MD 1999 CONCERNING SEVERE POTENTIAL…SEVERE THUNDERSTORM WATCH LIKELY FOR PORTIONS OF NC INTO THE MID-ATLANTIC
Mesoscale Discussion 1999
NWS Storm Prediction Center Norman OK
1228 PM CDT Tue Aug 15 2023
Areas affected…Portions of NC into the Mid-Atlantic
Concerning…Severe potential…Severe Thunderstorm Watch likely
Valid 151728Z – 152000Z
Probability of Watch Issuance…80 percent
SUMMARY…The threat for scattered damaging winds and isolated hail
should increase this afternoon. One or more Severe Thunderstorm
Watches will likely be needed as thunderstorms develop.
DISCUSSION…An upper trough/low centered over the Great Lakes/OH
Valley will continue moving slowly eastward this afternoon. Modest
ascent preceding this feature and low-level convergence along a
surface cold front will likely foster robust convective initiation
within the next 1-2 hours (by around 3 PM EDT) across parts of
western/central NC into the coastal Mid-Atlantic. Strong daytime
heating has already warmed surface temperatures into the upper 80s
and 90s across this region. A rather moist airmass, with
precipitable water values of 1.5 to 2+ inches and surface dewpoints
generally in the 70s, should help offset poor mid-level lapse rates
to some extent. Around 1500-3000+ J/kg of MLCAPE has already
developed given the ample diurnal heating that has occurred.
While weak west-southwesterly low-level winds exist, they do
strengthen with height to around 45-60 kt through mid levels.
Related 35-50 kt of deep-layer shear will act to organize updrafts,
with a mix of bowing clusters and supercells possible. Isolated
severe hail may occur with the more discrete convection that
initially develops. A tendency for upscale growth into multiple
clusters appears likely given the linear forcing of the front and
mainly boundary-parallel flow aloft. Scattered damaging/severe wind
gusts should be the main threat as this convection spreads eastward
through the rest of the afternoon and evening. One or more Severe
Thunderstorm Watches will likely be needed as robust convection
develops over the next couple of hours.
..Gleason/Hart.. 08/15/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…PHI…AKQ…CTP…LWX…RAH…RNK…GSP…
LAT…LON 35918159 37517862 39257730 39697670 39997571 39737451
39277435 37747544 36387708 35227845 35017985 35318153
35918159
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