A relatively brief but intense heat wave peaks Wednesday from the Ohio Valley, Tennessee Valley eastward into the New York to Washington corridor.
Threat level: Heat advisories and warnings are in effect for 55 million people in at least 10 states as temperatures soar into the low 100s°F, and heat indices climb to dangerous levels as high as 115°F.
Why it matters: The reduced activity highlights the challenge of long-term forecasting, even as short-term forecasts indicate things will soon kick back up.
UN Secretary-General António Guterres warned Tuesday that rising sea levels will "soon swell to an almost unimaginable scale with no lifeboat to take us back to safety," highlighting the dire threat the crisis poses to Pacific Island nations.
The big picture: Guterres' forecast of a "worldwide catastrophe" coincides with the release of reports from the United Nations and the World Meteorological Organization that detail the acceleration of rising sea levels — and its "severe and disproportionate impacts" on Pacific Islands.
The hottest weather of the summer is likely Tuesday in Chicago, with a widespread area of sizzling conditions from the Midwest to the Mid-Atlantic.
Threat level: The unusually hot air mass for late August already smashed records in the Southern Plains, and is focused on the Midwest, Ohio and Tennessee Valleys before shifting Southeast, breaking historical benchmarks.
