A strong positive phase global atmospheric angular momentum combined with the convection phase of the Madden Julian oscillation in the tropical East Pacific helps to force a semi-permanent global wind oscillation in phase_7. In this regime, there is a tendency to force negative North Atlantic oscillation. -NAO ahead forces an upper ridge near and southeast of Greenland with compensating upper troughs in northeast/east portions of North America and through Eastern Europe. Cooling results for Eastern Europe and eventually the Eastern U.S.

The latest Climate Impact Company U.S. cooling degree day assessment for summer 2026 given the recent decline in natural gas prices. Regenerating important warmth is likely for later summer while hotter operational models continue to battle cooler AI forecasts in the extended range.

The North Atlantic basin has warmed 0.34C during the past 30 days to +0.70C, a (fairly) warm signature. However, the main development region is almost exactly normal and has cooled slightly in July so far. The Caribbean Sea warmed to +0.53C although all of the surface warming in in the northwest basin. The Gulf of Mexico is warming rapidly reaching +1.10C. The western North Atlantic basin has (also) warmed to +1.10C.

The estimated U.S. CDD forecast for week 3-5 ahead remains hot according to ECM while AI models are consistently much cooler. Interestingly, CFS V2 is sharply cooler for week-3 then bounces hotter for week-4/week-5. The primary issue is whether the East U.S. is hot (or not). The East cools off later July but should gradually reheat although not as aggressively as ECM. CFS V2 has the right “trend” and AI models are too cool.