Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 301 AM EST Sun Jan 20 2019 Valid 12Z Sun Jan 20 2019 - 12Z Tue Jan 22 2019 ...Major winter storm moving across much of the interior northeastern U.S. today followed by frigid temperatures... ...Heavy rain could result in flash flooding across parts of northern California today... ...Developing low pressure system over the Rockies on Monday will become the next winter storm for the northern Plains on Tuesday... A major winter storm is currently progressing from the Ohio Valley into the northeastern U.S. The center of the low pressure system responsible for this winter storm will move rapidly across the northern Mid-Atlantic into southern New England today before exiting into the Gulf of Maine this evening. The storm will produce a swath of heavy snow from parts of the Ohio Valley northeastward into the Northeast with more than two feet of snow expected for northern Maine. A narrow zone of sleet and freezing rain is also expected to slide across southern and central New England as well as coastal Maine today into tonight before the precipitation tapers off early on Monday. Showers and thunderstorms will move off the Mid-Atlantic and Southeast U.S. by midday with the passage of a strong cold front. The coldest air this season will then usher into the eastern U.S. tonight under blustery northwesterly winds with frigid temperatures expected to spread from the upper Midwest this morning into much of the Northeast Monday and Tuesday. Heavy lake effect snow will develop over parts of the upper Peninsula of Michigan through tonight, spreading downwind into the rest of the Great Lakes through Monday. Meanwhile, a deep upper-level trough over the eastern Pacific will move onshore into the western U.S. during the next couple of days. A broad stream of moisture moving into northern California today will produce heavy rain that could result in flash flooding in some areas. The moisture will then penetrate further inland, leading to widespread higher elevation snow on Monday from the Sierra Nevada northeastward across much of the Great Basin and into the Intermountain region followed by the northern Rockies. A low pressure system will gradually take shape over the central Rockies on Monday and exit into the central Plains Monday night. This low is expected to develop into the next winter storm for the northern Plains with snow expanding across the region early on Tuesday. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php