Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Mon Dec 17 2018 Valid 00Z Tue Dec 18 2018 - 00Z Thu Dec 20 2018 ...Active pattern continues for the West, with rain in lower elevations and heavy snow in higher elevations... ...Snow for the Interior Northeast through Monday night... ...Rainy for the Southern Plains by Tuesday evening, moving into the Lower Mississippi Valley and Southeast by Wednesday... Strong onshore flow will continue bringing moisture to the Pacific Northwest and the Northern Great Basin through the first half of the workweek, and a frontal system moving through is expected to enhance precipitation chances. Along the coast and in lower elevations, the precipitation will remain rain, and a Marginal Risk of excessive rainfall is in place now through Wednesday morning, with an embedded Slight Risk in far southern Oregon and far northern California for Tuesday. In higher elevations of the Washington Cascades, snowfall will be measured in multiple feet rather than inches, with colder temperatures and ascending air over mountains. Through Wednesday, the Northern Rockies could see 12 to 18 inches of snow. Strong winds are also forecast with this event, with High Wind Warnings and Watches and Wind Advisories in place. A low pressure system off the New England coast is forecast to keep tracking northward overnight Monday into the Canadian maritimes. In the meantime, wraparound snowfall is expected for the Interior Northeast through Monday night, with 2 to 4 additional inches possible in eastern Maine. An upper-level low is forecast to develop and move through the Four Corners region on Monday night, tracking eastward into the Plains on Tuesday. Showers and thunderstorms are expected to form ahead of the upper-level low by Tuesday evening in the Southern Plains, and will move into the Lower Mississippi Valley and Southeast on Wednesday. Rainfall is forecast to be generally under an inch in these areas, with locally higher amounts above an inch. Temperature-wise, a cold front moving through will lead to temperatures 5 to 15 degrees below average in the Northeast on Tuesday. Florida could see slightly below average temperatures as well. The rest of the U.S. will generally be warmer than normal; the Northern Plains in particular is expecting high temperatures 15 to 25 degrees above average. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php