAK INSTABILITY AND VEERING OF THE
LOW LEVEL WINDS EXPECTED TO LIMIT OVERALL SEVERE THREAT.

..EVANS.. 01/31/2004

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.

$$