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.


Gerhardt


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