Oct 11, 2012 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Thu Oct 11 07:30:44 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20121011 0730 UTC Day 3 Outlook Graphic
Probabilistic Graphic
20121011 0730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
   SPC AC 110728
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0228 AM CDT THU OCT 11 2012
   
   VALID 131200Z - 141200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SAT INTO SAT NIGHT ACROSS PARTS
   OF THE MID/UPPER MISSISSIPPI VALLEY INTO THE UPPER GREAT
   LAKES...SOUTHWARD INTO THE SOUTHERN PLAINS...
   
   ...SYNOPSIS...
   MODELS INDICATE THAT SPLIT BELTS OF STRONGER WESTERLIES WILL BEGIN
   TO CONSOLIDATE ACROSS NORTH AMERICA DURING THIS FORECAST PERIOD...AS
   THE REMNANT SOUTHERN STREAM CLOSED LOW CONTINUES ITS EAST
   NORTHEASTWARD ACCELERATION OUT OF THE SOUTHWEST.  VARIABILITY IS
   INCREASING AMONG THE MODEL DATA CONCERNING THE EVOLUTION OF THIS
   FEATURE...FROM WHICH A COUPLE OF MORE DISTINCT SMALLER SCALE
   IMPULSES COULD EMERGE AS IT PROGRESSES EAST OF THE ROCKIES INTO THE
   PLAINS/MISSISSIPPI VALLEY REGION.  NAM/SREF APPEAR TO MAINTAIN THE
   INITIAL CIRCULATION FORECAST TO REACH THE CENTRAL HIGH PLAINS BY 12Z
   SATURDAY AS THE PRIMARY UPPER IMPULSE...AND ACCELERATE IT EASTWARD
   INTO THE UPPER GREAT LAKES BY 12Z SUNDAY...MUCH AS GENERALLY HAS
   BEEN INDICATED BY MEDIUM RANGE GUIDANCE THE PAST FEW DAYS. 
   HOWEVER...THE GFS SUGGESTS THAT A DISTINCT SECONDARY
   IMPULSE...TRAILING TO THE SOUTHWEST...MAY BECOME THE MORE PROMINENT
   IMPULSE SATURDAY...AS IT LIFTS EAST OF THE SOUTHERN ROCKIES...ACROSS
   THE SOUTH CENTRAL HIGH PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY. 
   ECMWF ALSO NOW IS MORE SUGGESTIVE THAT STRONGER MID-LEVEL FORCING
   MAY DEVELOP SOUTH OF THE INITIAL IMPULSE...BUT NORTH OF THAT OF THE
   GFS.
   
   REGARDLESS...ALL GUIDANCE INDICATES THE CONTINUED DEVELOPMENT OF A
   SUB-1000 MB SURFACE LOW...GENERALLY EAST OF THE MIDDLE MISSOURI
   VALLEY TOWARD THE GREAT LAKES REGION.  WITHIN THE WARM SECTOR OF
   THIS FEATURE...AND SOUTHWARD AHEAD OF THE TRAILING COLD FRONT/DRY
   LINE ADVANCING EASTWARD THROUGH THE SOUTHERN PLAINS...A BROAD
   SOUTHERLY 850 MB JET IS FORECAST TO STRENGTHEN FROM 50-70
   KT...BENEATH A 70+ KT SOUTHWESTERLY 500 MB JET.  THIS WILL
   CONTRIBUTE TO THE NORTHWARD ADVECTION OF SEASONABLY HIGH MOISTURE
   CONTENT AIR /PRECIPITABLE WATER UP AROUND 1.5+ INCHES/...WITH 60F+
   SURFACE DEW POINTS AS FAR NORTH AS PORTIONS OF THE UPPER MISSISSIPPI
   VALLEY.
   
   DESTABILIZATION SHOULD BE SUFFICIENT TO SUPPORT WIDESPREAD
   CONVECTIVE DEVELOPMENT...INCLUDING PERHAPS CONSIDERABLE POTENTIAL
   FOR SEVERE THUNDERSTORMS FROM PORTIONS OF THE UPPER MISSISSIPPI
   VALLEY SOUTHWARD THROUGH THE SOUTHERN PLAINS.
   
   ...UPPER MISSISSIPPI VALLEY INTO THE SOUTHERN PLAINS...
   GIVEN THE STRENGTH OF THE WARM SECTOR DEEP LAYER MEAN FLOW
   FIELDS/SHEAR AND FORCING FOR UPWARD VERTICAL MOTION...SEVERE
   POTENTIAL ON SATURDAY MAY ULTIMATELY BE HIGHER THAN CURRENTLY
   INDICATED BY THE SLIGHT RISK CATEGORICAL OUTLOOK.  CONDITIONS MOST
   SUPPORTIVE OF THIS POTENTIAL STILL APPEAR MOST PROBABLE TO EVOLVE
   FROM PARTS OF EASTERN NEBRASKA AND KANSAS THROUGH CENTRAL AND
   NORTHERN MISSOURI...IOWA AND ADJACENT PORTIONS OF SOUTHERN
   MINNESOTA...SOUTHWEST WISCONSIN AND NORTHWESTERN ILLINOIS. 
   HOWEVER...UNCERTAINTY LINGERS CONCERNING THE DEGREE OF WARM SECTOR
   BOUNDARY LAYER DESTABILIZATION THAT MAY OCCUR...DUE TO THE
   POSSIBILITY OF CONSIDERABLE EARLY PERIOD CONVECTION WHICH MAY SLOW
   OR INHIBIT INSOLATION.  COUPLED WITH THE AFOREMENTIONED MODEL
   VARIABILITY...TOO MUCH UNCERTAINTY STILL EXISTS FOR HIGHER SEVERE
   PROBABILITIES.  BUT A SIGNIFICANT CONVECTIVE DAMAGING WIND EVENT
   APPEARS A POSSIBILITY.  IT MAY NOT BE OUT OF THE QUESTION THAT
   CONDITIONS COULD BECOME FAVORABLE FOR TORNADIC SUPERCELLS.
   
   ..KERR.. 10/11/2012
   
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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z