- A northward bulge in the jet stream will be in place as June ends over parts of the U.S.
- This shift in the jet stream has allowed heat and humidity to surge northward into the Plains, Midwest and East.
- Above-average temperatures are expected this weekend in parts of the Plains, Midwest and East.
June is wrapping up on a hot, humid note in parts of the Plains, Midwest and mid-Atlantic states, including a few areas that have not seen much in the way of summery weather so far this year.
This northward surge of heat and humidity is due to a northward bulge in the jet stream that will be in place across parts of the central and eastern U.S. through the weekend.
However, showers and thunderstorms are expected to rumble across portions of the northern tier at times, keeping temperatures a bit lower in those areas.
Otherwise, temperatures up to 15 degrees above average will stretch from the central and northern Plains into parts of the Midwest and East. Dew points will also rise into the upper 60s and 70s, making it feel humid and hotter than the actual air temperature.
(MAPS: Current Temperatures)
How Hot Will It Get?
High temperatures will approach or top 90 degrees in many areas from the central Plains into the upper Midwest and mid-Atlantic this weekend.
Several locations could experience a heat wave, or an extended period of unusually hot weather. A heat wave across the northern U.S. is often considered a three-day stretch of 90-degree temperatures.
Saturday, 100-degree heat pushed as far north as Pierre, South Dakota, with 100s also registered in parts of western Nebraska, western and northern Kansas and southeast Colorado.
North Platte, Nebraska and Lamar, Colorado hit 100 degrees Saturday afternoon for a brief time.
Through Saturday, Washington, D.C., has already seen 13 days with a high of at least 90 degrees this year.
Kansas City recorded its first 90-degree day of the year on Thursday. Chicago, Detroit, Cincinnati, Syracuse and Albany, New York, finally saw their first 90-degree temperature on Friday and Indianapolis hit the 90-degree mark for the first time Saturday.
The combination of high dew points and high temperatures means that conditions could be dangerous to the elderly, young and others sensitive to the heat.
The National Weather Service has issued an excessive heat warning this weekend for the Minneapolis-St. Paul metro area. Heat advisories have also been issued for parts of the central U.S., including Omaha, Nebraska, and Des Moines, Iowa, where heat indices may top 105 or 110 degrees.
People in these communities will be more susceptible to heat-related illnesses. Please drink plenty of fluids, stay in air conditioning if possible, limit physical activity, and check in on your elderly neighbors when possible. Also, don’t forget to look in the backseat before you lock your car to make sure your children or pet isn’t left in a hot car.
High dew points will also keep low temperatures high. Lows will not drop below 70 degrees at times over the next few days, especially near the larger cities in the Midwest and mid-Atlantic.
(MAPS: 10-Day Forecast)
Although a prolonged period of hot and humid conditions is anticipated, widespread record highs or record-warm low temperatures are not likely, given that it is late June and the bar is high.
Temperatures in the Northeast and mid-Atlantic will be cooler on Sunday, but the cooldown won’t last and temperatures are expected to rebound into the middle of the week as high as the mid-90s. Parts of the Plains and Midwest will see temperatures closer to average once again by the middle of next week.
However, NOAA’s Climate Prediction Center has highlighted areas of the East as having at least a 50 percent chance of experiencing above-average temperatures for early July, and excessive heat is also a possibility.
Summer’s Late Arrival
Temperatures have generally been below average for June from the Plains to the interior Northeast and for parts of the Midwest, so this will be the first real taste of summer heat this year.
Indianapolis and Milwaukee and are among the places that have yet to see temperatures reach 90 degrees this year in the Midwest. In the Northeast, New York City, Boston and Pittsburgh have yet to climb to 90 degrees.
This first occurrence of 90-degree temperatures is later than average for those cities listed above. The average date for the first 90-degree temperature of the year is in early to mid-June for many of these spots, with the exception of New York City.
A persistent southward dip in the jet stream has helped to keep temperatures more on the mild side and has brought rounds of rain to already-soaked regions of the Plains, Midwest and East.
But the heat hasn’t been completely absent across the U.S.
Some cities in the northern Plains and upper Midwest have already experienced temperatures in the 90s this year. This includes Minneapolis, which reached 90 degrees on June 7, and Bismarck, North Dakota, where 90s were reached on June 3 and June 7.
Farther south, the Florida Peninsula has seen one of its hottest Junes on record. Both Tampa and Miami hit 98 degrees earlier this week, tying their second-hottest all-time temperatures on record.
A few surprising spots in the West saw temperatures soar into the 90s earlier in June. The temperature climbed to 97 degrees in downtown San Francisco on June 10, part of the city’s hottest three-day stretch in meteorological summer history (June-August). On June 12, Seattle reached 95 and Portland, Oregon, climbed to 98 degrees.