World's First Chief Heat Officer's Tips

A long-awaited warm spell is finally emerging across the Midwest and Northeast as May begins.

The jet stream pattern has flipped from its recent configuration. A large ridge of high pressure, or northward bulge in the jet stream, has set up over the eastern half of the nation while a trough of low pressure, or southward dip in the jet stream, has taken shape in the West.

Surface high pressure near the Southeast coast is allowing a warm, southerly flow to persist in the Midwest and Northeast.

Meanwhile, the jet stream dip is nudging eastward out of the Rockies into the Plains and Mississippi Valley, setting the stage for severe thunderstorms in those regions. This is a classic setup for severe weather in the spring months.

(MORE: Multi-Day Threat of Severe Weather This Week)

Warmup Details

A widespread warmup will greatly expand in the Midwest and Northeast as an area of high pressure and the upper-level ridge slide eastward.

Minneapolis/St. Paul reached 84 degrees Monday, its first 80-plus-degree day since Sept. 24, 2017. Chicago recorded a high temperature of 80 degrees Monday, making it the first 80-degree day there since Oct. 9, 2017. The Windy City then reached 86 degrees Tuesday, just 4 degrees shy of the daily record for May 1.

Indianapolis saw its first 80-degree day of the year Tuesday, when the high was 81 degrees. New York City and Rochester, New York, both reached 80 degrees Tuesday, as well. New York City had previously reached 82 degrees on April 13.

The warmth will continue building in the Northeast through Thursday. High temperatures will be 10 to 25 degrees above average for much of the Great Lakes, Ohio Valley, Northeast and mid-Atlantic states.

Highs will top out in the 70s into northern New England, with 80s expected in the New York City Tri-State area and portions of New England. Temperatures in Boston Wednesday will finally climb above 70 degrees for the first time since Feb. 21. In fact, highs in Boston will be in the 80s Wednesday and Thursday.

(MAPS: 10-Day Forecast Highs and Lows)

Washington D.C. could top out near 90 degrees Thursday, which would approach the daily record high of 91 degrees for that day. A few other cities in the mid-Atlantic will also be close to record highs Thursday, including Baltimore and Philadelphia.

Low temperatures will also be above average, generally in the 50s and 60s. In fact, for many locations, low temperatures will be close to the average highs for early May.

The Southeast will also see warmer temperatures, with highs climbing well into the 80s midweek.

This stretch of above-average warmth will only last a few days, however, as temperatures are expected to cool back to near-average this weekend.

(MORE: Another Pattern Change Will Lead to a Cooler East, Hot Southwest)