Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 253 PM EST Sun Jan 10 2021 Valid 00Z Mon Jan 11 2021 - 00Z Wed Jan 13 2021 ...Snow ongoing in Texas will shift eastward into parts of the Lower Mississippi Valley overnight... ...Precipitation is forecast to increase in the Pacific Northwest for the beginning of the workweek and cause flooding in coastal areas... A low pressure system is forecast to track eastward across the northern Gulf of Mexico over the next couple of days, causing precipitation to its north across the south-central and southeastern CONUS. Accumulating snow ongoing across portions of Texas will shift into parts of the Lower Mississippi Valley tonight, where a few inches of snow is possible. Winter Storm Warnings and Winter Weather Advisories remain in effect for these areas. Some light snow or mixed precipitation could spread into the Tennessee Valley and into the Southern/Central Appalachians on Monday into Tuesday, but not much accumulation is expected there. Farther south along the Gulf Coast, light to moderate rain is forecast, and light rain will move into the Southeast and Carolinas Monday/Tuesday as low pressure shifts into the Atlantic. A plume of deep Pacific moisture (atmospheric river) is forecast to take aim at the Pacific Northwest on Monday onward, causing multiple rounds of heavy rain along the coast and in lower elevations. Several inches of rain is likely over the next few days, which will lead to river flooding/flash flooding. Slight and even Moderate Risks of excessive rainfall are in place for those lower elevations of the Pacific Northwest. Meanwhile, in higher elevations of the Washington Cascades, a couple of feet of snow is expected through Tuesday evening, with some snow spreading into the Northern Rockies as well. Elsewhere, some lake effect snow showers are possible through Tuesday with generally light accumulations, though downwind of Lake Ontario could see a few inches of snow. Temperatures will stay cooler than normal by 15 to 25 degrees in Texas into parts of the Southeast on Monday, moderating somewhat on Tuesday. Meanwhile, milder than average temperatures should take hold across the northern tier of the U.S., especially in the Northern Plains, where highs could be 15 to 25 degrees above normal by Tuesday. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php