Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 330 PM EST Mon Nov 20 2017 Valid 00Z Tue Nov 21 2017 - 00Z Thu Nov 23 2017 ...Heavy rain possible for the Pacific Northwest... ...Light lake effect snow downwind of the Great Lakes... ...Light snow over parts of Northern New England... A front extending from the Upper Mississippi Valley/Northern Plains northwestward into the Northern High Plains will move south and eastward to off the Eastern Seaboard and off the Gulf Coast States by Wednesday. Light snow will develop over parts of the Upper Great Lakes overnight Monday that will become rain and snow over the Lower Great Lakes/Ohio Valley by Tuesday evening. The rain and light snow will move to the Northeast overnight Tuesday into Wednesday. Meanwhile, upper-level energy over the Pacific Northwest will move southeastward to the Western Gulf Coast while weakening. The energy will aid in developing rain and higher elevation snow over parts of Pacific Northwest into the Northern Rockies that will move southeastward to the Central Rockies/Central Plains and dissipate by Tuesday evening. In addition, another area of upper-level energy over the Western Gulf Coast will move eastward to the Southeast by Tuesday evening then move northeastward out over the Western Atlantic by Wednesday aiding in the development of an area of low pressure off the North Carolina Coast overnight Tuesday into Wednesday. Showers and thunderstorms will develop over parts of the Southeast/Florida on Tuesday into Tuesday afternoon. On Tuesday afternoon, rain and thunderstorms will move northward along the Southeast Coast into the Southern Mid-Atlantic overnight Tuesday into Wednesday. Rain will move into parts of the Northern Mid-Atlantic Coast on Wednesday. Additionally, a plume of moisture streaming into Central California will move northward paralleling the coast into the Northwest Monday night into Wednesday. Rain will develop over parts of Northern California on Monday evening moving into the Northwest overnight Monday into Tuesday. The rain will move inland over the Pacific Northwest expanding into the Northern Intermountain Region/Northern Rockies Tuesday afternoon into Wednesday. Overnight Monday into Tuesday the snow level rises over the Northwest into the Northern Rockies, limiting the amount of precipitation that will fall as snow. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php