There’s a whole lot going on with the hemispheric weather pattern. Locally, we’ll get a pretty big push of cold air Tuesday and Wednesday before we moderate. Starting off, the strong Arctic front Tuesday morning looks pretty impressive.
850mb temperatures across most of the eastern half of the lower 48 dip to more than 2 standard deviations below normal. An impressive cold anomaly. Here in Connecticut, temperatures up at 850mb fall below -10ºC which will yield temperatures falling through the 30s during the day on Tuesday. Cold for sure. A quick coating of snow in the hills is possible before daybreak on Tuesday as the front races through.
Beyond Wednesday we slowly moderate. Here’s the 500mb GFS ensemble height anomalies for next Saturday. The biggest feature across the northern hemisphere is the giant ridge over the western Aleutians, Bering Strait, and Kamchatka. While that is helping to dislodge the cold off the North Pole into a large chunk of central Canada there’s not much of a delivery system to get it into New England. In fact, this is an above average pattern for the eastern seaboard.
What gets interesting is what happens by Thanksgiving week. Our models try to develop some blocking in the North Atlantic (a -NAO) and at the same time they show ridging over Alaska (neutral or maybe negative EPO).
After a mild week (11/18) the week of 11/25 could become colder (closer to or maybe even below normal) and possibly a bit stormy.
Bottom line – enjoy the cold shot on Tuesday and Wednesday. It appears that we’re going to begin a slow but steady warm up that may have a fairly lengthy duration. That said, there are signs of a flip to colder and possibly stormier by the end of the month. Stay tuned!