Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
440 AM EDT Mon May 20 2013

Valid 12Z Mon May 20 2013 - 12Z Wed May 22 2013

...Moderate risk of severe weather for eastern Oklahoma and the southern
Ozarks through Tuesday morning...

...Slight risk of severe weather for the Midwest and upper half of the
Mississippi Valley today and tonight...

...Heavy rainfall possible for the Upper Missouri and Mississippi
Valleys...

...Slow-moving Pacific system to bring rainfall...windy conditions and
cooler weather to the Pacific Northwest and northern Rockies...

Deep...slow-moving trough of low pressure in the north central Plains and
broad fetch of moist...southerly flow off the Gulf of Mexico is expected
to produce widespread showers...thunderstorms and locally heavy rainfall
over a large portion of the Plains...Midwest and central Great Lakes today
and Tuesday. Along with the threat of heavy rainfall...there is a moderate
risk of severe storms for the southern Plains and Ozarks and a slight risk
of severe weather for the upper half of the Mississippi Valley. Please
refer to the Storm Prediction Center for the latest information and
updates concerning the potential severe weather threat through Tuesday
morning.

Out West...low pressure in the Gulf of Alaska will slowly move across the
Pacific Northwest and northern Rockies. Inland...low pressure is expected
to intensify over southwest Canada with an increase in southerly flow and
threat for mountain showers and thunderstorms. By Tuesday morning...a
strong cold front and windy conditions surges across the Cascades and
spreads cooler and wetter weather into the northern Rockies and produces
scattered showers and a few thunderstorms into western sections of
Washington and Oregon.

In the East...scattered showers will continue across Maine and portions of
northern New England through this evening...as a slow-moving Canadian cold
front sweeps into the north Atlantic. For Monday night and Tuesday...a
broad warm front and more humid conditions will work their way up the East
Coast...with the threat of showers and a few thunderstorms for the
mid-Atlantic states...Appalachians and Northeast...including the upper
Ohio valley and Eastern Great Lakes.

Vojtesak

Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php