Record-setting 'bomb cyclone' threatens holiday travelers in western US
By
Courtney Travis, AccuWeather senior meteorologist
Published Nov 23, 2019 4:52 PM EDT
Dangerous travel conditions are being reported across portions of the western U.S. on the busiest travel day of the year and the detrimental impacts from snow, rain and gusty winds are set to continue into Thanksgiving Day.
Weather watches, warnings and alerts peppered the western half of the nation as the potent storm, also known as a "bomb cyclone," began to make its impacts felt on Tuesday. The storm, AccuWeather forecasters warned, could be historic in its strength and scope and so far that has been the case.
An accident along Interstate 80 in California Tuesday night, Nov. 26. (Photo/Cal Fire)
As the storm system came ashore Tuesday night in southern Oregon and Northern California, an all-time record low sea level pressure in the state of California had been surpassed. Crescent City, California, has now surpassed the storm system that set the previous record back in 2010 according to NOAA's Weather Prediction Center.
On late Tuesday afternoon, Interstate 5 was closed to trucks north of Redding, California, due to bad weather conditions.
The California Department of Forestry and Fire Protection (Cal Fire) responded to numerous vehicles accidents along the Interstate 80 corridor Tuesday night where treacherous travel was reported along Donner Summit. Severe people were taken to a nearby hospital as a result.
The system came on the heels of an early-week storm, which brought heavy snow to the Denver area and wind gusts of 70-80 mph to the Los Angeles area on Monday night, according to the NWS, set the stage across much of the West, allowing for a winterlike chill to be entrenched across the Northwest and into much of California and Nevada. This included a small thunderstorm that dropped hail across part of the Seattle area.
A look at some of the top reported wind gusts as of Nov. 27. 2019.
In Acton, California, wind gusts reached hurricane force (74 mph or higher).
The wet weather, combined with gusty winds across the state will cause travel concerns for much of the region on Wednesday and Thursday.
"This storm threatens to bring rain and mountain snow to much of California, including places like San Francisco and Sacramento, places that were largely spared by the past week's rain," said AccuWeather Senior Meteorologist Brian Thompson.
A satellite image showing the record 'bomb cyclone' making its final approach late Tuesday night along the west coast of the U.S. (NOAA)
(NOAA)
Since Monday night, the barometric pressure of the storm system itself went from 1,018 millibars (mb) to 970 mb Tuesday evening. This 48 mb drop in 24 hours doubles the requirement of a 24-mb drop in 24 hours -- the National Weather Service's (NWS) threshold for an official "bomb cyclone."
While burn scar areas may experience flooding and mudslides, travel woes are anticipated with the rounds of heavy rain expected as the storm system brings rain and snow into Southern California.
Slick roadways will be a concern for motorists in places like Santa Barbara, Los Angeles and San Diego from Tuesday night through Thursday night.
Flash flood watches were in effect for parts of Southern California Wednesday morning, including San Diego and San Bernardino.
More than 55 million travelers are expected between the weekends before and after Thanksgiving, according to the American Automobile Association (AAA).
San Francisco's worst travel time is expected between 2 p.m. and 4 p.m. on Wednesday, by which time the city's heaviest rain is expected to be over. However, for Los Angeles, the estimated timeframe for most travelers is 5 p.m. to 7 p.m. on Wednesday, when periods of rain are expected to continue.
This image shows weather-related travel disruptions through Wednesday night.
In addition to the impacts the rain will have on the region, the cold coming in with this storm will allow for high snowfall accumulations that can contribute to the travel disruptions.
With snow levels, down to around 4,000 feet, feet of snow will pile up in the Sierra Nevada of California. Some parts of the Sierra Nevada mountains could see an AccuWeather StormMax of up to 42 inches of snowfall. Snow will even reach as far south as the Peninsular Mountains in Southern California.
Along Interstate 5, just north of the border between California and Oregon, over Siskiyou Summit, slippery conditions are expected for travelers through Wednesday night.
Donner Pass, along Interstate 80, has already begun to receive heavy snow, leading to travel delays. A foot or more of snow is forecast from the storm.
Farther south, snow will dip down to the passes north and northeast of Los Angeles into Wednesday night.
