US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 238 PM EST Mon Feb 22 2021 Valid Thursday February 25 2021 - Monday March 01 2021 Hazards: - Heavy rain across portions of the Southern Plains, the Middle/Lower Mississippi Valley, the Tennessee Valley, the Ohio Valley, and the Central/Southern Appalachians, Thu-Mon, Feb 25-Mar 1. - Heavy snow across portions of the Pacific Northwest, the Northern Rockies, and the Northern Great Basin, Thu-Fri, Feb 25-Feb 26. - Flooding possible across portions of the Southeast. - Flooding occurring or imminent across portions of the Southeast and the Mid-Atlantic. - Flooding likely across portions of the Southeast. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sat-Sun, Feb 27-Feb 28. - High winds across portions of the Aleutians, Sun-Mon, Feb 28-Mar 1. - Much above normal temperatures across portions of mainland Alaska, Thu-Sat, Feb 25-Feb 27. Detailed Summary: The medium range period (Thursday, February 25 - Monday, March 1) will feature periods of upper-level troughing generally located over the western half of the U.S., with an upper-level high over the Gulf of Mexico and Caribbean. This pattern should lead to moist and relatively warm air flowing from the Gulf of Mexico into the eastern half of the CONUS. A couple of fronts with waves of low pressure along them are expected to provide areas for this moisture to focus, leading to a couple of rounds of moderate to potentially heavy rain. The current forecast shows rain on Thursday into Friday across portions of the Southern Plains, Lower Mississippi Valley, and into the Tennessee Valley. Then another round begins around Saturday as moisture increases and lasts into Monday, and rain could spread slightly northward into the Ohio Valley as well. However, timing and location uncertainties were still high enough not to separate Heavy Rain areas spatially or temporally on today's Hazards graphic, though every area may not see heavy rain each of those days. Light wintry precipitation is possible north of the heavy rain axis. In the West, heavy snow is possible particularly for the Cascades and Northern Rockies for the latter part of the workweek as a frontal system passes through. Lower snow amounts are expected for the Wind River Mountains/Tetons toward the Wasatch and Central Rockies. Gusty winds are also possible for the Northern Great Basin, Northern Plains, and the Rockies in between on Thursday and Friday, but at this point seem to remain below high winds thresholds. Precipitation could once again increase in the Northwest early next week, but amounts do not seem terribly high. With the aforementioned troughing across the West, somewhat below normal temperatures are forecast for the Great Basin, Rockies, and portions of the Plains. High temperatures could be 15 to 25 degrees below normal across central and southern portions of the High Plains on Thursday, but still nothing near the cold experienced over the last couple of weeks. Temperatures will likely be warmer than normal across the eastern third of the country. For Alaska, a surface low pressure system is forecast to move across the Bering Sea and produce some precipitation and gusty winds over the Aleutians and western Alaska for the latter part of the workweek. However, heavier amounts of precipitation are expected for Southcentral Alaska into the Panhandle as the low pressure system reforms in that area Saturday into Sunday. Most of the heavy precipitation is likely on Saturday, but should linger across the southeastern Panhandle on Sunday. Across the southwestern mainland, a period of upper-level ridging centered around Friday could cause much above normal temperatures, which could be hazardous as temperatures may rise above freezing. Then, another frontal system is forecast to track across the Aleutians early next week, which could lead to gusty winds and some precipitation there, as well as high waves offshore. Tate