Mesoscale Precipitation Discussion 0654
NWS Weather Prediction Center College Park MD
523 PM EDT Mon Aug 13 2018

Areas affected...Northeast PA...Ext South Central NY...

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

Valid 132121Z - 140130Z

SUMMARY...Wedge of Training Moderate Rainfall just east of flooded
area may exceed longer term FFG for possible flooding with
isolated flash conditions.

DISCUSSION...GOES-16 WV suite depicts deep low over SW PA with jet
streak 70kt 3H speed max lifting north along the Delaware River,
placing the area of concern in the left exit for broad scale
ascent.  Visible imagery depicts low level shear axis from Centre,
county to Northampton county to NYC.  While clear skies existed
this afternoon from North Central PA (Potter, county) to Bucks
county rebuilding instability with surface temps into the low/mid
70s with saturated profiles to 5H above, leading to SBCAPEs back
to 1000-1500 J/kg.  As such the intersection of the axes is
supporting enhanced convective development in Northampton county.

A wedge of instability is advected aloft to support weak elevated
convection into Lackwanna, PA and northward into Binghampton, NY. 
While not very deep, the saturated profiles and warm cloud
processes support .5" further north to near 1" further south. Mean
cell motions support training to the north persistently for the
next 4-6 hours. Locales near Scranton, PA have received 1.5" in
the last 3hrs.   As such,and additional 1.5-3" totals are expected
along this N-S axis over a longer duration.  As such flash
flooding may be possible but longer duration inundation is more
likely, especially given this axis is just east of the worst flash
flooding this morning.

Gallina

ATTN...WFO...BGM...CTP...PHI...

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

LAT...LON   42427571 42067529 41287525 40557530 40537562
            41147638 41857673 42367627