SPC AC 250810
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0310 AM CDT WED MAY 25 2005
   
   VALID 271200Z - 281200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   
   THE UPPER TROUGH CURRENTLY OVER SRN CANADA AND THE NRN PLAINS WILL
   AMPLIFY SEWD INTO THE OH VALLEY AND NERN STATES FRIDAY. AN UPPER
   RIDGE WILL PERSIST OVER THE SWRN U.S. WHILE AN UPSTREAM SHORTWAVE
   TROUGH MOVES INTO THE NWRN STATES. AT THE SURFACE A FRONT WILL
   OCCLUDE OVER THE GREAT LAKES. BY FRIDAY MORNING THIS BOUNDARY SHOULD
   EXTEND SWD THROUGH THE ERN PART OF THE OH VALLEY...THEN SWWD AS A
   COLD FRONT THROUGH THE TN VALLEY...BECOMING A STATIONARY FRONT
   ACROSS TX AND NM. 
   
   
   ...OH VALLEY THROUGH MID ATLANTIC...
   
   SEVERAL JET STREAKS AND THEIR ASSOCIATED VORTICITY MAXIMA WILL MOVE
   THROUGH THE BROADER UPPER TROUGH INTO THE OH VALLEY AND MID ATLANTIC
   AREAS. COLD MID LEVEL TEMPERATURES ON THE ORDER OF -20C WILL SPREAD
   EWD THROUGH THE REGION RESULTING IN STEEP MID LEVEL LAPSE RATES. THE
   ATMOSPHERE IS EXPECTED TO DESTABILIZE IN AREAS WHERE SURFACE HEATING
   CAN BE REALIZED DURING THE AFTERNOON. HOWEVER...EXPECTED MODEST LOW
   LEVEL MOISTURE WITH ANTICIPATED BOUNDARY LAYER DEWPOINTS IN THE 40S
   SHOULD LIMIT MLCAPE TO GENERALLY AOB 500 J/KG. SCATTERED STORMS ARE
   EXPECTED TO DEVELOP AND INTENSIFY DURING THE AFTERNOON SUPPORTED BY
   DESTABILIZING BOUNDARY LAYERS AND FORCING FOR ASCENT ACCOMPANYING
   PASSING SPEED MAXIMA. ACTIVITY WILL BE DEVELOPING WITHIN STRONG
   UNIDIRECTIONAL VERTICAL SHEAR...AND THE THERMODYNAMIC ENVIRONMENT
   MIGHT BECOME SUFFICIENT FOR STORMS TO PRODUCE HAIL. AT THIS TIME THE
   OVERALL THREAT APPEARS LIMITED BY ANTICIPATED MARGINAL INSTABILITY. 
   
   
   
   ...TX AND NM...
   
   THE COLD FRONT IS EXPECTED TO STALL ACROSS TX INTO ERN NM. THE
   ATMOSPHERE MAY BECOME MODERATELY UNSTABLE WITHIN THE WARM SECTOR
   ACROSS PARTS OF TX WWD INTO SRN NM WHERE SURFACE HEATING CAN BE
   REALIZED. STORMS MAY DEVELOP AND INTENSIFY ALONG ANY RESIDUAL
   OUTFLOW BOUNDARIES AS WELL AS OVER THE MOUNTAINS OF SW TX AND NM.
   HOWEVER...THE WARM SECTOR WILL RESIDE S OF THE STRONGER FLOW ALOFT
   WHICH SUGGEST STORMS MAY NOT BE VERY ORGANIZED. ISOLATED HAIL AND
   STRONG WIND GUSTS MAY ACCOMPANY SOME OF THE STORMS...BUT OVERALL
   THREAT DOES NOT APPEAR SUFFICIENT TO WARRANT MORE THAN 5% SEVERE
   PROBABILITIES.
   
   
   ...NWRN U.S....
   
   A SHORTWAVE TROUGH IS FORECAST TO ADVANCE INTO THE NWRN U.S. BY LATE
   FRIDAY AFTERNOON OR FRIDAY EVENING. MODELS DIFFER ON TIMING AND
   WHERE IT MAKES LANDFALL...WITH THE GFS AND ECWMF BEING SLOWER AND
   FARTHER S. IF THIS FEATURE MOVES INLAND FRIDAY AFTERNOON...THE
   POTENTIAL WILL EXIST FOR THUNDERSTORMS TO DEVELOP OVER THE HIGHER
   TERRAIN OF OREGON THROUGH NRN CA AS THE ATMOSPHERE DESTABILIZES
   DURING THE AFTERNOON. VERTICAL SHEAR WILL STRENGTHEN WITH THE
   APPROACH OF THIS FEATURE AND STEEP LAPSE RATES WITH DRY BOUNDARY
   LAYERS MAY PROMOTE A THREAT OF ISOLATED DAMAGING WIND. SOME HAIL MAY
   ALSO BE POSSIBLE. EXPECTED LIMITED LOW LEVEL MOISTURE AND
   UNCERTAINTIES REGARDING THE TIMING AND LANDFALL LOCATION OF THE
   SHORTWAVE TROUGH SUGGEST ONLY LOW PROBABILITIES ARE WARRANTED AT
   THIS TIME.
   
   ..DIAL.. 05/25/2005
   
   ...NOTICE...
   THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
   SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
   WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
   IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
   CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
   WILL PROVIDE DETAILS ON THE TRANSITION.
   
   CLICK TO GET WUUS03 PTSDY3 PRODUCT

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z