Will MJO Reach Tropical Atlantic and Trigger East U.S. Cold?
02/14/2023, 2:46 pm ESTNorthern U.S. Snow and Ice Storms Next Week
02/17/2023, 8:51 am EST
Fig. 1-3: Ice accretion risk areas according to the GFS 15-day outlook plus two potential Northeast snowstorms.
Discussion: Stratospheric warming on the North America side of the North Pole is the catalyst to a late season arctic air mass across Canada. Forecast models remain unsure as to how much of this air can infiltrate the U.S. However, the battle zone between the Canadian chill and lingering U.S. warmth is likely to cause a vigorous storm track that can pull pieces of the Canadian chill into the U.S. for brief periods of time. This scenario will lead to an increase in both freezing rain/icing and snowfall event POTENTIAL. The GFS indicates up to 4 icing events in the 15-day outlook stretching from the Midwest to the Northeast Corridor in the 15-day outlook (Fig. 1). Additionally, the GFS also indicates two potential snowstorms for southern New England and the northern Mid-Atlantic during the last third of February (Fig. 2-3). These areas have witnessed very mild to record mild climate since the 1st of the year so the late season colder/snowy/icy pattern change will be abrupt. Once again, the ice and snow potential is dependent on how much cold from Canada can work its way into the prevailing storm track.
While ice and snow forecasts are uncertain, springtime severe thunderstorms are likely. An outbreak occurs across the Mid-South States today and features a tornado risk centered on the Arkansas/Mississippi state line (Fig. 4). On Thursday, severe thunderstorms will stretch from the central Gulf Coast to the eastern Ohio Valley with tornado risk centered on the Mississippi/Alabama state line (Fig. 5).
Fig. 4-5: NOAA/SPC severe weather risk areas for Wednesday and Thursday.
The latest U.S. gas population weight HDD forecast reveals a colder trend for next week and late FEB/early MAR where national heating demand is edging above normal (Fig. 6).
Fig. 6: U.S. gas population weight HDD forecast utilizing all models, their consensus compared to 48 hours ago compared with the 30-year/10-year normal.