Mesoscale Precipitation Discussion 0590
NWS Weather Prediction Center College Park MD
914 AM EDT Fri Aug 03 2018

Areas affected...Maryland panhandle, extreme northeastern West
Virginia, central Pennsylvania, south-central New York

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

Valid 031313Z - 031658Z

SUMMARY...Randomly oriented elevated thunderstorm clusters
continue to dump heavy rainfall across large chunks of central
Pennsylvania. Any such convective element could produce flash
flooding conditions, particularly where cells repeat.

DISCUSSION...Early morning GOES-16 0.64 micron visible satellite
imagery showed a broad axis of stratus clouds encapsalating vast
sections of the mid-Atlantic region. However, enough
mid/upper-level forcing juxtaposed with areas of MUCAPE values in
the 500 to 1000 J/kg range continues to drive random elevated
convection. Some of these elements have proven to be rather slow
moving as they drift toward the northeast. Given such low flash
flood guidance values in place, anticipate future hydrologic
issues as local watersheds cannot tolerate too much additional
water. Would anticipate further coverage of thunderstorm activity
further into the morning and early afternoon, especially where
areas are able to destabilize. A few breaks in the clouds are
noted which additional instances expected during the next few
hours. High-resolution guidance generally agrees on the heavy
rainfall signal but is struggling with smaller-scale placement.
Expect hourly rainfall rates to approach or potentially exceed
1.50 inches within some of the more robust cells. 

Rubin-Oster

ATTN...WFO...BGM...CTP...LWX...PBZ...

ATTN...RFC...MARFC...NERFC...OHRFC...

LAT...LON   42647556 42327513 41817533 41027645 40187756
            39717826 39367890 39587961 40197966 41057886
            41917774 42527641