Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 346 PM EST Mon Feb 19 2018 Valid 00Z Tue Feb 20 2018 - 00Z Thu Feb 22 2018 ...Heavy snow possible over parts of the Northern Plains... ...Heavy rain possible for portions of the Southern Plains to the Western Ohio Valley and into the Lower Great Lakes... ...Rain/freezing rain possible from of the Middle/Upper Mississippi Valley into the Upper Great Lakes... ...Temperatures will be 15 to 35 degrees below average over the Northern Rockies into parts of the Northern/Central Plains... A quasi-stationary front extending from the Great Lakes to the Middle Mississippi Valley/Central Rockies will slowly begin to move eastward overnight Tuesday to the Lower Great Lakes to the Southern Plains by Wednesday. The system will produce snow over parts of the Upper Great Lakes southwestward into the Northern Plains by Monday evening. Upper-level energy over the Northern/Central Rockies will move northeastward into the Upper Great Lakes by Wednesday. The energy will produce additional snow over parts of the Northern/Central High Plains overnight Monday moving to the Upper Mississippi Valley and parts of the Northern/Central Plains by Tuesday morning while snow continues over the Upper Great Lakes. The snow will end over the Northern/Central Plains on Tuesday afternoon while ending over the Upper Great Lakes/Upper Mississippi Valley overnight Tuesday. Additionally, showers and thunderstorms will develop over parts of the Southern Plains into Middle Mississippi Valley/Ohio Valley that will continue over the region through Tuesday afternoon when the area of showers and thunderstorms moves slightly eastward to the Ohio Valley southwestward to the Southern Plains/Western Gulf Coast by Wednesday. Showers and thunderstorms will also develop over parts of the Tennessee Valley Tuesday afternoon into Wednesday. In addition, rain will develop over parts of the Great Lakes extending into the Eastern Ohio Valley into parts of the Northeast with an area of rain/freezing rain developing over Northern Maine on Monday evening continuing through Wednesday morning. Elsewhere along the rain/snow line, a band of rain/freezing rain will develop over parts of the Middle Mississippi Valley into parts of the Upper Great Lakes on Monday evening. The band of rain/freezing rain will expand southwestward over parts of the Central Plains overnight Monday. On Tuesday into Wednesday morning, the band of rain/freezing rain will move eastward extending from parts of the Great Lakes to the Middle Mississippi Valley by Monday. Meanwhile, upper-level energy over the Southwest into Central High Plains will move northeastward to the Upper Great Lakes to the Central Plains by Wednesday. The energy will produce snow from parts of the Pacific Northwest and Northern/Central California eastward to parts of the Northern/Central High Plains southward to parts of the Southwest and Central/Southern Rockies on Monday evening along with rain at lower elevations of the Southwest/Southern Rockies. Overnight Monday, the snow will wane over the Pacific Northwest/California and parts of the Great Basin/Southwest. The snow over the Rockies ends overnight Tuesday. Another region of upper-level energy just off the Pacific Northwest Coast on Tuesday morning will move southward to off the Central/Southern California Coast by Wednesday. Additional upper-level energy will move over the Pacific Northwest on Tuesday evening into Wednesday. Snow will develop over parts of the Pacific Northwest Coast on Tuesday afternoon that will change over to rain along the Northwest and Northern California Coast by Tuesday evening. The snow will continue just inland over parts of the Northwest into Northern California through Wednesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php