ZCZC SPCSWODY1 ALL
ACUS01 KWNS 270508
SPC AC 270457

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK 
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.

VALID 271200Z - 281200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
65 N IWD 65 N EAU 10 SW FSD 25 WNW LBF 45 SSE AKO 15 SSE DEN
40 ESE DGW 45 S BIS 75 NE DVL.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
40 SSE JAX 10 SW CTY 20 SSE TLH MGR 40 W SAV 55 WNW CHS 40 ENE CAE
35 E CLT 25 SW GSO 20 SE DAN 55 NNE RWI 20 ESE ORF.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 WSW DUG 80 S 4BL
25 NW CAG 45 SSW BIL 60 N OLF ...CONT... 45 SSE IMT 10 NW OSH
45 ESE DBQ 35 WNW BRL 30 N EMP 20 ENE P28 15 S EHA 40 W AMA
40 N MAF 40 ENE SJT 30 WNW TPL 35 NE LFK MCB 60 NNE MOB 40 E TOI
25 SSE ATL 45 SW LEX 45 S AZO 20 S APN ...CONT... 40 NW SYR
45 WNW GFL 15 WSW EEN 30 SW HYA.

...SYNOPSIS...
BLOCKY PATTERN WILL CONTINUE INTO MID-WEEK AS UPPER LEVEL TROUGH
REMAINS OVER THE NERN STATES AND A BUILDING RIDGE STRENGTHENS OVER
THE DESERTS TO THE CNTRL ROCKIES.  A MIDLEVEL JETLET IS EXPECTED TO
MOVE SEWD THROUGH THE NRN PLAINS AND INTO THE MIDWEST WHILE A
SECONDARY SHORTWAVE TROUGH MOVES EWD ACROSS THE TN VLY/NRN GULF
COAST INTO THE SERN STATES.  AT THE SURFACE...A COLD FRONT WILL
MOVE FROM THE ERN MT ACROSS THE DAKS ON TUESDAY AND SHOULD EXTEND
FROM WRN WI-CNTRL IA-WRN KS BY WEDNESDAY MORNING.  OTHERWISE...A
LOW PRESSURE OVER THE CAROLINAS WILL DEEPEN AND MOVE NEWD INTO THE
WRN ATLANTIC WHILE THE ATTENDANT COLD FRONT MOVES SEWD THROUGH THE
CAROLINAS...GA AND NRN FL.

...NRN/CNTRL PLAINS...
SLY FLOW SHOULD ADVECT MID 50S SURFACE DEW POINTS ALONG/AHEAD OF
THE APPROACHING COLD FRONT BENEATH 7-7.5 C/KM MID LEVEL LAPSE
RATES.  THIS WILL CONTRIBUTE TO AFTERNOON MLCAPES OF 500-1000 J/KG.

TSTMS ARE LIKELY TO DEVELOP ALONG PRE-FRONTAL TROUGH/COLD FRONT
OVER THE NRN PLAINS BY MID AFTERNOON.  APPROACH OF HIGHER MIDLEVEL
NWLY FLOW OF 50-60 KTS WILL RESULT IN AROUND 40 KTS OF 0-6KM
SHEAR...SUFFICIENT FOR INITIAL DEVELOPMENT TO BE SUPERCELLS WITH
LARGE HAIL.  HOWEVER...INCREASING LINEAR FORCING AND GIVEN THAT
TSTMS WILL BE HIGH BASED SUGGEST THAT A QUICK TRANSITION INTO 
OUTFLOW-DOMINANT LINE OR LINES WILL BE LIKELY...GIVING MAINLY WIND
DAMAGE.  STORMS WILL MOVE EWD ACROSS THE DAKS AND INTO MN
OVERNIGHT. 

FARTHER SW...TSTMS ARE EXPECTED TO FORM ALONG THE HIGHER TERRAIN OF
ERN WY/BLACK HILLS/NERN CO.  SBCAPE WILL BE HIGHER IN THIS
AREA...BUT DEEP LAYER SHEAR LESS THAN FARTHER NORTH.  ACTIVITY WILL
MOVE SEWD ACROSS THE CO PLAINS/SWRN NEB DURING THE EVENING...BUT
LIKELY WEAKEN WITH TIME.

...SERN STATES...
THETA-E AXIS HAS SURGED BACK NEWD ACROSS MUCH OF SC AND INTO
CNTRL/ERN NC LATE MONDAY EVENING.  THIS VERY MOIST AIR MASS WILL
CONTINUE INTO TUESDAY...RESULTING IN A MODERATELY UNSTABLE AIR MASS
FROM SRN GA/NRN FL INTO THE ERN CAROLINAS WITH MLCAPES OF 1500-2000
J/KG.  GIVEN WEAK CAP...TSTMS SHOULD BEGIN TO FORM RATHER EARLY IN
THE DAY...ALONG THE COLD FRONT/SURFACE LOW IN THE MOUNTAINS AND
ALONG SURFACE TROUGH IN THE LOWLANDS.  REGION WILL REMAIN ON SRN
PERIPHERY OF 55 KT MIDLEVEL FLOW...AND DEEP LAYER SHEAR WILL REMAIN
FAVORABLE FOR STORM ORGANIZATION.  UNIDIRECTIONAL FLOW REGIME WILL
RESULT IN SHORT LINE SEGMENTS/BOWS WITH DAMAGING WINDS/HAIL THE
MAIN THREATS.  

...OH VLY...
COLD POCKET ALOFT ASSOCIATED WITH UPPER LOW WILL ROTATE SEWD INTO
THE OH VLY TODAY.  SURFACE DEW POINTS IN THE 50S BENEATH 5H
TEMPERATURES NEAR MINUS 20C SUGGEST THAT ANY TSTM THAT FORMS COULD
PRODUCE HAIL.  BUT...THE SEVERE THREAT/COVERAGE WILL REMAIN LIMITED
TO ISOLD CASES AND NOT WARRANT A CATEGORICAL RISK.

...CNTRL/SRN TX...
A FEW TSTMS MAY DEVELOP ALONG RESIDUAL BOUNDARIES ACROSS CNTRL/SRN
TX...PARTICULARLY IN THE UPSLOPE REGIONS OF SWRN TX.  WHILE
TROPOSPHERIC FLOW WILL BE RATHER WEAK...ISOLD DAMAGING WIND GUSTS
OR HAIL MAY OCCUR WITH THE STRONGER TSTMS. 
 
..RACY/TAYLOR.. 05/27/03
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