Overview
- A strong upper‑level ridge, described by forecasters as a heat dome, continues to trap heat across the central and southern U.S. producing dangerous daytime highs and unusually warm nights that keep heat‑index values often between 105°F and 115°F.
- The Weather Prediction Center and local NWS offices have issued concentrated flood alerts for the Northeast with a Moderate Risk of excessive rainfall for parts of the New York tri‑state area Tuesday and repeated training thunderstorms expected to produce intense downpours.
- Monsoonal flow is supplying deep moisture to the Desert Southwest and Four Corners, producing daily afternoon thunderstorms that bring flash‑flood risk in burn scars and mountain terrain while record or near‑record desert highs are possible later this week.
- The combined hazards are already disrupting travel and power: widespread flight cancellations and rail delays in the Midwest and large storm‑related outages in the Upper Midwest have been reported by FlightAware and PowerOutage.com.
- Forecasts show a cold front and an unusually deep upper‑level low moving east‑northeast midweek that should temporarily ease heat in parts of the Plains and Midwest while shifting the core heat west and keeping emergency alerts and heat/flood watches in place for millions.