THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN AND TONIGHT ACROSS PARTS OF THE NRN PLAINS/UPPER MS VALLEY INTO THE UPPER GREAT LAKES

Categorical Graphic
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.

   SPC AC 021943
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0243 PM CDT MON JUL 02 2012
   
   VALID 022000Z - 031200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN AND TONIGHT

   ACROSS PARTS OF THE NRN PLAINS/UPPER MS VALLEY INTO THE UPPER GREAT

   LAKES...
   
   ...20Z OUTLOOK UPDATE...
   NO SIGNIFICANT CHANGES HAVE BEEN MADE...ONLY A MINOR TWEAK TO 5
   PERCENT SEVERE PROBABILITY LINES TO ENCOMPASS A SLIGHTLY GREATER
   PORTION OF THE MIDDLE MISSISSIPPI VALLEY...WHERE DAYTIME HEATING HAS
   CONTRIBUTED TO STRONG INSTABILITY...AND CONVECTIVE DEVELOPMENT IS
   NOW UNDERWAY.  THE SEVERE THREAT ACROSS MUCH OF THE MIDDLE
   MISSISSIPPI VALLEY INTO THE SOUTHEAST STILL APPEARS LIMITED TO
   RELATIVELY LOCALIZED DOWNBURSTS...AND PERHAPS SOME HAIL IN SHORT-
   LIVED STRONGER UPDRAFT PULSES.
   
   SEVERE WEATHER POTENTIAL ACROSS PARTS OF THE EASTERN DAKOTAS INTO
   UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES REGION REMAINS THE
   PRIMARY CONCERN LATE THIS AFTERNOON INTO TONIGHT.  THERMODYNAMIC
   PROFILES ACROSS THIS REGION ARE CHARACTERIZED BY HIGH MOISTURE
   CONTENT IN LOW-LEVELS...STEEP MID-LEVEL LAPSE RATES...AND LARGE
   CAPE.  DEEP LAYER MEAN FLOW IS STILL SOMEWHAT WEAK...GENERALLY LESS
   THAN 30 KT...AS THE MAIN SHORT WAVE TROUGH WITHIN THE STRONGER
   WESTERLIES LIFTS NORTH OF THE CANADIAN/U.S. BORDER AREA...THROUGH
   MANITOBA.  HOWEVER...A WEAKER IMPULSE...OF EITHER SUBTROPICAL OR
   TROPICAL ORIGINS...IS IN THE PROCESS OF LIFTING THROUGH THE CENTRAL
   DAKOTAS...AND COULD CONTRIBUTE TO FORCING FOR UPWARD VERTICAL MOTION
   WITHIN A LINGERING LOWER/MID TROPOSPHERIC WARM ADVECTION REGIME
   ACROSS THE EASTERN DAKOTAS INTO WESTERN MINNESOTA LATE THIS
   AFTERNOON.  GUIDANCE REMAINS SUGGESTIVE THAT INHIBITION
   ...ASSOCIATED WITH VERY WARM ELEVATED MIXED LAYER AIR THAT REMAINS
   PRESENT ACROSS THIS REGION...WILL WEAKEN...WITH A CONSIDERABLE
   INCREASE IN STORM COVERAGE AND UPSCALE CONVECTIVE GROWTH.
   
   STRENGTHENING AND CONSOLIDATING COLD POOLS MAY BE ACCOMPANIED BY THE
   EVOLUTION OF AN ORGANIZED MESOSCALE CONVECTIVE SYSTEM THAT SHOULD
   TEND TO FORWARD PROPAGATE...EAST SOUTHEASTWARD INTO PARTS OF THE
   UPPER PENINSULA OF MICHIGAN AND NORTHERN WISCONSIN TONIGHT. 
   RESIDUAL BOUNDARY LAYER INSTABILITY...COUPLED WITH SOME
   STRENGTHENING OF LOWER/MID TROPOSPHERIC WIND FIELDS...PROBABLY WILL
   BE SUFFICIENT TO MAINTAIN A RISK FOR DAMAGING WINDS AND SOME HAIL
   OVERNIGHT.
   
