ZCZC SPCSWODY1 ALL
ACUS01 KWNS 031945
SPC AC 031941

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

VALID 032000Z - 041200Z

THERE IS A MDT RISK OF SVR TSTMS THROUGH MID EVE ACROSS PARTS OF W
CNRL MS...NRN LA...NRN TX...SRN OK AND SW AR TO THE RIGHT OF A LINE
FROM 40 SSW HEZ 40 SSW SHV 25 SSE DAL 35 NNE MWL 25 E SPS 40 ESE
FSI 20 S MLC 40 SW HOT 30 ENE ELD 45 SW JAN 10 NW MCB 40 SSW HEZ.

THERE IS A MDT RISK OF SVR TSTMS LATE THIS EVE AND OVERNIGHT ACROSS
MUCH OF CNTRL/ERN NEB AND PARTS OF EXTREME N CNTRL KS TO THE RIGHT
OF A LINE FROM MCK MHN ANW 10 W OFK 10 NNE OMA FNB CNK MCK.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
30 NNW BVE 10 ESE POE LFK TPL BWD CDS LBL AKO 81V 70 SSE GDV DIK
BIS 10 SE HON LWD SZL SGF 50 SE FYV LIT CBM CHA TYS TRI 50 NE HKY
35 SW FAY ILM ...CONT... 10 NNW MLB 55 SSE CTY.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 S INL STC FRM FOD
OTM STL MKL MSL CSV JKL CMH CAK 10 ESE YNG AOO 25 NW MRB 40 SW DCA
25 ENE RIC 35 NE ORF ...CONT... 15 SW GLS SAT 70 W COT ...CONT...
40 NW DRT BGS PVW 30 NNE CAO ALS CEZ GCN EED DAG 15 NW PMD SMX SJC
MHS RDM PDT PUW 90 WNW FCA.

...SOUTHERN PLAINS RED RIVER VALLEY INTO SOUTHEAST STATES...
LATEST SURFACE ANALYSIS INDICATED QUASI-STATIONARY SURFACE FRONT
CURVING FROM THE SOUTH CAROLINA COAST THROUGH THE NORTHERN GULF
STATES INTO THE VICINITY OF THE RED RIVER.  CLUSTER OF CONVECTION
HAS STABILIZED WARM SECTOR IN SWATH FROM CENTRAL ALABAMA INTO
WESTERN/CENTRAL GEORGIA...BUT OUTFLOW BOUNDARY IS BECOMING FOCUS
FOR NEW CONVECTIVE DEVELOPMENT FROM PARTS OF SOUTHERN MISSISSIPPI
INTO THE FLORIDA PANHANDLE AND PARTS OF SOUTH CENTRAL/ SOUTHEAST
GEORGIA.  SURFACE FRONT ACROSS NORTHERN GEORGIA AND THE WESTERN
CAROLINAS IS ALSO BECOMING FOCUS FOR ADDITIONAL THUNDERSTORM
ACTIVITY.  

DAYTIME HEATING OF MOIST AIR MASS NEAR BOUNDARIES HAS CONTRIBUTED
TO MODERATE INSTABILITY...WITH GREATEST INSTABILITY WHERE SURFACE
DEW POINTS ARE NEAR 70...FROM THE VICINITY OF THE EASTERN GULF
COAST INTO LOWER MISSISSIPPI VALLEY AND THE SOUTH CENTRAL PLAINS. 
SUBSTANTIAL LOW/MID-LEVEL CAP IS EVIDENT IN 18Z SOUNDINGS FROM FORT
WORTH AND SHREVEPORT...BUT WEAKER INHIBITION SHOULD ALLOW FOR
CONTINUED DEVELOPMENT AND INTENSIFICATIONS OF THUNDERSTORM ACTIVITY
IN PEAK AFTERNOON HEATING ACROSS THE GULF AND SOUTH ATLANTIC COAST
STATES NEXT FEW HOURS.  THOUGH LOW-LEVEL FLOW IS RATHER WEAK...WEST
NORTHWESTERLY MID-LEVEL FLOW ON THE ORDER OF 30/40 KTS WILL
CONTRIBUTE TO SUFFICIENT SHEAR FOR ISOLATED SUPERCELLS IN
ENVIRONMENT WITH SURFACE BASED CAPE OF 1500 TO 3000 J/KG.  

