The Weather Prediction Center

Short Range Forecast Discussion

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Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
435 AM EDT Sun Sep 21 2014

Valid 12Z Sun Sep 21 2014 - 12Z Tue Sep 23 2014

...Coastal low near the Outer Banks to move into the Gulf of Maine
and Atlantic Canada later tonight through Monday...

...Scattered areas of showers and thunderstorms expected across
the southwestern states...

A fast-moving disturbance migrating across the the Great Lakes
this morning---will produce scattered showers and thunderstorms 
along its path---from lower Michigan, Indiana and northwest Ohio
to Pennsylvania, New York and the upper reaches of the Ohio Valley
later today. The area of disturbed weather will eventually reach
New England tonight. This disturbance will likely pass over---and
briefly interact with the coastal low moving up the US portion of
the Atlantic shoreline.

This coastal low---currently producing a narrow band of
moderate-to-heavy rainfalls and intermittent rain showers over the
Outer Banks will press northeastward into the Gulf of Maine later
tonight. It is already producing light rain and a few showers
along the New Jersey coast, Long Island and interior portions of
southern new England. Later today and through tonight---the
entirety of the coastal low moves very near Cape Cod and
precipitation will become more widespread for a time over New
England. By Monday morning, most of the rainfall will be moving
into Downeast Maine, Nova Scotia and New Brunswick---with much of
the Northeast and Mid-Atlantic region---replaced with a cooler and
drier Canadian airmass.

An upper-level low centered over southern Nevada will be moving
slowly northwestward today---and tonight, settle over the northern
Great Basin. Increasing clouds and the threat of thunderstorms
will gradually shift from the high deserts of Nevada and the
Sierra Nevada---to the southern Cascades and high deserts of
southeast Oregon and southern Idaho.

With the flow pattern aloft---a light southerly to southeasterly
wind---the southwest deserts, Rio Grande Valley, and Texas
Panhandle---will experience a Subtropical-like airmass with
mid-level moisture lifting upward along the south and
southeast-facing slopes of the Southern Rockies. Expect isolated
thunderstorms to move from the higher terrain into the adjacent
lower valleys, with occasional moderate rainfall intensity across
southern Texas, south-central New Mexico, southern Utah and
east-central Arizona.

Vojtesak

Graphics available at www.wpc.ncep.noaa.gov




Last Updated: 435 AM EDT Sun Sep 21 2014