Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 308 AM EST Mon Feb 25 2019 Valid 12Z Mon Feb 25 2019 - 12Z Wed Feb 27 2019 ...Heavy rain likely for southwestern Oregon and northern California, with flooding possible... ...Heavy snow expected in the Cascades, Sierra Nevada, and higher elevations of the Northwest... ...Bitterly cold temperatures of 20 to over 40 degrees below average forecast for the Northern Plains to Upper Midwest... ...High winds continue for the Mid-Atlantic to Northeast today, which could create blizzard conditions in the Great Lakes... A relatively weak but persistent moisture plume will take aim at the Northwest for the beginning of the workweek, while an upper-level low spins near Washington state and British Columbia. This will help create heavy precipitation in the form of both rain and snow. Along the southern Oregon and northern California coast, heavy rain is likely, and there is a Slight Risk of excessive rainfall in place there for Monday and Monday night. Additional upper-level energy will come in late on Tuesday, shifting the axis of heavy rain and the potential for flooding to mainly northern California, including the Bay Area. In terms of snow, the Sierra Nevada will see the heaviest snow over the next couple of days, with over 4 feet of snow forecast! The Oregon Cascades could see 1 to 2 feet of snow, and the Shastas and higher elevations of the Northern Great Basin and Northern Rockies can expect 1 to 3 feet of snow. Some snow is possible even in lower elevations (including Portland) due to the persistently cold temperatures. As a high pressure system slowly sinks into the Northern Plains, it will bring bitterly cold temperatures with it. Temperatures will be much below average, with highs over 40 degrees below normal in the Northern High Plains on Monday and Tuesday! High temperatures of 20 to 40 degrees below average are likely into the Central Plains and Upper Midwest. Wind Chill Warnings and Advisories are in effect. After trekking from the Southwest to Northeast, the low pressure system that has been discussed the past few days will exit the U.S. today. A tight pressure gradient and strong winds aloft will remain across the Northeast in its wake, so high winds will continue--widespread Wind Advisories and High Wind Warnings are in effect through Monday morning in the Southern/Central Appalachians, and in the Mid-Atlantic and Northeast through the day on Monday. Additionally, lake enhanced snow is expected across the Great Lakes region today, and combined with the strong winds, blizzard conditions are possible through Monday morning in the Upper Great Lakes and downwind of Lake Ontario all day. Elsewhere, showers and thunderstorms are expected to overspread the Gulf Coast states by Monday night into Tuesday as a warm front approaches and the flow of Gulf moisture returns, with a few strong storms possible. Farther north, a swath of light snow (1 to 4 inches) will accumulate across the Northern/Central Plains Monday night and spread to the Upper Midwest and Upper Great Lakes by Tuesday. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php