The big weather story for the NYC region this week is going to be the return of bitterly cold temperatures across the region, thanks in part to our least favorite visitor, the polar vortex. By the end of the week, we’re looking at high temperatures in the mid to low 20s in the city, with lows in the teens to single digits. To put that into perspective, highs in the low 20s are 20 degrees below normal for this time of year, and just over two standard deviations from the mean.

There is one shot at precipitation during the work week, which is coming Wednesday. Fortunately for us, this storm will be taking a more southerly track, meaning that we’ll likely see under 1″ in the city, with slightly higher amounts out in eastern Long Island. Areas north and west should see trace to no accumulation from this system.

Today – increasing clouds with a high near freezing.

Wednesday – high near freezing, snow flurries likely, especially from the city east. Light accumulation under 1″ in the city – slightly higher east.

Thursday – the polar vortex returns along with a reinforcing dry arctic cold front. Mostly sunny with temps near freezing, but dropping rapidly during the evening hours with an overnight low in the teens.

Friday – clear skies but a high temp only in the mid 20s, overnight low in the teens.

Next shot of precipitation comes Saturday, associated with another arctic cold front. An area of strong high pressure will build in behind the front, pumping in frigid air from Canada for the end of the week.

Interesting to note that the ensemble forecast for the Arctic Oscillation is unanimous at this point that we’ll see a negative phase. As I noted in the earlier post linked above, these negative phases of the AO are often associated with the abnormally cold temperatures, and that certainly looks to be the case again this time around.