Boise is on the precipice of tying a heat record this summer and very well could reach territory not seen since records started being kept 147 years ago.
The City of Trees has recorded 18 days of at least 100 degrees this summer and is just two triple-digit days away from tying the record of 20 set in 2003.
And that could happen as early as next week.
The National Weather Service has tracked temperature data since 1875. Even if Boise had no more 100-degree days this year, the total of 18 still would be tied as second-most in a summer. There also were 18 days of triple-digit heat last year.
“We’re currently forecasting on Tuesday a high of 99 degrees, and we’re looking on Wednesday at 98 (degrees). So those are two days that we’re continuing to monitor,” Katy Branham, a meteorologist at the National Weather Service in Boise, told the Idaho Statesman.
“Some of the model data or computer models that we use are indicating the potential for us to reach or surpass that 100-degree mark again on those two days.”
There’s also a small chance that Boise could tick over the 100-degree mark on Friday, Branham said. As of Friday morning, the Weather Service had a high temperature of 96 forecast for the day.
It’s been a historically hot summer for Boise because the region keeps getting anchored underneath areas of high pressure. A high-pressure system pushes air away from the system’s center, resulting in clear skies and warmer temperatures.
The average high temperature in the Treasure Valley is on a downward trend for the rest of the summer — peaking at 95 degrees from July 21 to Aug. 1 — but a couple of days surpassing the 100-degree mark are still possible.
“There’s definitely an opportunity,” Branham said. “If we get underneath any other strong areas of high pressure and we clear out, we certainly could heat up enough to reach (100 degrees) again.”
A stretch of seven days this summer at or above 100 degrees in the Treasure Valley — between July 26 and Aug. 1 — significantly contributed to Boise’s approach on the record. That seven-day stretch is the second-longest stretch in city history, according to the weather service, tied with 1931 and 1960, and behind the nine consecutive days seen in 2003.
Chance for storms on Friday
Monsoonal moisture brought some much-needed rain to Southwest Idaho this week. Just 0.04 inches of precipitation fell in Boise, but storms to the south and east of the city gave some areas heavier rain.
There’s the potential for storms Friday afternoon and evening in Boise — with the National Weather Service predicting a 20% chance— and Branham said high-resolution models predict some isolated storms to enter the Treasure Valley.
“While we can’t guarantee that one would definitely go over the Boise metropolis, we are seeing at least some potential for activity again today,” Branham said.
Branham said that there is still a lot of moisture in the atmosphere, so any storms that formed would most likely produce heavy rain and gusty winds.