A pair of intense storm systems threaten to result in Thanksgiving travel disruptions for millions, unleashing heavy rain and snow, strong winds, and thunderstorms.
One storm was expected to spin up late Monday in the Rockies before sweeping through the Great Plains today and the Great Lakes on Wednesday. Winter storm watches and warnings stretch from northeast Colorado to the Upper Peninsula of Michigan as a result of potential for heavy snowfall and gusty winds.
The other storm, which the National Weather Service is predicting will be "historic" and "unprecedented" for southwest Oregon and northwest California, will pound the West Coast today through Thanksgiving with areas of damaging winds, heavy mountain snow and heavy rain at the coast.
The stormy duo will result in challenging if not impossible Thanksgiving travel conditions in some areas, with disruptions to air service almost certain in some spots. And signs point to another storm system potentially developing into the weekend.
The weather disturbance that will manifest itself into a Great Plains rain/snowstorm was bursting out of the Great Basin of Nevada, set to tiptoe through the Four Corners region into Colorado before blasting across the central/southern Plains today.
First in line is Colorado. Winter storm warnings start near Denver, where 5 to 10 inches of snowfall was expected Monday night. The first bands of moderate to heavy snow were forecast to arrive late Monday.
"Travel will be difficult or impossible on Tuesday," the weather service office serving Denver and Boulder warned. Some mountain locations are predicted to receive as much as 30 inches.
Meanwhile, winds sustained at 30 to 40 mph gusting to 60 mph at times are possible in the Texas and Oklahoma panhandles as the system intensifies today before charging northeastward through the Corn Belt and Great Lakes.
In cities such as Kansas City, Omaha, Des Moines and Minneapolis, stormy conditions will arrive later today, while cities such as Madison, Chicago, and Detroit will deal with their travel headache into Wednesday.
On the warm side of the storm, roughly from Des Moines to Madison and to the south and east, a widespread 1 to 1.5 inches of rain is forecast.
North and west of the storm's track, however, that water will come down as snow.
Omaha is expected to see rain change to up to several inches of wind-whipped snow with heavier amounts to the north.
Minneapolis is forecast to receive 5 to 9 inches of snow with similar amounts projected for central northern Wisconsin, while the Upper Peninsula of Michigan could be plastered with nearly a foot.
The storm will exit northeast Wednesday evening into the first half of Thursday, but strong high pressure will quickly build in, steepening the pressure gradient and brewing a period of forceful winds even in the storm's blue-sky wake. That could prolong disruptive travel into Thanksgiving itself.
For the East Coast, the storm largely looks like a miss to the north -- with the exception of New England, where showers and mild weather is likely Wednesday.
Unseasonably mild weather is possible in the Mid-Atlantic today and Wednesday within the breezy southerly flow ahead of the system. Highs in Washington both days could flirt with 60 degrees.
Very windy weather is expected in the Northeast on Thanksgiving Day, with gusts to 40 mph possible.
A risk of severe thunderstorms will accompany the storm's trailing cold front today for parts of the lower Mississippi Valley, including Arkansas, Louisiana, and the Golden Triangle region of the Texas Gulf Coast. While instability will be unimpressive, feisty wind dynamics in the upper atmosphere could favor a few isolated strong to locally severe storms popping up.
Tranquil weather returns across the South on Wednesday.
An unseasonably cold and potent storm system will undergo "explosive cyclogenesis" off the coast of the Pacific Northwest today. This means the storm will be intensifying at a very fast clip, its air pressure dropping quickly enough to qualify it as a "meteorological bomb."
The storm will pack strong winds as it arrives in northern California and southern Oregon late today, meandering inland and weakening some Wednesday evening. It will also bring large waves, heavy rain at the coast, and substantial mountain snow.
The National Weather Service in Medford, Ore., is calling this a "historically strong low pressure system."
"We have seen 100 mph gusts at Cape Blanco with [similar conditions] in the past," forecasters wrote.
As the system progresses east toward the Sierra Nevada, strong winds, cool temperatures, and mountain snow are possible off and on late today and continuing through Thanksgiving. Up to 3 feet of snow is expected, with snow levels in spots dropping to just 2,000 feet. Forty to 60 mph winds are possible in the higher elevations, while wind advisories are also in effect for many of the valleys.
A Section on 11/26/2019