SPC MD 1659
MD 1659 CONCERNING SEVERE THUNDERSTORM WATCH 548... FOR PORTIONS OF THE MID-ATLANTIC INTO SOUTHERN NEW ENGLAND

Mesoscale Discussion 1659
NWS Storm Prediction Center Norman OK
0520 PM CDT Tue Jul 16 2024

Areas affected...Portions of the Mid-Atlantic into southern New
England

Concerning...Severe Thunderstorm Watch 548...

Valid 162220Z - 170015Z

The severe weather threat for Severe Thunderstorm Watch 548
continues.

SUMMARY...A corridor of severe/damaging wind potential is becoming
apparent across far eastern Pennsylvania, northern New Jersey, and
into adjacent portions of southern New York and southwest
Connecticut. Further south into Maryland and Virginia, thunderstorm
development appears probable in the coming hours with an attendant
wind risk.

DISCUSSION...GOES IR imagery and lightning trends over the past hour
have shown a steady intensification trend of convection across far
eastern PA into northern NJ with a few wind damage reports already
noted. Given favorable buoyancy and steep (8 C/km) low-level lapse
rates immediately downstream, this wind damage threat should persist
as storms move towards the coast and/or southwest CT. 

Further to the southwest into MD and VA, convection has largely
struggled to remain sustained over the past hour - likely due to
generally weak forcing for ascent driven mainly by diurnal heating
and some lift along a diffuse lee trough axis. However, early signs
of convective development has been recently along an outflow
boundary associated with upstream convection across WV. Deeper
convection may materialize east of the Appalachians as the boundary
moves into a more buoyant air mass. Very warm surface conditions
(temperatures in the upper 90s, low 100s) are resulting in deep
boundary-layer mixing up to 2 km, which, when combined with PWAT
values around 1.75 inch, should be supportive of wet downbursts with
an attendant severe/damaging wind risk. Convective coverage remains
uncertain, but recent WoFS guidance continues to show at least
scattered thunderstorm development, suggesting the wind risk
continues across southern portions of WW 548.

..Moore.. 07/16/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...OKX...ALY...PHI...CTP...LWX...

LAT...LON   39867407 39627477 39437574 38947644 38487699 38337734
            38377772 38447797 38697822 38927823 39147803 39537766
            39807736 40027698 40177662 40277629 40547556 40627512
            40917478 41197465 41507433 41617396 41627364 41567344
            41387319 41157316 40967338 40737358 40637371 40297394
            39997397 39867407 

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