SPC AC 040548
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1148 PM CST SAT APR 03 2004
   
   VALID 041200Z - 051200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 WNW
   MRF 45 SE GDP 40 NE FST 70 E FST DRT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 70 NW WMC BNO 65 ENE
   RDM 40 SSE ALW 40 SSE S80 10 NW HLN 3HT BIL 10 E WRL MLD 15 NNW EKO
   70 NW WMC.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SSE FHU GBN 10 ESE
   BLH EED 10 SW SGU 25 SSW U17 15 SE FMN 10 S SAF TCC ABI ACT 35 SW
   LFK 10 SW GLS.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 ENE SBY 10 NNE PHL
   15 NNE ABE MSV PSF EWB 30 SSE EWB.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SW TX/TX BIG
   BEND REGION....
   
   CLOSED LOW WILL REMAIN OVER THE SOUTHERN PLATEAU THROUGH THIS
   FORECAST PERIOD...CUT-OFF FROM THE STRONGER WESTERLIES.  MODELS
   SUGGEST LITTLE NET EASTWARD MOTION WILL OCCUR UNTIL...PERHAPS...LATE
   TONIGHT INTO EARLY MONDAY...AS ANOTHER SHORT WAVE TROUGH PROGRESSES
   INTO THE BRITISH COLUMBIA/PACIFIC NORTHWEST COAST.  THIS
   FEATURE...LIKE CURRENT SHORT WAVE PROGRESSING ACROSS THE CANADIAN
   ROCKIES...IS PROGGED TO WEAKEN AS IT APPROACHES MEAN UPPER RIDGE
   AXIS.  EASTWARD ACCELERATION OF SOUTHERN PLATEAU LOW APPEARS MORE
   LIKELY TO AWAIT INFLUENCE OF MORE POWERFUL UPSTREAM PACIFIC SHORT
   WAVE TROUGH...PROGGED TO APPROACH THE BRITISH COLUMBIA/PACIFIC
   NORTHWEST COAST LATER MONDAY/MONDAY NIGHT.
   
   IN THE EAST...LARGE-SCALE TROUGHING WILL PERSIST TODAY.  A COUPLE OF
   SHORT WAVE TROUGHS ARE CURRENTLY DIGGING IN THE LEE OF CANADIAN/
   NORTHERN U.S. ROCKIES UPPER RIDGE...THE MOST SIGNIFICANT OF WHICH IS
   NOW APPROACHING THE NORTHERN MID ATLANTIC COAST STATES.  MODELS
   SUGGEST BOTH SHORT WAVES WILL GRADUALLY MERGE...FORMING BROAD CLOSED
   LOW ACROSS THE NORTH ATLANTIC COAST REGION BY EARLY MONDAY.
   
   ...SOUTHERN PLATEAU/SOUTHERN ROCKIES/TEXAS...
   CONVECTIVE POTENTIAL ACROSS A LARGE PART OF CENTRAL/SOUTHERN NEW
   MEXICO AND THE SOUTHERN TEXAS PANHANDLE WILL RAPIDLY DIMINISH BY/
   SHORTLY AFTER 12Z.  THIS WILL BE DUE TO THE STABILIZATION OF LAPSE
   RATES BY WIDESPREAD ONGOING CONVECTIVE DEVELOPMENT.  WHILE RAIN
   APPEARS LIKELY TO SLOWLY DIMINISH THROUGH THE MID DAY HOURS...THICK
   CLOUD COVER WILL PERSIST...AND COOL/STABLE LOW-LEVEL ENVIRONMENT IS
   EXPECTED TO PRECLUDE FURTHER THUNDERSTORMS NORTH OF A SAN ANGELO/
   MIDLAND/CARLSBAD/HOLLOMAN AFB LINE.
   
   SUBSTANTIAL HEATING STILL APPEARS LIKELY TO OCCUR TODAY ALONG/WEST
   OF LOW-LEVEL MOIST AXIS...WHICH WILL MAINLY EXTEND WEST OF THE LOWER
   RIO GRANDE VALLEY THROUGH THE BIG BEND AREA INTO SOUTHWEST TEXAS. 
   OROGRAPHY...AND POSSIBLY TIGHTENING FRONTAL ZONE ACROSS THE FORT
   STOCKTON AREA...WILL PROVIDE FORCING FOR CONVECTIVE DEVELOPMENT IN
   ENVIRONMENT WITH MEAN MIXED LAYER CAPE UP TO AROUND 1000 J/KG. 
   SHEAR PROFILES/DIVERGENT UPPER FLOW FIELD IN EXIT REGION OF UPPER
   JET MIGRATING AROUND SOUTHERN PERIPHERY OF CLOSED LOW WILL ENHANCE
   ACTIVITY...WITH ISOLATED SUPERCELLS POSSIBLE. LARGE HAIL APPEARS TO
   BE PRIMARY THREAT.
   
   MORE UNCERTAINTY EXISTS ABOUT CONVECTIVE POTENTIAL SOUTHEASTWARD
   ALONG THE HIGHER TERRAIN WEST OF THE RIO GRANDE RIVER TOWARD THE
   BROWNSVILLE AREA.  ETA MODEL SUGGESTS WEAK SHORT WAVE MAY SUPPORT
   DEVELOPMENT DURING THE LATE AFTERNOON HOURS. HOWEVER...EVEN IF THIS
   OCCURS...INTENSE STORMS ARE EXPECTED TO WEAKEN EAST OF THE
   RIVER...IN ENVIRONMENT LESS CONDUCIVE TO VIGOROUS CONVECTION.
   
   ...NORTHERN INTERMOUNTAIN REGION...
   SOME MOISTENING HAS OCCURRED IN ASSOCIATION WITH INITIAL WEAKENING
   SHORT WAVE TROUGH...WHICH WILL CONTINUE EAST OF THE ROCKIES TODAY. 
   THIS MOISTURE...AND STRONG SURFACE HEATING...WILL CONTRIBUTE TO AT
   LEAST WEAK DESTABILIZATION BY LATE THIS AFTERNOON...WITH WIDELY
   SCATTERED THUNDERSTORMS POSSIBLE.  LOW-LEVEL WARM ADVECTION REGIME
   AND CONFLUENT LOW-LEVEL FLOW IN WAKE OF INITIAL SHORT WAVE WILL
   PROVIDE FOCUS FOR ACTIVITY...FROM PARTS OF EASTERN OREGON INTO
   SOUTHWEST MONTANA.
   
   ...NORTHERN MID ATLANTIC COAST STATES...
   MODELS INDICATE STRONG FORCING FOR UPWARD VERTICAL MOTION DEVELOPING
   NEAR/JUST EAST OF DEEPENING SURFACE LOW...WHICH IS  PROGGED TO
   MIGRATE FROM EASTERN PENNSYLVANIA THROUGH THE LONG ISLAND AREA FROM
   04/12-18Z.  LOW-LEVEL ENVIRONMENT ACROSS THIS REGION IS MOIST...AND
   WHILE NOT PARTICULARLY WARM...LAPSE RATES ARE PROGGED TO STEEPEN
   SUFFICIENTLY FOR CONVECTIVE DEVELOPMENT.  DUE TO VERY WEAK
   CAPE...CONVECTION WILL BE RELATIVELY SHALLOW... BUT FORECAST
   SOUNDINGS SUGGEST THERMODYNAMIC PROFILES MAY BECOME SUFFICIENT FOR
   AT LEAST SCATTERED WEAK THUNDERSTORM ACTIVITY.
   
   ..KERR/CROSBIE.. 04/04/2004
   
   ...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 1300Z