ACUS11 KWNS 212357
SWOMCD
SPC MCD 212357
MDZ000-VAZ000-DCZ000-WVZ000-220200-

Mesoscale Discussion 1702
NWS Storm Prediction Center Norman OK
0657 PM CDT Tue Jul 21 2026

Areas affected...Portions of northern Virginia into southern
Maryland

Concerning...Severe Thunderstorm Watch 509...

Valid 212357Z - 220200Z

The severe weather threat for Severe Thunderstorm Watch 509
continues.

SUMMARY...Thunderstorms approaching from the west will pose an
increasing risk of damaging wind gusts and possibly a tornado or two
across portions of northern Virginia this evening.

DISCUSSION...A cluster of thunderstorms is crossing the high terrain
of eastern WV and western VA this evening, aided by an MCV in
Rockingham County VA. As these storms continue eastward across
northern VA during the next few hours, a relatively warm and moist
air mass and 40-50 kt of 0-6 km shear (per LWX VWP) may promote re-intensification into organized clusters and possibly supercell
structures. This would favor an increasing risk of damaging wind
gusts (especially if a north/south-oriented cold pool/gust front can
evolve). Additionally, a gradually strengthening low-level jet and
resultant increase in low-level hodograph curvature could support a
brief tornado risk as well. Parts of Severe Thunderstorm Watch 509
may eventually need to be extended in time, or a new watch may be
needed.

..Weinman.. 07/21/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!7Uh8lj-FTeY0aJjKmKtXxXwskAXLxHTgBITtXAyy3eCFmEGYjP3cIH4g7TvKvPCiPuUTJjbk43YLJWL1f2XQFRy6GZE$ for graphic product...

ATTN...WFO...AKQ...LWX...

LAT...LON 37767757 37987852 38197896 38517901 39067861 39137817
39027741 38797685 38477673 37837701 37767757

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


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