A storm over eastern Russia this week will drop in along the British Columbia coast by early next week bringing a push of cool air with it, but not before the atmosphere heats up.
The overall weather pattern appears to be about to break out of its summer mode over part of North America.
A big push of cool air will end the 100-degree heat in Texas and will chase tropical humidity out of the East this weekend.
Ahead of the storm dropping southeastward across Alaska this weekend, temperatures will climb to hot levels in much of the northwest United States into Saturday.
Highs of 90 degrees are likely at least one day in Portland, and highs will be in the 80s in Seattle, perhaps setting a record on Saturday. (The record at Seattle-Tacoma Airport is 85 degrees Saturday, set last year.)
The cooler air pushing across the region Sunday and Monday will shave 20 degrees and perhaps more off temperatures in some areas. By early next week, temperatures will average 5 to 10 degrees below normal.
The change to cool weather will be accompanied by spotty showers and perhaps a locally gusty thunderstorm along the coast and in the mountains Sunday night and Monday.
Stiff winds are possible over the passes for a time as the cooler air tries to squeeze through early next week.
The gusty winds could raise wildfire concerns over the northern Rockies for a time.
Meanwhile, tropical moisture associated in part with the remnants of Tropical Storm John have eased fire concerns slightly in the San Gabriel Mountains north of Los Angeles.
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The coldest air of the season so far is settling in around New York City. A new storm will move in this weekend and tap into part of the cold air.
The coldest air of the season so far has descended on Harrisburg and south central Pennsylvania. A new storm will move in Saturday and tap into some of that cold air.
The coldest air of the season so far has moved in around Baltimore. A new storm will move in Saturday with a wintry mix.
A snowstorm and travel delays late Friday night into Saturday will mark the end of the worst of the frigid air hitting the Pittsburgh area.
The coldest air of the season so far has moved in around Washington, D.C. A new storm will move in this weekend with a wintry mix.
Kent, WA (near Seattle) (1969)
Waterspout moved inland over Kent, south of Seattle; 5 mile path, damage to residences; 0 killed.
Dover, DE (1899)
24.0" snow; December record.
Charleston, SC (1899)
3.9" snow; greatest single storm total and 24- hour total for city.