Long Range Weather Forecast Discussion December 25-January 8
James Munley
Long Range Weather Forecast Discussion December 25-January 8
407 PM EST Fri. Dec. 22, 2023
Dec. 25-29: An El Nino-like pattern persists across the nation. An upper low is forecast across Alaska and the northeast Pacific, a ridge builds in the West. Above normal heights cover much of the nation and Canada.
A central Plains upper low is forecast to lift northeastward early next week and then strong northern stream energy will reach the East by the mid-week period. The Plains system will spread a broad area of rain over the East early to mid-week with some locally heavy in some locations. Portions of the north-central Plains could see significant snow on the back side of the system on Christmas Day. Pacific energy will push into the western ridge aloft bringing some episodes of precipitation to the central and northern West Coast.
Dec. 30-Jan. 3: An upper low remains over Alaska and the Northeast Pacific. Mixed height anomalies are forecast across the Arctic. A ridge builds in the West with above-normal heights across Canada with below normal heights across the south.
Above normal temperatures are forecast for most of the West, the central and northern Plains, and the middle and upper Mississippi Valley into the Great Lakes region. Anomalies could exceed 6°F. Below normal temperatures are forecast for the central, southern, and eastern Texas, the lower Mississippi Valley, the Gulf States, the Southeast and the lower Mid-Atlantic. Anomalies are expected to be near 2°F.
Below normal precipitation is forecast for the Northwest, western Montana, a portion of the Great Lakes region, the Ohio and Tennessee Valleys, the northern Mid-Atlantic and the Northeast. The probability of occurrence is nearly 35 percent. Above-normal precipitation is forecast for southern California, the southern Four Corners, the southern Plains, the Gulf Coast and most of Florida. The probability of occurrence is nearly 35 percent.
Jan. 4-8: Moat of the guidance indicates a zonal flow across the nation with above normal heights across Canada with below normal heights across California, the southern states and along the East Coast. The GFS is the exception.
Little change is expected in the temperature anomalies from the previous period.
The change in the precipitation anomalies from the previous period is to extend the area of 35 percent chance of above-normal precipitation to cover much of California.
Jim Munley
Youtube: Jimmunleywx
Twitter: @jimmunley
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