Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 251 AM EST Thu Dec 10 2020 Valid 12Z Thu Dec 10 2020 - 12Z Sat Dec 12 2020 ...Low pressure system to track through the Southwest today, then into the central U.S. on Friday... ...Active weather pattern to returning to the Northwest... ...Warmer than normal temperatures to engulf the East by the start of the weekend, cooler temperatures return to the West... An area of low pressure tracking into northwest Mexico this morning is sending showers into the drought-stricken Southwest today. As moisture ahead of the storm makes its way into the southern Rockies, precipitation will fall in the form of snow and may fall heavily at times. Winter Storm Warnings and Winter Weather Advisories are out for portions of the southern Rockies that are forecast to pick up as much as a foot of snow over the next couple days. As the upper trough responsible for developing this storm system heads east, so will its slug of Pacific moisture as rain and snow breakout in the southern and central High Plains Thursday night. By Friday, the storm will tap into moisture from the Gulf of Mexico and the upper trough looks to strengthen across the central U.S., supporting a growing area of precipitation from the Southern Plains to the Midwest. Thunderstorms are possible in the South Central U.S. with some storms potentially becoming severe. Meanwhile, a cold front plunging south through the Midwest ushers in temperatures cold enough to support accumulating snowfall from the plains of Colorado to the Midwest Friday into Saturday. The current snowfall forecast for Friday through early Saturday morning suggests a swath of 3 to 6 inches is possible from northern Kansas and southern Nebraska to south-central Iowa, making for potentially treacherous travel conditions in these areas. Residents in the Midwest and Great Lakes will want to monitor this storm system closely over the next day or two as heavy snow is possible in these areas on Saturday. Active weather is also on tap in the Pacific Northwest as a series of Pacific disturbances track towards the region to close out the week. The first round of precipitation arrives this afternoon with rainfall and mountain snow accumulations generally on the light side. Lingering showers and mountain snow are likely to continue across western Oregon and Washington on Friday before another disturbance arrives Friday evening, marking the arrival of moderate-to-heavy showers and mountain snow up and down the Cascades. The Cascades can expect over a foot of snow through Saturday morning with the heaviest totals focused in the Oregon. Rain and mountain snow are also anticipated over northern California Friday night into early Saturday morning. A storm system packing even more Pacific moisture then makes its way into the Pacific Northwest on Sunday. The Plains and Mississippi Valley are in for one more day of considerably mild temperatures with highs soaring into the 70s throughout the South Central U.S.. Even a few record highs could be broken in spots. As the dome of high pressure responsible for the warm first half of the week in the Intermountain West and Plains slides east, so will the expansive area of mild temperatures. This means the chilly first half of the week along the East Coast will be a thing of the past as more seasonal temperatures return today and warm to above normal levels on Friday. The Ohio and Tennessee Valleys in particular can expect highs in the 60s on Friday. Saturday gets even warmer with high temps in parts of the Mid-Atlantic reaching 60 degrees. Meanwhile, the broad troughing pattern in the West will mean the return of cooler than normal conditions. The coldest anomalies should become focused in the central High Plains on Friday where daytime high temps in some locations struggling to get above freezing. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php