Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Wed Aug 02 2017 Valid 00Z Thu Aug 03 2017 - 00Z Sat Aug 05 2017 ...Excessive heat to continue for the western U.S. over the next few days... ...Severe weather and flash flooding possible along a front moving from the Plains to Great Lakes... ...Showers and thunderstorms expected over the Gulf Coast states... A major heat wave will continue through the end of the week across the West Coast and into the Intermountain West. An upper level ridge extends from the Pacific Northwest to the Desert Southwest which will give way to high temperatures being over 15 degrees above average especially in the usually-temperate Pacific Northwest. Temperatures reaching the century mark will be possible across both Oregon and Washington state; temperatures in the immediate Pacific coastline are expected to reach the mid 90s. As a result, widespread excessive heat warnings and heat advisories extend from the Pacific Northwest southward into central California and northwestern Nevada. Meanwhile, a strong cold front will plunge from the central and northern Plains today and will move through the Upper Midwest on Thursday. Showers and thunderstorms will move with the primary surface low--reaching the western portions of the Upper Midwest by early Thursday morning. Some of these storms could be severe in the central Plains. By Thursday evening, the front will stretch from the Upper Great Lakes to the central Rockies with showers and thunderstorms forming along and ahead of the front. The heaviest rainfall will occur mostly in the Great Lakes and middle Mississippi Valley--with flash flooding and severe weather being potential hazards. As the front continues its eastward progression on Friday, precipitation will spread into the Lower Great Lakes to the Tennessee Valley. Severe weather will be possible for the lower Great Lakes and portions of the Ohio Valley. A frontal boundary along the Gulf Coast will act as a focal point for convection across this region over the next few days. Daytime heating will lead to instability and combining this with moisture from the Gulf of Mexico will lead to an increase in thunderstorms in the afternoon and early evening. In the Desert Southwest and central/southern Rockies, monsoonal moisture along with assistance of daytime heating will also lead to typical afternoon thunderstorms through the short term period. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php