SOUTHERN UTAH — The National Weather Service has issued a “High Wind Watch” across Utah as far south as Iron County and a “Red Flag Warning” for all of southern Nevada, all of Mohave County, Ariz., and the Colorado River Valley in San Bernardino County, Calif. Both are in effect for Tuesday from morning through evening.
A High Wind Watch means that there is the possibility of sustained wind speeds over 40 mph, or gusts of 58 mph or stronger. There is also potential for a hazardous high wind event. A red flag warning means that that critical fire weather conditions are either occurring or are imminent.
Related to the Red Flag Warning, the weather service advises in its alert that a vigorous low pressure system moving out of California into Nevada will bring strong winds to the area Tuesday. This system has very little moisture associated with it and low relative humidity values are expected at the surface.
Affected areas across Utah for high winds – Affected areas include the northern, central and southern Wasatch Front, Sanpete and Sevier valleys, west central and southwest Utah, including the cities of Brigham City, Ogden, Bountiful, Salt Lake City, Tooele, Lehi, Provo, Nephi, Manti, Richfield, Delta, Fillmore, Beaver, Cedar City and Milford.
Affected areas across California, Nevada, Arizona for Red Flag warning – Lake Mead National Recreation area, Colorado River on the Arizona side, northwest deserts and northwest plateau, lower Colorado River Valley, Nye County deserts, Sheep Range-Spring Mountains, Clark and southwest Lincoln County deserts.
Winds and humidity – Across Utah, Southwest winds of 35-45 mph with gusts near 60 mph are expected. For the Salt Lake, Tooele and Utah valley areas, winds will switch to the northwest late afternoon or early evening Tuesday at 35-45 mph with gusts to near 60 mph.
Across southern Nevada and Mohave County, Ariz., widespread southwest winds of 25-35 mph with gusts of 35-50 mph are expected through Tuesday afternoon. Locally higher winds with gusts near 60 mph will be possible near exposed ridgetops and canyon openings. Humidity is forecast with minimum values of 5-15 percent.
Timing – South winds will increase across Utah through the morning hours Tuesday and peak during the afternoon. Winds will switch to the northwest late afternoon or early evening then diminish.
Strong winds will develop across southern Nevada and Mohave County, Ariz., by late Tuesday morning hours around the same time that relative humidities begin to fall below 15 percent. Winds will peak during the afternoon before decreasing Tuesday evening.
Impacts – The weather service warns that dangerous crosswinds could occur across all east-to-west oriented roadways, especially U.S. Highway 6 and state Route 50 in west-central Utah. High profile vehicles and trailers will be most susceptible to these winds. Blowing dust will likely reduce visibilities at times. Outdoor items such as trampolines and lawn furniture should be secured or moved into a protected area.
The combination of gusty winds, low relative humidity and dry fuels can create conditions that are favorable for extreme fire behavior.
Road conditions from the Utah Department of Transportation
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