ZCZC SPCSWODY1 ALL
ACUS01 KWNS 271629
SPC AC 271629

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT WED AUG 27 2003

VALID 271630Z - 281200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 ESE
ORF 10 SSE SSU 35 SSW LUK 35 NW LUK 25 NNW DAY 10 N HLG PSB 15 ENE
NEL

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 NNE
ELO FSD 60 SSE 9V9 VTN 20 N CDR 70 SW RAP 15 E 81V 75 NE ISN

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM CZZ 30 WNW EDW 20 W
TVL 35 ESE SVE 55 NNW WMC 45 S BKE 25 WNW S80 40 N FCA ...CONT... 35
SSE CMX 50 N EAU 45 ESE MSP 25 W ALO 25 W CID 25 E MLI CGX 45 E TOL
BUF 20 NNE BID ...CONT... 25 ENE ECG 30 NW RWI 15 SE CLT 15 SW AND
35 NNE MCN 70 ESE MCN 25 ESE SAV ...CONT... 10 ENE CRP 50 WSW COT

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 ENE PWM 30 WNW PWM
30 NW PBG

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER OH VALLEY INTO
THE DELMARVA REGION...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE NRN PLAINS REGION...

...OH VALLEY/MID ATLANTIC STATES...
SATELLITE IMAGERY SHOWS PRIMARY UPPER TROUGH MOVING EWD ACROSS THE
LOWER GREAT LAKES/ST LAWRENCE VALLEY WITH A BAND OF STRONG WLY/WNWLY
FLOW ALOFT EXTENDING ACROSS THIS REGION.  ALONG THE SRN EDGE OF THE
STRONGER FLOW FROM OH INTO THE DELMARVA AREA...WATER VAPOR IMAGERY
SHOWS SEVERAL SUBTLE SHORT WAVE TROUGHS MOVING EWD ACROSS INDIANA
AND WRN PA.  CLUSTERS OF THUNDERSTORMS HAVE DEVELOPED OVER WRN OH
AND PA/MD IN ASSOCIATION WITH THESE FEATURES.

DOWNSTREAM CONVECTION OVER PA/MD HAS WEAKENED OVER THE LAST HOUR
WITH IR CLOUD TOPS WARMING AND CG LIGHTNING STRIKE DENSITY
DIMINISHING.  HOWEVER...STRONG HEATING HAS OCCURRED TO THE SOUTH OF
THIS CONVECTIVE SYSTEM FROM WV INTO THE DELMARVA WHERE DEW POINTS
REMAIN IN THE 70S...CONTRIBUTING TO MODERATE INSTABILITY WITH MLCAPE
OF 1500-2000 J/KG.  WNWLY FLOW OF 30-40 KT ACROSS THIS AREA IS
PROVIDING SUFFICIENT DEEP LAYER SHEAR TO ENHANCE SEVERE THUNDERSTORM
POTENTIAL THIS AFTERNOON.  CURRENT STORMS WILL NEED TO BE MONITORED
FOR INTENSIFICATION AND NEW DEVELOPMENT...WITH THREAT FOR LARGE HAIL
AND DAMAGING WIND GUSTS WITH STRONGER CELLS THROUGH THE EVENING
HOURS.

FARTHER WEST...CONVECTION HAS BEEN SLOWLY INCREASING OVER SWRN OH
WHERE AIR MASS HAS BECOME MODERATELY UNSTABLE WITH MLCAPE AROUND
2000 J/KG.  ALTHOUGH THIS ACTIVITY IS SOUTH OF THE STRONGER FLOW AND
RESULTANT VERTICAL SHEAR...STEEPER LAPSE RATES AND PRESENCE OF DRY
AIR ALOFT INDICATE MORE FAVORABLE THERMODYNAMIC SUPPORT FOR SEVERE
STORMS WITH LARGE HAIL AND OCCASIONAL DAMAGING WIND GUSTS.  A WATCH
MAY BE NEEDED FOR THIS AREA SOON.

...NRN PLAINS/UPPER MS VALLEY...
SATELLITE IMAGERY SHOWS A STRONG SHORT WAVE TROUGH BECOMING
NEGATIVELY TILTED AS IT MOVES ENEWD INTO THE NRN ROCKIES.  THIS
SYSTEM IS FORECAST TO MOVE ACROSS THE NRN PLAINS TONIGHT.  AT THE
SURFACE...A LOW OVER ERN MT WILL DEEPEN AS IT MOVES INTO NWRN ND
THIS EVENING CONTINUING INTO SRN MANITOBA LATER TONIGHT...WITH A
TRAILING COLD FRONT MOVING EWD ACROSS THE NRN PLAINS.  LOW LEVEL
MOISTURE IS BEGINNING TO INCREASE NWD INTO THE DAKOTAS...WITH
SURFACE DEW POINTS IN THE 60-65F RANGE EXPECTED THIS AFTERNOON.  12Z
SOUNDINGS EXHIBITED STEEP LAPSE RATES WHICH WILL COMBINE WITH 
STRONG LOW LEVEL HEATING AND MOISTURE ADVECTION TO PRODUCE AN
UNSTABLE ENVIRONMENT WITH MLCAPE AROUND 1000-1500 J/KG.

THUNDERSTORMS ARE EXPECTED TO DEVELOP NEAR THE ADVANCING COLD FRONT
LATE THIS AFTERNOON AND EVENING OVER PARTS OF THE WRN DAKOTAS...WITH
ACTIVITY GRADUALLY DEVELOPING INTO AN EWD MOVING LINE TONIGHT. 
LARGE HAIL AND DAMAGING WIND GUSTS WILL BE POSSIBLE THROUGH THE
EVENING HOURS...WITH THE THREAT BECOMING PRIMARILY WIND DAMAGE
DURING THE OVERNIGHT HOURS AS THE SYSTEMS MOVE RAPIDLY ENEWD ACROSS
THE DAKOTAS TOWARD WRN MN.

...LOWER CO RIVER VALLEY INTO PARTS OF UT...
WATER VAPOR IMAGERY INDICATES WELL-DEFINED MID/UPPER LEVEL MOISTURE
DISCONTINUITY EXTENDING FROM THE AZ/CA BORDER INTO CENTRAL UT. 
AMPLE DEEP LAYER MOISTURE IS PRESENT ALONG/EAST OF THIS
BOUNDARY...WITH LOW LEVEL MOISTURE PERSISTING FROM SRN NV INTO SERN
CA.  SRN END OF THE NRN ROCKIES SHORT WAVE TROUGH IS EXPECTED TO
MOVE ACROSS UT WITH POTENTIAL FOR STRONG THUNDERSTORMS TO DEVELOP
ACROSS THIS AREA WITH THREAT FOR ISOLATED HAIL/STRONG WIND GUSTS. 
FARTHER SOUTH...STRONG CONVECTION WILL CONTINUE TO DEVELOP BUT
WEAKER FLOW ALOFT/MINIMAL VERTICAL SHEAR SUGGEST A PULSE-STORM
ENVIRONMENT WITH POTENTIAL FOR LOCALIZED WET MICROBURSTS.

..WEISS/TAYLOR.. 08/27/2003

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.

$$