The Madden Julian oscillation (MJO) shifts across the warm eastern equatorial Pacific during the next 1-2 weeks. U.S. climatology during an MJO phase_7 to phase_8 transition favors a cooler East U.S. regime. Although not super confident, the most likely (ECM ENS mega-cluster ensemble) upper air pattern in 15 days is a new upper trough centered on Ontario to deliver cooler weather into the East U.S.

The Asia/Bering Sea/North America (ABNA) index remains very positive and is the lead climate signal influence on the North America upper air pattern for the first half of June. The +ABNA regime is present when a strong trough is near the Bering Sea and compensated for by an upper ridge over East-central North America.

While the number of hurricanes is diminished during El Nino, damaging hurricanes can still form. Famous moderate-to-strong El Nino year hurricanes include Category-4 Major Hurricane Idalia striking the Big Bend Region of Northwest Florida (2023), Category-4 Major Hurricane Lili striking the Southwest Louisiana Coast (2002), and Category-3 Major Hurricane Bob making 2 landfalls in Rhode Island (1991).

The U.S. population weight CDD forecast indicates much below normal electricity demand for next week while June 5-11 reverses to above normal demand due to warming in the Northeast U.S. supported by a positive phase of the North Atlantic oscillation.