The combination of extreme temperature, high humidity and blazing sunshine will have millions sweltering in a dangerous heat wave in much of the southern Plains and lower Mississippi Valley during the third week of June.
Temperatures already surged to above-average levels over much of the central and southern Plains at midweek. However, the heat wave is only in the early stages of development in some locations.
Actual temperatures will climb well into the 90s to near 100 F in parts of the lower Mississippi Valley and past 100 in parts of the central and southern Plains.
AccuWeather RealFeel® Temperatures will be significantly higher than the actual temperature.
The RealFeel Temperature factors in temperature and humidity, just as the Heat Index, but also incorporates other conditions that impact how hot it feels, such as sunshine and wind.
RealFeel Temperatures will approach and exceed 110 in a broad area.
The extreme conditions will make it dangerous for those partaking in vigorous physical activity or for those without access to air-conditioning.
Heavy rainfall over part of the region in recent months has dampened the soil in some areas and saturated it in others.
Some of this moisture will evaporate and add to the high humidity levels in the region.
"The magnitude of the humid air like we have now over the High Plains is quite infrequent," according to AccuWeather Enterprise Solutions Chief Innovation Executive Mike Smith. "For that reason, this heat wave will be extraordinary over the High Plains."
The heat will have some benefits, however.
In the past week or so, downpours have affected a relatively small area of the winter wheat belt.
"After a very wet May in winter wheat areas of Oklahoma and Kansas, the hot and mainly rain-free weather during June will create nearly ideal harvest conditions in many locations," Smith said.
As the weekend progresses, the core of heat will migrate slowly westward and will take root in the Southwest states, where the most extreme temperatures are likely and could rival levels rarely felt over the past 100 years.