Mar 20, 2018 1630 UTC Day 1 Convective Outlook
Updated: Tue Mar 20 16:14:26 UTC 2018 (20180320 1630Z Day 1 shapefile | 20180320 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180320 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 40,324 11,294,144 Jacksonville, FL...Tampa, FL...St. Petersburg, FL...Orlando, FL...Savannah, GA...
SLIGHT 20,828 2,465,497 Cape Coral, FL...Wilmington, NC...Palm Bay, FL...Melbourne, FL...Fort Myers, FL...
MARGINAL 28,778 3,731,085 Fayetteville, NC...Port St. Lucie, FL...Columbia, SC...Jacksonville, NC...Lehigh Acres, FL...
Probabilistic Tornado Graphic
20180320 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
10 % 26,144 9,272,340 Jacksonville, FL...Tampa, FL...St. Petersburg, FL...Orlando, FL...Savannah, GA...
5 % 24,486 3,109,187 Charleston, SC...Palm Bay, FL...North Charleston, SC...Melbourne, FL...Mount Pleasant, SC...
2 % 13,972 1,794,393 Cape Coral, FL...Wilmington, NC...Fort Myers, FL...Lehigh Acres, FL...North Fort Myers, FL...
Probabilistic Damaging Wind Graphic
20180320 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
30 % 30,279 10,235,548 Jacksonville, FL...Tampa, FL...St. Petersburg, FL...Orlando, FL...Gainesville, FL...
15 % 21,206 2,869,294 Cape Coral, FL...Savannah, GA...Port St. Lucie, FL...Wilmington, NC...Palm Bay, FL...
5 % 22,134 2,469,344 West Palm Beach, FL...Jacksonville, NC...Wellington, FL...Jupiter, FL...Lehigh Acres, FL...
Probabilistic Large Hail Graphic
20180320 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
30 % 39,403 11,183,633 Jacksonville, FL...Tampa, FL...St. Petersburg, FL...Orlando, FL...Savannah, GA...
15 % 21,818 2,578,829 Cape Coral, FL...Port St. Lucie, FL...Wilmington, NC...Fort Myers, FL...Port Charlotte, FL...
5 % 28,728 3,728,186 Fayetteville, NC...Columbia, SC...West Palm Beach, FL...Jacksonville, NC...Wellington, FL...
   SPC AC 201614

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1114 AM CDT Tue Mar 20 2018

   Valid 201630Z - 211200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL FL TO
   COASTAL SC...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
   SOUTHEAST...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE
   SOUTHEAST...

   ...SUMMARY...
   Scattered to numerous severe storms are likely this afternoon with
   tornadoes, large hail, and damaging winds from central Florida to
   coastal South Carolina. This risk will end during the evening.

   ...FL Peninsula...
   Isolated storms are ongoing across the north/central FL, with
   scattered strong storms evident in the northeast Gulf. This offshore
   activity should spread inland during the next few hours. Modified
   12Z Tampa Bay and 14Z Jacksonville soundings suggest MLCAPE of
   1500-2000 J/kg is prevalent with effective shear around 50 kt.
   Low/deep-layer wind profiles will strengthen with approach of the AL
   shortwave trough. This should result in several supercells evolving
   across the peninsula this afternoon capable of producing all
   hazards. Veered surface winds along with the early afternoon timing
   of storms inland should limit the potential for 10% or greater
   coverage of significant severe, however a strong tornado and 2-inch
   hail are possible. The severe threat will diminish during the early
   evening as large-scale ascent subsides.

   ...Coastal Plain of GA/SC/NC...
   West-east oriented trailing outflow in the wake of an early morning
   MCS is evident across the central portion of the SC coast. This
   demarcates the warm/moist air mass to the south with
   recovery/modification occurring to its north into extreme southern
   NC. While further diffusing of the outflow boundary is anticipated,
   the bulk of moderate buoyancy will likely be confined to coastal SC
   southward this afternoon. Scattered to numerous storms should
   emanate out of ongoing cumulus field evident over southeast GA as
   mid-level height falls associated with the AL shortwave trough
   increase. Embedded supercells appear probable amid nearly
   unidirectional wind profiles and strengthening deep-layer shear. All
   hazards are anticipated mainly near the immediate coast before the
   bulk of severe convection moves offshore by the early evening.

   ..Grams/Cook.. 03/20/2018

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