   ..KERR.. 07/02/2012
   
   .PREV DISCUSSION... /ISSUED 1113 AM CDT MON JUL 02 2012/
   
   ...ERN ND/FAR NERN SD INTO UPR GRTLKS...
   LATE MORNING OBSERVATIONS SHOW A RESERVOIR OF LWR 70F SFC DEW POINTS
   SITUATED BENEATH LAPSE RATES IN EXCESS OF 7-9 DEG C PER KM FROM ERN
   ND SEWD INTO THE UPR MS VLY.  UNINHIBITED AFTN HEATING WILL
   THEREFORE SET THE STAGE FOR MLCAPE VALUES APPROACHING 3000-4000
   J/KG.  
   
   ALTHOUGH THERE REMAINS UNCERTAINTY AMONG DETERMINISTIC...ENSEMBLE
   AND CONVECTION ALLOWING MODELS...THE ELEVATED TSTM CLUSTER OF
   CNTRL/NRN ND SHOULD CONTINUE EWD TOWARD NRN MN THROUGH MID-AFTN.  AS
   DOWNSTREAM INHIBITION CONTINUES TO WEAKEN...STORMS SHOULD BECOME
   MORE SFC-BASED.  DEEP LAYER SHEAR OF 35-40 KTS AND MAGNITUDE OF
   LAPSE RATES SUGGEST INITIAL STORMS COULD EVOLVE INTO SUPERCELLS WITH
   VERY LARGE HAIL AND PERHAPS A TORNADO.  EVENTUALLY...AS COLD POOLS
   CONGLOMERATE...A BOW ECHO MAY EVOLVE AND ACCELERATE ESE ACROSS NRN
   AND CNTRL PARTS OF MN BY EVENING...ALTHOUGH CONFIDENCE IN THIS
   SCENARIO IS SOMEWHAT LIMITED.  IF THE MODE INDEED DEVELOPS IN THIS
   MANNER...STORMS COULD REACH PARTS OF CNTRL/NRN WI AND UPR MI BY LATE
   THIS EVENING WITH AN ATTENDANT RISK OF SIGNIFICANT DMGG WIND GUSTS. 
   IT IS POSSIBLE THAT A PORTION OF THE SLIGHT RISK AREA
   COULD BE UPGRADED TO A MODERATE RISK IN LATER D1 UPDATES.
   
   ...CNTRL/ERN SD INTO THE CNTRL HIGH PLAINS...
   ISOLD TO WDLY SCTD TSTMS WILL BE PSBL ALONG A PRE-FRONTAL/LEE TROUGH
   ACROSS THE REGION LATE THIS AFTN/EVE.  HERE...VERTICAL SHEAR WILL
   REMAIN COMPARATIVELY WEAKER THAN POINTS FARTHER N. 
   HOWEVER...PRESENCE OF STEEP LAPSE RATES ATOP A DEEPLY-MIXED BOUNDARY
   LAYER WILL SUPPORT GUSTY WINDS AND SOME HAIL IN STRONGEST STORMS.  
   
   ...SERN STATES...
   THIS MORNINGS UPR AIR ANALYSIS CLEARLY SHOWS THAT THE
   LOW/MID-TROPOSPHERE HAS COOLED SINCE LAST EVE AS EXTENSIVE MCS
   CLUSTERS MOVED THROUGH THE REGION.  STRONGEST POTENTIAL FOR TSTMS
   WILL LIKELY EXIST ALONG/W OF A CONVECTIVELY INDUCED BOUNDARY FROM
   PARTS OF THE MID-SOUTH SEWD INTO AL/WRN FL PNHDL.  IN THIS
   REGION...ERN FRINGE OF A STRONG EML STILL EXISTS AMIDST PWAT VALUES
   OF 1.8 INCHES. AS A RESULT...ANY STRONGER CORE THAT EVOLVES MAY
   PRODUCE A MICROBURST OR SOME HAIL.
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
   CURRENT UTC TIME: 1947Z (2:47PM), RELOAD THIS PAGE TO UPDATE THE TIME