Weekly Weather Watch: Wednesday, November 20th, 2024
Heavy rain from an atmospheric river event brings 12 to 18 inches of rain to far northern California and southwest Oregon. Meanwhile, a storm system in the northern Plains will bring blizzard conditions to North Dakota and northwestern Minnesota. Heavy snow is expected to spread across parts of the central Appalachians starting Thursday, with another round of snowfall possible in Pennsylvania and nearby areas into Friday. Wind with heavy precipitation to hit British Columbia, snowfall for Alberta, Saskatchewan and Manitoba, wind in Quebec, and rain for parts of the Maritimes. Those are the biggest impact areas in this week’s weather briefing, but here are some other notables.
HEADLINERS:
Moderate risk of much below normal temperatures across parts of the Northern Plains, Thu-Sat, Nov 28-Nov 30.
Slight risk of much below normal temperatures across parts of the Northern Plains and Upper Mississippi Valley, Thu-Wed, Nov 28-Dec 4.
Slight risk of heavy precipitation for parts of the Ohio, Tennessee, and Middle and Lower Mississippi Valleys, and Southern Appalachians, Thu, Nov 28.
Slight risk of periods of heavy snow including Lake Effect snow across parts of the Ohio Valley, Great Lakes and Northeast, Thu-Sat, Nov 28-30.
Slight risk of episodic high winds across many parts of the eastern CONUS, Southern Plains, and Middle and Lower Mississippi Valley, Thu-Sat, Nov 28-30.
ON THE RADAR:
IN THE GAUGES:
For Northern California, storm total rainfall may reach as high as 12-18", with dangerous flash flooding, rock slides, and debris flows likely.
GRAB A RULER:
heavy wet snow is expected for the Cascades and far northern California associated with the Atmospheric River events. Heavy snowfall will also cover the Central to Northern Rockies, with snowfall stretching across Canada.
RECORDS MADE TO BE BROKEN:
TROPICAL TIDINGS:
Nothing imminent at this time.
ARE YOU CIRRUS?!
On this day in weather history
1944 "Darkness at Noon." After a decade of drought, dust storms frequented Australia. On this day a thick dust blanketed Mildura for eight hours, and the railway lines to Balranald and Moulamein were blocked by sand.
1979 A blizzard struck Cheyenne, WY producing a record 19.8 inches of snow in 24 hours, and a record total of 25.6 inches in 40 hours. Strong winds created huge drifts stopping all transportation.
As we close out 2025 and ring in the new year, the weather pattern stays anything but quiet. A multi-day lake-effect snow event is burying areas downwind of Lakes Erie and Ontario, where over 3 feet of snow could fall in the most persistent bands—creating whiteout squalls and treacherous travel through New Year's Day. Meanwhile, Arctic air is spilling deep into the Southeast, sending temperatures below freezing as far south as Florida, with frost and freeze alerts in place. On the other side of the country, a Pacific storm system will bring rounds of heavy rain and a flash flood threat to Southern California, especially around Los Angeles, starting late New Year's Eve. Elsewhere, a couple of fast-moving clippers will spread freezing rain and snow to Alberta, then snow across the Midwest, Ohio Valley, and into New England, while a developing storm may bring soaking rain and thunderstorms from the Deep South to the Southeast Coast by the weekend. Even Northern California faces an atmospheric river event late week, setting the stage for an active and disruptive start to 2026.