Outside of California, snow will spread across Oregon into Nevada, Idaho and Utah. Snowfall accumulations will very much depend on elevation in these areas, although some of the highest snowfall totals could be in southwestern and northern Utah.
Winter storm watches and warnings have been issued for many of the mountains across the region ahead of the storm's arrival.
The western half of the U.S. was peppered with all manner of weather warnings and advisories on Wednesday as an active storm pattern caused a host of impacts. (AccuWeather)
Snow will also stretch into Arizona, starting in northwestern parts of the state late Wednesday night, then spreading across the northern two-thirds of the state into Friday.
Just a little more than 6.5 inches of snow fell in Flagstaff with the last storm that moved through the region, with another dose of snow likely for the middle and end of the week. The higher terrain around the region could have a fresh foot of snow before the end of the month.
Snow showers across Arizona, Utah and western Colorado may linger as late as Friday morning, continuing to add to any snowfall totals.
Parts of New Mexico will also get in on the wintry weather.
A stream of moisture from Mexico will arrive in New Mexico and western Texas late Wednesday and Wednesday night, bringing a swath of snow, wintry mix and heavy rain.
Several inches of snow are possible across New Mexico, and a wintry mix can occur in parts of the northern Texas Panhandle and Oklahoma Panhandle before the storm moves into the central Plains.
The last time Amarillo, Texas, observed one inch or more of snow on Thanksgiving was in 1958 when exactly 1 inch fell. If enough cold air filters in Wednesday night into Thursday morning, there is a chance it could happen again.
The storm is expected to move eastward during the final days of November and cause more travel disruptions for those in the Plains and East heading home following the Thanksgiving holiday.
Behind both of these storms, a winterlike chill will settle into places west of the Rockies. Those out and about on Black Friday and through the weekend will need to bundle up to protect themselves from the cold.
"A second storm is expected to move into the West later on Saturday, and could bring both snow and rain for much of the region through Monday," said AccuWeather Meteorologist Randy Adkins.
With the potential for another several feet in the Sierra mountains, and locally heavy rainfall in the southern terrain, early indications are that travel conditions could again be difficult for those traveling for the holiday weekend.
Download the free AccuWeather app to check the forecast in your area. Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
Report a Typo
News / Winter Weather
Record-setting 'bomb cyclone' threatens holiday travelers in western US
By Courtney Travis, AccuWeather senior meteorologist
Published Nov 23, 2019 4:52 PM EDT
Dangerous travel conditions are being reported across portions of the western U.S. on the busiest travel day of the year and the detrimental impacts from snow, rain and gusty winds are set to continue into Thanksgiving Day.
Weather watches, warnings and alerts peppered the western half of the nation as the potent storm, also known as a "bomb cyclone," began to make its impacts felt on Tuesday. The storm, AccuWeather forecasters warned, could be historic in its strength and scope and so far that has been the case.
An accident along Interstate 80 in California Tuesday night, Nov. 26. (Photo/Cal Fire)
As the storm system came ashore Tuesday night in southern Oregon and Northern California, an all-time record low sea level pressure in the state of California had been surpassed. Crescent City, California, has now surpassed the storm system that set the previous record back in 2010 according to NOAA's Weather Prediction Center.
On late Tuesday afternoon, Interstate 5 was closed to trucks north of Redding, California, due to bad weather conditions.
The California Department of Forestry and Fire Protection (Cal Fire) responded to numerous vehicles accidents along the Interstate 80 corridor Tuesday night where treacherous travel was reported along Donner Summit. Severe people were taken to a nearby hospital as a result.
The system came on the heels of an early-week storm, which brought heavy snow to the Denver area and wind gusts of 70-80 mph to the Los Angeles area on Monday night, according to the NWS, set the stage across much of the West, allowing for a winterlike chill to be entrenched across the Northwest and into much of California and Nevada. This included a small thunderstorm that dropped hail across part of the Seattle area.
A look at some of the top reported wind gusts as of Nov. 27. 2019.
In Acton, California, wind gusts reached hurricane force (74 mph or higher).
The wet weather, combined with gusty winds across the state will cause travel concerns for much of the region on Wednesday and Thursday.
"This storm threatens to bring rain and mountain snow to much of California, including places like San Francisco and Sacramento, places that were largely spared by the past week's rain," said AccuWeather Senior Meteorologist Brian Thompson.
