Summer weather advisory from the National Weather Service on June 15, 2021 (National Weather Service, Billings, Montana).
For the next day or so — but maybe longer — Montana’s weather is being, well, Montanan.
In a state that frequently sees weather shifts from heat to snow and then back, the scorching hot weather that has gripped the central and eastern part of the state should subside by Wednesday and Thursday, bringing heat back to more typical temperatures for the state.
The National Weather Service branch locations throughout Montana have been producing maps that show colors not usually seen — deep reds, browns and purples symbolizing triple digit heat.
The good-news, bad-news is that while the temperatures will be cooling, it will bring a chance of much needed moisture. The bad news is that moisture in Montana during the summer usually comes with lightning and thunder, meaning an increased chance of fires.
“Unfortunately, rain without thunder is really hard to do in summer,” said meteorologist Tom Humphrey of the National Weather Service in Billings.
He said that the area usually only averages two 100+-degree days per year, mostly frequently in late July or August. That means the June highs were earlier and substantially so for many parts of the state.
The National Weather Service forecast for Billings predicts 106 degrees on Tuesday, noting that temperature has only been achieved six other times, with the record of 108 in 2002. Meanwhile, Miles City has the top temperature record in the central region with 111 degrees in 2012.
The high temperature in Hardin for Tuesday is 108, while Forsyth could see 109. Even Livingston is on pace to reach 100, something that has never happened for that community in June.
In central Montana, the National Weather Service is predicting slightly lower temperatures, mostly in the 90s, but has sent out its own warnings about windy weather, with relative humidity dropping to as low as 10 percent. Gusts between Great Falls and Lewistown could reach 45 mph, which means the conditions are ideal for fast-spreading fires.
The weather is being caused by a ridge of high pressure from California and Nevada. As air comes off the slope of the Rocky Mountains, it’s already dry and it is heating up, Humphrey said, making it particularly dangerous for fire. By Wednesday into the later week, the more typical weather pattern from the Northwestern Pacific region will come back into play, bringing cooler, more humid air, lowering the temperature to the expected temperatures for this time of year, in the 80s.
“This is usually the green-up period where plants are still accessing the moisture from the soil, but March was so dry for us that there’s just not that much moisture,” Humphrey said.
Eastern Montana will also see temperatures ranging in the high 90s and low triple digits. The already drought-impacted Hi-Line will see temperatures in the upper 90s, with Plentywood’s high expected at 95, according to the National Weather Service in Glasgow. And Jordan, Montana could see 108 while Terry could see 106 degrees.
Though the unusual and unseasonably high temperatures are noteworthy, the rest of the summer’s long-term forecast will still likely be average or just slightly above average, Humphrey said.
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