Heat Wave to Ease, Rain Chances Rise Next Week Over America's Worst Current Drought in Dakotas, Montana

Jon Erdman
Published: July 14,2017
Another searing heat wave will bake the northern Plains, northern Rockies and Great Basin into early next week before a pattern change finally eases this long-lived hot pattern over the nation's most rapidly worsening drought in parts of the Dakotas and Montana.
(MORE: Pattern Change Next Week Will Bring Heat Relief to Northern Plains, Rockies and Heat Will Build in the East)
Known as a flash drought for its relatively rapid development, this northern Plains drought developed quickly by late May over a sizable swath of eastern Montana, North Dakota and South Dakota.

Animation of the drought monitor analysis from May 16 through July 11, 2017, indicating the development of the northern High Plains flash drought. More dire areas of drought are denoted by the darker orange and red contours.

A drought emergency was declared in eastern Montana by Gov. Steve Bullock in late June. Local ranchers and farmers told KRTV-TV this is the worst drought in northeast Montana since 1988.
Glasgow, Montana, in the state's northeast corner, shattered its previous record-driest April-through-June period – a record that stood for 99 years.
It's also been their driest year-to-date on record, through July 12, in Glasgow, where only half the average precipitation has fallen year-to-date.
This is the most widespread occurrence of "extreme drought" in North Dakota in almost nine years, the second worst category on the Drought Monitor analysis.
Fifteen North Dakota counties were designated as agricultural disaster areas at the end of June, KFYR-TV reported. The declaration by the U.S. Department of Agriculture made emergency loans available for affected farmers and ranchers.
"There are some areas of western North Dakota into Montana that haven't had good rain going on three months, other than isolated spots," Daryl Ritchison, executive director of the North Dakota Agricultural Weather System, told the Williston Herald.
Some farmers in McIntosh County, North Dakota, resorted to "hauling water" and some pastures had "zero growth," according to the June 27 U.S. national drought summary.
(MORE: Wildfires Burn in British Columbia)

Heat Wave Returns...

Only the Dust Bowl of 1936 had a hotter first 11 days of July in Williston, North Dakota, according to data from the Southeast Regional Climate Center.
Billings, Montana, topped out at 100 degrees last Saturday, a threshold the city hadn't crossed in almost three years.
Bismarck, North Dakota reached the century mark on Friday afternoon.
One location in South Dakota topped 110 degrees last Sunday – hotter than Needles, California.
Unfortunately, the heat is only ramping back up as high pressure aloft bulges back northward into the Canadian prairies through early next week.
This means highs well into the 90s or low 100s are likely to persist in the northern High Plains drought area, as well as lower elevations of the northern Rockies and Great Basin, not to mention parts of the southern Canadian prairie, through early next week.
(MAPS: 10-Day U.S. Forecast Highs/Lows)

Forecast Highs This Weekend

...But Relief is Finally Ahead

Change in the jet-stream pattern expected to finally take the extremity off the persistent heat in the northern Plains and northern Rockies.

While there has been a day or so here and there of heat relief during this rather sustained hot period, an important pattern change should finally bring an end to this extended hot spell next week.
Instead of the warm dome of high pressure aloft bulging into Canada, the jet stream will flatten, or track more west-to-east, across the northern tier of states later in the week.
(MORE: Pattern Change Next Week Will Bring Heat Relief to Northern Plains, Rockies and Heat Will Build in the East)
This pattern will squeeze the worst of the heat out of the northern Plains and northern Rockies.
Instead of upper 90s and 100s in the low elevations, generally 80s or low 90s can be expected later in the week.
Yes, it's baby steps, but given how hot this summer has been, it's a welcome baby step.
(MORE: July is Warmest Time of Year in Much of U.S.)

Any Rain Relief, Too?

There have been isolated thunderstorms in parts of the drought area even during this prolonged heat wave, mainly firing off the mountains, or when surface temperatures get so hot that thunderstorms ignite.
However, we haven't seen the kind of soaking, mid-summer thunderstorm complexes in the drought-suffering northern High Plains that have flooded out parts of the Midwest and Northeast.
(MORE: Why Dry Thunderstorms are a Danger)

Rainfall Outlook Over the Drought Area: Next 7 Days

One concern is the feedback that often occurs during flash droughts. Namely, a lack of soil moisture to transfer to the atmosphere means less rain generated by either scattered thunderstorms or any larger-scale weather system that moves in.
This dry ground then heats up faster than moist ground, essentially sucking any scant moisture out of the soil, leading to hotter temperatures and helping to reinforce the large-scale pattern that created the heat in the first place.
Fortunately, the pattern change in the week ahead does raise the chance of rain, in a general sense, in the drought area.
Jet-stream disturbances, combined with summer heat and increased humidity, tend to increase the coverage of afternoon and evening thunderstorms.
This seems to be in the cards for the drought area next week.
In fact, at least parts of the region may see the kind of soaking mid-summer thunderstorm clusters later next week.
Again, welcomed baby steps for a region increasingly desperate for relief.
Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Facebook and Twitter.
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