Flash Flood Guidance
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836
AWUS01 KWNH 061545
FFGMPD
NYZ000-PAZ000-062130-

Mesoscale Precipitation Discussion 0404
NWS Weather Prediction Center College Park MD
1144 AM EDT Thu Jun 06 2024

Areas affected...Central and Eastern Upstate New York...Far
Northeast PA...

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

Valid 061545Z - 062130Z

Summary...Deep convection was oriented favorably for localized
training/cell mergers, resulting in estimated 1-1.5 inch/hr rain
rates in spots.  Flash flooding is possible as storms translate
eastward across the southern half of Ohio through 04-05Z, with
convection potentially reaching western Pennsylvania/northern West
Virginia around/after that timeframe.

Discussion...Broad low-level confluence both along and ahead of a
surface front in Indiana was providing enough lift for scattered
to numerous thunderstorms across central Ohio recently.  The
storms were organized as a series of both cells and small linear
segments, with a focused axis of training/cell mergers noted
near/north of Columbus.  The storms were in an moist and
sufficiently unstable environment for deep updrafts with efficient
rainfall rates, which exceeded 1 inch/hr beneath the more
persistently training storms in the area.  These rain rates were
approaching FFG thresholds of 1.5 inch/hr across the region,
suggesting a continued, and at least isolated, flash flood threat
in the short term.

These cells will continue to shift eastward at approximately 15-25
mph, with slow movement and 1.7 inch PW values continuing to
support efficient rainfall.  Over time, some degree of boundary
layer cooling is expected, although upper 60s to 70F dewpoints
should maintain some degree of buoyancy to support deep convection
over at least the next 3-4 hours.  Potential exists for this
activity to reach more sensitive ground conditions in eastern
Ohio/western Pennsylvania beginning after 04Z or so.  The flash
flood scenario will be re-evaluated for any potential eastward
persistence after 05Z.

Cook

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

ATTN...WFO...ALY...BGM...BTV...BUF...

ATTN...RFC...MARFC...NERFC...NWC...

LAT...LON   45017500 44837398 43557381 42217354 41617433
            41517562 41967661 42327725 42897723 43377691
            43627642 44187634