Severe thunderstorms affect the East-central U.S. today. Tornadoes are expected in Iowa/Illinois to Missouri to Arkansas today. On Wednesday, the severe weather risk expands to include the Ohio Valley to Arkansas and Louisiana and includes additional tornado risk centered on the Ohio/Western Tennessee Valley.

The SSTA pattern in the Northeast Pacific and Gulf of Mexico identifies in-part why the weekend severe weather outbreak was so intense (2-day total of 1, 264 severe weather reports). The West U.S. trough well-correlated to persistent cool SSTA off the U.S. West Coast entrained more abundant moisture than normal from the much warmer than usual Gulf of Mexico.

A major storm reaching Iowa by early this afternoon spawns almost coast-to-coast hazards including a blizzard in South Dakota to Minnesota, severe thunderstorms featuring a tornado risk in Iowa and eastern Arkansas, and widespread damaging wind gusts from the southwest Great Plains to the Appalachian States.

An updated climatology for North Atlantic tropical cyclone activity according to El Nino southern oscillation (ENSO) phase plus a review of long-term cycles of ENSO, the Atlantic multi-decadal oscillation (AMO), and tropical North Atlantic (TNA) index.