Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 430 PM EDT Thu Jun 03 2021 Valid 00Z Fri Jun 04 2021 - 00Z Sun Jun 06 2021 ...Record heat spreading from the western U.S. into the northern Plains and upper Midwest... ...Severe weather and scattered flash flooding possible into this evening across the Northeast and Mid-Atlantic... ...Thunderstorms and heavy rain expected to shift from southern Texas toward the Louisiana coast during the next couple of days... A strong upper-level ridge of high pressure over the interior western U.S. responsible for the record-breaking heat from the Great Basin to the Intermountain West today will gradually give way to an upper-level trough moving into the Pacific Northwest. The record heat will then shift northeastward into the northern Plains towards the upper Midwest on Friday behind a warm front, where widespread high temperatures in the upper-90s to near the century mark are in the forecast. Temperatures this hot can increase the potential for heat-related illnesses. As such, Heat Advisories are in effect from eastern Washington to portions of Montana. Parts of the Great Basin into California and the Desert Southwest are under Excessive Heat Warnings. Much of this region is also in the middle of extreme or exceptional drought conditions, which will also promote the danger of wildfires in portions of these areas. A cold front entering the Pacific Northwest today will filter in much cooler temperatures during the next couple of days for sections of Washington, Oregon, and Idaho. This frontal boundary could also trigger scattered thunderstorms from the northern Rockies to the northern High Plains on Friday. For the eastern and south-central United States, an increasingly warm and humid airmass will promote scattered showers and thunderstorms from the Northeast to the western Gulf Coast. High pressure located in the western Atlantic will continue to bring southerly winds and ample moisture up the eastern third of the country, with a weak cold front located across the Ohio and Tennessee valleys to help spark thunderstorm activity. A few severe thunderstorms are possible into this evening across the Mid-Atlantic and Northeast, with damaging wind gusts and isolated tornadoes possible. In addition, WPC has highlighted the Mid-Atlantic for a slight potential for flash flooding due to scattered heavy rain. Further south, linger precipitation will also be found across portions of Louisiana and southern Texas. This section of the country has experienced a plethora of rainfall over the last month, which has made ground conditions susceptible for flash flooding. Due to this concern and the potential for an additional 1 to 3 inches of rain today across southern Texas, WPC has issued Slight Risk of Excessive Rainfall for the region. Rain chances will continue into the early part of the weekend as well, thanks to a slow-moving upper level low located over the Lone Star State, with a tendency to shift the heavy rain toward the Louisiana coast by Saturday. Kong/Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php