Virginia Beach, VA...Tampa, FL...St. Petersburg, FL...Norfolk, VA...Chesapeake, VA...
Probabilistic Damaging Wind 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.
SPC AC 151251
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Sun Apr 15 2018
Valid 151300Z - 161200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SAVANNAH VALLEY
TO SOUTHERN VA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTH FL TO VA...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SOUTH FL TO THE
UPPER OH VALLEY...
A line of strong to severe thunderstorms will move northeast across
the Southeast and Lower Mid-Atlantic States today into tonight.
Damaging winds and tornadoes are most likely from the Savannah
Valley into southern Virginia this afternoon and early evening.
...North FL to VA...
A generally decaying line of thunderstorms is ongoing from southwest
GA to the eastern FL Panhandle. With a nadir in instability inland
ahead of this line, severe risk with this activity should remain
localized through most of the morning. But as the large-scale
outflow impinges on the Atlantic coastal plume of mean mixing ratios
near 14 g/kg per 12Z Jacksonville and Charleston soundings,
convection will intensify towards midday amid MLCAPE of 500-1000
J/kg. The line will also expand northward given robust mid-level
height falls downstream of a 100-kt 500-mb southerly jet. In spite
of highly meridional deep-layer wind fields, 50-60 kt low-level
southerlies atop backed southeasterly surface winds (in response to
cyclogenesis) will result in enlarged hodographs. A few supercells
embedded within or just ahead of the line seem probable, with the
tornado risk appearing maximized from the Savannah Valley into parts
of southern VA during the afternoon. Otherwise, swaths of scattered
damaging winds and brief QLCS tornadoes are expected through early
evening. The severe threat will nocturnally wane tonight but at
least an isolated wind/brief tornado risk may persist towards the
Mid-Atlantic Coast within a low CAPE/high shear environment.
The severe threat should decrease with southern extent given minimal
mid-level height falls and weaker deep-layer shear. While multiple
rounds of convection should affect the peninsula, focusing on the
east-coast sea breeze this afternoon and along the impinging cold
front in the afternoon and evening, overall severe potential should
remain marginal, favoring locally strong winds and marginal hail.
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z