Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
630 FXUS01 KWBC 082028 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 328 PM EST Mon Dec 08 2025 Valid 00Z Tue Dec 09 2025 - 00Z Thu Dec 11 2025 ...Atmospheric river to usher in several days of heavy rain into the Pacific Northwest and snow into the northern Rockies... ...Snow across North Carolina and Virginia is expected to taper off this evening... ...A clipper will bring a period of snow across the upper Midwest and the Great Lakes through Tuesday... ...A stronger clipper is expected to bring the threat of heavy snow and high winds across the upper Midwest on Tuesday then across the Great Lakes on Wednesday... A weather pattern that supports heavy rain across coastal Pacific Northwest will transition to cold and snowy weather for the northern tier states. This will be in stark contrast with dry and milder than normal conditions across the Southwest. In the short-term, snow associated with an upper-level trough and a developing low pressure system is in progress across North Carolina and Virginia this afternoon. The low pressure system is forecast to rapidly intensify and rapidly move off the Mid-Atlantic coast tonight, which will bring the snow to an end while dragging arctic air farther south into the East Coast tonight with temperatures down into the teens Tuesday morning as far south as North Carolina. The arctic chill will challenge some low temperature records across the interior Mid-Atlantic to southern New England Tuesday morning. Meanwhile, a prolonged atmospheric river event is beginning to take shape over the Pacific Northwest. The arrival of widespread to heavy rain today signals the beginning of several days of heavy rainfall expected to impact western Washington and northwestern Oregon. The potent trans-Pacific jet stream will continue to transport sub-tropical moisture from the Pacific and dump the moisture as heavy rain closer to the coast, and more than a foot of new snow for the northern Rockies in northwestern Wyoming. Isolated to scattered instances of flash flooding are possible near the coast and into the Cascades through midweek, where a slew of Flood Watches are in effect. Rainfall aside, parts of the Pacific Northwest, northern Rockies, and northern Plains can also expect very gusty winds through the next couple of days as the same Pacific jet develops a strong clipper system in the Canadian Rockies. As this clipper system ejects eastward into the northern Plains and upper Midwest late Tuesday, a swath of moderate to locally heavy snow is expected develop along the northern flank of the low center. Snowfall amounts of 4 to 8 inches can be expected from northeastern corner of North Dakota through the central Great Lakes. This clipper system is forecast to quickly intensify, producing an expanding area of very strong and gusty winds to accompany the snow. The snow will be tapering off across the northern Plains on Wednesday behind the storm but snow will be expanding through the lower Great Lakes and into interior Northwest as the storm center approaches. Rain will be falling farther south across the Ohio Valley on Wednesday, moving into the northern Mid-Atlantic later that day. Prior to the aforementioned clipper, a weaker clipper will bring a period of snow across the upper Midwest and the Great Lakes into tonight and through Tuesday. Meanwhile, the central and southern Plains as well as the Deep South will enjoy fine and dry weather with a warming trend especially for the Plains. The Southwest will remain dry and milder than normal while much milder than normal conditions are forecast for the Northwest into the northern High Plains along with the inclement weather. A gradual drying trend is forecast for the Sunshine State as a cold front pulls out to sea. Kong/Asherman Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$