ZCZC SPCSWODY1 ALL
ACUS01 KWNS 140609
SPC AC 140608

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

VALID 141200Z - 151200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
25 NW BVE 25 N HUM 35 SSE ESF 50 WNW POE 65 WNW LFK 35 WNW AUS
40 E JCT 15 SSW ABI 35 NE CDS 20 N GAG 50 W P28 30 SW HUT
55 NNW SGF 50 SSW UIN 30 SW PIA 25 N BMI 40 NNW LAF 40 E LAF
55 ESE IND 25 WSW LEX 20 ESE BWG 25 NW BNA 40 SW BNA 25 N HSV
15 WSW CHA 45 ESE CHA 30 W AHN 30 NNW MCN 25 SSW TOI 20 SSW CEW.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SW 7R4 10 ENE LCH
55 N VCT 60 WSW COT ...CONT... 15 S P07 50 E FST 30 NNE MAF
50 S CVS 30 SW LVS 15 WNW DAG FAT 60 SE RBL LMT 50 ENE RDM
30 NNE ALW 50 ENE 63S ...CONT... 55 N GGW 30 WSW BIL 25 ESE CYS
50 SSE AKO 25 W HLC 30 NW TOP 20 NNW STJ 30 ENE OMA 10 WSW SUX
30 WSW BKX 55 NNE ATY BRD 35 SW RHI 20 WSW UNI 45 NNE HKY
25 SE OAJ.

...SYNOPSIS...
PROGRESSIVE UPPER FLOW IS EXPECTED OVER THE U.S. TODAY WITH AN
UPPER TROUGH TRACKING FROM THE NRN PLAINS TO THE WRN GREAT LAKES/
LOWER OH VALLEY...AND WEAKENING BY THE END OF THE PERIOD.  UPPER
SHORT WAVE TROUGH...CURRENTLY OVER THE ERN PACIFIC AT 32N 128 W PER
WV IMAGERY...WILL MOVE INTO THE LOWER CO RIVER VALLEY BY 12Z
THURSDAY...WITH DOWNSTREAM SHORT WAVE RIDGING EXPECTED OVER THE
CENTRAL/SRN ROCKIES/HIGH PLAINS.

AT THE SURFACE...A LOW INITIALLY OVER SWRN MN WILL BECOME OCCLUDED
OVER IA DURING THE DAY AS A SECOND LOW DEVELOPS OVER NERN MO AND
THEN TRACKS SEWD INTO CENTRAL IL BY 00Z AND NEAR CVG BY 12Z
THURSDAY.  SURFACE COLD FRONT TRAILING SWWD THROUGH CENTRAL MO TO
SRN KS WILL MOVE SEWD WITH THE SURFACE LOW TO THE LOWER OH VALLEY. 
A WARM FRONT WILL EXTEND SEWD FROM THE MO/IL SURFACE LOW INTO THE
LOWER OH VALLEY. 

WEAK LOW-LEVEL FLOW AND WLY MID/UPPER LEVEL FLOW OVER THE SRN
PLAINS WILL LIMIT THE SWD MOVEMENT OF THE COLD FRONT ACROSS THIS
REGION...WITH THIS BOUNDARY LIKELY BECOMING STATIONARY OVER FAR SRN
KS OR INTO NRN OK BY MID-DAY.  A CONVECTIVE OUTFLOW BOUNDARY...FROM
TUESDAY NIGHT CONVECTIVE COMPLEX OVER OK...IS EXPECTED TO EXTEND
FROM THE RED RIVER REGION INTO NRN LA.  

...OK/NRN TX/LOWER MS VALLEY/CENTRAL GULF COAST STATES...
CONVECTIVE COMPLEX IS EXPECTED TO BE ONGOING AT THE BEGINNING OF
THE PERIOD OVER PORTIONS OF CENTRAL/ERN OK...WITHIN A REGION OF
STRONG LOW-LEVEL WAA ON THE NOSE OF A 40-50 KT SWLY LLJ WHICH WILL
EXTEND FROM WRN TX INTO FAR SRN OK AT 12Z.  ALTHOUGH THE LLJ WILL
BECOME WLY DURING THE MORNING FROM NRN TX INTO NRN LA/SRN AR...AND
WEAKEN BY MID-DAY...THE OVERNIGHT MCS SHOULD MOVE ESEWD INTO NRN
LA/SRN AR BY 18Z AS THE AIR MASS DESTABILIZES OVER THE LOWER MS
VALLEY.  

