ZCZC SPCSWODY1 ALL
ACUS01 KWNS 021249
SPC AC 021248

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

VALID 021300Z - 031200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
35 ENE SBY RIC FAY 50 NNW AYS DHN JAN MLU POE 45 NE HOU AUS ABI
65 N ABI SPS PRX DYR 25 ESE PAH BWG CRW 20 S MGW PSB IPT PSF ORH
30 S EWB.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
35 SSE LHX LHX 30 WSW LIC 20 SSE CYS BFF AIA 40 NNE IML 55 NNW GCK
25 N EHA 35 SSE LHX.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 4BK 50 ESE SLE EPH
40 NNW 63S ...CONT... 70 N GFK STC ALO 40 S IRK 20 NE COU STL MTO
45 S CGX SBN 45 N FWA FDY 10 W CMH PKB DUJ 25 NNE BGM BHB
...CONT... 35 ENE CRP LRD ...CONT... 35 NW DRT SJT PVW 40 SW DHT
RTN 15 W DEN 40 WNW FCL 40 SSE RWL 30 NNW VEL PUC 35 NW GCN IGM
20 NNW SAN.

--- SYNOPSIS ---
PROGRESSIVE PATTERN IS FORECAST THROUGH PERIOD BETWEEN WELL-DEFINED
UPPER LEVEL CYCLONIC CIRCULATIONS OFF CA COAST AND E OF CAROLINAS
ATTM.  LATTER SHOULD WEAKEN AND LIFT NEWD OVER ATLANTIC WHILE
INTENSE PACIFIC CYCLONE APPROACHES NRN CA COAST...MOVING ONSHORE
NEAR END OF PERIOD.  SHORTWAVE TROUGH -- NOW EVIDENT ON MOISTURE
CHANNEL IMAGERY OVER NRN IL/SRN WI...SHOULD MOVE EWD ACROSS LOWER
MI AND LE REGION BY 03/00Z.  AT SFC...COLD FRONT IS ANALYZED FROM
NWRN PA LOW SWWD ACROSS EXTREME SRN IL/WRN KY AREA...CENTRAL
AR...TO SRN/ERN PORTIONS DFW METROPLEX...THEN GENERALLY WWD INTO E-
CENTRAL NM.  FRONT MAY BE REINFORCED BAROCLINICALLY AS IT STALLS
OVER CENTRAL/N-CENTRAL TX TODAY...BY COMBINATION OF CONTINUED
PRESSURE RISES AND CAA TO ITS N WITH NWD-MOVING OUTFLOW BOUNDARY TO
ITS S.  

--- CENTRAL/NRN TX ---
OUTFLOW BOUNDARY FROM OVERNIGHT MCS -- NOW EVIDENT FROM HILL
COUNTRY SE SJT...SEWD ACROSS HOU AREA -- SHOULD LIFT NWD SLOWLY
TOWARD ABI...ACT AND PERHAPS EVEN METROPLEX.  MAIN FOCUS FOR SEVERE
POTENTIAL IS THIS BOUNDARY FROM DRYLINE INTERSECTION SEWD.  
EXPECT DEEP-LAYER SHEAR AROUND BOUNDARY TO BE AT LEAST MARGINALLY
FAVORABLE FOR STORM ROTATION WITH 30-40 KT 0-6 KM AGL SHEARS
POSSIBLE AND MOTION OF RIGHT-SPLITS DOWN BOUNDARY.  EXPECT HEAVY-
PRECIP CHARACTER AND PERHAPS QUICK OUTFLOW-DOMINANCE WITH BOW ECHO
TRANSITION POSSIBLE...CONSIDERING WEAK LOW-MIDLEVEL FLOW ABOVE
BOUNDARY AND DEEP/MOIST INFLOW LAYER FOR ANY CELLS NEAR GULF AIR
MASS.  

EXTREME INSTABILITY POSSIBLE WITH 70S F SFC DEW POINTS AND 8-9 DEG
C/KM MIDLEVEL LAPSE RATES CONTRIBUTING TO MLCAPES 3500-5000 J/KG BY
LATE AFTERNOON...SUPPORTING POTENTIAL FOR SEVERE HAIL/GUSTS.  VERY
LARGE/DAMAGING HAIL MAY OCCUR.  TORNADO POTENTIAL APPEARS MORE
BRIEF AND CONDITIONAL ATTM...BUT ALSO WILL BE RELATIVELY MAXIMIZED
NEAR BOUNDARY.  ORGANIZED MULTICELLS AND DISCRETELY PROPAGATING
STORMS ARE POSSIBLE S OF BOUNDARY CONSIDERING VERY WEAK LOW LEVEL
FLOWS OF LESS THAN 10 KT EXPECTED...LOW 0-3 KM SHEAR VALUES AND
SMALL HODOGRAPHS. 

