Quick Warmup Leading to Quick Nor'easter


It took long enough, but we got our first official snowflakes of the winter in Philadelphia last evening. Some nearby suburbs got a quick ½ inch or so, along with wind gusts over 40 mph in a snow squall. That led to some icy spots and accidents this morning after the hard freeze overnight.

It hasn’t even gotten to 30 degrees today, despite lots of sunshine. That’s more than 10 degrees below “normal." The last time we didn’t reach 30 degrees was March 6 of last year.

It may be hard to believe that we can warm up quickly enough for the next storm to bring rain by Friday night. But it will. A couple of days of winds from the south will do it. Having no snow on the ground allows us to warm up faster, too. By Thursday afternoon, we should get to at least 40 degrees, and then 50+ on Friday.

Quick Nor’easter: An El Nino “Classic”

Meanwhile, a storm is starting to form in the western Gulf of Mexico. The satellite animation shows the fast flow from Mexico, which is part of what is known as the “Subtropical Jet Stream." 

This feature often shows up on satellite, but is more common-and often stronger-during years with strong El Nino’s. So we tend to have a lot of Nor’easters during El Nino’s. The typical question, though, is: “Where’s the cold air?” It tends to be too warm along the East Coast for snow in such years. And it tends to make snow-lovers very frustrated.

That storm will end up as a pretty intense area of LOW pressure along the coast just south of Delaware, before continuing rapidly to the Northeast. Here is the way the Canadian model shows it:

That’s pretty close to an ideal track for snow lovers in January. But the lack of snow already on the ground plus no blocking pattern to keep the cold air in kills any chance for a big snowstorm. The –NAO that we’ve talked about frequently just isn’t negative enough. Otherwise, we would at least get a rain/snow mix.

And After Next Week?
Another shot of Arctic air will move in after the Nor’easter moves through. Here is the map of temperatures compared to normal (“anomalies”) for next Tuesday:

And below is the same map for next Saturday, Jan. 23rd:

You can see how the extreme cold has disappeared in the U.S. and Southern Canada. The blocking patterns that we’ve seen appear this month weaken a lot. This means more average January weather is likely after next week-maybe a bit warmer than average. Snow and cold lovers may have to wait until February for encouraging signs.

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