Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 420 PM EDT Thu Jul 01 2021 Valid 00Z Fri Jul 02 2021 - 00Z Sun Jul 04 2021 ...Excessive heat continues across interior sections of the Northwest, the Northern Rockies, and the Northern High Plains... ...Thunderstorms, heavy rain, and flood chances continue ahead of a cold front moving across the eastern U.S.... ...Heavy rain and thunderstorms likely throughout the Central and Southern Plains, Southern Rockies, and Desert Southwest.... An upper-level ridge remains in place across the western U.S. as the excessive heat continues for the interior Northwest, Northern Rockies, and Northern High Plains. Daily highs well above normal are expected through the end of the forecast period, with highs at or above 100 likely for the interior valleys and Northern High Plains and in the 90s at higher elevations. While these highs are not as hot as the historic temperatures seen earlier this week, the oppressiveness of the heat is compounded by the length of the heat wave. Excessive Heat Warnings remain in effect for portions of eastern Washington and Oregon, northern Idaho, the Snake River Valley of Idaho, northwestern Montana, and the high plains of eastern Montana. Heat Advisories remain in effect or the Northern Rockies of Montana as well as portions of southern Oregon and northern California. In the East, a cold front is progressing southward today through the interior Northeast, central Appalachians, and the Ohio Valley. The Storm Prediction Center has issued a Slight Risk for severe weather through this evening for the eastern Mid-Atlantic for the threat of high winds. A Slight Risk for excessive rainfall is also in effect from the Mid-Atlantic west through the central Appalachians and eastern Ohio and Tennessee Valleys. Rainfall totals between 2-4 inches are possible through Friday morning. The heavy rainfall and flood chances will continue Friday and Saturday as the front progresses southeastward. There is a Slight Risk of excessive rainfall in effect for eastern North Carolina for the risk of flash flooding as storms may have rainfall rates of 1-2 inches per hour. A Marginal Risk continues southwestward through the Southeast ahead of the front for more isolated instances of heavy rain. By Saturday, the front approaches the Gulf Coast and heavy rain is once again forecast, with a Marginal Risk of excessive rainfall in effect for potential rainfall totals of 1-2 inches. Behind the front, much cooler weather is expected than earlier this week, with highs only in the 60s in New England and the 70s to low 80s throughout the rest of the Northeast and Mid-Atlantic. Further west along the front, there will be daily thunderstorm and heavy rain chances in the Central and Southern Plains as the cold front continues southward and becomes stationary along the High Plains. There is a Slight Risk for excessive rainfall stretching from western Oklahoma northwest into the Central High Plains where rainfall totals over an inch are likely through Friday morning, with locally higher amounts of 2-3 inches possible. A Marginal Risk is in effect for Friday for the Southern High Plains as continued instances of heavy rainfall remain possible with storms along and ahead of the stationary front. Additionally, a moist airmass in place over the Southern Rockies and Desert Southwest through the end of the period will lead to the threat of heavy rain with any daily showers or thunderstorms. Marginal Risks for excessive rainfall are in effect for both Friday and Saturday with hourly rainfall rates of 1-2 inches possible with any downpours, leading to flash flooding concerns. As in the Northeast, cooler weather behind the front and daily storm chances along and ahead of the front will keep temperatures more comfortable for this time of year, with daily highs generally in the 80s outside of the Desert Southwest. Putnam Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php