Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon Aug 19 2024 22:31:40

AWUS01 KWNH 192231
FFGMPD
MEZ000-MAZ000-NHZ000-RIZ000-VTZ000-CTZ000-NYZ000-200329-

Mesoscale Precipitation Discussion 0908
NWS Weather Prediction Center College Park MD
630 PM EDT Mon Aug 19 2024

Areas affected...Portions of the Northeast...New England

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

Valid 192229Z - 200329Z

Summary...Periodic training thunderstorms containing 1.5-2"/hr
rainfall rates will shift the threat of scattered flash flooding
eastward across portions of the Northeast and New England.

Discussion...Regional radar across New England continues to track
linear segments of showers and thunderstorms ahead of a slow
moving cold front analyzed over western New England. Over the last
several hours, fairly slow eastward translation of these storms
combined with estimated 1.5"/hr rainfall rates at times led to
several reports of flash flooding, primarily focused over areas
affected by the flooding yesterday.

While persistent cloud cover is preventing more robust
destabilization of the pre-frontal airmass, low-level moistening
and some breaks in the clouds have allowed for 500-1000 J/kg
within a favorable "tall-skinny" distribution to develop ahead of
the line. With PWAT values locally exceeding the 90th percentile
for the region and warm cloud depths of 11,000 feet, efficient
cells with maximum rates of 1.5-2"/hr should continue this
afternoon. A large component of the cloud-layer steering winds
oriented parallel to the front will support periods of training,
although the generally more progressive nature of the synoptic
forcing should allow for a faster eastward translation of
precipitation compared to yesterday.

Through 3z, the 18z HREF LPMM depicts rainfall totals upwards of
2-3", generally focused over portions of New Hampshire and
Northwest Maine. However, HREF neighborhood probabilities of 1-3
HR FFG exceedence on the order of 25-30% are noted across much of
the MPD area through 3Z. This suggests additional instances of
scattered flash flooding are possible going into the evening.

Asherman=20=20=20=20=20

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!9diNQqQ-o-QnDBT2TSIeR8e6XXGhlipHdnqJohMh6AH_R9yzG5k8AkfT41ATHTcX5mZ3=
IjjjcjpAJN75QCtpzBIGSwI$  for graphic product...

ATTN...WFO...ALY...BOX...BTV...CAR...GYX...OKX...

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

LAT...LON   47646856 46926828 44827009 42437138 40847237=20
            40807319 41787314 43397227 45287138 45987080=20
            46607025 47056978=20

=3D =3D =3D
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