A satellite image showing the record 'bomb cyclone' making its final approach late Tuesday night along the west coast of the U.S. (NOAA)
Since Monday night, the barometric pressure of the storm system itself went from 1,018 millibars (mb) to 970 mb Tuesday evening. This 48 mb drop in 24 hours doubles the requirement of a 24-mb drop in 24 hours -- the National Weather Service's (NWS) threshold for an official "bomb cyclone."
While burn scar areas may experience flooding and mudslides, travel woes are anticipated with the rounds of heavy rain expected as the storm system brings rain and snow into Southern California.
Slick roadways will be a concern for motorists in places like Santa Barbara, Los Angeles and San Diego from Tuesday night through Thursday night.
Flash flood watches were in effect for parts of Southern California Wednesday morning, including San Diego and San Bernardino.
More than 55 million travelers are expected between the weekends before and after Thanksgiving, according to the American Automobile Association (AAA).
San Francisco's worst travel time is expected between 2 p.m. and 4 p.m. on Wednesday, by which time the city's heaviest rain is expected to be over. However, for Los Angeles, the estimated timeframe for most travelers is 5 p.m. to 7 p.m. on Wednesday, when periods of rain are expected to continue.
This image shows weather-related travel disruptions through Wednesday night.
In addition to the impacts the rain will have on the region, the cold coming in with this storm will allow for high snowfall accumulations that can contribute to the travel disruptions.
With snow levels, down to around 4,000 feet, feet of snow will pile up in the Sierra Nevada of California. Some parts of the Sierra Nevada mountains could see an AccuWeather StormMax of up to 42 inches of snowfall. Snow will even reach as far south as the Peninsular Mountains in Southern California.
Along Interstate 5, just north of the border between California and Oregon, over Siskiyou Summit, slippery conditions are expected for travelers through Wednesday night.
Donner Pass, along Interstate 80, has already begun to receive heavy snow, leading to travel delays. A foot or more of snow is forecast from the storm.
Farther south, snow will dip down to the passes north and northeast of Los Angeles into Wednesday night.
Outside of California, snow will spread across Oregon into Nevada, Idaho and Utah. Snowfall accumulations will very much depend on elevation in these areas, although some of the highest snowfall totals could be in southwestern and northern Utah.
Winter storm watches and warnings have been issued for many of the mountains across the region ahead of the storm's arrival.
The western half of the U.S. was peppered with all manner of weather warnings and advisories on Wednesday as an active storm pattern caused a host of impacts. (AccuWeather)
Snow will also stretch into Arizona, starting in northwestern parts of the state late Wednesday night, then spreading across the northern two-thirds of the state into Friday.
Just a little more than 6.5 inches of snow fell in Flagstaff with the last storm that moved through the region, with another dose of snow likely for the middle and end of the week. The higher terrain around the region could have a fresh foot of snow before the end of the month.
Snow showers across Arizona, Utah and western Colorado may linger as late as Friday morning, continuing to add to any snowfall totals.
Related:
Parts of New Mexico will also get in on the wintry weather.
A stream of moisture from Mexico will arrive in New Mexico and western Texas late Wednesday and Wednesday night, bringing a swath of snow, wintry mix and heavy rain.
Several inches of snow are possible across New Mexico, and a wintry mix can occur in parts of the northern Texas Panhandle and Oklahoma Panhandle before the storm moves into the central Plains.
The last time Amarillo, Texas, observed one inch or more of snow on Thanksgiving was in 1958 when exactly 1 inch fell. If enough cold air filters in Wednesday night into Thursday morning, there is a chance it could happen again.
The storm is expected to move eastward during the final days of November and cause more travel disruptions for those in the Plains and East heading home following the Thanksgiving holiday.
Behind both of these storms, a winterlike chill will settle into places west of the Rockies. Those out and about on Black Friday and through the weekend will need to bundle up to protect themselves from the cold.
"A second storm is expected to move into the West later on Saturday, and could bring both snow and rain for much of the region through Monday," said AccuWeather Meteorologist Randy Adkins.
With the potential for another several feet in the Sierra mountains, and locally heavy rainfall in the southern terrain, early indications are that travel conditions could again be difficult for those traveling for the holiday weekend.
Download the free AccuWeather app to check the forecast in your area. Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
Report a Typo