An Update On Regional SSTA Across The North Atlantic Basin

Fig. 1-4: The Climate Impact Company 2025 North Atlantic hurricane tracks outlook and CIC/CSU/TSR seasonal activity forecast.

Discussion: The Gulf of Mexico is very warm at 0.73C above normal, a warmer change of 0.17C during the past 2 weeks (Fig. 1). The bulk of the anomalous warmth is across the Northern Gulf of Mexico and linked to the very warm month of April across the Gulf States and more recently to heavy rains evolving over Texas. The Gulf of Mexico is nearly half of a degree C warmer than 1 year ago. The 2024-25 marine heatwave (MHW) across the Caribbean Sea, one of the strongest on record, has weakened. The daily basin SSTA is +0.40C although most of that warmth is in the east-central sea (Fig. 2). The Caribbean Sea has cooled 0.3C during the past 30 days and is about half as warm as this time last year. Similarly, the main development region (MDR) for hurricanes has cooled and is now near normal (Fig. 3). One year ago, the MDR was “cooking” at +1.32C. The western North Atlantic basin is warmer than normal (+0.26C) and has warmed moderately during the past week (Fig. 4). The warm Gulf Stream and frigid counter current just to the north remain vividly on display. Global SSTA forecasts vary widely on details of SSTA conditions during the summer season. Forecast confidence is low due to the predictable barrier the spring season brings to SSTA (and climate) forecasting. Forecast confidence will increase dramatically in 30 days. Currently, the consensus of SSTA forecasts is a less anomalous warm deep tropics ocean surface as compared to recent years while the bulk of anomalous warmth is in the subtropics and mid-latitudes. There is potential for a vivid North Atlantic warm hole (NAWH) east of Labrador this summer season which would contribute to the location of subtropical high-pressure centers governing the steering currents for the 2025 tropical cyclone season.