Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 AM EDT Sun May 21 2017 Valid 12Z Sun May 21 2017 - 12Z Tue May 23 2017 ...There is a slight risk of severe thunderstorms over parts of the Lower Rio Grande Valley... ...Heavy rain possible from portions of the Southeast to the Central/Western Gulf Coast... Low pressure over the Upper Mississippi Valley/Upper Great Lakes will slowly move northward into Ontario on Monday. The associated front will become quasi-stationary from the Lower Great Lakes to Central Appalachians/Tennessee Valley to the Western Gulf Coast through Monday. High pressure aloft is expected to strengthen along the West Coast through early next week, resulting in dry conditions and rapidly warming temperatures. High temperatures on Sunday will rise will into the 80s and 90s for much of the interior West Coast states, but 90s will become much more widespread by Monday, with some areas of interior California approaching 100. These temperatures will be 10 to 20 degrees above average for many areas. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php