Mesoscale Precipitation Discussion 0524
NWS Weather Prediction Center College Park MD
952 PM EDT Thu Jun 26 2025

Areas affected...Northern VA...Eastern MD

Concerning...Heavy rainfall...Flash flooding possible

Valid 270150Z - 270450Z

SUMMARY...Thunderstorms will continue across portions of northern
VA and eastern MD for a few more hours. Hourly rainfall rates up
to 2"/hr are possible with urbanized areas most prone to flash
flooding.

DISCUSSION...Outflow boundaries emanating from several different
afternoon thunderstorm complexes have collided over northern VA,
while a cold front races in from the DelMarVa Peninsula. This cold
front is helping to ignite thunderstorms near Annapolis while the
outflows have triggered storms from the southern Capital Beltway
on west to the south of Interstate 66. The 00Z IAD RAOB shows
depicts a more tropical air-mass aloft, highlighted by PWs of
2.34" and MUCAPE >3,500 J/kg. This atmospheric setup is resulting
in tropical-downpour rainfall rates with MRMS 15-minute
radar-estimated rainfall rates ranging between 0.5-1.0" within the
storms stretching from Routes 28 & 17 on east towards the MD
Eastern Shore. The lack of vertical wind shear should ultimately
lead to these cells dissipating within the next few hours.
However, these storms are packing quite the punch with >2.0"/hr
rainfall amounts likely to be realized in some of these areas. The
flash flood threat continues across northern VA on east to the MD
Eastern Shore this evening with the more urbanized communities
within the "DMV" most at-risk for flooding should storms ensue
over more densely populated locations.

Mullinax

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

ATTN...RFC...RHA...NWC...

LAT...LON   39157657 39157618 38967600 38677591 38467602
            38137631 37907662 37577726 37427752 37337803
            37397831 37517855 37707882 37827904 38027932
            38357925 38597901 38807864 38977821 39117766
            39127715