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