Unseasonably warm temperatures on Thursday along with dry and breezy conditions will result in elevated fire danger, especially in grassy/shrubby vegetation where fuel moisture is low. A Red Flag Warning for fire danger is in effect for the Jackson Hole Valley and Gros Ventre Range from noon-8 p.m. on Thursday.
Highs on Thursday will soar into the upper 80s in the valley, which is around record levels for this time of year. The good news is that smoke is also becoming lighter compared to recent days as the heaviest smoke has lifted north of Teton County.
Winds will pick up on Thursday afternoon out of the southwest at 10-20 mph with gusts to 25 mph in the valley, and out of the west/southwest at 15-25 mph with gusts to 35 mph over the higher peaks.
Our pattern will begin to change on Friday as we undergo a transition from a summer pattern to a fall pattern. A weak storm system approaching from the west will lead to increasing clouds and perhaps a few isolated sprinkles early in the day, followed by a good chance of thunderstorms in the afternoon.
Winds will be even stronger on Friday out of the southwest at 10-20 mph with gusts to 35 mph in the valley and 15-25 mph with gusts to 45 mph over the higher peaks. Smoke is also expected to further decrease with improving air quality.
The system will move across the area on Friday night and early Saturday morning with more widespread showers developing. Snow levels will dip to 11,000 feet or so by early Saturday morning.
Most of the showers will taper off by shortly after sunrise on Saturday, but additional clouds and isolated light showers can be expected over the Tetons and surrounding ranges during the day on Saturday.
Total rain amounts from this system will range from 0.2-0.4 inches in the Tetons, Gros Ventre’s and Yellowstone, and 0.05-0.2 inches for the Jackson Hole Valley, Northern Star Valley and the Northern Wind River Range with less rain farther south.
Saturday will be noticeably cooler behind a cold front that moves through on Friday night with highs in the low 70s in the JH Valley. Winds will remain strong on Saturday out of the west/southwest at 10-20 mph with gusts to 30 mph in the valley and 20-30 mph with gusts to 55 mph over the higher peaks.
All areas will see dry conditions and clearing skies on Saturday night. Sunday is shaping up to be the nicer of the two days this weekend with dry conditions, mostly sunny to partly cloudy skies and highs in the mid 70s in the valley. Winds will start out lighter on Sunday morning but will become stronger again on Sunday afternoon.
The next system is expected to arrive on Monday and is trending stronger for Jackson Hole, though there is still some uncertainty. Right now, it looks like a few leading edge showers could develop Sunday night, giving way to a better chance of more widespread rain during the day on Monday.
It’s possible we could see some solid rain totals out of this system, and temperatures will also be cooler on Monday. At this time, snow levels look to range from 10,000-11,000 feet for most of this event, but that could change as we get closer to the event.
We could see some lingering showers persist into Tuesday, followed by a break in the action on Wednesday. The pattern for late next week is also trending more unsettled with an overall cooling trend expected along with brisk winds. Smoke should also be less of an issue compared to recent weeks.
The heaviest and most widespread precipitation late next week is projected to stay north of our area, but there is at least a chance we could see a little bit of rain and high elevation snow late next week and into the weekend of September 18-19.
Alan Smith, Meteorologist
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