940
ACUS11 KWNS 171811
SWOMCD
SPC MCD 171811 COR
NJZ000-MDZ000-DEZ000-VAZ000-DCZ000-WVZ000-171930-

Mesoscale Discussion 1667
NWS Storm Prediction Center Norman OK
0111 PM CDT Wed Jul 17 2024

Areas affected...Virginia into Maryland

Concerning...Severe potential...Watch possible

Valid 171811Z - 171930Z

CORRECTED FOR GRAPHIC LABEL PLACEMENT

Probability of Watch Issuance...60 percent

SUMMARY...A severe thunderstorm watch could be needed this afternoon
as thunderstorm coverage increases, with the primary threat being
for some damaging wind gusts.

DISCUSSION...A severe thunderstorm watch may be needed this
afternoon as thunderstorm coverage increases. Surface temperatures
in northern Virginia and into Maryland have warmed into the
mid-to-upper 90s F, with dew points in the mid-to-upper 60s F. While
the boundary layer moisture is only supportive of modest MLCAPE
(currently 500 J/kg, forecast to be 1000-1500 J/kg), and deep-layer
shear is only around 25 kts, forecast profiles and SPC Mesoanalysis
show very steep 0-3 km lapse rates across the Mid Atlantic. These
steep lapse rates will allow for efficient mixing of thunderstorm
winds to the surface, and perhaps even some microburst activity,
which could result in some localized reports of damaging winds. This
is supported by recent WoFS guidance, which shows increasing
confidence in 40-50 MPH wind gusts.

Additionally, an ongoing MCV progressing eastward out of West
Virginia may result in a localized threat for damaging wind gusts as
it moves east-southeast through Virginia. The environment only
supports meager buoyancy in the short term, and radar trends don`t
indicate much intensification at this time, but steep low-level
lapse rates support at least some damaging wind threat.

..Halbert/Squitieri/Hart.. 07/17/2024

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

ATTN...WFO...PHI...AKQ...LWX...RNK...RLX...

LAT...LON   37378017 37458033 37588040 37738045 37868045 38018039
            38208028 38368012 38907926 39147895 39377858 39557831
            39647797 39647746 39647673 39657599 39647548 39667478
            39617441 39427445 39197465 38887488 38597507 38447525
            38327558 38197593 38087640 37737737 37467837 37337936
            37337980 37378017