Prognostic Meteorological Discussion
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FXUS01 KWBC 202031

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
430 PM EDT Sun May 20 2018

Valid 00Z Mon May 21 2018 - 00Z Wed May 23 2018

...Shower and thunderstorm activity will continue across portions
of the southern Plains, Ohio Valley, and Mid-Atlantic states...

...Another day of heavy rain with embedded thunderstorms expected
for much of Florida on Monday...

...Afternoon showers and thunderstorms will continue to develop
over California, the central Great Basin, and northern Rockies...

Showers and thunderstorms will continue to develop along and south
of a wavy frontal boundary stretched from the southern Plains to
the Ohio Valley and Mid-Atlantic states.  Given the moist and
unstable airmass in place, locally heavy rain and strong storms
may be possible within developing convection.  Activity should be
mostly scattered in nature, with the exception of across portions
of the middle Mississippi and Ohio Valleys Sunday night into
Monday, where dampening shortwave energy lifting through aloft
should help enhance precipitation across the region.  Also,
moisture surging out of the Gulf of Mexico, ahead of an amplifying
western U.S. trough, could help focus organized areas of heavy
rain or strong to severe storms over the southern High Plains
Monday into Tuesday.

Heavy rain with embedded thunderstorms will continue to develop
within an axis of highly anomalous moisture aligned over Florida
Sunday evening.  The moisture axis will be slow to edge westward,
keeping rain and thunderstorms in the forecast for much of Florida
again on Monday and potentially Tuesday.

Afternoon showers and thunderstorms are expected beneath a large
scale upper trough amplifying over the western U.S. early this
week.  The amplifying trough should also keep daytime temperatures
below normal across California, the central Great Basin, and
Southwest, while a warming trend is expected with upstream ridging
building over the Northwest.


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