BILLINGS — Expect unseasonably warm and dry weather to stick around through Friday due to steady zonal flow. Daytime highs will hover around the mid-70s Wednesday, then mid-70s to near 80° on Thursday.
A trough dropping into southern British Columbia will set up a surface low over southern Alberta and Saskatchewan. This puts much of Montana right in the dry slot, fueled by strong downslope winds, so fire danger will creep up Friday afternoon. Critical fire weather conditions will be a real possibility as daytime highs rise into the low to mid-80s, humidity percentages drop into the teens, and winds turn stronger with widespread 20 mph gusts, pushing between 30 to 40 mph (or stronger) across the western foothills.
A big pattern shift will bring cooler, wetter weather across the weekend and into early next week. Models are in good agreement that a cold front will sweep across Montana beginning Saturday morning, shifting winds to a brisk north-northeast and bringing a drop in temperatures, with highs ranging from the mid-60s to mid-70s. As an upper low moves into the Pacific Northwest, shower chances will increase over the west during the day. Early Saturday also brings the potential for modest mountain waves in the lee of the Beartooth and Bighorn mountains. Watch out for strong winds!
Confidence is much higher for widespread below-average high temperatures on Sunday and Monday, with daytime highs falling into the 30s and 40s. Most of the region will also experience its first hard freeze of the season.
Although ample Pacific moisture will be available, there is still some uncertainty regarding overall precipitation amounts and precipitation type, although expectations are growing. For now, the timeline for rain/snow will run from Saturday afternoon through early Monday afternoon.... give or take. Mountain and foothill areas are favored to receive the highest precipitation and have the best odds of seeing measurable snow.
Here's the latest thinking on snowfall potential:
The chance of receiving 1 or more inches of snow sits at 70% to 80% along the western foothills, 40% in Billings, and 10% in the east. For 6 or more inches, Billings has a 10% chance, while the western foothills sit at 35% to 45%, with even higher totals in the mountains. If remnants of Hurricane Rachel get caught up in this storm system, heavier wet snowfall could significantly impact travel.
In terms of total moisture (rain and snow), around 1 inch is possible in the west, compared to 0.5 inches centrally and 0.15 inches to the east.
Details will become clearer as models fine-tune over the next few days, so keep checking back for updates.
Light lingering precipitation will taper off early Tuesday morning. A trend toward warmer and drier weather begins on Tuesday, with high temperatures recovering into the mid-40s to mid-50s.
Miller Robson
Q2 Morning Meteorologist
miller.robson@ktvq.com
