Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 PM EST Tue Nov 20 2018 Valid 00Z Wed Nov 21 2018 - 00Z Fri Nov 23 2018 ...Unsettled weather in the western U.S. with rain in lower elevations and snow in higher elevations... ...Lake enhanced snow likely on Wednesday in the Great Lakes region... ...Record lows and record low maximum temperatures likely for Thanksgiving in the Northeast... A series of fronts and a strengthening jet stream will lead to an increase in precipitation chances for the western U.S. over the next couple of days. This will be a relief to fire-stricken areas of California, and help clear out Air Stagnation Advisories that are in effect across parts of the Northwest. However, hazardous conditions could be created as well. Heavy rain is possible in lower elevations in the West Coast. On Wednesday and Wednesday night, there is a Marginal Risk of excessive rainfall in parts of California, with embedded Slight Risks where the recent fires have created burn scars, which can flash flood quickly as water runs off. In higher elevations, snow is expected, ramping up Wednesday night and Thursday. Snow of over a foot is forecast through Thursday evening in the Sierra Nevada, with snow of 6 to 10 inches in the Cascades. A surface low pressure system will move across the Great Lakes region Tuesday night and into the Northeast on Wednesday. The low combined with lake enhancement is forecast to produce snow in those regions. Downwind of the Upper and Lower Great Lakes, 4 to 6 inches of snow is expected Tuesday night into Wednesday, and 1 to 3 inches is forecast for northern New England. This could create slick travel conditions. A cold surface high will build into the Northeast and Mid-Atlantic on Thursday, Thanksgiving Day. Very cold conditions are expected because of this, with low temperatures in the single digits in northern New England, and high temperatures below freezing in the Northeast and northern Mid-Atlantic. Setting new record low minimum and maximum temperatures will be widespread across those regions. In contrast, the Northern and Central Plains will be 10 to 20 degrees above normal on Wednesday and Thursday. Elsewhere, rain showers are possible across the western Gulf Coast on Wednesday and spreading into the central Gulf Coast on Thursday, as an upper-level disturbance moves through. Florida could see showers over the next couple of days as well. The central U.S. will remain dry through Thanksgiving. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php