Tropical forcing on the prevailing climate across North America increases during April. The Madden Julian oscillation (MJO) increases strength dramatically as the middle third of April arrives. The MJO shifts toward and across the Dateline during this time. In the extended range, ECMWF maintains the MJO intensity and indicates a progressive character shifting eastward through the tropical longitudes of the Americas to West Africa by early May.

The initial North Atlantic basin seasonal activity forecast for the North Atlantic basin by Climate Impact Company is issued. The forecast is updated in late May as the onset of tropical cyclone season arrives and again near August 1st when the onset of highest seasonal activity arrives. The forecast projects 13 tropical storms, 5 hurricanes, and 3 intense hurricanes. An El Nino episode develops during the tropical cyclone season inhibiting development and 2026 is the second least busy year during the 2016-2025 active period.

Record low snowpack provides much below normal snowmelt and river inflows sustaining and intensifying a water supply drought across much of the West U.S.. The intensified snow drought of winter 2026-27 and the attendant record warm temperatures was inspired by persistent intense high pressure ridging in the upper atmosphere across and downwind the highest aerial coverage of a marine heatwave (MHW) on record in the Northeast Pacific.

About 75% of the U.S. is experiencing dry-to-drought conditions. Impactful wetter trend is occurring in the Great Lakes region and vicinity in March while most of the dry soil zones are missing important precipitation. The 15-day outlook for the U.S. offers significant rainfall in the Mid-south States, more wet weather for the soaking wet Great Lakes region, but is mostly dry and shifting drier for the western Great Plains where drought is forecast to expand during late spring.

The North Atlantic basin is marginally warmer than normal (+0.33C) and similar with this time last year. However, in the lower latitudes, the Caribbean Sea, and main development region (MDR) are somewhat cooler than last year at this time. The Gulf of Mexico basin is near +0.4C although nearly 1C cooler than one month ago. Upper ocean heat in the Gulf of Mexico and main development region (MDR) for North Atlantic hurricanes is second coolest in the 2013-26 climatology.