Will MJO Reach Tropical Atlantic and Trigger East U.S. Cold?

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Highlight: MJO shifts across the Pacific and weakens but may return and shift into the Atlantic in March. The Atlantic shift would signal cold into the East.

Fig. 1-2: The Madden Julian oscillation 15-day forecast via the GFS reveals a quick transit through the tropical West Pacific the next few days followed by weakening in the East Pacific tropics this weekend and next week (left). The 30-day outlook by ECMWF reveals MJO may regain strength in the Atlantic tropics Mar. 8-16 (right).

Discussion: The latest Madden Julian oscillation (MJO) forecast according to GFS reveals moderate intensity while shifting quickly across the tropical West Pacific this week and then into the equatorial East Pacific while steadily weakening next week into early the following week (Fig. 1). MJO weakens in the equatorial East Pacific due to the cooler waters. ECMWF indicates MJO may recharge during the final week of their 30-day outlook. During Mar. 8-16 MJO is resurgent in the tropical Atlantic (Fig. 2). In phase_8, MJO has the tendency to cause a colder regime into the East (Fig. 3). Of interest is the stratospheric warming occurring over the North America side of the North Pole the next 10 days which generates arctic air and causes Canada to turn very cold. The late winter chill is likely to linger into March across Canada with potential for a release into the U.S. (Fig. 4). A catalyst to push the cold air into the U.S. is not obvious in February although any increase in snow cover certainly invites the Canadian chill southward. However, MJO phase_8 would generate an East U.S. trough that would allow cold to infiltrate the East U.S. Consequently, careful eye on the extended-range forecast is warranted for potential significant cold across the East U.S.

Fig. 3-4: The March temperature anomaly climatology for when MJO shifts into and across The Atlantic tropics (left) and daily mega-cluster ensemble temperature anomaly forecast for the U.S. for Feb. 28th.