Jacksonville, FL...Virginia Beach, VA...Raleigh, NC...Tampa, FL...St. Petersburg, FL...
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.
Day 1 Wind Risk
Area (sq. mi.)
Some Larger Population Centers in Risk Area
Jacksonville, FL...Charlotte, NC...Virginia Beach, VA...Miami, FL...Raleigh, NC...
Washington, DC...Atlanta, GA...Arlington, VA...Alexandria, VA...Sandy Springs, GA...
Probabilistic Large Hail 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.
SPC AC 150607
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0107 AM CDT Sun Apr 15 2018
Valid 151200Z - 161200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
WESTERN NORTH CAROLINA...NORTHWEST SOUTH CAROLINA...AND A SMALL PART
OF SOUTHWEST VIRGINIA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FLORIDA TO
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
THE SOUTHEAST AND MID ATLANTIC...
Widespread thunderstorms, some severe, will spread across the Mid
Atlantic and Southeastern states today into the evening. The
greatest threat will be across parts of the Carolinas into southwest
Virginia with a few tornadoes possible.
An upper trough will pivot in a negative-tilt fashion from the MS
Valley across the Southeast during day, continuing across the Mid
Atlantic overnight. This will result in lift over a large area with
rapid cooling aloft and height falls. At the surface, low pressure
will deepen from OH across WV and across the lee of the
Appalachians, with strong southeasterly low-level flow contributing
to moisture advection as well as upslope flow into the higher
terrain. Dewpoints into the low to perhaps mid 60s F will contribute
to sufficient instability given extreme shear to support severe
storms focused over the Enhanced Risk area, as well as farther south
along the advancing cold front across GA and FL.
Surface winds will strengthen out of the southeast in response to
the deepening low, with strong meridional flow aloft. Hodographs
will favor supercells, and/or QLCS structures just ahead of or near
the main front. Heating as well as upslope flow may contribute to
destabilization and updraft strength. CAM solutions indicate a
relative concentration of updraft helicity during the afternoon
across the Enhanced Risk area where a few tornadoes will be
possible. Given the strong backed low-level winds, an isolated
severe threat may extend a bit farther west or north than currently
Farther north, a stationary front will likely extend from northern
VA across the Delmarva, with stable air to the north. As storms
approach this boundary, they should cross quickly with only a
marginal hail risk. A low chance of a severe storm or two may also
exist across WV into OH, near the surface low and where shear will
be strong but instability quite weak.
A broken line of storms is expected to push eastward across the Gulf
of Mexico, traversing the Florida Panhandle during the morning.
Cells will likely affect much of the peninsula during the late
afternoon and evening as they move ashore. Supercells will be
possible given veering winds with height. Preceding the cold front,
another broken line of storms is expected to form during peak
heating, and affect mainly eastern FL and into southeast GA.
Marginal hail, locally strong winds or a brief tornado will all be
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