It's Always Sunny

Some isolated thunderstorms will be possible too given mid-level instability, albeit marginal.

Very rare event for NYC/LI in December. Graphics below show that meridional wind and precipitable water values exceed all climatological values for this time of year. Many spots will fall between 2-3" with amounts in excess of 4-5" definitely in the cards. Daily max precip values will likely be broken (set only last year for most), along with daily max temperature values (set in 2015 for most).

Not a bad thing to see for back half prospects...

Yeah somewhere across the MS Valley would be ideal. You'd want to give the storm enough room to cut northeast too without swinging and missing.

50/50 low is irrelevant to this storm's track in my opinion. What's important is where this storm develops. It's all about the timing/location of jet stream phasing. 12Z ECMWF similar to what GFS has been showing past couple runs:

Sensitivity analyses will be fun to unpack once this event gets a bit closer. Trying to dissect an ensemble analysis at 180 hours lead time won't serve much purpose, however quickly glancing at it since its hard to resist, it does highlight the timing and strength of the jet stream phasing across Baja CA and NW Mexico as a key proponent to this materializing into anything good, in addition to any blocking potential across northern New England.

Not to offend anyone but GIFs & YT video posts are annoying af...it pains me to waste my energy scrolling past them every time.

Same can be said for the jet stream:

December has been mostly an El Nino look. Southern tier of the U.S. not textbook but upper latitudes playing the part mostly.

Too much stock is going into "background state". We still get snow during La Nina winters people seemingly have forgot. I'm seeing El Nino signals of late.

Quite the shift in guidance since yesterday...synoptic feature to watch will be the timing of jet stream phasing across Baja California/NW Mexico. Earlier phasing-->deeper/more amplified trough.

I'd stop short of saying to get excited as this is still no guarantee of anything, however it's what you currently want to see.

More reason to buy stock for end of January/early February.

Westerly momentum across the poles appears to be refracting back towards subtropics....could possibly speed up the MJO progression a bit which *could* be a favorable thing timing wise when considering end of January/early February becoming more active. Conjecture, but food for thought.

After such a Pac Jet extension you will generally have a retraction of sorts, which is that trough you see develop across the W US. It's normal and inherently part of any sort of pattern change to right the ship to a pattern most people want to see.