Wednesday, December 31, 2014

Winter Storm Frona: Snow, Ice Causing Travel Nightmares in Southern California, Arizona, Texas

By Linda Lam and Nick Wiltgen and Jon Erdman
Published Dec 31,2014 06:35PM,EST
weather.com
 
 
 

Who Gets the Worst of Frona?

Winter Storm Frona will big lots of snow and high winds to part of the Southwest. 
Winter Storm Frona is already snarling travel in parts of the Desert Southwest this New Year's holiday, and is only ramping up for a cross-country trek through the first weekend of 2015.
(MORE: Expert Analysis | Winter Storm Central)
Winter Alerts - Rockies, Plains
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Winter Alerts - Rockies, Plains
Over 100 vehicles were stranded on mountainous, snow-covered state highway 138 near Crestline, California and also in two separate locations near Mount Baldy, California Tuesday evening. This is about 80 miles east-northeast of downtown Los Angeles. San Bernardino County Fire Department personnel brought some of the stranded to shelters while some simply abandoned their vehicles and walked home.
(MORE: Crashes, Closures Blamed on Frona)
Snow has ended over southern California, but winter storm warnings have been posted for other parts of the Southwest, including the canyonlands of southern Utah, Grand Canyon National Park, higher elevations to the north and east of Phoenix and Tucson, western New Mexico, and a swath of western and central Texas and southeast New Mexico.
An arctic air mass is supplying the necessary frigid temperatures for snow, and the accompanying very strong area of high pressure from Canada has helped force the cold air through multiple mountain ranges all the way down into the Desert Southwest. Meanwhile, energy in the upper atmosphere is providing the necessary lift to squeeze out moderate to heavy snowfall over a large area.
(MORE: Arctic Chill Returns to End 2014)
Current Winter Radar
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Current Winter Radar
Information updates every 5 minutes. Note that mountain ranges may block radar signals, causing some areas of snowfall to not appear on the map.
48-Hour Snowfall Forecast
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48-Hour Snowfall Forecast

Snow on the Desert Floor

A strong jet-stream disturbance in the upper atmosphere has plunged into the Desert Southwest, meeting up with more arctic air arriving from the north and northeast and ingesting some additional moist air, as well.
Snow began to fall throughout the Southwest on Tuesday, generating even a light amount of accumulation in the deserts of Joshua Tree National Park. Up to 3 inches had accumulated in Murrieta, California early Wednesday morning, prompting vehicles to pull off Interstate 15 due to slick roads. As much as 6 inches of snow has already fallen near Lake Elsinore, California, at an elevation of only 1400 feet, breaking many tree limbs, according to a National Weather Service spotter.
The airport in Flagstaff, Arizona reported 6.8 inches of snow as of 10:45 am MST Wednesday.
Wednesday, snow will intensify over much of Arizona's higher elevations and the canyonlands of southern Utah, spreading into southwest Colorado and parts of northern New Mexico through early Thursday, New Year's Day. Locally over a foot of snow may fall in parts of northern Arizona, southern Utah, and southwest Colorado.
(FORECAST: Bryce Canyon Nat'l Park | Flagstaff, Arizona)
Some rare light snow has also fallen on the valley floor in Las Vegas. McCarran International Airport, the official observation site for Las Vegas, reported light snow Wednesday from 9:40 to 9:54 a.m. and again from 10:45 to 11 a.m. Only a trace fell, but that was enough to tie Las Vegas's record snowfall for New Year's Eve.
Accumulating snow in Vegas is not unheard of, but significant snowfall on the valley floor is quite rare. Here are the dates of the last five one-inch snowfalls at McCarran:
  • Dec. 17, 2008: 3.6 inches
  • Dec. 30, 2003: 1.3 inches
  • Dec. 6, 1998: 1.0 inch
  • Feb. 19, 1990: 1.4 inches
  • Jan. 30-Feb. 1, 1979: 7.8 inches
(MORE: 10 Shocking Snow Cities)
Travel will become increasingly difficult in the Southwest through New Year's Day, with the following main interstates likely to have snowy travel, or even closures of some stretches:
  • Interstate 17: North of Phoenix to Flagstaff, Arizona
  • Interstate 25: Roughly Socorro to Las Vegas, New Mexico, including Albuquerque
  • Interstate 40: West of Albuquerque to the Arizona-California border
(MORE: Check the Commuter Forecast)
Thursday's Forecast
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Thursday's Forecast

