Sep 1, 2014 1300 UTC Day 1 Convective Outlook
Updated: Mon Sep 1 12:52:00 UTC 2014 (20140901 1300Z Day 1 shapefile | 20140901 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140901 1300 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 165,146 25,658,631 Detroit, MI...Indianapolis, IN...Tulsa, OK...St. Louis, MO...Toledo, OH...
Probabilistic Tornado Graphic
20140901 1300 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.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 26,873 1,446,636 Springfield, MO...Joplin, MO...Bartlesville, OK...Ponca City, OK...Bella Vista, AR...
2 % 113,688 18,546,062 Indianapolis, IN...Tulsa, OK...St. Louis, MO...Toledo, OH...Fort Wayne, IN...
Probabilistic Damaging Wind Graphic
20140901 1300 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.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 160,987 25,582,316 Detroit, MI...Indianapolis, IN...Tulsa, OK...St. Louis, MO...Toledo, OH...
5 % 332,245 32,865,866 Chicago, IL...Columbus, OH...Milwaukee, WI...Oklahoma City, OK...Cleveland, OH...
Probabilistic Large Hail Graphic
20140901 1300 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.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 27,027 1,424,895 Springfield, MO...Joplin, MO...Bartlesville, OK...Ponca City, OK...Pittsburg, KS...
15 % 152,088 22,499,361 Detroit, MI...Indianapolis, IN...Tulsa, OK...St. Louis, MO...Toledo, OH...
5 % 254,265 32,778,046 Chicago, IL...Columbus, OH...Milwaukee, WI...Wichita, KS...Cincinnati, OH...
   SPC AC 011252

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0752 AM CDT MON SEP 01 2014

   VALID 011300Z - 021200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
   FROM LOWER MI TO THE NE OK/SE KS BORDER REGION...

   ...SUMMARY...
   A FEW SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL ARE EXPECTED
   LATER TODAY FROM PARTS OF ILLINOIS INTO LOWER MICHIGAN.  A SOMEWHAT
   LONGER-DURATION SEVERE STORM THREAT IS EXPECTED THIS AFTERNOON INTO
   TONIGHT FROM THE KANSAS/OKLAHOMA BORDER REGION INTO SOUTHERN
   MISSOURI...WHERE A COUPLE TORNADOES WILL ALSO BE POSSIBLE. 
   OTHERWISE...ISOLATED STORMS WITH STRONG WINDS ARE POSSIBLE ACROSS
   THE CENTRAL HIGH PLAINS THIS AFTERNOON.

   ...SE KS/NE OK BORDER TO LOWER MI TODAY INTO TONIGHT...
   A LEAD SHORTWAVE TROUGH OVER THE UPPER MS VALLEY THIS MORNING WILL
   MOVE NEWD OVER UPPER MI BY THIS AFTERNOON...WHILE AN UPSTREAM WAVE
   OVER ID/WY PROGRESSES EWD TO THE CENTRAL HIGH PLAINS THIS AFTERNOON
   AND THE MID MS VALLEY BY SUNRISE TUESDAY.  AT THE SURFACE...AN
   ASSOCIATED COLD FRONT WILL MOVE EWD ACROSS IA/WI TODAY TO WRN LOWER
   MI AND NW IL BY THIS EVENING...WHILE THE SW EXTENT OF THE FRONT WILL
   BECOME QUASI-STATIONARY NEAR THE KS/OK BORDER.  

   OUTFLOW FROM OVERNIGHT CONVECTION HAS PROGRESSED WELL AHEAD OF THE
   SURFACE COLD FRONT...AND THE POTENTIAL FOR ADDITIONAL SEVERE STORM
   DEVELOPMENT TODAY FROM NRN MO TO SE WI APPEARS TO BE DIMINISHING AS
   A RESULT OF THE STABILIZING INFLUENCE OF THIS OUTFLOW...AS WELL AS
   EARLY DAY PASSAGE OF THE LEAD SHORTWAVE TROUGH.  FARTHER E...A
   BROKEN BAND OF PRE-FRONTAL CONVECTION WILL BE POSSIBLE THIS
   AFTERNOON FROM NRN INDIANA INTO LOWER MI.  HERE...A FEW DAMAGING
   GUSTS WILL BE POSSIBLE AS BOUNDARY LAYER DEWPOINTS NEAR 70 F AND
   DAYTIME HEATING CONTRIBUTE TO MLCAPE AROUND 2000 J/KG...IN AN
   ENVIRONMENT WITH SOME ENHANCEMENT TO DEEP-LAYER VERTICAL SHEAR WITH
   THE LEAD SHORTWAVE TROUGH.  

   THE MORE FOCUSED SEVERE WEATHER THREAT AREA WILL BE FARTHER S FROM
   THE OK/KS BORDER INTO SRN MO...ALONG THE RESIDUAL OUTFLOW BOUNDARY
   FROM THE ONGOING STORMS IN MO/KS.  CONTINUED MOISTURE INFLUX INTO
   THE BOUNDARY FROM THE S...IN CONJUNCTION WITH STRONG DAYTIME
   HEATING...WILL MAINTAIN MLCAPE OF 2500-3000 J/KG ALONG THE SRN
   FRINGE OF THE STRONGER WLYS...AND THE NRN FRINGE OF THE WARMER
   ELEVATED MIXED LAYER/CAP.  DESTABILIZATION IN THE WARM SECTOR AND
   CONTINUED WAA/ASCENT OVER THE REMNANT OUTFLOW/EFFECTIVE FRONT WILL
   SUPPORT ADDITIONAL THUNDERSTORM DEVELOPMENT FROM N CENTRAL/NE OK AND
   SE KS INTO SRN MO THIS AFTERNOON INTO TONIGHT.  THE MODERATE-STRONG
   BUOYANCY AND EFFECTIVE BULK SHEAR OF 30-40 KT WILL SUPPORT A WSW-ENE
   ORIENTED BAND OF STORMS WITH SOME EMBEDDED SUPERCELLS CAPABLE OF
   PRODUCING LARGE HAIL/DAMAGING WINDS.  LOW-LEVEL SHEAR AND MOISTURE
   WILL BE SUFFICIENT FOR SOME TORNADO RISK WITH STORMS ON THE
   IMMEDIATE COOL SIDE OF THE BOUNDARY...AS SWD MOTION OF THE BOUNDARY
   ENDS AND THE OUTFLOW AIR MASS MODIFIES BY THIS AFTERNOON.

   ...CENTRAL HIGH PLAINS THIS AFTERNOON..
   HIGH-BASED AND LOW-TOPPED CONVECTION IS EXPECTED THIS AFTERNOON FROM
   ERN WY INTO THE NEB PANHANDLE IN ADVANCE OF THE SPEED MAX MOVING EWD
   FROM ID/WY.  BUOYANCY WILL BE LIMITED BY POOR LOW-LEVEL
   MOISTURE....BUT SUFFICIENT DEEP-LAYER SHEAR FOR SUPERCELLS SUGGESTS
   ORGANIZED STORMS WITH SOME RISK FOR STRONG OUTFLOW WINDS.

   ..THOMPSON/MOSIER.. 09/01/2014

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z