Frozen Desert Southwest, Great Basin Begins Slow Thaw
UPDATED 11 AM PST, January 15, 2013
UPDATED By WeatherBug Meteorologist, Fred Allen and James West
The big western deep freeze is finally starting to fade, with southern California slowly seeing a return to warmer temperatures today and Wednesday. However, below-freezing temperatures will once again freeze the Desert Southwest tonight, with Phoenix once again getting into the act.
A huge upper-level trough that dipped as far south as the U.S.-Mexico border is finally going to give way to a building ridge off the Pacific. This will push arctic air that froze much of the Western half of the U.S. the last several days northward, allowing a slow return to more seasonal temperatures for the week`s second half.
The Northwest and Southern California will be the first one to see the return of more seasonal air today, with the rest of the West getting in on the act Wednesday and Thursday. Lows will slowly warm from below freezing into the lower 40s by Friday in places like Phoenix and Las Vegas with highs rebounding into the 50s and 60s instead of the colder early week 40s.
Even so, another night of clear skies and calm wind will produce single-digit temperatures by Wednesday morning in Flagstaff, Ariz. Upper 20s will be found in Phoenix while Phoenix sees low 30s.
Freeze and Hard Freeze Warnings continue through tonight and early Wednesday across southern and central Arizona.
Plants and flowers should be covered by a towel or cloth to avoid exposure to the cold. Pets should be kept inside to avoid cold weather-related problems. In addition, exposed water pipes could burst.
Meanwhile across southern California, strong and potentially damaging winds rushing through the canyons and passes across the foothills outside of Los Angeles and San Diego will gust in excess of 60 mph; a few gusts could top 70 mph today and Wednesday. High Wind Warnings, and Wind Advisories are in place here. The winds will create difficult travel along Interstates 5, 10 and 15 in southern California through this afternoon.
Temperatures will stay 15 to 25 degrees below average across the southern Great Basin and Southwest today. Even more impressive, Phoenix could have its fifth consecutive night below freezing tonight, first time since December 1988.
Significant cold weather outbreaks in the Mojave Desert and southern Great Basin are not uncommon in January. The coldest month for this region is January 1937 when Las Vegas averaged a temperature of 31.2 degrees. The most recent cold snap was February 2 and 3, 2011 when downtown Las Vegas dipped to 30 degrees.
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