Icy Southern Plains

Hazardous driving conditions developed in west Texas as an area of light freezing rain and freezing drizzle developed Tuesday. Accidents were reported in the Midland-Odessa area Tuesday afternoon. Light snow was reported farther north in west Texas.
This light precipitation has diminished somewhat Wednesday, but spotty freezing drizzle and temperatures well below freezing have kept road conditions treacherous across much of west Texas. More significant precipitation should blossom again Wednesday night into Thursday as the upper-level system finally begins lifting out of the Southwest.
With cold air near the surface in place, that should spawn an area of light to moderate freezing rain and sleet across a large part of west and central Texas, and possibly parts of north Texas as well. The Dallas-Fort Worth Metroplex, particularly the north and west sides, could see some light freezing rain for a time Thursday.
Patchy light freezing rain or drizzle is also possible over parts of Oklahoma into western and northern Arkansas, particularly early Thursday.
(FORECAST: Midland | Okla. City | Fayetteville)
Ice accumulations will be sufficient to make roads, especially bridges and overpasses, treacherous. Dallas-Fort Worth is notorious for its many freeway flyover ramps, which can turn into skating rinks when freezing rain falls. Fortunately, Thursday morning is a holiday -- but if you absolutely must travel, you should try to avoid the freeway system and stay on surface roads as much as possible until temperatures warm up later Thursday.
Thursday morning flights out of Dallas-Fort Worth International Airport may be delayed by de-icing requirements.
Interstates impacted may include:
  • Interstate 10: From the I-20 junction to near San Antonio
  • Interstate 20: From Midland-Odessa to the Dallas-Fort Worth Metroplex
  • Interstate 35: Elevated sections from Austin to Dallas-Fort Worth could be slick. North of the Metroplex, colder temperatures may cause more problems from Denton, Texas, to Oklahoma City.
  • All Interstates, freeways and tollways in the immediate Dallas-Fort Worth area (30, 635, 820, etc.)
There is a chance, though not a high chance, that ice accumulations could be heavy enough to cause some power outages in some areas of west-central Texas.
Saturday's Forecast
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Saturday's Forecast
Sunday's Forecast
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Sunday's Forecast

Frona: Midwest/East Threat

Winter Storm Frona (froh-na; Greek, short for Sofronia; related to the word for wise) will write its final chapter this weekend in the Midwest and East.
Our forecast guidance is beginning to consolidate around a general scenario, combining Frona with a reinforcing arctic front diving into the northern Plains to spin up a quick-moving snowstorm this weekend in parts of the Midwest and interior Northeast.
(MAPS: 7-Day U.S. Snow/Ice/Rain Forecasts)
Saturday: Snow blankets the central Plains. Freezing rain changing to snow may lead to hazardous travel from parts of Kansas into northern and central Illinois. Freezing rain changing to rain from the southern Great Lakes, Shenandoah Valley and parts of interior Pennsylvania, central and Upstate New York. Snow, sleet, freezing rain may develop late in New England. A band of snow associated with the arctic front will blanket areas from the Front Range of the Rockies to northern Minnesota.
Sunday: Snow winds down quickly in the Great Lakes and Ohio Valley. Snow to freezing rain near the U.S. Canadian border in the northeast. Rain farther south.
For now, this doesn't appear to be a crippling, heavy snowstorm in the Midwest or East, as it will be moving quickly into Canada and some areas will be starting as snow before changing quickly to rain.
Parts of the Upper Midwest, Upstate New York and northern New England could pick up 6 inches or more of total snowfall thorugh Sunday.
That said, this may be the first significant accumulating snow in quite some time to parts of the Upper Midwest and interior Northeast. Frona may snarl post-holiday travel at some major airport hubs, not simply due to snow, but also due to low clouds and wind.
(FORECASTS: Chicago | New York)
Check back with us at weather.com and The Weather Channel for the latest forecast updates on this potential weekend event.
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Snow from Winter Storm Frona blankets Breckenridge, Colorado on Dec. 29, 2014.   (Jessie Unruh/GoBreck)

So Far: Over Two Feet of Snow, Damaging Winds Reported

Winter Storm Frona has already brought significant snowfall to the mountains of the Northwest, and to a lesser extent portions of the northern Rockies and the Wasatch Range.
Top reported snowfall totals so far include 28 inches over Santiam Pass, Oregon; 26 inches outside of Jaype in Clearwater County, Idaho; 20 inches in Alta, Utah; 19 inches at Jackson Hole (mid-mountain), Wyoming; 18 inches at Mount Spokane Ski Resort in Washington; and 6.5 inches in the Flatirons just west of Boulder, Colorado.
In the Great Plains, as much as 4 inches of snow has been reported in Scottsbluff, Nebraska; 3.1 inches of snow was reported at the Rapid City, South Dakota airport; 7 inches was recorded in Oberlin, Kansas; and 4.7 inches of snow has fallen in Goodland, Kansas.
Valley locations have also seen some snow as the cold air dives southward, though not as much as the mountains. The official snow total for Boise, Idaho, was 1.7 inches Saturday evening into Sunday.
Downslope damaging winds also raked parts of northern Utah and California as the cold air poured in behind Winter Storm Frona.
Along the Wasatch Front of Utah, wind gusts as high as 78 mph were recorded in Farmington. Centerville and Snowbasin, Utah also clocked wind gusts as high as 69 mph. At the University of Utah in Salt Lake City, 60 mph wind gusts were also reported.
The wind and freshly fallen snow have prompted the Utah Avalanche Center to issue an avalanche warning for the foothills and canyon mouths from Salt Lake County north to the Utah-Idaho border. The agency says avalanches could occur "in low elevation areas where people do not normally see avalanches."
Damaging winds also buffeted parts of the Bay Area Tuesday. Wind gusts over 60 mph were clocked on the north side of Oakland (1402 feet elevation), atop Mt. Diablo, and at Las Trampas in Contra Costa County. Numerous trees were downed, some on homes.
Winds gusted up to 69 mph in the L.A. County mountains at Warm Springs. An incredible 167 mph gust was clocked atop Mammoth Mountain, at an elevation of just over 11,000 feet.
Tune into The Weather Channel for continuing coverage.
MORE ON WEATHER.COM: Winter Storm Frona Photos
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A man walks along the 16th Street Mall as snow falls in downtown Denver, Dec. 29, 2014. The Denver area could see up to four inches of snow with this storm. (RJ Sangosti/The Denver Post) 

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