Apr 9, 2011 0600 UTC Day 2 Convective Outlook
Updated: Sat Apr 9 06:01:55 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110409 0600 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20110409 0600 UTC Day Probabilitic Graphic
Probability Legend Image
   SPC AC 090600
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT SAT APR 09 2011
   
   VALID 101200Z - 111200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF IA...WI..SE MN
   AND NW IL...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER TO
   MID-MS VALLEY...GREAT LAKES...OZARKS AND SRN PLAINS...
   
   ...TORNADO OUTBREAK POSSIBLE SUNDAY AFTERNOON AND EVENING ACROSS THE
   UPPER MS VALLEY...
   
   ...UPPER MS VALLEY...
   AN IMPRESSIVE UPPER-LEVEL TROUGH WILL MOVE INTO THE GREAT PLAINS
   SUNDAY AS A POWERFUL 90 TO 110 KT MID-LEVEL JET EJECTS NEWD ACROSS
   THE CNTRL STATES. AT THE SFC...A STRONG LOW WILL MOVE NEWD INTO IA
   SUNDAY AFTERNOON WITH SFC DEWPOINTS REACHING THE LOWER TO MID 60S F
   SOUTH OF A WARM FRONT ACROSS MUCH OF THE UPPER MIDWEST. THE EXIT
   REGION OF THE JET WILL OVERSPREAD THE UPPER MS VALLEY SUNDAY
   AFTERNOON CREATING STRONG DEEP LAYER SHEAR PROFILES VERY FAVORABLE
   FOR SEVERE STORMS. THIS COMBINED WITH STRONG INSTABILITY WILL RESULT
   IN A SIGNIFICANT POSSIBILITY FOR SUPERCELLS AND TORNADOES ACROSS THE
   MODERATE RISK AREA. AN UPGRADE TO HIGH RISK APPEARS LIKELY ACROSS A
   PORTION OF THE UPPER MS VALLEY IN LATER OUTLOOKS.
   
   THE CURRENT THINKING IS THAT CELLS WILL FIRST DEVELOP IN NRN IA AND
   SE MN AND MOVE INTO NRN WI DURING THE AFTERNOON AHEAD OF THE TRACK
   OF A SFC LOW AND ALONG A WARM FRONT. FORECAST SOUNDINGS AT 21Z NEAR
   THE WARM FRONT SHOW MLCAPE VALUES AROUND 2000 J/KG...0-6 KM SHEAR
   VALUES NEAR 60 KT AND 0-3 STORM RELATIVE HELICITIES OF 250 TO 350
   M2/S2. LOW-LEVEL SHEAR SHOULD INCREASE WITH TIME AS A LOW-LEVEL JET
   STRENGTHENS AND APPROACHES FROM THE SOUTH. THIS ENVIRONMENT SHOULD
   SUPPORT THE DEVELOPMENT OF TORNADIC SUPERCELLS WITH A POTENTIAL FOR
   LONG-TRACK TORNADOES WITH CELLS THAT TRACK ENEWD ALONG THE WARM
   FRONT. ADDITIONAL SEVERE STORM DEVELOPMENT SHOULD OCCUR SWD ACROSS
   THE WARM SECTOR FROM ERN IA NEWD INTO SRN AND CNTRL WI BY EARLY
   EVENING. THIS ACTIVITY SHOULD ALSO RAPIDLY BECOME SUPERCELLULAR WITH
   TORNADOES AND LARGE HAIL LIKELY WITH THE MORE DOMINANT CELLS. A
   THREAT FOR STRONG TORNADOES SHOULD CONTINUE THROUGH MUCH OF THE
   EVENING AS A CLUSTER OF SUPERCELLS MOVES ENEWD ACROSS WI. SEVERE
   STORMS SHOULD ALSO DEVELOP SWD INTO NRN AND WRN IL WHERE THE
   STRONGER CELLS SHOULD HAVE A TORNADO...WIND DAMAGE AND LARGE THREAT
   DURING THE EVENING.
   
   ...OZARKS/SRN PLAINS...
   AN IMPRESSIVE UPPER-LEVEL TROUGH WILL MOVE INTO THE GREAT PLAINS
   SUNDAY AS A WELL-DEVELOPED 90 TO 110 KT MID-LEVEL JET EJECTS NEWD
   ACROSS THE SRN PLAINS AND OZARKS. THE JET WILL CREATE STRONG DEEP
   LAYER SHEAR PROFILES ACROSS MUCH OF THE REGION AS A COLD FRONT
   ADVANCES SEWD. THUNDERSTORM DEVELOPMENT SHOULD OCCUR LATE SUNDAY
   AFTERNOON FROM NCNTRL MO SWWD ACROSS NW AR INTO ERN OK AND ECNTRL TX
   ALONG AN AXIS OF MODERATE INSTABILITY. THE SHEAR ENVIRONMENT SHOULD
   SUPPORT SUPERCELL DEVELOPMENT BUT THE FAVORED MODE COULD BE
   LINEAR...FORCED BY CONVERGENCE ALONG THE COLD FRONT. STORMS THAT
   REMAIN DISCRETE COULD BECOME SUPERCELLS WITH A THREAT FOR ISOLATED
   LARGE HAIL. WIND DAMAGE MAY BE THE FAVORED THREAT WITH LINE-SEGMENTS
   THAT PERSIST THROUGH THE EVENING WITH THE THREAT GREATEST FROM NW AR
   NEWD INTO WCNTRL IL WHERE A 30 PERCENT PROBABILITY IS LOCATED. IF A
   SQUALL-LINE DEVELOPS ON THE SERN SIDE OF THE MID-LEVEL JET THEN AN
   ENHANCED WIND DAMAGE THREAT COULD EXIST ACROSS ERN AND SRN MO.
   
   ...ERN GREAT LAKES AND UPPER OH VALLEY...
   AN UPPER-LEVEL RIDGE IS FORECAST TO BE LOCATED ACROSS THE SRN
   APPALACHIAN MTNS EXTENDING NWD INTO THE UPPER OH VALLEY SUNDAY. AN
   AXIS OF MODERATE INSTABILITY IS FORECAST FROM LOWER MI SEWD ACROSS
   OH INTO WV. THUNDERSTORM DEVELOPMENT MAY OCCUR BENEATH THE
   UPPER-LEVEL RIDGE AS SFC TEMPS WARM DURING THE DAY. HOWEVER...A LACK
   OF LARGE-SCALE ASCENT SHOULD KEEP ANY CONVECTION ISOLATED. STRONG
   DEEP LAYER SHEAR AND INCREASING LOW-LEVEL FLOW MAY RESULT IN A
   MARGINAL WIND DAMAGE THREAT DURING THE AFTERNOON WHEN LOW-LEVEL
   LAPSE RATES SHOULD BE STEEP.
   
   ..BROYLES.. 04/09/2011
   
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