Aug 19, 2014 1630 UTC Day 1 Convective Outlook
Updated: Tue Aug 19 17:16:39 UTC 2014 (20140819 1630Z Day 1 shapefile | 20140819 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140819 1630 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 89,890 16,675,421 Detroit, MI...Indianapolis, IN...Toledo, OH...Louisville, KY...Fort Wayne, IN...
Probabilistic Tornado Graphic
20140819 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.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20140819 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.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 89,846 16,598,811 Detroit, MI...Indianapolis, IN...Toledo, OH...Louisville, KY...Fort Wayne, IN...
5 % 299,993 29,602,300 Chicago, IL...Columbus, OH...Denver, CO...Nashville, TN...St. Louis, MO...
Probabilistic Large Hail Graphic
20140819 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.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 73,288 13,531,958 Detroit, MI...Indianapolis, IN...Fort Wayne, IN...Warren, MI...Sterling Heights, MI...
5 % 169,710 21,191,290 Chicago, IL...Nashville, TN...Omaha, NE...St. Louis, MO...Toledo, OH...
   SPC AC 191716

   DAY 1 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   1216 PM CDT TUE AUG 19 2014

   VALID 191630Z - 201200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON FROM SRN/ERN IL
   TO SE LOWER MI...

   CORRECTED FOR HAIL PROBABILITY GRAPHIC

   ...SUMMARY...
   A FEW SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL ARE EXPECTED
   THIS AFTERNOON FROM PARTS OF ILLINOIS AND INDIANA TO SOUTHERN LOWER
   MICHIGAN.  ISOLATED STRONG TO DAMAGING WIND GUSTS WILL BE POSSIBLE
   THIS AFTERNOON ACROSS SOUTHERN ALABAMA AND GEORGIA...AS WELL AS FROM
   NORTHEAST ARIZONA AND SOUTHEAST UTAH INTO WESTERN COLORADO. 
   ISOLATED LARGE HAIL MAY OCCUR OVERNIGHT ACROSS THE MIDDLE MISSOURI
   RIVER VALLEY.

   ...SRN AND ERN IL TO SE LOWER MI THIS AFTERNOON...
   AN EARLIER CLUSTER OF THUNDERSTORMS HAS WEAKENED OVER SE LOWER
   MI...WHILE A SEPARATE CLUSTER PERSISTS FARTHER TO THE SW IN IL AND E
   CENTRAL MO.  THE NRN PORTION OF THE IL CONVECTION IS EXPECTED TO
   DEVELOP NEWD AND MERGE WITH ANOTHER BAND OF CONVECTION DEVELOPING
   OVER SE LAKE MI...AND THE CONGLOMERATE OF STORMS WILL MOVE EWD
   ACROSS SRN LOWER/INDIANA/IL THROUGH THE AFTERNOON.

   A PLUME OF MIDLEVEL LAPSE RATES NEAR 7 C/KM EXTENDS AS FAR NE AS
   IL/INDIANA...IMMEDIATELY IN ADVANCE OF A MIDLEVEL TROUGH MOVING
   SLOWLY SEWD FROM THE UPPER MS VALLEY.  SURFACE HEATING WILL BE
   FOCUSED IMMEDIATELY E OF THE THICKER CLOUDS ASSOCIATION WITH ONGOING
   CONVECTION IN ADVANCE OF A WEAK SURFACE COLD FRONT.  AFTERNOON
   SURFACE TEMPERATURES IN THE 80S AND BOUNDARY LAYER DEWPOINTS OF
   68-70 F WILL COMBINE WITH THE MIDLEVEL LAPSE RATES TO RESULT IN
   MLCAPE VALUES OF 1500-2500 J/KG.  SOME ENHANCEMENT TO DEEP-LAYER
   VERTICAL SHEAR WITH THE APPROACHING MIDLEVEL TROUGH WILL SUPPORT
   ORGANIZED MULTICELL STRUCTURES AND ACCOMPANYING RISKS FOR A FEW
   DAMAGING GUSTS AND LARGE HAIL. 

   ...SRN AL/GA THIS AFTERNOON...
   A DIFFUSE SURFACE TROUGH AND OUTFLOW BOUNDARY WILL PERSIST FROM SE
   AL INTO S CENTRAL GA INTO EARLY AFTERNOON AND SERVE TO FOCUS
   THUNDERSTORM DEVELOPMENT BY EARLY AFTERNOON.  MLCAPE NEAR 3000 J/KG
   AND A BELT OF 25-30 KT WLY FLOW NEAR 700 MB WILL FAVOR ISOLATED
   STRONG/DAMAGING GUSTS WITH WET MICROBURSTS AND SOME MOMENTUM
   TRANSFER IN MULTICELL CLUSTERS.

   ...NE AZ/SE UT/WRN CO THIS AFTERNOON/EVENING...
   A WEAK MIDLEVEL TROUGH OVER UT/NW AZ AND AN ASSOCIATED MONSOONAL
   MOISTURE PLUME WILL MOVE NEWD TOWARD THE CENTRAL HIGH PLAINS BY
   TONIGHT...IN ADVANCE OF A NRN STREAM TROUGH OVER SK/AB.  ISOLATED
   STRONG WIND GUSTS WILL BE POSSIBLE WHERE CLOUD BREAKS ALLOW SOMEWHAT
   STRONGER SURFACE HEATING/DESTABILIZATION THIS AFTERNOON/EVENING
   ACROSS SE UT/NE AZ/WRN CO.

   ...CENTRAL HIGH PLAINS TO THE LOWER MO VALLEY THROUGH TONIGHT...
   OVERNIGHT...A WARM ADVECTION REGIME WILL STRENGTHEN FROM NEB TO SW
   IA/NRN MO ON THE NOSE OF A 25-35 KT SWLY LLJ.  MUCAPE AOA 2000 J/KG
   AND EFFECTIVE BULK SHEAR OF 25-35 KT WILL SUPPORT SOME RISK FOR
   ISOLATED LARGE HAIL AFTER 06Z.

   ..THOMPSON/KERR.. 08/19/2014

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z