Computer model projection of the "misery index" of heat and humidity on July 18, 2016. Image: http://earth.nullschool.net
A noteworthy weather pattern will evolve next week across the lower 48 states, featuring a massive and intense area of high pressure sprawled out across the center of the country, like an annoying partner taking up the entire bed while snoring loudly.
It's been clear for several days that a prolonged heat wave is coming, particularly for the Plains, portions of the Midwest and Southeast...
However, the details about this heat wave are only now coming into better focus, and this event is still about one week away. Based on computer model projections on Friday, the likelihood of hundreds of high temperature records during the height of the heat wave has fallen somewhat, but the health threat the heat poses has become more distinct.
Heat index forecast for July 21, 2016. Image: NWS
As Mashable reported on Wednesday, it is still likely that the high pressure area will be unusually intense, possibly coming close to a record based on one meteorological indicator.
The heat will be accompanied by high dew points, meaning that it will feel extremely humid and push heat index values into the 100s Fahrenheit from the Gulf Coast to Minneapolis late next week into next weekend.
The highest heat indexes look likely to set up across the Mississippi River valley, where heat index values of near or greater than 110 degrees Fahrenheit may be reached. Even in Des Moines, Iowa, heat index values on July 21 are forecast to peak at 111 degrees Fahrenheit, according to the Weather Service.
The high heat index values present health concerns since hot, humid air can sap the body's ability to cope with the heat, thereby causing heat-related illnesses among the elderly and the very young in particular.
8 to 14-day temperature outlook for the U.S. showing the bullseye of heat across the Midwest. Image: NWS
In addition, there is the issue of the heat wave's duration. This weather pattern may last beyond July 24, which would also mean the public health threat could be sizable despite a relative lack of record-shattering temperatures.
If the heat wave lasts long enough, it could push July 2016 past the all-time monthly heat record set in July 1936, during the Dust Bowl.
June of this year was the hottest such month on record for the lower 48 states, beating June of 1934 — another Dust Bowl month. July has been above average so far across much of the country, with the exception of the Pacific Northwest.
Human-caused climate change makes it more likely that warm temperature records will be set.
In addition, one of the most solid climate science findings is that heat waves will become more frequent, intense and longer-lasting.
The upcoming heat wave's evolution is illustrated in the below animation of computer model projections of temperature anomalies (the cooler periods largely correspond to overnight low temperatures).
'Ring of Fire' thunderstorms?
The heat dome across the central states — oscillating between a peak over Kansas midweek to the southwest by July 24 — may be accompanied by severe thunderstorms along its periphery.
The Northeast, in particular, which will be closer to the jet stream flowing west to east along the U.S. border with Canada, could see repeated complexes of severe thunderstorms.
These storms tend to erupt on the outer edges of heat domes like this one, where the influence of the sinking air at the center of the high pressure area is not as strong.
Such a pattern, with storms rippling along the edges of a dome of high pressure in the summertime, is known as a "ring of fire" pattern, and can result in flooding rains and damaging winds in many cases.
July 16th, 2016
original story HERE
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