After a few days of crisp, fall-like weather in the Midwest and Northeast, high temperatures and humidity soaring to levels more typical of mid-July will leave some residents wondering if the calendar truly reads September and if this is the last taste of summer. AccuWeather meteorologists predict that several major cities will see highs soar once again into this week -- with more opportunities for the mercury to hit 90 degrees Fahrenheit.
Cities from Chicago to New York City, had experienced temperatures that are more typical of late September over the past few days forcing many to dust off jackets and flannels to help combat morning temperatures in the low 60s and even the low 50s in some locations with afternoon highs only reaching the low 70s.
"After a brief taste of fall-like weather across portions of the Midwest and Northeast, a return of heat and humidity is in store this upcoming week," AccuWeather meteorologist Brandon Buckingham explained.
A northward lift in the jet stream pattern this week will allow for temperatures and humidity levels to gradually increase across the region. The warming trend will send the jackets and flannels back into closets and air conditions will hum once again across the East.
Typical early to mid-September, high temperatures range from the low 70s in the northern Great Lakes, northern New England and the highest elevations of the central Appalachians, to near 80 across much of the mid-Atlantic. Low temperatures tend to range from the low 50s in the northern tier and in the mountains, to the upper 50s over the Ohio Valley and the mid-Atlantic Interstate 95 corridor during the first part of September.
Through the middle of next week, high temperatures will trend upward to widespread highs in the mid- to upper 80s with a few 90-degree highs in some of the major cities in the Midwest and mid-Atlantic.
AccuWeather RealFeel® Temperatures will climb to near 90 in New York City by Monday afternoon, and for locations farther south in the mid-Atlantic, including Philadelphia, Washington, D.C., and Baltimore, RealFeel Temperatures will soar even higher, reaching as high as the low to middle 90s and near 100 in central Virginia.
A few different weather factors will be at play that will allow for the July-like warmth to filter into the Midwest and eastern United States this coming week.
"First, a dome of heat that is over the western United States will be dislodged and will shift eastward through the Plains and Midwest. Meanwhile, an area of high pressure known at the Bermuda High will expand along the East Coast, which will act to spread a warm and humid south-to-southwest breeze across the eastern third of the nation," Buckingham said.
The upcoming pattern will allow some locations to add to their number of 90-degree days in terms of actual temperatures, too. The peak of the heat in cities, such as Indianapolis, Detroit, St. Louis, Cincinnati and Louisville will come Monday and Tuesday, while the heat peaks midweek farther east. In cities such as New York City, Philadelphia, Boston, Pittsburgh and Washington, D.C., the hottest conditions will be Wednesday. Many of these cities, especially in the lower Ohio Valley and the mid-Atlantic have the potential to add a number of 90-degree days to their tally for the season with this late-season warmup.
Washington, D.C., has already exceeded its average of 36 days at or above 90 F with 46 such days recorded thus far. The same is true to Philadelphia, where the city has experienced 37 days at or above 90 F with 27 days a year being the average. New York City is tied with it annual average for days at or above 90 F with 17 days hot days. However, Cincinnati is lagging behind with 19 compared to a seasonal average near 20 days.
High temperatures at or above 90 will be short lived and many cities will fall short of recording another heat wave for the summer season, which is three days consecutive at or above 90 degrees in the eastern U.S., many cities will be on track to finish above average for the year in terms of afternoon high temperatures at or above 90 degrees.
Relief from the heat will come with afternoon showers and thunderstorms possible each day next week as humidity levels and afternoon temperatures soar. However, a slight shift in the weather pattern could come late next week.
A slight dip in the jet stream pattern is forecast to pivot from the Midwest and may put the brakes on the warming trend for some by late next week.