Mesoscale Precipitation Discussion 0613
NWS Weather Prediction Center College Park MD
214 PM EDT Wed Aug 08 2018

Areas affected...WESTERN AND CENTRAL NEW YORK

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

Valid 081812Z - 082300Z

Summary....Flash flooding is possible this afternoon into early
evening over portions of western and central New York.  There are
indications that the risk will be increasing during the afternoon.

Discussion...Convection should continue to expand this afternoon
over parts of New York as a system makes its way eastward out of
the Great Lakes.  Low level flow is weak and is expected to remain
weak, while a speed maximum at the jet stream level will be
providing a mechanism for deep layered lift aloft.  Surface low
presure moving northeast along a quasi-stationary boundary early
this afternoon will provide a focus for convection.  The front
should become a cold front once low level winds become north and
northwest in response to the surface low...which in turn will
allow the front to also become a focus for convection. 

WPC rainfall forecast places the highest amounts during the
afternoon and early evening in areas where Flash Flood Guidance is
in generally in excess of 2 inches per 3 hours...only clipping a
small area of FFG values that are barely an inch located east of
BGM and north of MSV.  Despite the fact that Precipitable Water
values will be approaching or exceeding 1.75 inches, think that
flas flooding will be possible given the slow motion and high
rainfall intensities...but not likely.

Bann

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

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

LAT...LON   43727564 43537514 43197441 42687410 42377486
            42037597 42257670 42367702 42517736 42767758
            43157714 43427663 43697600