Dec 30, 2010 0600 UTC Day 1 Convective Outlook
Updated: Thu Dec 30 05:58:45 UTC 2010
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20101230 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20101230 1200 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20101230 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20101230 1200 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 300555
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1155 PM CST WED DEC 29 2010
   
   VALID 301200Z - 311200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   AMPLIFICATION OF THE LARGE-SCALE UPPER FLOW PATTERN IS NOW UNDERWAY
   ACROSS THE U.S...WITH A SERIES OF DIGGING SHORT WAVE IMPULSES
   CONTRIBUTING TO THE EVOLUTION OF AN UPPER TROUGH ACROSS THE PACIFIC
   COAST STATES/INTERMOUNTAIN WEST AND ROCKIES...WHILE RIDGING BEGINS
   TO BUILD ACROSS THE EASTERN STATES.  A DEEP SURFACE TROUGH HAS
   ALREADY DEVELOPED TO THE LEE OF ROCKIES...AND ONE SIGNIFICANT LOW
   CENTER IS PROGGED TO LIFT OUT OF THE PLAINS THROUGH THE UPPER
   MISSISSIPPI VALLEY DURING THE DAY TODAY...IN ASSOCIATION WITH ONE
   IMPULSE EMERGING FROM THE WESTERN TROUGH.  MODELS SUGGEST THAT
   ANOTHER DEEP LOW CENTER WILL THEN FORM ACROSS THE SOUTH CENTRAL HIGH
   PLAINS LATE THIS AFTERNOON AND EVENING... BEFORE TURNING EASTWARD
   INTO THE CENTRAL PLAINS TONIGHT...AS A MUCH STRONGER IMPULSE
   MIGRATES THROUGH THE BASE OF THE UPSTREAM TROUGH.
   
   THIS LATTER FEATURE APPEARS LIKELY TO BE ACCOMPANIED BY THE
   DEVELOPMENT OF A CYCLONIC 100+ KT 500 MB JET STREAK ACROSS NORTHWEST
   TEXAS AND WESTERN OKLAHOMA BY 12Z FRIDAY.  WHILE THE CORE OF
   STRONGEST MID-LEVEL COOLING AND FORCING FOR UPWARD VERTICAL MOTION
   NOSES THROUGH THE CENTRAL HIGH PLAINS LATE TONIGHT/EARLY
   FRIDAY...THE DEEPER RETURN FLOW OF MOISTURE OFF THE GULF OF MEXICO
   IS PROGGED TO BE FOCUSED NEAR A 40-50+ KT SOUTHERLY 850 MB JET
   ACROSS THE LOWER MISSISSIPPI VALLEY.  WEAK FORCING IN THE MOIST
   SECTOR...COUPLED WITH THE PRESENCE OF CAPPING ELEVATED WARM
   LAYERS...PROBABLY WILL INHIBIT CONVECTIVE DEVELOPMENT THROUGH MUCH
   OF THE FIRST HALF OF THE PERIOD...AND POSSIBLY WELL INTO TONIGHT. 
   HOWEVER...THE RISK FOR THUNDERSTORMS SHOULD INCREASE BY LATE TONIGHT
   ACROSS PARTS OF THE SOUTHEASTERN PLAINS OR LOWER/MIDDLE MISSISSIPPI
   VALLEY.
   
   ...PLAINS/MISSISSIPPI VALLEY...
   THERE ARE INDICATIONS THAT FORCING ASSOCIATED WITH AN EASTWARD COLD
   FRONTAL SURGE INTO THE SOUTHEASTERN PLAINS COULD BE ACCOMPANIED BY
   THE DEVELOPMENT OF THUNDERSTORMS TOWARD 12Z FRIDAY.  HOWEVER...A
   PRE-FRONTAL CONFLUENCE ZONE ASSOCIATED WITH THE LOW-LEVEL JET SEEMS
   TO PROVIDE AT LEAST A SOMEWHAT MORE LIKELY FOCUS FOR THE INITIATION
   OF STORMS...A BIT FARTHER TO THE EAST...AND PERHAPS AS EARLY AS LATE
   EVENING...ACROSS PARTS OF EAST TEXAS INTO WESTERN/CENTRAL ARKANSAS
   AND SOUTHERN MISSOURI.  UPPER FLOW IS EXPECTED TO BECOME
   INCREASINGLY DIFLUENT AND AT LEAST WEAKLY DIVERGENT...WITH WEAK
   COOLING ALSO POSSIBLE AT MID-LEVELS.  ONCE INHIBITION IS
   OVERCOME...IN THE PRESENCE OF STRONG LOW-LEVEL AND DEEP LAYER
   SHEAR...PROBABILITIES FOR SEVERE STORMS WILL EXIST.  HOWEVER...THESE
   PROBABILITIES STILL SEEM TOO LOW FOR A CATEGORICAL SLIGHT RISK...DUE
   TO RELATIVELY WEAK MID-LEVEL LAPSE RATES...AND THE WEAK NATURE OF
   THE CAPE...EVEN FOR POSSIBLE SURFACE OR NEAR SURFACE BASED STORM
   ACTIVITY.
   
   ..KERR/HURLBUT.. 12/30/2010
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z