FORCING ON TAIL END OF SHORT WAVE TROUGH NOW AMPLIFYING AND DIGGING
TOWARD THE CENTRAL/SOUTHERN APPALACHIANS MAY AID EVOLUTION OF
ORGANIZED CONVECTION NEAR FRONTAL BOUNDARY ACROSS THE CAROLINAS BY
EARLY EVENING...WHILE ANOTHER CLUSTER WITH ASSOCIATED SURFACE COLD
POOL EVOLVES IN MORE UNSTABLE AIR MASS OVER SOUTHERN GEORGIA/
NORTHERN FLORIDA.

UPSTREAM...ACROSS THE ARKLATEX/RED RIVER VALLEY...FORCING IS MORE
UNCERTAIN...BUT MODELS SUGGEST AREA OF ENHANCED UPPER DIVERGENCE ON
NORTHEAST PERIPHERY OF BUILDING SOUTHERN PLAINS RIDGE MAY SUPPORT
ANOTHER CLUSTER OF STORMS BY EARLY EVENING.  GIVEN FAVORABLY
SHEARED ENVIRONMENT...VERY STEEP MID-LEVEL LAPSE RATES ACROSS THIS
REGION PROVIDE POTENTIAL FOR VERY LARGE HAIL IN MOST VIGOROUS
STORMS.

...HIGH PLAINS/CENTRAL PLAINS...
STRONG HEATING IS ONGOING IN LEE SURFACE TROUGH ACROSS THE HIGH
PLAINS...WITH LOW-LEVEL MOISTURE BEGINNING TO RETURN NORTHWARD
THROUGH THE PLAINS ON STRENGTHENING SOUTHERLY LOW-LEVEL FLOW.   
THOUGH BOUNDARY LAYER MOISTURE IS STILL QUITE MARGINAL ACROSS
WESTERN NEBRASKA AND WESTERN SOUTH DAKOTA...WHERE FORCING IN EXIT
REGION OF UPPER JET WILL SUPPORT INCREASING CONVECTIVE DEVELOPMENT
LATE THIS AFTERNOON...ENVIRONMENT IS STILL SUPPORTIVE OF ISOLATED
SUPERCELLS.  ACTIVITY IS MOST LIKELY SHORTLY AFTER PEAK HEATING...
POSSIBLY AS FAR SOUTH AS THE TEXAS PANHANDLE BY EARLY THIS EVENING.

SOUTHERN PLAINS ACTIVITY WILL BE SHORTER LIVED IN MORE STRONGLY
CAPPED ENVIRONMENT...BUT STORMS SHOULD PERSIST AND SPREAD EASTWARD
ACROSS THE NORTH CENTRAL PLAINS.

LATER THIS EVENING/OVERNIGHT...MORE RAPID NORTHWARD TRANSPORT OF
MOISTURE ON STRENGTHENING SOUTHERLY LOW-LEVEL JET IS EXPECTED TO
CONTRIBUTE TO MORE SUBSTANTIAL DESTABILIZATION...WITH CAPE FOR
PARCELS LIFTED FROM MOIST LAYER ABOVE LOW-LEVEL INVERSION ON THE
ORDER OF 1000 TO 2000 J/KG.  DESTABILIZATION AND LIFT SHOULD BECOME
MAXIMIZED ACROSS CENTRAL NEBRASKA NEAR/SHORTLY AFTER
04/06Z...NORTHEAST OF DEEPENING SURFACE LOW.  THIS IS EXPECTED TO
SUPPORT INCREASINGLY WIDESPREAD CONVECTION...WITH VERTICAL SHEAR
PROFILES SUPPORTIVE OF SUPERCELLS WITH VERY LARGE HAIL.  ACTIVITY
WILL GRADUALLY SPREAD EASTWARD INTO PARTS OF THE LOWER/MID MISSOURI
VALLEY BY THE END OF THE FORECAST PERIOD.
 
..KERR.. 05/03/03

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