SPC AC 210605
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1205 AM CST MON FEB 21 2005
   
   VALID 211200Z - 221200Z
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 S UKI 30 SSW RBL
   40 ESE RBL 55 WNW BIH 35 NNW NID 65 SSW LAS 30 E IGM 30 WNW PHX 60
   SSW GBN.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 ESE JAX 45 WNW CTY
   ...CONT... 10 WNW BVE LCH 20 NNE PSX 25 WNW VCT 30 SE SAT 35 WSW AUS
   65 SW TYR 35 ESE PRX 35 ENE FSM 35 SW JLN 30 NNW SGF 45 ESE VIH 15
   WNW EVV 20 E SDF 30 NNE HTS 50 WSW EKN 10 NW SHD 25 SSW DCA 15 ENE
   SBY.
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   SPLIT FLOW PATTERN ALOFT IS FORECAST ACROSS THE HALF OF THE CONUS
   THIS PERIOD...WITH STRONG VORT MAX INITIALLY OVER OK / SRN KS
   FORECAST TO MOVE RAPIDLY ENEWD BUT WEAKEN AS IT MOVES THROUGH
   CONFLUENT FLOW.  MEANWHILE UPPER LOW MOVES SEWD ALONG THE CA COAST
   THROUGH THE PERIOD.  
   
   AT THE SURFACE...COLD FRONT IS FORECAST TO EXTEND INITIALLY FROM THE
   LOWER GREAT LAKES WSWWD ALONG THE OH VALLEY INTO OK.  WHILE NRN
   PORTION OF THIS BOUNDARY SHOULD MOVE RAPIDLY EWD AND OFF THE
   MID-ATLANTIC COAST BY AFTERNOON AHEAD OF UPPER VORT MAX...THE REST
   OF THE ROUGHLY W-E FRONTAL ZONE WILL MOVE SLOWLY SWD WITH TIME.  BY
   LATE IN THE PERIOD...FRONT SHOULD EXTEND FROM THE CAROLINAS WWD
   ACROSS NRN PORTIONS OF THE GULF COAST STATES AND INTO NRN / CENTRAL
   TX.
   
   ...UPPER TX COAST / E TX ENEWD ACROSS THE LOWER MS / TN VALLEYS...
   COLD FRONT IS FORECAST ACROSS NRN PORTIONS OF THIS REGION -- FROM
   ROUGHLY THE RED RIVER VALLEY INTO THE TN VALLEY -- AT THE START OF
   THE PERIOD.  THUNDERSTORMS WILL LIKELY BE ONGOING ALONG THIS FRONTAL
   ZONE...FROM PARTS OF AR EWD ACROSS THE TN VALLEY...WITH A FEW STORMS
   POSSIBLY SEVERE.  HOWEVER...WITH FRONT FORECAST TO MAKE LITTLE SWD
   PROGRESS WITH TIME...WIDESPREAD PRECIPITATION INVOF FRONTAL ZONE /
   AHEAD OF UPPER VORT MAX SHOULD LIMIT POTENTIAL FOR HEATING /
   DESTABILIZATION DURING THE DAY.  THEREFORE...EXPECT THAT THREAT FOR
   HAIL / LOCALLY DAMAGING WINDS SHOULD REMAIN LIMITED THROUGH THE
   PERIOD ACROSS THIS PART OF THE REGION. 
   
   FARTHER S -- FROM E TX ACROSS THE GULF COAST STATES... SLY COMPONENT
   OF LOW-LEVEL FLOW WILL ADVECT MID 60S DEWPOINTS NWD ACROSS MUCH OF
   THIS REGION CONTRIBUTING TO THE DEVELOPMENT OF 1000 TO 2000 J/KG
   MEAN-LAYER CAPE DURING THE AFTERNOON.  HOWEVER... MINIMAL LOW-LEVEL
   CONVERGENCE ANTICIPATED S OF SURFACE FRONT AND FORECAST LACK OF ANY
   SIGNIFICANT FEATURE ALOFT SUGGEST THAT WIDESPREAD / ORGANIZED
   CONVECTIVE DEVELOPMENT WILL BE UNLIKELY.  
   
   NONETHELESS...DEGREE OF MOISTURE / INSTABILITY WILL LIKELY SUPPORT
   SCATTERED CONVECTIVE DEVELOPMENT ALONG MESOSCALE LOW-LEVEL
   BOUNDARIES.  WITH STRENGTH OF UPPER FLOW / DEEP SHEAR SUPPORTIVE OF
   STORM ORGANIZATION...A FEW SEVERE STORMS WILL LIKELY EVOLVE WITHIN
   THIS REGION.  OVERALL COVERAGE OF POSSIBLE SEVERE WEATHER SHOULD
   REMAIN LIMITED HOWEVER...SO WILL MAINTAIN ONLY LOW-PROBABILITY
   SEVERE THREAT OVER THE ENTIRE AREA.
   
   ...SRN CA...
   LARGE UPPER LOW IS FORECAST TO MOVE SEWD ALONG THE CA COAST THIS
   PERIOD...WITH MODERATELY-STRONG / DIFFLUENT SWLY FLOW ALOFT FORECAST
   ACROSS SRN CA DURING THE AFTERNOON WITHIN SERN QUADRANT OF THE LOW. 
   
   
   THOUGH DESTABILIZATION SHOULD REMAIN LIMITED...LOW-LEVEL CONVERGENCE
   / UPSLOPE FLOW COMBINED WITH UPPER DIFFLUENCE WILL BE SUPPORTIVE OF
   THUNDERSTORMS -- PARTICULARLY ACROSS COASTAL PORTIONS OF SRN CA
   DURING THE AFTERNOON.  DEEP-LAYER SHEAR SHOULD BE SUFFICIENT FOR
   SEVERE STORMS...WITH THE MAIN QUESTION ATTM BEING POTENTIAL FOR
   DESTABILIZATION WITHIN WHAT COULD BE AN AREA OF WIDESPREAD CLOUDS /
   PRECIPITATION.
   
   WILL MAINTAIN A LOW-PROBABILITY THREAT FOR HAIL / DAMAGING WINDS AND
   PERHAPS A TORNADO OR TWO...WITH UPGRADE TO SLIGHT RISK POSSIBLE IN
   LATER FORECASTS ONCE EVOLUTION OF AIRMASS BECOMES MORE CLEAR.
   
   FURTHER N...HAVE ADDED A LOW-PROBABILITY HAIL THREAT INTO THE
   CENTRAL VALLEY...AS IT APPEARS THAT DRY SLOT MAY OVERSPREAD THIS
   REGION ALLOWING SOME HEATING / DESTABILIZATION.  THOUGH SHEAR SHOULD
   REMAIN MUCH WEAKER ACROSS THIS AREA...COLD TEMPERATURES ALOFT WOULD
   SUPPORT A MARGINAL HAIL THREAT SHOULD SUFFICIENT INSTABILITY
   DEVELOP.
   
   ..GOSS.. 02/21/2005
   
   ...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 BY 1300Z