AWUS01 KWNH 231237
FFGMPD
MEZ000-NHZ000-231735-

Mesoscale Precipitation Discussion 0706
NWS Weather Prediction Center College Park MD
835 AM EDT Tue Jul 23 2024

Areas affected...Portions of Southern and Eastern Maine...Southern
New Hampshire

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

Valid 231235Z - 231735Z

SUMMARY...Bands of heavy showers and thunderstorms will continue
to impact areas of southern and eastern Maine, and possibly
southern New Hampshire going through midday. Heavy rainfall rates
of 1 to 2 inches/hour may result in some additional concerns for
flash flooding.

DISCUSSION...The latest radar and satellite imagery show a rather
expansive area of showers and thunderstorms across areas of
southern New Hampshire through southern and eastern Maine,
including some cells that are producing rather heavy rainfall
rates that are upwards of 1 to 2 inches/hour.

The convection this morning is being driven by the arrival of an
mid-level shortwave trough across the Northeast which is showing
up very well in the GOES-E WV suite. This energy is interacting
with a weakly buoyant, but moist airmass characterized by MUCAPE
values of around 500 J/kg and PWs that are near 1.75 inches.

There is a corridor of stronger low-level moisture convergence
noted along and just inland of the coast of Maine, with the
stronger parameters generally noted over Downeast Maine ahead of
the main axis of convection. This should support areas of heavy
rain overspreading these areas, while also continuing locally
farther to the southwest near and inland of the Maine coast. Radar
imagery shows the southwest tail of the overall band of shower and
thunderstorm activity still lingering a bit of southern New
Hampshire as well, and this is suggestive of a band of lingering
low-level convergence across these areas.

Given the very moist and rather efficient environment through the
vertical column for elevated rainfall rates, some additional
rainfall totals of 2 to 3+ inches will be possible going through
midday, and this may result in additional concerns for runoff
problems and flash flooding. The recent hires model CAMs support
conditions improving though early this afternoon as the
upper-level shortwave trough begins to exit the region.

Orrison

ATTN...WFO...CAR...GYX...

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

LAT...LON 45536795 45426718 44796719 43876891 43207053
43157155 43527212 43797159 44207054 44846893

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