Despite the start of astronomical fall, ongoing heat from the central United States will spread toward the Atlantic coast into next week.
While Hurricane Maria cruises northward but off the US East Coast, hot air more typical of the middle of summer will expand to encompass much of the eastern two-thirds of the nation in the coming days.
Many areas over the central and eastern U.S. will have higher temperatures during this spell of hot weather than during all of August.
Ninety-degree Fahrenheit air extended from the Gulf Coast to the Plains, Ohio Valley and the central Great Lakes on Thursday. An even larger area covering more than 1,000 square miles had highs in the 80s or higher. A few locations in Texas and Kansas topped 100.
These conditions will continue this weekend and into early next week.
Across the Northern states, a heat wave is defined as three or more days with high temperatures of 90 or above. This criteria will be met in many locations including Kansas City, Missouri; St. Louis; Chicago and Cincinnati.
Many areas in the Appalachians and coastal areas of the mid-Atlantic and New England that have escaped the peak of the heat thus far will join in as the influence of Jose's circulation, offshore in the Atlantic, wanes.
Cities such as New York City, Philadelphia, Washington, D.C., and Baltimore may record a September heat wave with the weather pattern.
Some daily records established during the late-1800s will be challenged or broken. Temperatures will average 10-20 degrees above normal.
AccuWeather RealFeel® Temperatures will reach the upper 90s to near 100 over much of this swath during the middle and latter part of the afternoon hours each day.
The heat and high humidity will be no stranger to the Southern states, especially in areas undergoing strenuous cleanup following hurricanes Harvey and Irma.
People should exercise caution and restrict strenuous physical activity during the hottest conditions. Intake of non-alcoholic fluids and frequent breaks are a must under these conditions to avoid dehydration, heat exhaustion and heat stroke.
Mother Nature, however, will offer some comfort. Long nights, compared to the summer, will allow temperatures to fall to cool levels during the evening and remain there into the daylight morning hours. This will be the least stressful time for vigorous exercise.
In addition, some of the cool weather being experienced in the West will work eastward during the middle and latter part of next week.
This push of cool air is also likely help to keep Maria from making landfall on the U.S. mainland.