SPC DAY-1 CONVECTIVE OUTLOOK

08 Mar 1999 - 20:05:19 UTC 

ZCZC MKCSWODY1 000
ACUS1 KMKC 082005
MKC AC 082005

CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O.

VALID 082000Z - 091200Z

REF WW NUMBER 0076...VALID TIL 0000Z

THERE IS A HIGH RISK OF SVR TSTMS OVER PORTIONS OF LA..SRN AR..ERN
TX..AND FAR WRN MS..TO THE RIGHT OF A LINE FROM 35 S PBF 30 WNW JAN
MCB BTR 30 NE LCH 40 SSE LFK 30 WNW LFK 35 SW TXK 20 N TXK 40 WSW
PBF 35 S PBF.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
30 NNE GLS 40 ESE CLL 25 NE CLL 30 WSW TYR 30 SSW DUA 15 SW MLC
15 WSW FSM 20 NE LIT 15 S TUP 25 WNW BHM 40 NNE MGM 15 S TOI
20 ENE PNS.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM BLI SEA PDX MFR
60 NW UKI.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 SW GLS 45 NNW VCT
20 N AUS 40 NNE MWL 45 ENE CSM 15 ESE P28 25 NNE CNU 10 E SDF
35 S JKL 40 SSE TYS PFN.

...SEVERE THUNDERSTORM FORECAST DISCUSSION...
MID/UPPER LEVEL TROUGH IS BECOMING MORE NEGATIVELY TILTED EARLY
THIS AFTERNOON...AND IS NOW MOVING INTO WRN OK. ASSOCIATED LOW
CENTER IS OVER NWRN OK AT THIS TIME WITH LEADING COLD FRONT MOVING
EWD INTO CENTRAL OK/CENTRAL TX. SYNOPTIC WARM FRONT APPEARS TO BE
LOCATED FROM CENTRAL OK INTO SWRN AR/CENTRAL MS CURRENTLY...WITH
NRN EDGE OF DEEPER MOISTURE/COASTAL WARM FRONT NOW INTO E-CENTRAL
TX/CENTRAL LA.  

MAIN LINE OF THUNDERSTORMS WITH PERSISTENT LEWP/SMALL BOWS HAS
PROPAGATED EWD OFF DRY LINE...WITH MORE CELLULAR ACTIVITY BEGINNING
TO DEVELOP AHEAD OF LINE OVER SERN TX INTO CENTRAL LA. THIS MAY
REFLECT WEAKENING OF CAP OVER HIGH RISK AREA...AND INCREASE IN
UVV/S WITHIN STRONG LOW LEVEL WAA AND AHEAD OF APPROACHING UPPER
TROUGH. EXPECT LINE OF STORMS OVER ERN TX WILL CONTINUE TO DEVELOP
EWD AS INTO STRONGLY SHEARED ENVIRONMENT. MORE ISOLATED/CELLULAR
ACTIVITY SHOULD ALSO INCREASE INTO CENTRAL LA OVER THE NEXT FEW
HOURS. VWP/S AND 18Z SOUNDING FROM SHV YIELDED IMPRESSIVE SHEAR
VALUES WITH BRN SHEARS OVER 100 M2/S2 AND SFC-1 KM HELICITIES OVER
600 M2/S2...WHICH SUGGESTS AN ADDITIONAL THREAT OF TORNADOES. 
INSTABILITY REMAINS MARGINAL BUT WILL INCREASE THROUGH THE DAY WITH
SURFACE-BASED CAPES EXPECTED TO REACH INTO THE 1000-1500 J/KG
RANGE...WHICH WILL BE MORE THAN SUFFICIENT FOR TORNADIC SUPERCELLS.

AS MAIN UPPER TROUGH SHIFTS EWD INTO THE EARLY EVENING...ACTIVITY
SHOULD DEVELOP/INTENSIFY FROM SERN OK INTO NERN TX AS LEADING COLD
FRONT ABSORBS DRY LINE AND STRONG CONVERGENCE SHIFTS EWD INTO THE
ARKLATEX REGION. THOUGH SOME OF THIS AREA HAS BEEN AFFECTED BY
EARLIER CONVECTION...STRENGTH OF UVV/S AND CONVERGENCE SHOULD ALLOW
FURTHER DEVELOPMENT TO OCCUR AS STEEPER LAPSE RATES SHIFT INTO THIS
AREA. THESE STORMS WILL THEN SHIFT EWD ACROSS SRN/CENTRAL AR THIS
EVENING...AND INTO THE TN VALLEY/CENTRAL GULF COAST LATER TONIGHT. 
SRN END OF THIS LINE WILL REMAIN NEAR DEEPER GULF MOISTURE ACROSS
SRN AR/NRN LA AND CENTRAL MS WHICH WILL MAINTAIN A THREAT OF SEVERE
STORMS ACROSS THIS REGION.
  
..EVANS.. 03/08/99

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