SPC AC 301221
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0621 AM CST FRI JAN 30 2004
   
   VALID 301300Z - 311200Z
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM DRT 45 SW ALI 15 E
   ALI 35 NNE PSX 35 ENE HOU 20 ESE LCH 40 WNW HUM 25 SE BVE.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 W CLM 50 WSW PDT
   MSO 40 S GTF LVM 20 SSE JAC 35 S TWF 70 WNW WMC 25 SE MHS 15 S CEC.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 WNW FMY 20 NNE
   PBI.
   
   ...NO SVR TSTM AREAS FORECAST...
   
   A SPLIT IN THE LARGE-SCALE UPPER FLOW PATTERN WILL PERSIST THROUGH
   THIS FORECAST PERIOD ACROSS THE EAST CENTRAL PACIFIC...WITH A COUPLE
   DISTINCT BELTS OF STRONGER FLOW EXTENDING EASTWARD ACROSS THE
   INTERMOUNTAIN WEST/ROCKIES...AND PLAINS.  BELTS CURRENTLY MERGE OVER
   THE MID/LOWER MISSISSIPPI VALLEY...BUT MODELS SUGGEST THAT THIS
   CONFLUENCE WILL SHIFT EASTWARD ACROSS THE APPALACHIANS INTO THE
   MID/SOUTH ATLANTIC COAST STATES BY LATE TONIGHT.  THIS WILL OCCUR IN
   RESPONSE TO THE EASTWARD PROGRESSION OF A COUPLE OF UPSTREAM SHORT
   WAVE TROUGHS...ONE IN THE SOUTHERN BRANCH...THE OTHER IN THE
   NORTHERN BRANCH.
   
   THE SOUTHERN BRANCH TROUGH...NOW OVER TEXAS AND THE NORTHERN MEXICAN
   PLATEAU...WILL CONTINUE EASTWARD ACROSS SOUTHEAST TEXAS AND THE
   LOWER RIO GRANDE VALLEY TODAY. MODELS INDICATE POSITIVELY TILTED
   SYSTEM WILL TAKE ON INCREASINGLY NEUTRAL TILT TONIGHT...AS UPSTREAM
   NORTHERN BRANCH TROUGH DIGS FROM THE NORTHERN PACIFIC COAST INTO THE
   ROCKIES.
   
   IN RESPONSE TO EVOLVING UPPER FLOW REGIME...A SURFACE RIDGE WILL
   REDEVELOP SOUTHEASTWARD FROM THE NORTHERN PLAINS INTO THE OHIO
   VALLEY TODAY.  LEADING EDGE OF COLD AIR ASSOCIATED WITH THIS FEATURE
   WILL SURGE THROUGH MUCH OF THE GULF COAST SATES ...REINFORCING
   PREVIOUS COLD FRONT...WHICH NOW EXTENDS NEAR/SOUTH OF THE FLORIDA
   KEYS INTO THE VICINITY OF A  DEVELOPING SURFACE LOW OVER THE WESTERN
   GULF OF MEXICO.  THUS...ENVIRONMENT WILL REMAIN STABLY STRATIFIED
   ACROSS MUCH OF THE NATION EAST OF THE ROCKIES...AND CONVECTIVE
   POTENTIAL QUITE LOW THROUGH AT LEAST EARLY SATURDAY.
   
   ...GULF OF MEXICO/GULF COAST STATES...
   THUNDERSTORM ACTIVITY IS ONGOING IN SEVERAL CLUSTERS ACROSS THE
   WESTERN GULF OF MEXICO...WHERE BOUNDARY LAYER HAS WARMED/MOISTENED
   AND DESTABILIZED.  CONVECTION MAY CONSOLIDATE INTO ONE LARGE
   CONVECTIVE CLUSTER DURING THE DAY TODAY...AIDED BY DIVERGENT UPPER
   FLOW FIELD IN RIGHT ENTRANCE REGION OF HIGH-LEVEL JET STREAK...
   DOWNSTREAM OF SOUTHERN BRANCH TROUGH.  THIS CONVECTION WILL SLOWLY
   DEVELOP EASTWARD ACROSS THE GULF OF MEXICO...WITH ADDITIONAL
   THUNDERSTORMS POSSIBLE IN MOISTENING AIR MASS NEAR/JUST NORTH OF
   SURFACE FRONT ACROSS THE SOUTHERN FLORIDA PENINSULA/FLORIDA KEYS.
   
   VERTICAL SHEAR PROFILES ACROSS SOUTHERN FLORIDA WILL BE MORE THAN
   SUFFICIENT FOR SUPERCELLS...PRIMARILY DUE TO STRENGTH OF
   MID/HIGH-LEVEL FLOW.  HOWEVER...GIVEN RELATIVELY WEAK LOW-LEVEL
   FLOW...MOIST ENVIRONMENT WITH WEAK LOW/MID-LEVEL LAPSE RATES DOES
   NOT APPEAR LIKELY TO BECOME SUPPORTIVE OF AN APPRECIABLE SEVERE
   THREAT.
   
   IN CLOSER PROXIMITY TO SOUTHERN BRANCH SHORT WAVE TROUGH AND
   ASSOCIATED MID-LEVEL COLD POOL...PRIMARY CONVECTIVE POTENTIAL DURING
   THE DAY APPEARS TO EXIST IN UPSLOPE LOW-LEVEL FLOW REGIME NEAR
   HIGHER TERRAIN SOUTH/WEST OF THE RIO GRANDE RIVER.  CONVECTION IS
   POSSIBLE ACROSS DEEP SOUTH TEXAS LATE THIS AFTERNOON AND NEAR TEXAS
   COASTAL AREAS THIS EVENING...BUT ANY ACTIVITY SHOULD BE VERY
   ISOLATED.  LATEST MODELS CONTINUE TO SUGGEST BETTER LARGE-SCALE
   FORCING FOR UPWARD VERTICAL MOTION WILL REMAIN NEAR SURFACE LOW WELL
   EAST OF COASTAL AREAS THROUGH THE FORECAST PERIOD.
   
   ...PACIFIC NORTHWEST INTO NORTHERN INTERMOUNTAIN REGION...
   VERY COLD MID-LEVEL AIR MASS WILL ACCOMPANY UPPER TROUGH AS IT
   PROGRESSES INLAND...WITH 500 MB TEMPERATURES AT OR BELOW -30C AT
   CORE OF COLD POOL.  SCATTERED THUNDERSTORMS DEVELOPED NEAR THE
   SOUTHERN OREGON COAST EARLIER THIS MORNING...ALONG LEADING EDGE OF
   MID-LEVEL COOLING IN EXIT REGION OF UPPER JET STREAK.  THIS FORCING
   IS PROGGED TO SPREAD IN SWATH ACROSS EASTERN OREGON INTO THE
   MOUNTAINS OF SOUTHWEST MONTANA BY LATE AFTERNOON...AND DAYTIME
   HEATING WILL CONTRIBUTE TO POTENTIAL FOR OCCASIONAL ADDITIONAL
   THUNDERSTORM ACTIVITY. OTHERWISE...ANOTHER JET STREAK DIGGING
   ACROSS THE NORTH CENTRAL PACIFIC COAST LATER THIS AFTERNOON AND
   EVENING MAY SUPPORT A FEW MORE WEAK THUNDERSTORMS WEST OF THE
   CASCADES.
   
   ..KERR.. 01/30/2004
   
   ...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 1630Z