Ooh, it was cold this morning. Ooh, it is still cold now. How cold was it? It was so cold Gothamist gave up our spot in line at the Shake Shack. Oh, we know the Shack is closed for the winter. We're staking out our spot for when they open next spring. It was so cold that 1010 WINS is running a story called "Wind Chill Causes New Jerseyans to Bundle Up". When it rains do they have reports on people using umbrellas? The official thermometer in Central Park bottomed out at 18, yes eighteen, degrees this morning. Wind chills were in the single digits. Good thing those New Jerseyans were smart enough to wear coats!
The cause of last night's rapid cooling is a big-assed Arctic air mass. The leading butt cheek arrived between eight and nine last night. The trailing butt cheek is out of here by Sunday. In between cheeks (you know, it occurs to Gothamist that this is not the most pleasing analogy we could have made), we've got about 48 hours of some mighty cold air. It will barely reach 30 degrees today and tonight will be another cold one. Tomorrow should be much warmer, lower-40s, and Sunday warmer still, lower-50s. The air is so dry that there's no precipitation in the forecast for the next several days.
The current GOES visible satellite image (via the University of Wisconsin) is a classic view of what happens when an Arctic air mass makes it this far south in December. The clear skies over the metropolitan area quickly give way to stratocumulus clouds over the ocean as the cold air becomes saturated by water evaporating off the relatively warm sea surface. The same process is causing the other classic feature –lake effect snow. Follow the clouds northwest from the NY/NJ and NY/PA borders and you'll see an arc of heavier clouds curving through the Finger Lakes and over Lake Ontario. Areas under that band of clouds are forecast to get up to a foot of snow.