Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Sat Jun 27 2020 Valid 12Z Sat Jun 27 2020 - 12Z Mon Jun 29 2020 ...Severe thunderstorms are possible across the northern Mid-Atlantic/Northeast today and the southern Mid-Atlantic/Carolinas tomorrow... ...Flash flooding is forecast for the Mississippi and Ohio Valleys through the weekend... ...Saharan dust should continue to affect the Gulf Coast states and Tennessee Valley today, easing some Sunday... ...Much cooler temperatures and increasing precipitation likely for the Northwest, while the Central Great Basin and Southwest will see fire danger... A frontal system is forecast to push eastward through the Great Lakes region and then through the Northeast and Mid-Atlantic Sunday into Monday. Ahead of the front, conditions will be favorable for severe weather, particularly high winds, and a Slight Risk of severe weather is delineated by the Storm Prediction Center for northern portions of the Mid-Atlantic and southern portions of the Northeast today. The risk shifts southward tomorrow over parts of the Carolinas and southern Mid-Atlantic. Meanwhile, the western end of the front is expected to stall in the Midwest and then lift slowly northward through the weekend. A Slight Risk of flash flooding is in place today across parts of the Middle Mississippi Valley and Ohio Valley, where the stalling front could lead to training storms causing locally heavy rainfall totals. Then on Sunday, Slight Risks of flash flooding are outlooked for portions of the Upper Mississippi Valley and the Ohio/Tennessee Valleys. Surface high pressure is expected over the Southeast, influenced by the western edge of the Bermuda High. This flow pattern will lead to continued inflow of Saharan dust into the southeastern part of the country. The main impacts of the Saharan dust will be hazy skies during the day, locally reduced visibility, and degraded air quality. However, this could also make for some very colorful sunrises and sunsets with deeper oranges and reds compared to normal. On Sunday, the highest concentration of dust looks to focus mainly over Florida. Additionally, temperatures over Florida should be hotter than normal, and could even set records with highs in the upper 90s through Sunday. A potent upper-level trough is forecast to dive southward into the West through the weekend. Ahead of the trough, another day of heat is expected across California and the Central Great Basin, and Heat Advisories are in place over the San Joaquin Valley. Widespread Red Flag Warnings are also in effect for portions of California toward the Four Corners along with Critical Risks of fire weather as the hot temperatures combine with the potential for gusty winds and low humidity. But in the Northwest, a dramatic cooldown is expected on Sunday, with highs 15 to 25 degrees below normal. Precipitation is also forecast to become more widespread and heavy as the weekend progresses, with rain totals locally exceeding 2 inches over the Northern Rockies. Light snow is even possible for higher elevations of the Cascades and Northern Rockies given the cold temperatures. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php