Nor'easter Brings First Snow and Season's Coldest Air East

A nor'easter is forecast to form off the East Coast late this week, bringing the season's first snowfall and its coldest air so far. [Winter weather incoming as forecast suddenly shifts — USA Today, reporting NOAA forecasters] [Extended Forecast Discussion — NOAA Weather Prediction Center, National Weather Service]

NOAA's Weather Prediction Center expects highs 5 to 15 degrees below average on Friday and Saturday from the Southeast to the Mid-Atlantic and central Appalachians, with heavier rain over the northern Mid-Atlantic and early snow in higher terrain. [Winter weather incoming as forecast suddenly shifts — USA Today, reporting NOAA forecasters] [Extended Forecast Discussion — NOAA Weather Prediction Center, National Weather Service]

The center's extended forecast discussion, issued Sunday, traces the setup: an upper trough deepens over the Great Lakes and Midwest, a surface low develops across the Mid-Atlantic by Thursday, and the low strengthens as it exits the coast Friday, with a nor'easter possible as it tracks offshore. The discussion notes good model agreement on the East Coast system, with the Canadian model running less intense than the GFS and European solutions. The same discussion flags the week's other half: a ridge from the southern Plains to central Canada keeps the interior mild, and highs in parts of the Plains could run 10 to 20 degrees above mid-November averages. [Extended Forecast Discussion — NOAA Weather Prediction Center, National Weather Service]

The cold isn't staying. The Climate Prediction Center expects temperatures to return to above-average levels across the East next week, and the month as a whole is still tracking toward one of the ten warmest Novembers on record nationally. The West gets the opposite pattern meanwhile: repeated shortwaves and fronts brush the Pacific Northwest all week, and a more organized storm arrives Saturday into Sunday, pushing heavier rain and high mountain snow south into northern California. For the East, the practical read is a December-feeling weekend inside a warm month: first snow on the high ground, December-grade cold for a weekend, and mild air back by next week. [Winter weather incoming as forecast suddenly shifts — USA Today, reporting NOAA forecasters] [Extended Forecast Discussion — NOAA Weather Prediction Center, National Weather Service]