142
AWUS01 KWNH 150134
FFGMPD
PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-150632-

Mesoscale Precipitation Discussion 0438
NWS Weather Prediction Center College Park MD
933 PM EDT Sat Jun 14 2025

Areas affected...Portions of the OH Valley...Central Appalachians
and Mid-Atlantic

Concerning...Heavy rainfall...Flash flooding likely

Valid 150132Z - 150632Z

SUMMARY...Additional areas of slow-moving showers and
thunderstorms are expected to continue to develop and locally
persist into a portion of the overnight period. Given the high
rainfall rate potential and slow cell-motions, additional
scattered areas of flash flooding are expected.

DISCUSSION...The latest surface analysis shows a quasi-stationary
front still draped across the Mid-Atlantic region and stretching
back up across the higher terrain of the central Appalachians and
the upper OH Valley. 00Z RAOB data and the latest RAP analysis
shows a substantial amount of moisture still remaining in place
with PWs locally over 1.75 inches and with a moderate amount of
instability pooled along the front with MLCAPE values of near 1500
J/kg.

Areas of central to northern VA are generally the most unstable,
and there are pockets of locally strong low-level convergence near
the front that should help maintain the ongoing convective threat
across the region for a few more hours. Local orographics near the
Blue Ridge and also deeper back into the high terrain of the
central Appalachians will also facilitate areas of ascent for
convection to redevelop and locally persist.

Expect areas of slow-moving showers and thunderstorms to still be
capable of producing rainfall rates of up to 2 inches/hour, and
the slow cell-motions may yield some additional localized totals
of 3 to 4+ inches. The most recent HRRR/RRFS guidance generally
supports this.

Given the additional rainfall potential and moist antecedent
conditions overall, there should tend to be scattered areas of
additional flash flooding going through the remainder of the
evening and a part of the overnight period. This will include a
localized urban flash flood concern as well.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...CTP...LWX...PBZ...RLX...RNK...

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

LAT...LON   40678047 40567966 39947837 38797727 38387668
            38077618 37737574 37427585 37347631 37577803
            38087958 38778059 39858121 40338116