Aug 2, 2015 1300 UTC Day 1 Convective Outlook
Updated: Sun Aug 2 12:56:52 UTC 2015 (20150802 1300Z Day 1 shapefile | 20150802 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150802 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 90,388 24,164,156 Chicago, IL...Detroit, MI...Milwaukee, WI...Madison, WI...Grand Rapids, MI...
SLIGHT 84,997 5,909,443 Toledo, OH...Fort Wayne, IN...Joliet, IL...Cedar Rapids, IA...Peoria, IL...
MARGINAL 196,970 16,698,384 Indianapolis, IN...Cleveland, OH...Omaha, NE...Minneapolis, MN...Buffalo, NY...
Probabilistic Tornado Graphic
20150802 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 62,054 7,253,004 Milwaukee, WI...Madison, WI...Grand Rapids, MI...Flint, MI...Green Bay, WI...
2 % 135,261 24,017,615 Chicago, IL...Detroit, MI...Toledo, OH...Fort Wayne, IN...Aurora, IL...
Probabilistic Damaging Wind Graphic
20150802 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
30 % 90,253 24,038,785 Chicago, IL...Detroit, MI...Milwaukee, WI...Madison, WI...Grand Rapids, MI...
15 % 73,771 5,876,895 Toledo, OH...Fort Wayne, IN...Joliet, IL...Cedar Rapids, IA...Peoria, IL...
5 % 193,122 16,271,358 Indianapolis, IN...Cleveland, OH...Omaha, NE...Minneapolis, MN...Buffalo, NY...
Probabilistic Large Hail Graphic
20150802 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 36,998 3,395,888 Madison, WI...Cedar Rapids, IA...Green Bay, WI...Appleton, WI...Waterloo, IA...
30 % 43,742 3,214,855 Green Bay, WI...Appleton, WI...Oshkosh, WI...Sheboygan, WI...Midland, MI...
15 % 131,785 26,878,145 Chicago, IL...Detroit, MI...Milwaukee, WI...Toledo, OH...Fort Wayne, IN...
5 % 196,475 16,672,140 Indianapolis, IN...Cleveland, OH...Omaha, NE...Minneapolis, MN...Buffalo, NY...
   SPC AC 021256

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0756 AM CDT SUN AUG 02 2015

   VALID 021300Z - 031200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS CENTRAL/ERN WI...NERN
   IL...CENTRAL/SRN LM...LOWER MI...NRN INDIANA...EXTREME NWRN OH...

   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING ENH RISK...

   ...THERE IS A MRGL RISK OF SVR TSTMS ELSEWHERE FROM PORTIONS CENTRAL
   PLAINS TO GREAT LAKES...

   ...SUMMARY...
   SEVERE STORMS ARE EXPECTED ACROSS THE GREAT LAKES REGION
   TODAY...POTENTIALLY AS FAR WEST AS NEBRASKA.  THIS MAY INCLUDE ONE
   OR TWO ORGANIZED STORM CLUSTERS CAPABLE OF GENERATING SWATHS OF
   POTENTIALLY DAMAGING WIND GUSTS...IN ADDITION TO SEVERE HAIL...AND
   PERHAPS A COUPLE OF TORNADOES FROM THE UPPER MISSISSIPPI VALLEY AREA
   TO LOWER MICHIGAN.

   ...SYNOPSIS...
   IN MIDDLE-UPPER LEVELS...HIGH-AMPLITUDE SYNOPTIC PATTERN WILL
   PERSIST ACROSS CONUS...CHARACTERIZED BY WRN RIDGING AND ERN
   TROUGHING...DOWNSTREAM FROM BROAD/QUASISTATIONARY CYCLONE OVER NERN
   PAC.  STRONGEST PART OF CYCLONIC-FLOW FIELD ASSOCIATED WITH BIG
   HUDSON BAY GYRE WILL CONTINUE TO TRAVERSE UPPER GREAT LAKES BUT WILL
   BACK DIRECTIONALLY AS SHORTWAVE TROUGH -- NOW OVER SRN MB --
   AMPLIFIES AND MOVES SEWD.  THAT PERTURBATION IS EXPECTED TO REACH LS
   AND NRN MN BY 00Z...MOVING TO LH...LOWER MI AND SRN WI BY 12Z.  AS
   THAT OCCURS...BOTH CURVATURE AND GRADIENT OF HEIGHT FIELD ALOFT WILL
   TIGHTEN OVER THIS REGION...WHILE HEIGHT FALLS WILL OVERSPREAD MUCH
   OF CONUS N OF ABOUT 37N AND FROM MID/UPPER MS VALLEY EWD.  

   AT SFC...11Z ANALYSIS SHOWED SFC LOW OVER ND/SD/MN BORDER
   CONFLUENCE...WITH COLD FRONT ARCHING WSWWD THEN WNWWD OVER
   CENTRAL/WRN SD AND SERN MT.  WAVY WARM FRONT WAS DRAWN ESEWD THROUGH
   SECONDARY LOW OVER NWRN WI THEN ACROSS CENTRAL/SRN LM TO SRN LOWER
   MI.  WARM FRONT SHOULD MOVE NEWD ACROSS SLGT/ENH-RISK AREAS TODAY
   PRIOR TO COLD FROPA.  BY 00Z COLD FRONT SHOULD REACH CENTRAL/NRN
   LOWER MI...SRN WI...WRN IA...CENTRAL NEB AND SERN WY. BY 12Z COLD
   FRONT SHOULD REACH FROM SRN ONT ACROSS NRN INDIANA TO NRN KS AND ERN
   CO...DECELERATING OVER CENTRAL PLAINS. 

