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.
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
No Risk Areas Forecast
SPC AC 020550
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1250 AM CDT Wed Sep 02 2020
Valid 021200Z - 031200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
THE NORTHEAST/MID-ATLANTIC INTO THE OHIO VALLEY/MID-SOUTH...
...SUMMARY...
Isolated strong to severe thunderstorms may occur today from parts
of the Northeast/Mid-Atlantic into the Ohio Valley/Mid-South.
...Northeast into the Mid-Atlantic...
Shortwave trough currently moving through far northwest Ontario and
the Upper MS Valley is forecast to continue eastward through central
Ontario and the Upper Great Lakes before then pivoting into central
Quebec. Cold front associated with this shortwave is expected to
progress eastward/southeastward across the Northeast Wednesday
evening. Air mass ahead of this front will be moist, but the cooler
mid-level temperatures associated with the shortwave will remain
north of the region. As a result, overall buoyancy will be tempered
by poor lapse rates. Southwesterly flow aloft will also result in
abundant cloud cover, limiting diurnal heating.
Even so, the ample low-level moisture in place ahead of the front is
expected to foster erosion of any convective inhibition as
temperatures gradually increase into the upper 70s/low 80s.
The strongest forcing for ascent will be displaced north of the
region but broad, modest ascent is anticipated throughout the warm
sector ahead of the front. This is expected to result in widely
scattered to scattered thunderstorm coverage ahead and along the
front. Modest shear will be in place and the potential exists for a
few stronger updrafts capable of damaging wind gusts.
Best overlap between vertical shear and instability will exist from
central PA in central VA, and higher probabilities were considered
for this outlook. However, this region is also on the far southern
extent of the overall system, limiting large-scale forcing for
ascent. Surface winds are also expected to veer ahead of the front,
limiting convergence. These factors coupled with the generally
marginal thermodynamic environment result in too much uncertainty
regarding severe coverage to introduce higher probabilities.
...Mid-South into the Middle OH Valley...
A convectively augmented shortwave trough is forecast to eject
northeastward out of north TX as a deeper, more mature shortwave
trough moves out of the southern High Plains into OK and north TX.
Thunderstorm development is anticipated ahead of the lead wave as it
encounters the very moist air mass in place from the Mid-South into
the OH Valley. Modestly enhanced low to mid-level flow will
accompany this lead wave, contributing the potential for a few
damaging wind gusts and a tornado or two.
..Mosier.. 09/02/2020
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