Dealing With Cold Weather After Holiday Season in U.S.
12/24/2024, 9:47 am EST
Forecast Change: Models See Arctic Air Western Canada Days 6-10; Ejected Eastward Days 8-14/11-15!
12/27/2024, 7:22 am EST
Charts of the day: Stratospheric cooling in eastern North America could negate previously expected cold polar vortex forecast.
Discussion: In a new twist, ECM is forecasting a cold stratosphere across the polar region and eastern North America in the 11-15-day period. Elusive stratospheric warming shifts to Eurasia. Beneath the cold stratosphere, GFS indicates a mild ridge pattern in the East U.S. instead of an evolving polar vortex pattern as previously reported.
Week-2 Ahead Forecast valid January 5-11, 2025 (previous below): Not as cold in the East; Increased storminess Northwest.
Discussion: A developing conflict…GFS is warm in the East while other forecast models remain cold. The mega-cluster ensemble is used to indicate “less cold: in the East while the western warmth is broader. The storm track is stronger into the Northwest U.S. increasing mild Pacific influence on the pattern.
Week-3 Ahead Forecast valid January 12-18, 2025: Chilly Southeast; Warmer elsewhere.
Discussion: The milder changes in the week-2 forecast extend to week-3. Most notably is the expansive warming across Canada and the western half of the U.S. The Southeast States are chilly.
Week-4 Ahead Forecast valid January 19-25, 2025: No important cold.
Discussion: Mild pattern across Canada indicates no arctic air supply risk. The western states remain mild. In the East, ECM is temperate.