Boxing day storm 2025

 We bookended Christmas with a small storm on the 23rd that left an inch, but then this odd clipper like system came in for the 26th.  

The set up was a cold front passing through Christmas day, dry, with wind and temps dropping into the teens at night. Meanwhile, a weak shortwave would move across the lakes to our south. What made this odd is the SE direction of the storm and that the snow would set up in a NW to SE path from Lake Ontario to CT and Long Island. Parts east of CT get little, parts west of NJ get sleet and freezing rain.

This just doesn't look like much and at first it was just 4-5", setting up over PA/NJ. You can see the trend on the GFS - using depth change as an example as it eliminates sleet, kinda.

So what ends up happening is a very strong push of warm air into newly establshed cold air with a blocking yet retreating high. The low scoots south, keeping upstate ny, nnj and ct in the coldest sector. Meanwhile the folks in PA and SNJ on west and south get snow to rain/freezing rain/sleet. 

That push of warm air that brings western areas rain/sleet/zr is also what forces tremendous lift in the 700mb layer which creates a dump of snow up front.  See frontogenesis map and vertical velocity map 

And with the column well below 0c, that Omega (left side of skew) and temps produce a ton of snow.

But it only lasts a few hours, then is a regular snow. 

And this is what the 12z model suite put out day before the event

And the morning of

Weather service prediction that evening increased the 8-10 range across CT and LI

As I write this we had 4" within the first hour of the storm and this is what it looked like.