Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Sat Feb 23 2019 Valid 12Z Sat Feb 23 2019 - 12Z Mon Feb 25 2019 ...HIGH Risk of excessive rainfall/flash flooding continues into Saturday for the Tennessee Valley... ...MODERATE Risk of severe weather for the Lower Mississippi and Tennessee Valleys... ...Blizzard conditions forecast for the Central Plains into the Middle/Upper Mississippi Valley... ...Heavy snow likely for higher elevations of the Northwest... An upper-level low and surface low are expected to strengthen today as they track northeastward through the Plains and Mississippi Valley and into the Upper Great Lakes region. This potent system will bring a myriad of hazardous weather to the central and eastern U.S. First, copious amounts of moisture will continue streaming into the Lower Mississippi and Tennessee Valleys and the Southeast ahead of the low and associated cold front, creating additional rain and thunderstorms over already oversaturated ground. A High Risk of excessive rainfall is in place for the Tennessee Valley, where any additional rain will cause more dangerous flooding. Widespread severe thunderstorms are likely for the southeastern U.S. as well. The Storm Prediction Center has currently outlooked a Moderate Risk for northern Mississippi, northwestern Alabama, and southwestern Tennessee, where strong long-track tornadoes, strong winds, and hail are all forecast. The rain and thunderstorms are expected to finally end for the Tennessee Valley on Saturday night and for the Southeast on Sunday after the cold front sweeps through the region, drying out the atmosphere. Record-breaking warmth is possible for the Central/Eastern Gulf Coast region on Saturday before the cold front passes. North of this low, winter weather is expected across the Central Plains, Middle/Upper Mississippi Valley, and into the Upper Great Lakes region. A swath of heavy snow of 6 to 10 inches is expected today in parts of the Central Plains and into the Upper Midwest, and snow continues into Sunday for the Upper Great Lakes region, where 12 to 18 inches of total snow is forecast. As the surface low strengthens, it will produce strong winds, which combined with the snow will cause blizzard conditions. Even after the accumulating snow ends across the Plains and Upper Midwest, high winds will contribute to considerable blowing and drifting snow through Sunday. Additionally, accumulating freezing rain is forecast, with over a tenth of an inch of ice likely in Wisconsin and northern Michigan. Difficult travel and power outages are to be expected with this storm. High winds will spread into the Ohio Valley and parts of the Central/Northern Appalachians by Saturday night and Sunday. In the Northwest, the wintry pattern continues as another upper low is expected to drop southward through the region and lead to moderate to heavy precipitation through the weekend. Though mainly rain along the Pacific Northwest coast, snow could mix in even in the lower elevation cities (Seattle and Portland for example) with the persistent cold conditions. Where rain does fall, it could be heavy at times, so a Marginal Risk of excessive rainfall is in place for the northern California and southern Oregon coasts on Sunday. In higher elevations of the Oregon Cascades, snow is likely to be 2 to 4 feet, and the Northern Rockies can expect heavy snow of 1 to 3 feet.Temperatures will remain colder than average in the western half of the CONUS. A surge of bitterly cold temperatures (20 to 40 degrees below average highs) is expected by Sunday in the Northern Plains. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php