Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Tue Aug 04 2020 Valid 00Z Wed Aug 05 2020 - 00Z Fri Aug 07 2020 ...Tropical Storm Isaias reaches southeast Canada tonight with improving conditions across the Northeast overnight and into Wednesday... ...Severe thunderstorms are possible in the High Plains today and Wednesday... ...The Southwest and Intermountain West stays hot, cooler conditions arrive on the West Coast and continue in the Midwest... After leaving a trail of wind damage, power outages, and both coastal and inland flooding earlier today, Tropical Storm Isaias is marching quickly through Northeast this afternoon. The threat for both flash flooding and severe weather moves into northern New England this evening. A moderate risk for flash flooding is located from the Hudson Valley to the Champlain Valley while a large slight risk area for severe storms and potential tornadoes engulfs much of southern New England. The quick moving Isaias will reach Ontario overnight with a cold front associated with a surface low in western Ontario ushers in cooler and drier conditions late tonight and into Wednesday. By Wednesday morning, Isaias is forecast to become a post tropical system and track deeper into eastern Canada. The Great Lakes and Northeast will enjoy drier and more comfortable conditions as high pressure moves in aloft, but the front is expected to stall over the Mid-Atlantic with additional showers and storms possible through Thursday. There is a marginal risk for excessive rainfall from the northern Mid-Atlantic to the Carolinas both Wednesday and Thursday. In the central U.S., a pair of frontal boundaries will be responsible for triggering showers and thunderstorms in parts of the Plains. There is a slight risk for severe storms in the central High Plains today, along with a marginal risk for flash flooding. The front makes little progress east on Wednesday leading to yet another round of severe storms in the central High Plains. Farther west, spotty dry thunderstorms are possible Wednesday over the Snake River Valley, Blue Mountains, and the Great Sandy Desert of the interior Northwest. By Thursday morning, a cold front approaching from the northeast Pacific slams into the Pacific Northwest with showers and perhaps a few thunderstorms. Temperature-wise, the hottest conditions will remain confined to the Southwest as triple digit high temps occur each afternoon West Texas to the Desert Southwest. The Intermountain West can also expect abnormally hot temperatures with daytime highs in the 90s and occasionally reaching the century mark in the valleys. By Thursday, sizzling summer heat returns to the northern High Plains. The aforementioned Pacific cold front looks to cool off the West Coast. Abnormally cooler conditions stick around in the Midwest while hot and humid conditions persist in the Southeast. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php