Dec 23, 2015 0600 UTC Day 1 Convective Outlook
Updated: Wed Dec 23 06:00:01 UTC 2015 (20151223 1200Z Day 1 shapefile | 20151223 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20151223 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 158,472 16,798,132 Memphis, TN...Nashville, TN...Cincinnati, OH...Lexington-Fayette, KY...Louisville, KY...
SLIGHT 266,591 42,862,044 Chicago, IL...Indianapolis, IN...Columbus, OH...Atlanta, GA...St. Louis, MO...
MARGINAL 335,229 41,345,321 Detroit, MI...Charlotte, NC...Milwaukee, WI...New Orleans, LA...Cleveland, OH...
Probabilistic Tornado Graphic
20151223 1200 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
SIG SEVERE 43,040 3,264,218 Memphis, TN...Clarksville, TN...Jackson, TN...Jonesboro, AR...Pine Bluff, AR...
10 % 119,877 9,897,504 Memphis, TN...Nashville, TN...Little Rock, AR...Huntsville, AL...Evansville, IN...
5 % 166,127 20,827,335 Atlanta, GA...St. Louis, MO...Cincinnati, OH...Lexington-Fayette, KY...Louisville, KY...
2 % 343,021 53,195,964 Chicago, IL...Indianapolis, IN...Columbus, OH...Charlotte, NC...Milwaukee, WI...
Probabilistic Damaging Wind Graphic
20151223 1200 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 % 125,295 14,703,228 Memphis, TN...Nashville, TN...Cincinnati, OH...Lexington-Fayette, KY...Louisville, KY...
15 % 299,804 45,011,478 Chicago, IL...Indianapolis, IN...Columbus, OH...Atlanta, GA...St. Louis, MO...
5 % 334,212 41,251,306 Detroit, MI...Charlotte, NC...Milwaukee, WI...New Orleans, LA...Cleveland, OH...
Probabilistic Large Hail Graphic
20151223 1200 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
15 % 185,070 14,026,475 Memphis, TN...Nashville, TN...Birmingham, AL...Shreveport, LA...Little Rock, AR...
5 % 167,138 17,192,161 New Orleans, LA...St. Louis, MO...Louisville, KY...Baton Rouge, LA...Montgomery, AL...
   SPC AC 230600

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1200 AM CST WED DEC 23 2015

   VALID 231200Z - 241200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER/MID
   MS VALLEY....OH VALLEY... AND MID-SOUTH...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM MUCH OF THE MS VALLEY EWD
   TO THE UPPER OH VALLEY AND CNTRL APPALACHIANS...

   ...THERE IS A MRGL RISK OF SVR TSTMS MUCH OF THE GULF COAST NWD TO
   THE UPPER GREAT LAKES...

   ...SUMMARY...
   THE POTENTIAL FOR SEVERE THUNDERSTORMS WILL EXTEND FROM THE CENTRAL
   GULF COAST TO THE LOWER GREAT LAKES REGION TODAY AND TONIGHT. THE
   GREATEST POTENTIAL FOR SEVERE THUNDERSTORMS IS FORECAST ACROSS HE
   MID-SOUTH INTO PARTS OF THE OHIO VALLEY...WHERE TORNADOES...SOME
   SIGNIFICANT...ALONG WITH DAMAGING WINDS AND HAIL WILL BE POSSIBLE.

   ...SYNOPSIS...
   A SHORTWAVE TROUGH EMBEDDED WITHIN LARGER-SCALE CYCLONIC FLOW
   SITUATED ACROSS MUCH OF THE CONUS WILL QUICKLY ADVANCE NEWD FROM THE
   SRN PLAINS TOWARDS THE UPPER GREAT LAKES. AN ACCOMPANYING SFC LOW
   WILL SHIFT FROM THE MID-MO VALLEY TO THE UPPER MS VALLEY BY LATE
   AFTERNOON...WITH MODIFIED GULF AIR SPREADING NWD WITHIN THE WARM
   SECTOR. AN ATTENDANT SFC BOUNDARY WILL EXTEND SSWWD TO THE WRN GULF
   COAST...WITH A SECONDARY FRONTAL SURGE ENTERING THE SRN PLAINS. 

