Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 406 PM EDT Mon Jun 29 2020 Valid 00Z Tue Jun 30 2020 - 00Z Thu Jul 02 2020 ...Locally heavy precipitation, including snow, likely over the Northwest along with colder temperatures... ...Severe thunderstorms and flash flooding are possible in the Northern Plains especially Tuesday and Wednesday... ...Fire danger is expected to continue over the Four Corners states to High Plains... ...Flash flooding will be possible with thunderstorms over parts of the Mississippi and Ohio Valleys... ...Saharan dust continues to linger across Florida while another round of dust could affect the western/central Gulf Coast on Tuesday... A large upper-level low is forecast to settle into much of the western U.S. during the next few days. This will bring a surge of unseasonably cool to cold temperatures through the western U.S., where high temperatures of 15 to more than 30 degrees below average are forecast. Widespread precipitation is also expected over the Northwest, where elevation-enhanced rain totals of 1 to 3 inches are likely in the northern Rockies. Wet snow is expected again during the next couple of nights for the higher elevations of the northern Rockies as temperatures drop to near freezing. In fact, a foot of snow is possible at the peaks of the Bitterroot mountains in Idaho. By Tuesday morning, wet snow is forecast to reach the Yellowstone National Park, the higher elevations of northern Utah, and as far south as the Colorado Rockies as the cold air mass continues to plunge southward through the southern Rockies. The snow is expected to linger into Wednesday morning for western Wyoming. To the east of the upper-level low, clusters of thunderstorms are forecast to traverse the northern Plains for the next couple days ahead of a cold front and a developing low pressure system. Some severe thunderstorms are also possible. Farther east, a cold front is forecast to slowly move southward down the Eastern Seaboard during the next couple of days as the trailing end of the front remains nearly stationary across the Ohio Valley and Midwest through Tuesday. This will favor bouts of scattered thunderstorms across the Mississippi Valley, Ohio Valley, and toward the Southern Appalachians. Widespread severe weather is not forecast, but a few strong storms are possible. The bigger threat will be flash flooding. Some areas in the upper Midwest will see heavy rain and strong thunderstorms into tonight. From Tuesday to Wednesday, the main threat of heavy rain should remain farther south over the Mid-Mississippi to lower Ohio Valleys. Meanwhile, rain and some thunderstorms along with cool temperatures are expected to linger across the Northeast through midweek as another upper-level low lingers over the region. A significant amount of the Saharan dust is forecast to persist over Florida for the next few days as another dust plume from the Sahara could reach the western Gulf Coast and lower Mississippi Valley by Tuesday. The main impacts of the Saharan dust will be hazy skies during the day, locally reduced visibility, degraded air quality, but with potentially colorful sunrises and sunsets. Lower concentrations of dust are forecast to spread up the Plains states ahead of the western U.S. upper low, while some is expected to spread eastward into the Southeast. In the meantime, temperatures over Florida will remain hotter than normal, and could even set records with highs in the upper 90s. Meanwhile, widespread Red Flag Warnings and Critical Risks of fire weather are in effect for much of the Four Corners states into this evening due to gusty winds and low humidity. As a cold front moves through ahead of the upper low, temperatures will cool and humidity will increase, so the threat of fire weather should diminish farther west and north, but remain across the Southern Rockies to Southern High Plains Tuesday. Kong/Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php