--- SRN/CENTRAL APPALACHIANS TO SRN NEW ENGLAND ---
SCATTERED TSTMS POSSIBLE IN CLUSTERS NEAR FRONT FROM PA TO SRN NEW
ENGLAND.  WIDELY SCATTERED TSTMS POSSIBLE OVER MOUNTAINS AND INVOF
PIEDMONT TROUGH THIS AFTERNOON S OF FRONT.  PRIMARY THREATS ARE 
HAIL/GUSTS NEAR SEVERE LEVELS...WITH SOMEWHAT MORE CONCENTRATED
COVERAGE OF SEVERE EXPECTED INVOF FRONT WHERE LOW LEVEL ASCENT WILL
BE RELATIVELY MAXIMIZED.  SIGNIFICANT SFC HEATING/DESTABILIZATION
EXPECTED THIS AFTERNOON...WITH INCREASING DEW POINT DEPRESSIONS
LEADING TO INVERTED-V BOUNDARY LAYER THERMODYNAMIC SOUNDING
PROFILES.  MLCAPE 1500-2500 J/KG IS ANTICIPATED OVER PIEDMONT FROM
GA NEWD INTO WRN VA.  NEARLY UNIDIRECTIONAL VERTICAL WIND PROFILES
AND WEAK LOW-MIDLEVEL SHEAR SUGGEST CONVECTIVE MODE PRIMARILY BEING
ORGANIZED MULTICELLS...WITH POTENTIAL FOR BOWS AND MCS CONCENTRATED
IN NEARLY ZONAL CORRIDOR ALONG INSTABILITY GRADIENT ASSOCIATED WITH
FRONTAL ZONE.  ACTIVITY SHOULD WEAKEN WITH LOSS OF DIABATIC HEATING
AND MLCAPE DURING EVENING HOURS.

--- LOWER MS VALLEY...GULF COAST STATES ---
SCATTERED TSTMS IN CLUSTERS ARE EXPECTED TO DEVELOP INVOF FRONTAL
BOUNDARIES THIS AFTERNOON AND SWD INTO WARM SECTOR...IN ENVIRONMENT
OF WEAK LOW-MIDLEVEL SHEAR BUT FAVORABLE INSTABILITY WITH AFTERNOON
MLCAPE 2000-2500 J/KG POSSIBLE.  POTENTIAL EXISTS FOR SEVERAL
MESOBETA SCALE TSTM COMPLEXES TO DEVELOP BY LATE
AFTERNOON...LASTING ALMOST TO 06Z WITH POTENTIAL FOR WET
MICROBURSTS...A FEW BETTER-ORGANIZED BOW ECHO WIND EVENTS AND
OCCASIONAL HAIL.  SEVERE POTENTIAL...WHILE GENERALLY MAXIMIZED
INVOF SYNOPTIC FRONTS -- WILL BE CONCENTRATED NEAR AND GREATLY
DEPENDENT ON LOCATION OF SFC WIND SHIFTS...CONFLUENCE LINES AND
OUTFLOW BOUNDARIES YET TO BE PRODUCED.  

--- CENTRAL HIGH PLAINS ---
ISOLATED SUPERCELLS WITH ENHANCED HAIL POTENTIAL ARE POSSIBLE. 
50-60 KT 0-6 KM AGL SHEAR AND STRONG VEERING WITH HEIGHT ARE FCST.
VERTICAL SHEAR PROFILES WILL BE PRESENT TO SUPPORT SEVERE TSTMS E
OF FRONT RANGE TODAY AND INTO PORTIONS WRN KS/SWRN NEB.  BY MID-
LATE AFTERNOON...SFC-BASED TSTMS ARE OPTIMALLY POSSIBLE WITH MLCAPE
1000-1500 J/KG...USING DEW POINTS UPPER 30S TO MID 40S.  MOST AREAS
SHOULD EXPERIENCE LESS CAPE AND THERE ARE DOUBTS ABOUT EXTENT OF
AIR MASS RECOVERY IN POST-FRONTAL REGIME.  HOWEVER...THERE SHOULD
BE ENOUGH OROGRAPHICALLY AIDED INITIATION TO RESULT IN AT LEAST
MARGINAL CATEGORICAL SEVERE THREAT.
 
..EDWARDS/NADEN.. 05/02/03

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