eduggs

The largescale features are supportive of a wintry event around the 21st as everybody has been saying for days. But unlike with the recent and upcoming rain events with single waves traversing W to E, the synoptic details of the weekend event and the angle of trof approach require excellent timing with wave interaction. That factor would seem to make a positive outcome unlikely. By memory it seems like these tend to work out best for eastern NE.

Yeah. The ensemble spread reflects the uncertainty. But with the improvements to mid-range models, we probably only have another 24 hours to see improvements before the approx. final outcome starts to be resolved. I don't like the trends over the past few days towards a faster progressing, lower amplitude trof. And there are fewer and fewer deep individual members on the ensembles.

The wrapped up solutions that deepen and cut off near out latitude have multiple northern stream shortwaves phasing. The 12z ICON has a piece of energy giving south from Ontario late in the game. A well timed interaction between shortwaves will lead to rapid tilting and deepening of the ULL. But if it isn't well timed, the result will be a clipper or squashed system.

Ha Ha, yup! Almost all sightings can be attributed to airplanes, helicopters, and starlink satellites. New Jersey, and in particular northern NJ near the epicenter of reported drone activity, is an extremely high density commercial airspace with planes from Newark, JFK, LaGuardia, Teterboro, Morristown, Essex Co., and Westchester Co. all criss-crossing the area. At certain times there are at least a dozen aircraft visible in the sky from some vantage points.

12z ICON looks pretty interesting for the 12th. GFS a little less so, but still highly trackable. I'd like to see the thermal boundary get pushed southeast Sat - Mon so we at least have a chance at wintry if a shortwave can round the longwave trof and iniatiate a southeast low and eventual coastal SLP. The ICON at least is almost there.

Some nice radar returns streaking from central IN through OH. I don't think much is reaching the ground though. IF the models are underrepresenting this virga/precip, it could boost QPF slightly this evening across NEPA, extreme NNJ, the mid-HV, over to NWCT.

IF the ECM is close, we have a great week of model tracking ahead of us: Excellent trof alignment, STJ and polar jet phasing, shortwaves diving south through central US with fresh cold air, high pressure over upper midwest, moisture surging from the Gulf, and low SLP in the southeast. Oh how we dream. I'm pessimistic about this potential threat until we get multi-model and multi-cycle runs that are close enough to a wintry threat without huge run to run changes.

The increase in temperature is also disproportionately distributed towards the winter and geographically towards the higher northern latitudes. Plus the oceans have absorbed a good deal of the heat energy, which is just recently starting to have a noticeable impact. That has definitely shifted the mean winter climo a few degrees N in latitude.

In the interest of trying to be positive, there is a ton of vorticity passing through over the next day or so. That means it's always possible to get a burst of precipitation and an unexpected surprise. There could be multiple periods of precipitation... though somewhat widely scattered and favoring west facing terrain. From what I can tell looking at soundings, some ptype algorithms that show rain reflect lack of saturation in the snow growth region as opposed to a warm boundary layer.

FWIW, the 6z ECM didn't look bad for a possible 12/12 coastal threat. The 12z GFS also isn't completely hopeless. ICON too. The CMC needs work but I can see a path. Overall the 12z cycle gives a glimmer of hope. Ensembles anyone?

The meso models are not enthused about snow prospects Wed night. Maybe they will be wrong and the snow shield will be more widespread, but I doubt it. Downsloping off terrain with a SLP to our NNW rarely works out. Best chance of whitening the ground will probably come with scattered instability snow squalls on Thurs. morning.

Both the GFS and NAM look good for a C-1" of snow Wed night through Thurs. morning. Maybe 2" N&W for a few lucky spots that get some squalls on Thurs. the CMC, ICON, and 18z ECM don't show much snow for our area. It looks like at least two periods of precipitation. An initial burst with intense frontogenesis Wed night and then possible squalls early Thurs. The GFS and especially NAM are surprisingly wet in CT. If the wetter models are right and some of that works back into SENY and NENJ, it could be a fun night. Temperatures start chilly and get very cold aloft (i.e., steep lapse rates). But I won't really believe the snow threat until the ECM comes on board. Either way, the hills of interior CT and MA and esp. southern VT should get a few to several inches of snow.

I agree it probably is related to ocean heat content and continental/terrain-ocean interactions... plus the steadily strengthening geostrophic wind due to stronger temperature gradients. It's probably a feature that will become increasingly persistent in time due to planet warming.

We'll see how Wed night goes. And obviously the month just started. But I can see a way that December ends up less snowy than November for a lot of the NW suburbs. Long range modeling suddenly looks shockingly bad for snow.

ECM says welcome to the worst December weather since 1988. Cold & dry, rain, Cold & dry, rain, rain, Cold & dry, rain...

Another day, another shitty model cycle. It's been all down hill since a snowy, Friday November 22.

That's cause there's only about 8 hours of daylight this time of year. So chances of daytime snow are low

As expected, the 18z GFS shifted towards model consensus for the 10th and beyond and away from a wintry threat. "Pattern" is a misused and misunderstood phrase, but if we want to grossly generalize things then we can say this "pattern" or orientation and evolution of the synoptic flow field does not look to be very favorable for snow locally.

As soon as someone in the SNE subforum posted a thread about the best early December pattern in years, snow prospects for us fell to shit Those guys are generally too optimistic about future patterns that are just beyond the horizon. Same story for the past few years. But that is born out of a series of good years in the 2010s and significantly more margin for snow in NE compared to the northern mid-atlantic.

That's awesome about the semi-continuous snow up there. Those periods are the best when you never know how much snow will fall and for how long. The Green Mountains clearly block the radar beam in that region, which makes local observations all the more critical. Modeling seems to have correctly predicted an extension of the Lake Ontario LES band into the northern Greens. But since there was little on the NY side, I gotta figure that the snow at low elevations on the VT side was due to either Champlain enhancement or some kind of low level convergence.

Can be insufficient saturation in the snow growth region, lack of nucleation, temps too warm for crystallization etc... If conditions aren't sufficient, you get supercooled rain drops and then ice pellets instead of snowflakes even if the temperature is below freezing. But that sounding looks like snow or mostly snow.

Most likely outcome IMO. Pray for a snow squall Wed night.

Sign me up for the 12z GFS. Some snow to long duration frozen mix. Nice trof axis and pretty cold surface. But unlikely outcome.

12z GFS is pretty interesting around the 10th. That would probably work. But it's a long way off and too much run-to-run variability to have any confidence. The threat for the 8th keeps decreasing in likelihood.

Is that persistent band near Franklin County Airport in Vermont typical with these setups? It looks like some Lake Champlain enhancement from the Ontario LES band. The low elevation also probably enhances the reflectivity relative to the terrain due to better line-of-sight. I feel like I've seen that feature before, but I don't usually look carefully for it. There doesn't seem to be any mention in the NWS BTV forecast. Kinda cool.