Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 509 PM EDT Sat Aug 14 2021 Valid 00Z Sun Aug 15 2021 - 00Z Tue Aug 17 2021 ...There is a Slight Risk of excessive rainfall over parts of the Southwest/ Southern Rockies, Southern tip of Florida, and the Mid-Atlantic through Sunday morning: The Slight Risk of excessive rainfall continues over parts of the Southeast through Tuesday morning... ...There is a Slight Risk of severe thunderstorms over parts of the Central High Plains and the Mid-Atlantic through Sunday morning... ...Excessive Heat Warning and Heat Advisory over parts of the West Coast... ...Fred will reform and impact parts of Florida with heavy rain as it moves northwestward... Multiple features set up to the south of a typical summer jet stream focused along the northern U.S. and Canada. One area of concern is the Southwest, as showers and thunderstorms are forecast as above regular monsoonal moisture continues to flow into the region. As a result, flash Flood Watches and Flood Advisories cover the southern half of Arizona, parts of New Mexico, and Far West Texas through Sunday, with a Slight Risk of excessive rainfall also in place into tonight. Farther east, a surface cold front will propagate eastward across the northeastern quadrant of the county today while meandering over the Plains and Mississippi/Tennessee Valleys through Monday. As moisture flows into the front, the moisture will provide a focus for rain and thunderstorms, with flash flooding and possibly severe weather as threats. Isolated flash floods are possible across much of the south-central and the southeastern U.S. through Monday, with broad Marginal Risk areas outlooked for excessive rainfall. The heavy rain could be enhanced over portions of the Mid-Atlantic, especially given the wet antecedent conditions. Scattered flash floods are possible, with the Slight Risk of excessive rainfall is in place. Some severe storms also could occur in a few areas along the frontal where the Storm Prediction Center has Slight Risk areas in place--the Central High Plains and the Mid-Atlantic. Meanwhile, the Tropical Depression Fred surface low has been disrupted due to the storm crossing the high terrain in Cuba. The mid and upperâ€level center of the system will be a trough through late Saturday night when the systems surface low reforms. What should once again become Tropical Depression Fred heads northwestward over the Gulf of Mexico, moving towards the Central Gulf Coast by Tuesday. Heavy tropical rain could cause scattered flash flooding over much of Florida through the weekend associated with the system. A Slight Risk of excessive rainfall is in place for southern Florida through the weekend, while portions of the Florida Panhandle are added to the Slight Risk Monday as Fred approaches. Heavy rain aside, the ongoing oppressive heat continues to be a hazard during the short-range period, especially across the West. Excessive Heat Warnings and some Heat Advisories cover much of the Pacific Northwest, the Great Basin, and California as temperatures soar into the 100s. This heat could be record-breaking once again in terms of both high minimum and maximum temperatures. The heat is forecast to lessen somewhat, at least in the Seattle and Portland areas, by Sunday. Still, the interior will remain hot, and above-average temperatures are expected to spread toward the Northern Plains to begin next week. In addition to the heat, Air Quality Alerts are in place for the Northwest and into parts of the Rockies given smoke from fires and high ozone levels. Unfortunately, isolated dry thunderstorms and Elevated to Critical fire conditions remain a threat through at least Sunday as well, which could worsen the ongoing fire situation in the West. Meanwhile, temperatures are expected to be warmer than usual today across the Eastern Seaboard ahead of the cold front, and warm minimum daily records could be set this morning with high heat indices again this afternoon. However, by Sunday, temperatures should be near to below average behind the cold frontal passage. Ziegenfelder/Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php