Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 233 PM EST Sun Dec 04 2016 Valid 00Z Mon Dec 05 2016 - 00Z Wed Dec 07 2016 ...Flash flooding possible across portions of the Gulf Coast and Southeast through Monday night... ...Heavy snow possible for portions of the Cascades and the northern Rockies... ...Cold temperatures on the way for portions of the northern Rockies and northern plains by Tuesday... A frontal boundary with multiple waves of low pressure along it will continue to bring rain and thunderstorms to the Gulf Coast and southeastern states tonight through Monday night. Along the northern edge of the system, areas of snow and sleet are possible tonight and Monday from the Great Lakes to the Northeast. A stronger area of low pressure is forecast to develop in the northern Gulf of Mexico late Monday, spreading another round of precipitation inland across the Gulf Coast and Southeast. Heavy rain may lead to areas of flash flooding across portions of the Gulf Coast and Southeast through Monday night. On Tuesday, the low pressure system will move north into the Tennessee and Ohio valleys, while a new area of low pressure develops along the coast of the Carolinas, once again spreading precipitation into the Mid-Atlantic and Northeast, some of which could fall as a snow or sleet, especially at inland areas well above sea-level. Unsettled conditions will prevail through the short range from the Pacific Northwest to the northern Rockies. One frontal system will bring areas of snow and valley rain to portions of the northern Intermountain West and northern Rockies tonight into Monday. Heavy snow is possible across the northern Rockies. This system will move into the northern plains and upper Midwest by Monday afternoon, bringing areas of rain and snow to those regions. Behind this system, an Arctic cold front will sweep south into the northern Rockies and northern plain, bringing well below average temperatures by Monday night and Tuesday. High temperatures on Tuesday across these areas are forecast to be 20 to 35 degrees below average. Additionally, the Pacific Northwest will see the periods of precipitation over the next couple days. Rain and mountain snow will pick up in intensity tonight as a Pacific frontal system moves inland. Snow may be heavy across the Cascades tonight through Monday. Additionally, snow levels will lower substantially by Monday, with a mix of rain and snow possible even at the lower elevations around Puget Sound. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php