JACKSON, Wyo. – Following a cooler and wetter start to the week, summer weather conditions will return heading into Labor Day weekend and beyond with highs back into the 80s. Smoke from Idaho wildfires will also drift into the area at times.
Recent Weather Conditions
The past week has been on the cooler side of average for late August, with seven days in a row of high temperatures below 80ºF in Jackson.
Thunderstorms have been less frequent compared to earlier in the month, but we did have a few active days with widespread thunderstorms last Friday afternoon, Sunday afternoon, and early Monday morning.
The round of showers and thunderstorms on Monday morning produced the most widespread rainfall, with rain totals ranging from 0.2 to 0.5 inches in the Jackson Hole Valley. The town of Jackson received 0.37 inches of rain.
A chilly airmass accompanied Monday morning’s showers, and this resulted in snow levels dipping as low as 10,000 feet. A brief dusting of snow was noted at the top of the tram at Jackson Hole Mountain Resort, with more substantial accumulations over the higher peaks of the Tetons.
The snow that dusted the higher peaks did not stick around for long, but it’s just a reminder of two things… 1) snow can fall at any time of year in the mountains, and 2) fall is right around the corner (even though we will be reverting back to a summer pattern for the next little while).
For the month of August, temperatures are on track to end up slightly above average (remember, the first week of the month was very hot) and rainfall is on track to end up close to average in the Jackson Hole Valley.
Rainfall has been a bit lower than average around Driggs and Alta in Teton Valley, but there are not any publically available rain gauges in Victor to determine if heavier amounts have occurred there.
Fish Creek Fire Update
The Fish Creek Fire grew substantially during the middle part of last week, but since last weekend, fire growth has been minimal thanks in part to cooler and wetter conditions. As of the last report, the fire is about 25% contained as firefighters have made significant progress.
Upcoming Weather Pattern
Wednesday has been windy and relatively cool thanks to a cold front that moved through during the morning hours. The high on Wednesday afternoon has topped out around 70ºF in Jackson, which is below average for late August.
Based on webcams and satellite data, the Fish Creek Fire does not seem to have flared up significantly on Wednesday since the last official report despite the uptick in winds. The cooler temperatures are likely helping.
The future outlook for this fire is both good and bad, as lighter winds are expected from Thursday on, but warmer temperatures and lower relative humidity are also expected.
Before the warm-up begins, we will see a very chilly morning on Thursday with lows projected to drop into the 20s in the valleys. This would be the first freeze of the season for most locations.
However, highs will warm up into the mid 70s on Thursday afternoon. The warming trend will continue on Friday and Saturday with highs reaching the low to mid 80s as a ridge of high pressure builds over the Western U.S. Winds will also be lighter as the jet stream retreats northward into Canada.
While we have enjoyed plenty of sunshine and clear skies on Tuesday and Wednesday, a shift to west/northwest winds may bring some smoke into our area from Idaho wildfires on Wednesday night and Thursday morning.
Periods of smoke will remain possible through Friday, then winds will shift back to southwesterly on Saturday which should push most of the smoke out of our area. However, there is still an inherent uncertainty when it comes to smoke more than a few days out, as fluctuations in fire behavior for ongoing and potential new fires are major factors.
Warm temperatures and mostly dry conditions will continue on Sunday and Monday with highs in the 80s. However, we may see just enough monsoonal moisture sneak into our area for a chance of isolated thunderstorms, in response to a weak low pressure trough moving into the Western U.S.
This pattern may continue into the middle of next week with warm temperatures and at least a slight chance of isolated thunderstorms. Any rainfall looks light and spotty in this pattern.
Heading into the second half of next week, a drying trend is expected and temperatures are expected to remain above average with highs well into the 80s. For perspective, average highs are in the upper 70s in late August and early September, and in the mid 70s once we get past September 5.
Alan Smith, Meteorologist
