Sep 4, 2015 0100 UTC Day 1 Convective Outlook
Updated: Fri Sep 4 00:53:33 UTC 2015 (20150904 0100Z Day 1 shapefile | 20150904 0100Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150904 0100 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 31,684 12,490,785 Toledo, OH...Fort Wayne, IN...Aurora, IL...Rockford, IL...Naperville, IL...
Probabilistic Tornado Graphic
20150904 0100 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
20150904 0100 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 % 31,150 12,679,884 Chicago, IL...Toledo, OH...Fort Wayne, IN...Aurora, IL...Rockford, IL...
Probabilistic Large Hail Graphic
20150904 0100 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 040053

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0753 PM CDT THU SEP 03 2015

   VALID 040100Z - 041200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER PORTIONS OF THE LOWER
   GREAT LAKES...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER PORTIONS OF SOUTH-CENTRAL
   ARIZONA...

   ...SUMMARY...
   ISOLATED STRONG/DAMAGING WIND GUSTS WILL BE POSSIBLE ACROSS PORTIONS
   OF THE LOWER GREAT LAKES REGION THIS EVENING. OTHER STORMS WITH
   GUSTY WINDS MAY ALSO OCCUR THIS EVENING ACROSS SOUTH CENTRAL
   ARIZONA.

   ...LOWER GREAT LAKES...
   A SLOW-MOVING UPPER LEVEL TROUGH WAS LOCATED OVER THE GREAT LAKES
   THIS EVENING...WITH A COLD FRONT EXTENDING WEST FROM SOUTHEAST LOWER
   MICHIGAN INTO SOUTHERN WISCONSIN. AN AREA OF THUNDERSTORMS PERSISTS
   OVER SOUTHEAST LOWER MICHIGAN...WHERE WIDESPREAD CONVECTIVE
   OUTFLOW/CLOUDS HAVE SUBSTANTIALLY REDUCED SURFACE-BASED INSTABILITY.
   AN ISOLATED STRONG/BRIEFLY SEVERE STORM WILL BE POSSIBLE FROM
   EXTREME SOUTHERN LOWER MICHIGAN SOUTH ACROSS NORTHERN INDIANA AND
   NORTHWEST/NORTH-CENTRAL OHIO THE REMAINDER OF THIS EVENING...SOUTH
   OF THE CONVECTIVELY-REINFORCED FRONTAL BOUNDARY AND IN THE PRESENCE
   OF WEAK-MODERATE SURFACE-BASED INSTABILITY. STRONG WIND GUSTS WILL
   BE THE PRIMARY THREAT.

   FARTHER WEST ALONG THE FRONT...ISOLATED THUNDERSTORMS WERE LOCATED
   NEAR THE WISCONSIN-ILLINOIS BORDER. ISOLATED STRONG/SEVERE STORMS
   WITH GUSTY WINDS AND SMALL HAIL WILL REMAIN POSSIBLE THIS EVENING
   ACROSS PORTIONS OF NORTHERN ILLINOIS AS A LOBE OF ASCENT ASSOCIATED
   WITH THE UPPER LEVEL TROUGH PIVOTS SOUTHWARD ACROSS A
   MODERATELY-UNSTABLE AIR MASS NEAR/SOUTH OF THE FRONTAL BOUNDARY.

   ...SOUTHERN ARIZONA...
   ISOLATED STRONG WIND GUSTS MAY OCCUR WITH STRONGER STORMS ON THE
   WESTERN FLANK OF WIDESPREAD CLOUD COVER/COOLER AIR OVER
   SOUTH-CENTRAL ARIZONA THIS EVENING...WHERE STRONG HEATING HAS
   RESULTED IN A WELL-MIXED BOUNDARY LAYER. RISK APPEARS GREATEST FROM
   MARICOPA COUNTY SOUTHWARD OVER WESTERN PORTIONS OF PINAL/PIMA
   COUNTIES.

   ..BUNTING.. 09/04/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z