As mid-May approaches, just a few weeks before onset of tropical cyclone season, the North Atlantic basin is moderately warm (+0.48C) which is about 0.2C warmer than one year ago and generally cooler than basin SSTA for this time of year during the past decade. The warm regions are the Gulf of Mexico (basin average +0.88C) and eastward across the Bahamas to southeast of Bermuda. Other areas are cooler than normal, especially off the Mid-Atlantic Coast and southwest of Portugal. The North Atlantic warm hole (NAHW) south of Greenland is developing.

During April 2026, the Ohio and Tennessee Valley to Virginia observed record warmth. Most of the U.S. was MUCH WARMER than normal. The exception was slightly cooler than normal in North Dakota. The April 2026 precipitation pattern featured record amount in Wisconsin and Michigan and VERY WET conditions in Iowa and Missouri. Conversely, The Southeast and Mid-Atlantic States were very dry with several states in the to-5 all-time driest.

AI models (7) outperform dynamic models (5) in both the 6-10-day and 11-15-day timescales for North America by small margins. In Europe, AI models edge-out dynamic models in both time periods. Climate Impact Company regards 0.75-0.80 as a good skill score for 6-10-day forecasts and 0.55-0.60 as desirable in the 11-15-day period.

Forecast bias has generally been too wet so far this spring in the Central U.S. Included in that bias are the extended range 16-30-day forecasts. Borth ECM and CFS V2 are too wet in the Great Plains and Southeast U.S. during the past 30 days although ECM is less wet in the Central U.S.