Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
162 FXUS01 KWBC 152005 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 304 PM EST Mon Dec 15 2025 Valid 00Z Tue Dec 16 2025 - 00Z Thu Dec 18 2025 ...Heavy snow over parts of the Lakes Erie/Ontario coastline on Monday night into Tuesday... ...There is a Slight Risk of excessive rainfall over parts of the Pacific Northwest on Monday... ...Heavy snow for the Cascades and Northern Rockies... The high pressure over the eastern third of the country will slowly move eastward out over the Atlantic by Wednesday. Upper-level energy over the Lower Great Lakes will produce light to moderate snow downwind from Lakes Erie/Ontario from Monday night into Tuesday morning. See the WPC Heavy Snow Discussion for details and amounts. Meanwhile, a front over the Pacific Northwest will move eastward to the Northern Rockies and dissipate by Tuesday evening. Onshore flow over the Pacific Northwest will produce heavy rain Monday night into Tuesday morning. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over the Pacific Northwest through Tuesday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and burn scars being the most vulnerable. A second front moves over the Northwest overnight Tuesday, moving to the Northern Plains and Northern/Central Rockies by Wednesday evening. The rain will continue over the Northwest and Northern California through Wednesday. After the associated front moves over the area, moderate to heavy snow will develop across parts of the Cascades and Northern Rockies through Wednesday evening. Moreover, as the second front moves onto the Northern Plains, rain will develop over parts of the Northern Plains on Wednesday afternoon and evening. Lastly, moisture from the Gulf will start to stream northward over the Southern Plains, producing scattered showers and thunderstorms over the Western Gulf Coast overnight Tuesday into Wednesday. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$