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.
Baltimore, MD...Washington, DC...Virginia Beach, VA...Miami, FL...Norfolk, VA...
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.
Day 1 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
5 %
100,872
32,393,336
Baltimore, MD...Washington, DC...Virginia Beach, VA...Miami, FL...Tampa, FL...
SPC AC 110558
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Sun Apr 11 2021
Valid 111200Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN FLORIDA PENINSULA...
...SUMMARY...
Strong to severe thunderstorms are possible later this morning
through the afternoon across much of the Florida Peninsula, with
isolated strong to severe storms also possible across parts of the
Mid-Atlantic.
...Synopsis...
While traversing the Southeast U.S. through the day, a progressive
mid-level shortwave trough will pivot around a 500 mb cutoff low
meandering across the Ohio Valley. At the surface, lee troughing
will gradually shift eastward across the Mid Atlantic while a cold
front sags southeast across the Eastern Seaboard. Behind the front,
cooler and drier conditions will limit thunderstorm potential. Ahead
of the front, scattered thunderstorms are likely across portions of
the Mid Atlantic down to the FL Peninsula. Low-level confluence
along the lee-trough axis may support isolated strong to potentially
severe storms across the Mid Atlantic in a modestly buoyant
environment. More organized severe potential is likely in
association with an MCS that is expected to move across the FL
Peninsula through the day.
...Portions of the central and southern FL Peninsula...
By mid morning into the afternoon, a belt of 50+kt mid-level flow
will overspread the Florida Peninsula in advance of a developing
line of storms. This MCS is expected to propagate southeast through
the afternoon across the peninsula through the diurnal heating
cycle. Relatively steep (7-8 C/km) low to mid-level lapse rates atop
70F surface dewpoints are expected to contribute to 1500-2500 J/kg
MLCAPE values, with point forecast soundings from multiple guidance
members showing considerable dryness in portions of the sfc-600 mb
layer. Anticipated linear storm mode and associated cold pooling
suggest that ample evaporative cooling within the line should drive
strong downdrafts capable of damaging gusts, hence the introduction
of the Slight risk. While the aforementioned lapse rates would also
favor some severe hail production, overall hail potential is
expected to be limited by storm mode. While the buoyancy and modest
veering wind profiles support some potential for a tornado,
anticipated linear storm modes and deep-layer shear vectors oriented
parallel to the convective line suggest that damaging winds should
remain the primary threat.
...Mid Atlantic...
Modest clearing of preceding rainfall and clouds are expected during
the afternoon ahead of the surface lee-trough axis across portions
of the Mid Atlantic. Low 60sF dewpoints beneath 6.5-7 C/km mid-level
lapse rates may foster up to 500-1000 J/kg MLCAPE should adequate
surface heating take place. Mainly veered, unidirectional
tropospheric winds (with speeds aloft remaining generally below 40
kts) suggest that storm organization should be rather poor,
especially given mediocre instability. Nonetheless, a couple of
storms may produce a damaging gust or perhaps marginally severe hail
given the modest lapse rates. Storms should gradually weaken with
the onset of nocturnal cooling.
..Squitieri/Darrow.. 04/11/2021
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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