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.
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 2000Z