Apr 15, 2018 1630 UTC Day 1 Convective Outlook
Updated: Sun Apr 15 16:48:19 UTC 2018 (20180415 1630Z Day 1 shapefile | 20180415 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180415 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 57,432 10,888,643 Charlotte, NC...Raleigh, NC...Greensboro, NC...Durham, NC...Winston-Salem, NC...
SLIGHT 90,846 18,199,323 Jacksonville, FL...Virginia Beach, VA...Tampa, FL...St. Petersburg, FL...Norfolk, VA...
MARGINAL 92,606 22,076,314 Columbus, OH...Baltimore, MD...Washington, DC...Miami, FL...Hialeah, FL...
Probabilistic Tornado Graphic
20180415 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 % 44,970 8,049,064 Charlotte, NC...Greensboro, NC...Winston-Salem, NC...Savannah, GA...Columbia, SC...
5 % 61,210 13,024,166 Jacksonville, FL...Raleigh, NC...Tampa, FL...St. Petersburg, FL...Durham, NC...
2 % 91,903 18,685,784 Baltimore, MD...Washington, DC...Virginia Beach, VA...Norfolk, VA...Chesapeake, VA...
Probabilistic Damaging Wind Graphic
20180415 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 % 57,365 10,875,939 Charlotte, NC...Raleigh, NC...Greensboro, NC...Durham, NC...Winston-Salem, NC...
15 % 89,826 18,011,367 Jacksonville, FL...Virginia Beach, VA...Tampa, FL...St. Petersburg, FL...Norfolk, VA...
5 % 92,476 22,081,942 Columbus, OH...Baltimore, MD...Washington, DC...Miami, FL...Hialeah, FL...
Probabilistic Large Hail Graphic
20180415 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
5 % 90,797 25,384,583 Jacksonville, FL...Charlotte, NC...Miami, FL...Tampa, FL...St. Petersburg, FL...
   SPC AC 151648

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1148 AM CDT Sun Apr 15 2018

   Valid 151630Z - 161200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF GA...SC...NC INTO VA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FL TO VA...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM FL TO THE
   OHIO VALLEY AND MID-ATLANTIC STATES...

   ...SUMMARY...
   A line of strong to severe thunderstorms will move northeast across
   the Southeast and Mid-Atlantic States through tonight. Damaging
   winds and tornadoes are most likely from the Savannah Valley into
   Virginia this afternoon and early evening.

   ...North Florida to the Delmarva vicinity...
   The base of a prominent upper trough centered over the Midwest will
   continue to steadily spread northeastward over the Tennessee Valley
   toward the central/southern Appalachians with ample downstream
   height falls and a considerable strengthening of south-southwesterly
   winds through a deep layer. Persistent cloud cover and relatively
   weak mid-level level lapse rates will hinder robust destabilization,
   but this will be compensated by an increasingly moist air mass in
   conjunction with strengthening deep-layer/low-level shear.

   At midday, a nearly continuous squall line continues to intensify
   across east Georgia into north Florida while other bands of storms
   have more recently increased across the western Carolinas. Largely
   unidirectional/boundary-parallel wind profiles will initially limit
   the eastward progression of the convective bands, but
   northeastward-racing bowing segments are likely to evolve over time
   with some net east/northeastward acceleration. Damaging winds will
   likely be the most common impact, but some tornadoes can be expected
   given the degree of low-level SRH coincident with a moist
   environment. At least some severe risk may develop into the Delmarva
   vicinity late tonight within a weakly unstable/highly sheared
   environment.

   ...Central/South Florida...
   While the region will be influenced by more modest mid-level height
   falls and weaker deep-layer shear, an approaching squall line over
   the Gulf of Mexico will pose some severe risk while additional
   development could occur via the east-coast sea breeze. Damaging
   winds will exist along with the possibility of a tornado.

   ...Ohio Valley...
   Modest moisture and minimal buoyancy may be sufficient for a few
   strong updrafts/downdrafts capable of localized severe in relatively
   close proximity to the surface low track.

   ..Guyer/Leitman.. 04/15/2018

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