Severe thunderstorms and flash flooding will impact portions of theGulf Coast tonight and the Southeast on Tuesday......Above-average temperatures expected for South Florida and the West...A slow-moving frontal boundary extending along the Gulf Coast will remaina focus for unsettled weather, with severe thunderstorms and heavy rainexpected to impact portions of the region through Tuesday.  Ongoingshowers and storms are likely to continue through tonight, with severestorms expected from south-central and southeast Texas across southernLouisiana, as well as the Florida Panhandle.  The Storm Prediction Center(SPC) has highlighted these areas with an Enhanced Risk (level 3/5) forsevere weather, indicating the potential exists for multiple corridors ofdamaging winds, very large hail, and a few tornadoes.  In addition to thesevere weather threat, abundant moisture pooling along front will supportheavy rainfall and the potential for flooding.  A Slight Risk (level 2/4)for excessive rainfall extends along the Gulf Coast from southeast Texasthrough the Florida Panhandle, with a Moderate Risk (level 3/4) fromsoutheast Louisiana to the Florida Panhandle.Drier air will push through the western Gulf Coast, confining the threatfor severe storms and heavy rainfall to northern Florida and southernGeorgia on Tuesday.  SPC is indicating a Slight Risk (level 2/5) forsevere weather and WPC is highlighting the area with a Slight Risk forexcessive rainfall. Further to the north, a low pressure system will drift slowly east,spreading showers and thunderstorms from the lower Missouri and midMississippi valleys to the Ohio Valley tonight.  Showers and storms willcontinue across these areas on Tuesday while expanding east through theMid-Atlantic and the Northeast.  Unsettled weather will persist across theMid-Atlantic and the Northeast through Wednesday.  A brief window of drierweather over the Mississippi Valley late Tuesday into early Wednesday willbe followed by the next round of showers and storms that will begin tospread into the region by late Wednesday. Before impacting the central U.S. on Wednesday, this previously notedsystem will spread showers and storms followed by much cooler temperaturesfrom the northern Rockies into central Rockies and High Plains on Tuesday.Temperatures will remain well above-normal, with near to record hightemperatures expected across South Florida Tuesday and Wednesday.  Whilenot expected to be record-setting, temperatures will build across much ofthe West, reaching well-above normal highs across the region by