February Snowstorms Follow Early Next Week’s Brief Warm-up

Atmospheric Angular Momentum Contibutes to U.S. (and Elsewhere) High Wind Events
01/27/2019, 12:55 pm EDT
Emerging warm SSTA in the middle latitude southern hemisphere
01/30/2019, 5:45 pm EDT
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Warm surge weekend/early next week but snowstorms follow and cold will return although less excessive days 11-15.

Discussion: Arctic air moving into the Midwest U.S. for mid-to-late week will challenge all-time records. Many areas will be low zero for 60-72 hours. The arctic air moderates into the Northeast Corridor although exceptional cold is still likely. Due to an exceptionally strong and turbulent positive phase of the atmospheric angular momentum present went mid-latitude jet streams are stronger than normal, Pacific influence pushes the polar vortex north along with retreating arctic air early next week. A rapidly evolving very warm pattern follows also melting some of the southern expanse of snow cover.

Arctic air retreats to Canada early next week but remains intense. The boundary between the arctic air and much warmer air to the south ultimately drives a storm track that will produce streaks of moderate to heavy snow beginning early next week from the Upper Midwest to Quebec (Fig. 1) and followed by another similar event except shifting a little further south mid-to-late next week (Fig. 2). A third storm generates Feb. 7-8 and could bring southern New England heavy snow where snow cover has been absent most of winter (Fig. 3).

The south-shifting snow events indicate increased confidence in the colder day 11-15 forecasts (Fig. 4) which bring some modified arctic air out of Canada across the reborn U.S. snow cover.

Fig. 1: The ECMWF indicates moderate to heavy snow Upper Midwest to Quebec Feb. 3-5.

Fig. 2: The ECMWF indicates a large area of moderate to heavy snow stretching from Iowa to Quebec Feb. 5-7.

Fig. 3: The ECMWF indicates a snowstorm Pennsylvania to southern New England Feb. 7-8.

Fig. 4: The GFS ENS indicates the 11-15 day period turns cold again inspired by returning snow cover.