   ...UPPER MIDWEST GREAT LAKES REGION...
   ISOLATED TO WIDELY SCATTERED STG-SVR TSTMS ARE EVIDENT ATTM FROM
   UPPER MI AND LM WNWWD ACROSS NRN MN IN ZONE OF LOW-LEVEL WAA AND
   FAVORABLE MOISTURE JUST ABOVE SFC.  ACTIVITY IS MOVING SEWD NEAR NRN
   FRINGES OF OUTLOOK AND MAY CONTRIBUTE TO LATER DEVELOPMENT/UPSCALE
   SHIFT IN SVR POTENTIAL.  REF SPC MESOSCALE DISCUSSIONS 1582 AND 1583
   FOR NEAR-TERM GUIDANCE ON SVR SCENARIO FOR PARTS OF THIS REGION.  

   SVR THREAT IS EXPECTED TO INCREASE LATE THIS MORNING AND ESPECIALLY
   INTO AFTN WITH SEWD EXTENT.  THIS WILL OCCUR AS MID/UPPER-LEVEL
   HEIGHT FALLS...STRONGER FLOW ALOFT AND DCVA AHEAD OF AMPLIFYING
   SHORTWAVE TROUGH BECOME BETTER JUXTAPOSED WITH DIABATICALLY
   DESTABILIZING PARTS OF SFC WARM SECTOR NEAR SFC COLD FRONT.  ASIDE
   FROM FRONTAL FORCING...INTENSIFICATION OF ANY PERSISTENT ANTECEDENT
   CONVECTION ALSO MAY OCCUR WHILE MOVING INTO THIS REGIME. 
   DIFFERENTIAL-HEATING/OUTFLOW BOUNDARIES ALSO MAY SERVE AS FOCI FOR
   SUPPORTIVE PREFRONTAL LIFT.  MORNING MPX/ABR RAOBS SHOW
   RESIDUAL/ELEVATED MIXED LAYER AND RELATED PLUME OF STEEP
   LOW/MIDDLE-LEVEL LAPSE RATES.  MODIFIED RAOBS AND FCST SOUNDINGS
   SUGGEST THAT FACTOR...IN TANDEM WITH SFC DEW POINTS COMMONLY 60S F
   AND LOCALLY NEAR 70...WILL LEAD TO PEAK AFTN MLCAPE RANGING FROM
   AROUND 2000 J/KG OVER ERN LOWER MI TO 3500 J/KG NEAR MS RIVER PART
   OF OUTLOOK.  

   AS FOR KINEMATIC SUPPORT...DEEP SHEAR SHOULD BE STRONGEST IN THAT
   PART OF WARM SECTOR IMMEDIATELY ADJACENT TO COLD FRONT...WITH 40-50
   KT EFFECTIVE-SHEAR MAGNITUDES POSSIBLE...DIMINISHING WITH SWWD AND
   SEWD EXTENT.  DESPITE SWLY-WLY SFC FLOW...VEERING/STRENGTHENING OF
   WINDS WITH HEIGHT WILL IMPART SUFFICIENT HODOGRAPH CURVATURE FOR
   RISK OF SUPERCELLS AS LONG AS CONVECTION REMAINS RELATIVELY
   DISCRETE.  GIVEN THERMODYNAMIC ENVIRONMENT...ANY SUSTAINED
   SUPERCELLS MAY PRODUCE LARGE/DAMAGING HAIL AND OFFER AT LEAST
   TRANSIENT TORNADO RISK.  EVOLUTION OF ONE OR MORE
   ELONGATED/QUASI-LINEAR TSTM COMPLEXES IS EXPECTED INVOF FRONT...WITH
   HAIL SIZE DIMINISHING AND WIND POTENTIAL INCREASING INTO THIS
   EVENING.  SVR POTENTIAL SHOULD RAMP DOWNWARD LATE THIS EVENING INTO
   OVERNIGHT HOURS AS MUCH OF WARM SECTOR COOLS/STABILIZES...THOUGH AT
   LEAST ISOLD HAIL/WIND THREAT MAY PERSIST INTO CENTRAL PORTIONS OF
   OH/INDIANA/IL.  

   ...CENTRAL PLAINS TO CENTRAL/WRN IA...
   ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE INVOF FRONT MAINLY
   THIS AFTN INTO EARLY EVENING.  SPORADIC LARGE HAIL AND SVR GUSTS ARE
   POSSIBLE...THOUGH INCREASING MLCINH WITH WWD EXTENT FROM MS RIVER
   INTO WARMER EML AIR WILL DELAY INITIATION AND RESTRICT COVERAGE
   COMPARED TO AREAS OF GREATER UNCONDITIONAL SVR PROBABILITIES FARTHER
   NE.

   ..EDWARDS/DEAN.. 08/02/2015

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