SPC AC 200842
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0342 AM CDT MON SEP 20 2004
   
   VALID 221200Z - 231200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   LINGERING UPPER TROUGH OVER THE GRT BASIN EXPECTED TO EJECT NE
   ACROSS THE CNTRL PLNS ON WEDNESDAY AS WLY FLOW ALOFT CONTINUES TO
   INCREASE OVER THE NE PACIFIC/WRN CANADA AND THE PACIFIC NW. 
   CONSIDERABLE UNCERTAINTY EXISTS...HOWEVER...IN THE GUIDANCE
   REGARDING THE TIMING OF THIS EJECTION...WITH THE SELF-CONSISTENT
   ECMWF CONTINUING TO BE THE MOST PROGRESSIVE RELATIVE TO THE ETA/GFS
   CMC AND UKMET.
   
   AT THE SURFACE...PATTERN WILL BE DOMINATED BY STRONG ANTICYCLONES
   CENTERED OVER THE CNTRL APLCNS AND THE CNTRL RCKYS.  BETWEEN THE TWO
   RIDGES...STATIONARY FRONT LEFT FROM DAY TWO OVER PARTS OF THE SRN/
   CNTRL PLNS SHOULD BEGIN TO ACCELERATE E/SE AS UPPER SYSTEM BEGINS TO
   MOVE EWD.
   
   ...SRN HI PLNS...
   SIMILAR TO THE PATTERN ON TUESDAY...SETUP SHOULD ONCE AGAIN SUPPORT
   SCATTERED MAINLY DIURNAL STORMS ALONG/AHEAD OF COLD FRONT CROSSING
   PARTS OF NM AND W TX ON WEDNESDAY.  REGARDLESS OF THE TIMING OF THE
   EJECTING TROUGH...EXPECT THAT ANY ASSOCIATED LARGE SCALE FORCING FOR
   ASCENT WILL TRACK WELL N OF THE REGION.  IN ADDITION...PERSISTENT
   SURFACE RIDGE WILL CONTINUE TO INHIBIT LARGE SCALE MOISTURE
   TRANSPORT INTO REGION FROM THE GULF OF MEXICO. NEVERTHELESS...A
   MODEST AMOUNT OF BOUNDARY LAYER MOISTURE /SURFACE DEWPOINTS IN THE
   UPPER 50S TO LOW 60S/ SHOULD REMAIN PRESENT GIVEN WEAK SELY LOW
   LEVEL FLOW ON SWRN FLANK OF RIDGE.
   
   UPSLOPE FLOW AND SURFACE HEATING SHOULD ONCE AGAIN SUPPORT AFTERNOON
   STORM DEVELOPMENT OVER THE HIGHER TERRAIN OF CNTRL/ERN NM...AND
   PERHAPS ALONG COLD FRONT IN W TX.  30 KT MID LEVEL WSWLY FLOW
   FLANKING BASE OF UPPER TROUGH WILL CONTRIBUTE TO SUFFICIENT DEEP
   SHEAR FOR A FEW ORGANIZED/SUSTAINED CELLS...AND SURFACE HEATING
   SHOULD BOOST MLCAPE TO AOA 500 J/KG.  A FEW STORMS COULD YIELD
   LOCALLY DAMAGING WIND AND HAIL...BUT GIVEN RELATIVELY WEAK
   INSTABILITY AND LARGE SCALE FORCING FOR ASCENT...OVERALL THREAT WILL
   PROBABLY REMAIN LIMITED IN SCOPE/DURATION.
   
   ..CORFIDI.. 09/20/2004
   
   ...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 3 OUTLOOK IS SCHEDULED FOR 1100Z