VEERING SHEAR PROFILES ASSOCIATED WITH A 50-60 KT WLY 500 MB JET
MOVING FROM THE SRN PLAINS INTO THE GULF COAST STATES...AND LOW-
LEVEL WAA OVER THE LOWER MS VALLEY IS EXPECTED TO ALLOW STORMS TO
CONTINUE AND/OR REDEVELOP FROM LA EWD INTO AL DURING THE AFTERNOON.

THE AFTERNOON STORMS SHOULD DEVELOP ALONG OUTFLOW BOUNDARIES FROM
MORNING CONVECTION AND SYNOPTIC WARM FRONT EXPECTED OVER THE SRN
GULF COAST STATES.  STEEP LAPSE RATES EXTENDING EWD FROM THE SRN
PLAINS INTO MS/AL...MODERATE INSTABILITY AND STRONG DEEP LAYER
SHEAR WILL SUPPORT SUPERCELLS WITH HAIL/DAMAGING WINDS.  RICH
BOUNDARY LAYER MOISTURE /SURFACE DEWPOINTS IN THE UPPER 60S TO
LOWER 70S ACROSS LA/MS/AL AND INCREASING LOW-LEVEL SHEAR VALUES BY
LATE AFTERNOON WILL ALSO SUPPORT ISOLATED TORNADOES OVER THIS AREA.

DECREASING CLOUDS IN THE WAKE OF THE EARLY MORNING CONVECTIVE
COMPLEX OVER OK WILL ALLOW THE AIR MASS OVER MUCH OF THE SRN PLAINS
TO RECEIVE SUFFICIENT HEATING...CONTRIBUTING TO MODERATE
INSTABILITY.  THUNDERSTORMS WILL LIKELY DEVELOP WITHIN A WEAKLY
CAPPED ENVIRONMENT ALONG THE COLD FRONT IN FAR NRN OK AND ALONG THE
OUTFLOW BOUNDARY ACROSS THE RED RIVER REGION.  STEEP LAPSE RATES...
MODERATE INSTABILITY AND DEEP LAYER SHEAR WILL FAVOR LARGE HAIL...
WITH ISOLATED WIND GUSTS GIVEN WEAK LOW-LEVEL FORCING.  

...MID MS/LOWER OH VALLEYS...
SWLY LOW-LEVEL FLOW WITHIN THE WARM SECTOR WILL ADVECT LOWER TO
MIDDLE 60 SURFACE DEWPOINTS INTO THE MID MS/LOWER OH VALLEYS BY
EARLY AFTERNOON.  STEEP LAPSE RATES SPREADING SEWD ABOVE THE
INCREASING LOW-LEVEL MOISTURE WILL CONTRIBUTE TO MODERATE
INSTABILITY EXTENDING FROM ERN MO/CENTRAL IL INTO THE LOWER OH
VALLEY.  A 60 KT WNWLY 500 MB JET MAX IN THE BASE OF THE NRN UPPER
TROUGH WILL RESULT IN STRONG DEEP LAYER SHEAR FOR ORGANIZED STORMS
WITH SUPERCELLS.  LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY
THREATS.  SEVERE STORMS WILL TRACK ESEWD INTO IND/WRN KY DURING THE
EVENING...BUT SHOULD DECREASE IN INTENSITY WITH THE LOSS OF DAY
TIME HEATING.  ELEVATED STORMS MAY CONTINUE OVERNIGHT...WITH AN
ISOLATED HAIL THREAT...REACHING SWRN OH/CENTRAL KY.

...SERN MN/IA/NWRN IL...
LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE OCCLUDED LOW OVER IA
AND ALONG A SURFACE BOUNDARY INTO NWRN IL SHOULD BE SUFFICIENT TO
DEVELOP THUNDERSTORMS BY THIS AFTERNOON WITHIN A MARGINALLY
UNSTABLE AIR MASS.  STEEP LAPSE RATES AND COLD 500 MB TEMPERATURES 
/-20 TO -22C/ WILL RESULT IN HAIL WITH THE STRONGEST STORMS. 
HOWEVER...MARGINAL INSTABILITY AND DEEP LAYER SHEAR SHOULD LIMIT
THE COVERAGE...LEADING TO LOW SEVERE HAIL/WIND PROBABILITIES. 
 
..PETERS/BANACOS.. 05/14/03

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