Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 250 PM EST Wed Dec 19 2018 Valid 00Z Thu Dec 20 2018 - 00Z Sat Dec 22 2018 ...Widespread rain and thunderstorms will spread from the Lower Mississippi Valley east and north through Friday... ...Another low approaches the Northwest, bringing more rain and snow... ...Record warmth possible by Friday in the Mid-Atlantic region and Northeast... A deep upper-level trough will continue moving eastward through the Plains, Mississippi Valley, and Ohio Valley through the end of the workweek. This will push a surface low pressure system eastward across the Gulf Coast on Thursday and northward across the Eastern Seaboard by Friday. Gulf of Mexico and Atlantic moisture are expected to combine to create a heavy rainfall event for the eastern U.S. Widespread rainfall totals are forecast to be 1 to 2 inches across the Southeast and the Appalachians eastward, with higher widespread totals of 3 inches in the Florida peninsula, eastern North Carolina, and southern New England. Plus, locally higher rainfall amounts are expected in thunderstorms and where rain trains over the same location. Slight Risks of excessive rainfall/flash flooding are in effect on Thursday. Additionally, severe weather is possible along the Atlantic coast. On Thursday, there is an Enhanced Risk of severe weather in place across eastern Florida from the Storm Prediction Center. Behind a secondary cold front on Friday, snow could mix in on the back edge of the precipitation across the Ohio Valley and into the Appalachians. After a brief lightening of the precipitation in the northwestern U.S., a surface low approaches on Wednesday night and Thursday, increasing precipitation chances again as a cold front moves quickly through the region. The higher elevations of the Cascades could see 12 to 18 inches of snow, and the Northern Rockies are expecting 6 to 10 inches of snow. Precipitation will remain rain at lower elevations of the Pacific Northwest. Farther east, strong winds are expected for the Northern/Central Rockies and Plains through Wednesday night, and High Wind Warnings and Wind Advisories are in effect. Temperature-wise, the widespread rain will keep high temperatures below average for the Lower Mississippi Valley and the Southeast. The Pacific Northwest is expected to cool down to at or below average on Friday after the cold front. Conversely, the Mid-Atlantic region and Northeast will warm considerably through the end of the workweek. By Friday, temperatures of 20 degrees above average are forecast, and record high minimum and maximum temperatures are likely. In New England, the low temperatures could be above the average high for the date. The Southwest, Plains, and Midwest are expecting above normal temperatures as well. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php