Sep 25, 2016 2000 UTC Day 1 Convective Outlook
Updated: Sun Sep 25 19:31:51 UTC 2016 (20160925 2000Z Day 1 shapefile | 20160925 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160925 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 37,172 14,023,462 Chicago, IL...Milwaukee, WI...Aurora, IL...Rockford, IL...Naperville, IL...
Probabilistic Tornado Graphic
20160925 2000 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20160925 2000 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 37,882 14,105,814 Chicago, IL...Milwaukee, WI...Aurora, IL...Rockford, IL...Naperville, IL...
Probabilistic Large Hail Graphic
20160925 2000 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 251931

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0231 PM CDT SUN SEP 25 2016

   VALID 252000Z - 261200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE MIDWEST...

   ...SUMMARY...
   THUNDERSTORMS WILL BE POSSIBLE NEAR A COLD FRONT TODAY FROM THE
   UPPER GREAT LAKES TO CENTRAL AND SOUTHWEST TEXAS.  A FEW OF THEM MAY
   PRODUCE DAMAGING WIND...ESPECIALLY OVER PARTS OF ILLINOIS AND
   WISCONSIN.  THE OVERALL SEVERE-STORM THREAT APPEARS MARGINAL IN BOTH
   INTENSITY AND COVERAGE.

   ...DISCUSSION...

   NO APPRECIABLE CHANGES TO 1630Z OUTLOOK.

   ASIDE FROM ADJUSTING THE WESTERN-MOST EDGE OF SEVERE
   PROBABILITIES...ACCOUNTING FOR THE EWD ADVANCEMENT OF THE SFC
   FRONT...A MRGL RISK FOR DAMAGING WINDS CONTINUES ACROSS THE
   MIDWEST...ESPECIALLY FROM NRN IL INTO SERN WI.

   CONVECTION IS GRADUALLY INCREASING AHEAD OF THE COLD FRONT ALONG THE
   NRN EXTENT OF MODEST INSTABILITY.  THIS ACTIVITY WILL LIKELY EXPAND
   IN AREAL COVERAGE OVER THE NEXT FEW HOURS AS IT SPREADS TOWARD SRN
   LAKE MI.

   ..DARROW.. 09/25/2016

   .PREV DISCUSSION... /ISSUED 1104 AM CDT SUN SEP 25 2016/

   ...WI/IL/LM...
   A BROAD TROUGH IS PRESENT TODAY OVER THE PLAINS STATES AND
   ROCKIES...WITH THE MAIN SURFACE FRONTAL ZONE EXTENDING FROM MN/WI
   INTO KS/OK.  A PLUME OF MOIST/UNSTABLE LOW-LEVEL AIR ALONG/AHEAD OF
   THE FRONT WILL CONTINUE TO LEAD TO SCATTERED SHOWERS AND
   THUNDERSTORMS.  WEAK LAPSE RATES AND CONSIDERABLE CLOUD COVER WILL
   GREATLY LIMIT THE RISK OF ORGANIZED SEVERE STORMS TODAY. 
   HOWEVER...MOST MORNING MODEL SOLUTIONS SUGGEST A LOW THREAT OF A FEW
   STRONG/SEVERE STORMS OVER PARTS OF WI/NORTHERN IL AND SOUTHERN LAKE
   MI LATER TODAY. STRONG DAYTIME HEATING AND THE GLANCING INFLUENCE OF
   A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL ENHANCE
   THE RISK OF LOCALLY DAMAGING WIND GUSTS IN THIS REGION THIS
   AFTERNOON.

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z