Long Range Weather Forecast Discussion November 20-December 4
James Munley
Long Range Weather Forecast Discussion November 20-December 4
231 PM EST Mon. Nov. 17, 2025
Nov. 20-24: The GFS depicts a trough-ridge-trough pattern across the country, and the ECMWF and its ensembles show a flat flow across the eastern and central states with above-normal heights.
Energy within the southern stream will track from the Southwest to the south-central late in the work week. Height falls, moisture, and instability with a return flow into the frontal boundary will result in heavy rain and strong thunderstorms across the south-central states. This activity will spread eastward and weaken over the weekend. There will be a moderate risk of excessive rainfall. An east Pacific system will close-off over the West Coast on Thursday. This will bring additional precipitation chances to the West Coast and the Southwest over the weekend.
Nov. 25-29: The GFS has a trough over the Northwest and the eastern Pacific with a zonal flow and above normal heights across the remainder of the nation. The ECMWF has a trough over the north-central states. The ECMWF ensemble has the trough over the Rockies.
Above-normal temperatures are forecast across the Rockies to the Atlantic Coast. Anomalies are expected to be near 8°F.
Above-normal precipitation is forecast for most of California, the Northwest, and western Montana. The probability of occurrence is nearly 40 percent. Below-normal precipitation is forecast for most of the northern Plains, the upper Mississippi Valley, the southern Plains, the middle and lower Mississippi Valley, the Midwest, the Ohio and Tennessee Valleys, the Southeast, the Mid-Atlantic, and the Northeast. The probability of occurrence is nearly 40 percent.
Nov. 30-Dec. 4: As we end November and go into December, a trough is forecast in the West, and a zonal flow and above normal heights cover the eastern and central states. Guidance agrees on the flow.
Below normal temperatures are forecast mainly west of the Divide. Anomalies are expected to be near 4°F.Above normal temperatures are forecast for most of the Area east of the Mississippi River. Anomalies are expected to be near 6°F.
Below normal precipitation is forecast for central and northern California, the Northwest, the central and eastern Gulf Coast States, the Southeast, the Mid-Atlantic, and the Northeast. The probability of occurrence is 35 percent.
Jim Munley
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