Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Tue Nov 19 2024 Valid 00Z Wed Nov 20 2024 - 00Z Fri Nov 22 2024 ...Powerful Pacific storm to impact the West Coast with heavy rain, life threatening flooding, wind and higher elevation mountain snow beginning tonight... ...Heavy snow with gusty winds for North Dakota into northwestern Minnesota into Wednesday... ...Locally heavy snow for the Allegheny Mountains of West Virginia and Pennsylvania with lighter accumulations possible for surrounding portions of the Midwest into interior New York... An active weather pattern will unfold across the lower 48 this week with areas of heavy rain, snow and wind. First, a rapidly intensifying surface low will near the Pacific Northwest this evening and tonight. While the surface low should remain about 300 miles offshore the Washington coast, the tight pressure gradient will result in damaging winds from northern California into western Washington. Wind gusts of 60-70 mph (locally higher) are expected along the coast and into mountains portions of the region. A multi-day heavy rainfall event will impact northern California into southwestern Oregon beginning tonight, continuing into Friday as an atmospheric river stalls in and around northern California. Rainfall accumulations over 10 inches are likely for some areas through Friday morning which will lead to flooding rainfall and areas of flash flooding, especially across sensitive burn scars and any urban locations. WPC has issued a High Risk (level 4/4) of Excessive Rainfall across parts of northwest California on Thursday in order to further highlight the flooding threat. Into the mountains, heavy snow and strong winds will lead to blizzard conditions for portions of the Cascades into the northern Sierra Nevada. Residents and visitors throughout the Northwest are urged to have multiple ways to receive warnings, listen to advice from local officials, and avoid traveling through hazardous weather conditions if possible. Over the north-central U.S., an ongoing storm system will continue threats for gusty winds and snowfall from northeastern Montana into northwestern Minnesota. As a surface low slowly tracks north from Minnesota tonight, colder air is expected to allow a changeover to snow for most regions with additional snowfall accumulations of 3-6 inches (locally higher) for northern/eastern North Dakota. Winds combined with falling snow or snow on the ground will reduce visibility and result in hazardous travel conditions. Across the Midwest and Northeast, as the upper level storm system from the north-central U.S. moves eastward, colder temperatures and areas of snow are expected for portions of the Midwest, Pennsylvania and interior New York. Locally heavy snow with accumulations in excess of 6 inches should be expected for the higher elevations of the central Appalachians from West Virginia into Pennsylvania beginning Thursday and continuing into the night. Otto Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php