Long Range Weather Forecast Discussion November 25-December 8
James Munley
Long Range Weather Forecast Discussion November 25-December 8
229 PM EST Fri. Nov. 21, 2025
Nov. 25-28: All guidance agrees in bringing the western trough eastward with Above-normal heights along the West and East Coast. This occurs as a ridge builds into the West and a trough slides into eastern Asia.
A port of the system will move across the southern Plains on Monday, causing a surface low that interacts with deep moisture to support widespread heavy rain and thunderstorms. The system weakens through Tuesday as a system over in the northern system becomes the dominant system. This system will usher in a much colder Canadian air mass into the East around Thanksgiving. An active Pacific jet will cause rain and snow across the Northwest.
Nov. 29-Dec. 3: The trough in the East quickly lifts out as a trough builds into the West. This brings Above-normal heights back to the East.
Below-normal temperatures are forecast for the northern and central Rockies, the northern Plains, and the upper Mississippi Valley. Anomalies are expected to be near 6°F. Above-normal temperatures are forecast for the central and eastern Gulf Coast States, the Southeast, the Mid-Atlantic, and the Northeast. Anomalies are expected to be near 6°F.
Above-normal precipitation is forecast for parts of Oregon, northern and central California, into the Great Basin, and the central Four Corners. The probability of occurrence is nearly 40 percent. Below-normal precipitation is forecast for eastern Texas, the lower Mississippi Valley, the Ohio and Tennessee Valleys, to the Gulf Coast. The probability of occurrence is 35 percent.
Dec. 4-8: The GFS and the ECMWF have a trough in the West and a ridge in the East. Its ensembles are similar but depict a broader trough. The ECMEF ensembles have a trough in the East.
Above-normal temperatures are forecast for the West, the Plains, most of the Mississippi Valley, and most of the Southeast. Anomalies are expected to be near 6°F. Below-normal temperatures are forecast for the Mid-Atlantic and the Northeast. Anomalies are expected to be near 2°F.
Above-normal precipitation is forecast for central and northern California to the Northwest and western Montana. The probability of occurrence is nearly 35 percent. Below-normal precipitation is forecast for the Northeast, the Mid-Atlantic, the Ohio and Tennessee Valleys, the Southeast, and the central and eastern Gulf Coast States. The probability of occurrence is nearly 40 percent.
Jim Munley
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