SPC AC 080611
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1211 AM CST SUN MAR 08 2009
   
   VALID 091200Z - 101200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE SOUTHERN
   PLAINS...
   
   ...SYNOPSIS...
   A MEAN LONGWAVE TROUGH WILL PERSIST OVER THE WESTERN HALF OF THE
   CONUS THROUGH MONDAY. WITHIN THIS LONGWAVE TROUGH...THE PRIMARY
   FEATURE OF NOTE WILL BE A BROAD UPPER TROUGH TRANSITIONING EASTWARD
   OVER THE INTERMOUNTAIN WEST/ROCKIES...WITH A SOUTHERN
   SPLIT/SUBTROPICAL STREAM FROM BAJA/NORTHERN MEXICO TO THE MIDWEST.
   
   ...SOUTHERN PLAINS...
   MASS FIELDS ACROSS THE SOUTHERN PLAINS WILL BEGIN TO RESPOND TO THE
   APPROACHING WESTERN STATES TROUGH ON MONDAY...WITH LEE SIDE
   CYCLOGENESIS ACROSS THE SOUTH CENTRAL HIGH PLAINS AND A STEADY
   NORTH-NORTHWESTWARD RETURN OF A SURFACE WARM/MOIST SECTOR ACROSS
   PORTIONS OF NORTH TX/OK INTO KS/MO. WHILE LARGE SCALE HEIGHT FALLS
   WILL REMAIN LIMITED ACROSS THE EXPANDING MOIST SECTOR ACROSS
   TX/OK/KS DURING THE DAY...A SOUTHERN/SUBTROPICAL STREAM SHORTWAVE
   TROUGH/POTENTIAL SPEED MAX SHOULD CONTRIBUTE TO TSTM DEVELOPMENT
   DURING THE AFTERNOON...ALTHOUGH CONSIDERABLE SHORT TERM TIMING
   VARIABILITY EXISTS IN THE 00Z BASED NUMERICAL GUIDANCE.
   REGARDLESS...SUCH DEVELOPMENT WOULD BE MOST LIKELY INITIALLY ACROSS
   PORTIONS OF OK/NORTH TX ALONG/AHEAD OF A PROGRESSIVELY ESTABLISHED
   SURFACE LOW/DRYLINE.
   
   ASIDE FROM THE AFOREMENTIONED SHORTWAVE TROUGH TIMING...THE SEVERE
   SCENARIO IS FURTHER COMPLICATED BY THE POSSIBILITY OF AN EXPANSIVE
   CIRRUS CANOPY DURING THE AFTERNOON...AND ACCORDINGLY MID LEVEL LAPSE
   RATES WILL NOT BE PARTICULARLY STEEP BENEATH THE SUBTROPICAL PLUME.
   AROUND 60F SURFACE DEWPOINTS IN THE PREFRONTAL/DRYLINE WARM SECTOR
   MAY SUPPORT MLCAPE VALUES TO AROUND 750-1000 J/KG PROVIDED
   SUFFICIENT HEATING...ALTHOUGH MARGINAL MOISTURE QUALITY WILL BE
   CONDUCIVE FOR MIXING ESPECIALLY ACROSS TX. GIVEN SUFFICIENT
   HEATING/FAVORABLE TIMING OF UPPER FORCING GLANCING THE WARM
   SECTOR...RATHER FAVORABLE SHEAR PROFILES BENEATH 50-60 KT MID LEVEL
   FLOW WOULD SUPPORT SUPERCELLS WITH AN ASSOCIATED SEVERE RISK MONDAY
   AFTERNOON/EVENING.
   
   ...LOWER/MIDDLE MISSOURI VALLEY AND MIDWEST MONDAY NIGHT...
   AS THE UPSTREAM UPPER TROUGH APPROACHES THE CENTRAL HIGH PLAINS LATE
   MONDAY NIGHT...THE PASSING CENTRAL STATES LEAD SHORTWAVE TROUGH AND
   A STRENGTHENING SOUTHWESTERLY LOW LEVEL JET /50+ KT/ WILL LIKELY
   LEAD TO A NOCTURNAL INCREASE/NORTHEASTWARD EXPANSION OF TSTMS ACROSS
   THE REGION ALONG/NORTH OF A RETREATING WARM FRONT. AS A
   MOIST/UNSTABLE ELEVATED AIRMASS ADVECTS NORTHEASTWARD TOWARD THE
   REGION...AT LEAST AN ISOLATED HAIL THREAT WILL EXIST MONDAY NIGHT.
   IF ELEVATED INSTABILITY PROVES STRONGER THAN CURRENT
   EXPECTED...PORTIONS OF MO/IL/SOUTHERN IA COULD EVENTUALLY WARRANT AN
   UPGRADE TO A CATEGORICAL SLIGHT RISK FOR PRIMARILY A HAIL THREAT.
   
   ..GUYER.. 03/08/2009
   
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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z