New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Virginia Beach, VA...
Probabilistic Tornado 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 2 Tornado Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
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 2 Wind Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
5 %
63,466
41,151,630
New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Virginia Beach, 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 2 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
SPC AC 200538
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Tue Apr 20 2021
Valid 211200Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC INTO SOUTHERN NEW YORK...
...SUMMARY...
Isolated strong to severe storms capable of producing mainly
damaging winds will be possible across parts of the Mid-Atlantic
into southern New York on Wednesday.
...Mid-Atlantic...
Large-scale upper troughing will persist over much of the eastern
CONUS on Wednesday. Within this regime, a shortwave trough will move
quickly east-northeastward across the Mid-Atlantic and into New
England through the period. A surface low initially over central PA
should likewise develop northeastward in tandem with the shortwave
trough while deepening. A cold front attendant to the surface low is
forecast to sweep quickly eastward across the Mid-Atlantic through
the day. Modest low-level moisture return characterized by low to
mid 50s surface dewpoints should occur ahead of the frontal passage.
Diurnal heating and cool temperatures aloft associated with the
approaching shortwave trough should foster the development of weak
instability ahead of the front by late Wednesday morning. Even
though MLCAPE may only reach about 250-750 J/kg, it will probably be
enough to support surface-based storms.
Given the linear forcing of the front, storms will likely grow
upscale into a low-topped line fairly quickly. Most
convection-allowing model guidance suggests this line will develop
by early afternoon from central VA to PA, and then move quickly
eastward across the I-95 corridor before continuing offshore. Given
the forecast strength of the low to mid-level flow (30-40 kt at 850
mb and 50-65 kt at 500 mb), some threat for strong to damaging winds
via convective downdraft/mixing processes is apparent with the line
of storms. At this point, the limited instability forecast may tend
to keep the overall wind threat isolated. But, higher severe wind
probabilities may be needed in a later outlook if a corridor of
damaging wind potential associated with greater instability becomes
more apparent.
...South Florida...
A cold front is forecast to move southward across this region on
Wednesday. Both large-scale ascent and stronger mid-level flow will
likely remain displaced to the north of the southern FL Peninsula.
Low-level winds are also expected to veer to westerly early in the
period, which should limit convergence along the cold front. While
an isolated strong storm may occur along/near the Atlantic Coast
with the cold front/sea breeze intersection, any storm that does
form will move quickly offshore. Overall, the potential for
organized severe thunderstorms over land currently appears too low
to include any severe probabilities.
..Gleason.. 04/20/2021
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
| 
)
