Apr 22, 2011 1630 UTC Day 1 Convective Outlook
Updated: Fri Apr 22 16:37:07 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110422 1630 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20110422 1630 UTC Day 1 Tornado Probabilities 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
20110422 1630 UTC Day 1 Damaging Wind Probabilities 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
20110422 1630 UTC Day 1 Large Hail Probabilities 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 221632
   
   DAY 1 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   1132 AM CDT FRI APR 22 2011
   
   VALID 221630Z - 231200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS LATE THIS AFTERNOON AND EVENING
   OVER PORTIONS OF EASTERN OK...NORTHWEST AR...AND SOUTHERN MO...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM CENTRAL TX INTO THE MID MS
   AND MUCH OF THE OH VALLEY...
   
   CORRECTED FOR ERRORS IN SLIGHT RISK LINE OVER TN
   
   A FAST-MOVING UPPER TROUGH OVER THE CENTRAL PLAINS WILL TRACK
   EAST-NORTHEASTWARD DURING THIS FORECAST PERIOD INTO THE UPPER
   MIDWEST.  AS THIS OCCURS...STRONG SOUTH-SOUTHWESTERLY LOW LEVEL
   WINDS ACROSS THE PLAINS AND MS VALLEY WILL TRANSPORT GULF MOISTURE
   RAPIDLY NORTHWARD AND RESULT IN A RATHER LARGE AREA OF THUNDERSTORM
   POTENTIAL.  THE GREATEST CONCENTRATION OF SEVERE WEATHER WILL LIKELY
   EXTEND FROM OK INTO SOUTHERN MO.
   
   ...MO/IL INTO OH VALLEY...
   A CLUSTER OF INTENSE THUNDERSTORMS IS ONGOING THIS MORNING NEAR THE
   STL AREA.  THESE STORMS APPEAR TO BE ASSOCIATED WITH WARM ADVECTION
   NEAR THE NOSE OF THE LOW LEVEL JET...AND IN REGION OF MODERATE
   ELEVATED INSTABILITY.  THIS ACTIVITY APPEARS TO BE SUFFICIENTLY
   ORGANIZED TO MAINTAIN INTENSITY AND TRACK EASTWARD INTO THE OH
   VALLEY DURING THE AFTERNOON AND EVENING.  A RETREATING SURFACE WARM
   FRONT OVER THE OH VALLEY WILL LIKELY HELP FOCUS THE CONVECTION. 
   DAMAGING WINDS AND LARGE HAIL ARE THE MAIN THREATS.
   
   ...MO/AR/OK/TX...
   A SURFACE COLD FRONT IS SURGING SOUTHEASTWARD ACROSS NORTHWEST
   OK...AND SHOULD EXTEND FROM SOUTHEAST KS INTO CENTRAL OK BY LATE
   AFTERNOON.  AHEAD OF THE FRONT...SOUTHERLY WINDS HELPING TO ADVECT
   MOISTURE NORTHWARD WITH MID 60S DEWPOINTS LIKELY ACROSS THE REGION
   LATER TODAY.  CONSIDERABLE DAYTIME HEATING WILL WEAKEN THE CAPPING
   INVERSION AND HELP THE DEVELOPMENT OF SCATTERED THUNDERSTORMS ALONG
   THE FRONT...AND POTENTIALLY MORE DISCRETELY IN THE WARM SECTOR. 
   FORECAST SOUNDINGS SHOW RATHER LARGE HODOGRAPHS AND STEEP MID LEVEL
   LAPSE RATES.  THIS SUGGESTS SUPERCELL STORMS ARE LIKELY WITH VERY
   LARGE HAIL AND DAMAGING WINDS POSSIBLE.  TORNADOES APPEAR OF
   GREATEST CONCERN OVER SOUTHERN MO...FAR NORTHERN AR...AND EVENTUALLY
   INTO SOUTHERN IL WHERE ENHANCED LOW LEVEL SHEAR NEAR THE RETREATING
   WARM FRONT WILL BE PRESENT.  STORMS MAY PERSIST THROUGH MUCH OF THE
   NIGHT WITH ACTIVITY SPREADING ACROSS THE MID MS AND INTO THE OH
   VALLEY.
   
   ..HART/GARNER.. 04/22/2011
   
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