Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 304 PM EDT Wed Aug 04 2021 Valid 00Z Thu Aug 05 2021 - 00Z Sat Aug 07 2021 ...Heavy rain and scattered flash flooding possible tonight across southeastern New England, the southern Rockies, and the Florida Big Bend region... ...Dangerous heat found across the Desert Southwest and Interior Pacific Northwest through Thursday... A mid- to upper-level ridge building from the Southwest into the Pacific Northwest will continue to spread drier conditions across interior sections of the West Coast while shifting most of the monsoonal showers farther eastward from the central and southern Rockies into the High Plains. Locally heavy rain is possible this evening over the southern Rockies/High Plains before diminishing by Thursday. Scattered flash flooding will be a particular concern near burn scars. Meanwhile, the drying trend brought by the building ridge will lead to above average temperatures across the Desert Southwest northward to the interior Pacific Northwest. High temperatures in the 110s will be common in the Desert Southwest for the next couple of days while upper 90s to 100 degrees are forecast for the interior Pacific Northwest this afternoon. As a result, Excessive Heat Warnings are in effect for the Desert Southwest through Thursday evening while Heat Advisories are in effect for this afternoon across the interior Pacific Northwest. In addition, fire weather danger is forecast to increase over the Great Basin into Thursday. A system moving east from the Pacific will begin to bring cooler air into the Pacific Northwest on Thursday together with a round of rain/thunderstorms eastward into the northern Rockies. The rain/storms are expected to continue across the northern Rockies into early Friday as the heat spreads further east into the northern/central Plains and upper Midwest, where widespread high temperatures are forecast to reach into the upper-80s and 90s by Friday. Elsewhere, a frontal boundary is forecast to remain nearly stationary near the Gulf Coast as well as along and just off the East Coast through the end of the week. An axis of heavy rain is forecast to extend along the boundary and associated waves of low pressure. The heaviest rainfall should stay just off the coast; however, a modest influx of moisture is expected to enter southeastern New England tonight and could produce around 1-2 inches of rainfall. This region has experienced a very wet summer thus far, therefore isolated to scattered flash flooding is possible from eastern Connecticut to coastal Maine. Some heavy rainfall is also possible across northern Florida and the Big Bend region, as well as across southern Texas for the next couple of days. Snell/Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php