1st heat wave of the season to bake West with 100-degree temps
The hottest weather of the season so far is on the way for many places across the interior West as the first heat wave of the season looms. But, how long will the heat last?
AccuWeather’s Bernie Rayno spoke with the American Red Cross about the heat dangers to look out for.
Some of the hottest weather of the year so far is in store for the interior western United States from later this week to this weekend. Highs will be in the triple digits Fahrenheit in some areas during the heat wave before cooler air, showers and thunderstorms arrive, AccuWeather meteorologists say.
A strong area of high pressure is what will cause temperatures to surge.
Adding to this will be a general offshore flow, where the wind travels from the land to the water. This prevents any cooling by the chilly ocean water along the coast or the notorious "June gloom" this time of the year. The offshore flow will be caused by the strong high pressure area to the north and a storm setting up over the Pacific southwest of Southern California.
"This will be the first heat wave of the season in the West, outside of Southern California," AccuWeather Senior Meteorologist Heather Zehr said, "There have been other warm spells before, but not quite the scope of the upcoming heat."
Some daily record highs will be challenged.
Areas near the coast will be at their warmest level Friday, while the interior will be either warmest Saturday or similar for both days. The extreme heat will also reach farther north, into the Northwest, Saturday.
There should be a sea breeze kicking in each day, which will somewhat limit the heat for the coastal cities. However, even temperatures there will be able to rise to 5-10 degrees Fahrenheit above historical averages before the sea breeze arrives. For example, temperatures in San Francisco will peak in the middle to upper 70s, compared to the typical high in the upper 60s.
"The peak of the heat for Sacramento, California, will be 103 degrees on Friday, with 107 degrees for Redding, California, on the same day," Zehr said. "Redding will also get well above 100 on Saturday, reaching 106. Farther south, the hottest day for Fresno, California, will be Saturday with a high of 106."
Farther inland, Boise, Idaho, will experience temperatures reaching the upper 90s Saturday, with a chance of triple-digit readings.
The core of the heat will likely escape Southern California, with temperatures only reaching the 70s and 80s around Los Angeles. However, temperatures over parts of the interior Southwest can reach and top 100.
Las Vegas may touch 100 as early as Wednesday, with highs of 106 forecast for both Friday and Saturday. This would top the highest temperature of the year so far, which was 100 degrees reached on May 22.
Salt Lake City's highs are forecast to be well into the 90s this weekend, with a typical high in the upper 70s. The highest temperature so far this year was 89 on May 10 and 12.
Drought, wildfire risk to increase in short-term
There will be an expansion of the short-term drought conditions, including those with extreme or exceptional drought levels.
"There hasn't been widespread, meaningful rainfall in California since mid- to late March, so fuels have had a chance to dry considerably over the past two months," Zehr said, "Additionally, the air will be very dry to begin with, and the high heat will help to make it even drier. Gusty winds, while not reaching damaging levels, will also contribute to the dryness and make it easier for fires to start and quickly spread."
Rain for some areas may arrive this weekend to early next week
Two main storm systems will help break the heat wave, and they may bring some rainfall to the West.
The first will be a storm that drops southeastward from the northern Pacific and then pushes inland over the Northwest. That alone should be enough to trigger at least spotty showers and thunderstorms. Where there are lightning strikes and little or no rain, wildfires may erupt.
The other is associated with the mainly dry storm off the coast of Southern California. The track this storm takes and how much moisture it is able to pull northward from the tropics could help initiate the North American monsoon or mimic its activity for a time.
A tropical rainstorm that may soon become the first named system in the eastern Pacific could help send some moisture beyond the coast and mountains of Mexico and perhaps into part of the southwestern U.S. later this weekend to early next week.
Once again, where little or no rain falls and lightning occurs, the risk of wildfires may increase.
Both storms will work in conjunction to break the heat wave, causing temperatures to trend downward while humidity levels rise.
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