Western US wildfire danger to remain elevated this week

By Renee Duff, AccuWeather meteorologist

July 15,2017, 11:18:28PM,EDT

 

 The risk of wildfire ignition and spread will remain high across the western United States despite an uptick in thunderstorms early this week.

Thunderstorm coverage will increase across the Intermountain West as moisture and higher humidity spreads northward in response to the North American monsoon.
Thunderstorms in this type of pattern tend to blossom over the mountainous areas during the afternoon hours before drifting over valley locations toward the evening.

However, the wetter pattern will not translate to widespread wildfire relief and may only bring additional hazards to the region.
“Anytime lightning strikes parched and arid vegetation in the absence of meaningful rainfall, the possibility that a new wildfire will erupt is greatly enhanced,” AccuWeather Meteorologist Kyle Elliott said.
Valley locations will likely miss out on meaningful rainfall as the precipitation may not survive the long trip to the ground.
The northern Rockies, which will be far removed from the greatest source of moisture, will also be at a greater risk of dry lightning igniting new blazes. Dry, gusty winds early in the week will add to the wildfire danger.
Where more persistent rain falls in parts of Arizona and New Mexico, localized flooding and road washouts could occur. Use caution near arroyos which can quickly turn into raging rivers.

Gusty winds triggered by the thunderstorms will pose further hazards by causing blowing dust, reduced visibility and erratic wildfire behavior. Localized damage can occur should the winds be strong enough.
The storms will stay away from the Whittier Fire over the Santa Ynez Mountains northwest of Santa Barbara, California, which has burned over a dozen structures since beginning on July 8. Mandatory evacuations were ordered on Friday afternoon as localized winds fanned the flames and put additional communities at risk.
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Fire crews battling the Frye Fire in southeastern Arizona will be in a better position to receive meaningful rainfall that can help contain the nearly 50,000 acre blaze. Full containment of the fire is expected by the beginning of August.
Firefighters will not have to contend with extreme heat like earlier in the summer.

A firefighter sprays water as flames from a wildfire engulf a residence near Oroville, Calif., on Sunday, July 9,2017. Evening winds drove the fire through several neighborhoods leveling homes in its path. (AP Photo/Noah Berger)

“Increasing amounts of cloud cover and moisture in the southwestern U.S. should put a cap on how high temperatures can climb,” Elliott said.
High temperatures will trend downward in Phoenix from the upper 100s F at the start of the weekend to the middle 90s at midweek.
Even away from the bulk of storm activity, temperatures will dip to seasonable levels in parts of the interior Northwest through Monday, prior to a resurgence in heat later in the week.
The hottest conditions in comparison to normal will remain entrenched across central California, the Great Basin and Idaho’s Snake River Valley through early week.
Temperatures at the Salt Lake City International Airport dropped to only 73 F on Saturday morning, which led to the record for the longest consecutive days of lows at or above 70 F being tied.
"With temperatures expected to remain above that mark well into next week, that record will be shattered," AccuWeather Senior Meteorologist Kristina Pydynowski said.