Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Fri Aug 13 2021 Valid 12Z Fri Aug 13 2021 - 12Z Sun Aug 15 2021 ...Monsoonal thunderstorms expected in the Southwest through the end of the week... ...Rounds of thunderstorms likely along and ahead of a front from the Central Plains to Ohio/Tennessee Valleys to the Northeast/Mid-Atlantic... ...Fred is forecast to impact much of Florida with heavy rain as it crosses the Keys on Saturday... ...Oppressive heat continues across the Northwest, Eastern Seaboard, and south-central CONUS... A busy weather pattern is in place through the weekend as multiple features set up to the south of a slow-moving upper-level trough stretching from central Canada into the north-central U.S. One concern over the next few days is for heavy rain and flooding potential in the Southwest as monsoonal moisture continues to flow into the region. Slight Risks of excessive rainfall are in place for much of Arizona and New Mexico and into Far West Texas through Saturday, along with Flash Flood Watches. Farther east, as the aforementioned upper trough edges eastward, at the surface it will push a cold front eastward across the northeastern quadrant of the country while meandering slowly around the Central Plains/Middle Mississippi Valley. As moisture flows into the front, it should provide a focus for rain and thunderstorms, with both severe weather and flash flooding as possible threats. Today, the greatest chances for severe weather look to be on the back end of the front in the Central High Plains, as well as over Kentucky, with Slight Risks delineated by the Storm Prediction Center. Isolated flash floods are also possible today over a large Marginal Risk area stretching from Oklahoma north and eastward toward the Mid-South, Ohio Valley, Great Lakes, and Mid-Atlantic. Then on Saturday, heavy rain looks to focus over portions of the Mid-Atlantic, and especially given the wet antecedent conditions, scattered flash floods are possible and a Slight Risk of excessive rainfall is in place. A few severe thunderstorms could also occur. What is currently Tropical Depression Fred is expected to restrengthen into a Tropical Storm later today as it tracks northwestward. It is forecast to cross the Florida Keys on Saturday and then move into the eastern Gulf of Mexico, and should spread tropical rains to the Florida Peninsula today and through the weekend. The heavy downpours could result in flooding/flash flooding issues, and Marginal to Slight Risks increase in size over the state over the next few days. The ongoing heat will also be a hazard during the short range period across multiple regions. First, the Northwest can expect continued record-breaking heat in terms of both high minimum and maximum temperatures. Excessive Heat Warnings are in effect along with a few Heat Advisories on the periphery as temperatures soar into the 100s in the Pacific Northwest and the Northern Great Basin. The heat is forecast to lessen somewhat at least in the Seattle and Portland areas this weekend, but the interior will remain hot, and above normal temperatures are expected to spread toward the Northern Plains by Sunday. 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 remain a threat as well, which could spark additional fires. In the East, another day of high humidity and hot temperatures creating high heat indices is expected, and Heat Advisories are in effect from North Carolina to Maine and also into portions of West Virginia, with Excessive Heat Warnings embedded in the northern Mid-Atlantic. Heat Advisories are also in place for portions of the Ark-La-Tex region into southeastern Oklahoma. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php