   ...ARKLATEX INTO THE LOWER-MID MS VALLEY AND OH VALLEY...
   SCATTERED TSTMS WILL BE ONGOING ACROSS THE ARKLATEX INTO THE MID-MS
   VALLEY WITHIN A WAA REGIME SUPPORTED BY A 50-60 KT LLJ...AND WILL
   SHIFT NNEWD THROUGH THE LATE MORNING TOWARDS THE LOWER OH VALLEY.
   ADDITIONAL TSTM DEVELOPMENT IS EXPECTED LATE MORNING INTO EARLY
   AFTERNOON ALONG THE WRN FRINGE OF THE EARLY CONVECTION WHERE
   STRONGER HEATING WILL OCCUR...AND ALLOW FOR A CORRIDOR OF 1000-1500
   J/KG OF MLCAPE TO BECOME ESTABLISHED FROM NRN LA INTO SERN MO.
   SUPERCELLS CAPABLE OF ALL SVR HAZARDS WILL BE POSSIBLE ACROSS THIS
   AREA. OF GREATEST CONCERN IS THE VERY STRONG LOW-LEVEL SHEAR AND
   LARGE CURVED HODOGRAPHS FORECAST OVER THE REGION...SUPPORTIVE FOR
   TORNADOES /SOME POSSIBLY SIGNIFICANT/. THIS THREAT SHOULD PEAK
   DURING THE AFTERNOON INTO THE EARLY EVENING...SHIFTING INTO WRN TN
   AND THE MID-MS AND LOWER OH VALLEYS. EVOLUTION INTO A QLCS IS
   EXPECTED BY EVENING ACROSS THE OH VALLEY...WITH AN ACCOMPANYING DMGG
   WIND THREAT LIKELY INCREASING...ALTHOUGH EMBEDDED TORNADOES WILL
   REMAIN POSSIBLE. 

   FARTHER N...THE STRONGEST FORCING FOR ASCENT WILL BE MAXIMIZED
   ACROSS MO/IL DURING THE AFTERNOON AS THE UPPER WAVE TRACKS NEWD
   ACROSS THE REGION. PRIMARY UNCERTAINTY HERE IS THE DEGREE OF
   DESTABILIZATION CAN OCCUR IN THE WAKE OF THE AFOREMENTIONED EARLY
   PRECIPITATION...ESPECIALLY WITH A COOL/MODIFIED AIR MASS IN PLACE.
   HOWEVER...A CONDITIONAL THREAT FOR A COUPLE TORNADOES MAY EXIST
   NEAR/E OF THE SFC LOW GIVEN VERY STRONG LOW-LEVEL SHEAR. 

   ...CNTRL GULF COAST INTO THE TN VALLEY...
   A LARGE AREA OF PRECIPITATION OBSERVED EARLY THIS MORNING NEAR THE
   GULF COAST SHOULD SHIFT NE OF THE REGION BY LATE MORNING. THE
   STRONGEST FORCING FOR ASCENT ACCOMPANYING THE CNTRL CONUS UPPER WAVE
   WILL REMAIN DISPLACED TO THE N...BUT BROAD WAA REGIME WILL SUPPORT
   ISOLATED TO SCATTERED TSTM DEVELOPMENT BY LATE MORNING FROM THE GULF
   COAST INTO PARTS OF MS/AL. WITH A 50-60 KT LLJ REMAINING POSITIONED
   ACROSS THIS AREA THROUGH MUCH OF THE PERIOD...A TORNADO THREAT COULD
   ACCOMPANY ANY SUPERCELLS THAT EVOLVE...AND MAY PERSIST OVERNIGHT
   WITH ADDITIONAL TSTM DEVELOPMENT FOCUSED ALONG A LOW-LEVEL
   CONFLUENCE AXIS FROM SRN MS INTO NRN GA.

   ...CAROLINAS INTO SERN VA...
   TSTMS WILL BE POSSIBLE THROUGHOUT THE PERIOD ALONG THE ERN FRINGE OF
   THE LLJ POSITIONED ACROSS THE SOUTHEAST CONUS. DESPITE MID-UPPER 60S
   F DEWPOINTS...POOR LAPSE RATES ALOFT WILL GENERALLY LIMIT THE DEGREE
   OF DESTABILIZATION THAT WILL OCCUR. HOWEVER...A THREAT FOR A FEW
   STRONG TO SVR WIND GUSTS AND POSSIBLY A TORNADO MAY EXIST.

   ..ROGERS/PICCA.. 12/23/2015

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