ORH_wxman

MLK was a mid-level issue for you....850 0C line was like straddling Union CT....you are plenty cold at 850 this time...all the warmth is trying to get you in the boundary layer below 900mb. Those are the ones I'm frequently skeptical with on the models because the one bias model guidance always has in the low levels is that they are too geostrophic...they don't capture ageo flow very well. A model that is too geostrophic at 900-950 mb is going to bring the warmth too far west inland.

I've noticed those are always super low in marginal events like this. 12/5/20 is a recent example....I think they had low prob of even 3" for ORH and they had nearly 10" of paste but like 10 miles east lower down had 3". Kevin's area is def a bit tough to forecast for because it has elevation but it can be prone to warmth intrusion at 925 from the SE/ESE.

I have no doubt WOR (litchfield county) is a better spot...I'm just looking at some of these runs that show him at -1C at 925 with heavy precip and thinking "that is not rain at 1000 feet". We'll see how the guidance comes in today....small tick NW and he's prob skunked....but small tick colder/SE, and he could get warning snows.

My experience in these is that guidance overdoes the BL warmth....esp below the 925 layer. The latter is the caveat as some guidance is still a bit warm in that 925 zone....like the RGEM. But runs like NAM/GFS were plenty cold in that layer until around midday Friday for Tolland. If it's below 0C at 925, it won;t be raining where he is. Euro was like right on the line but it's been slowly cooling. I'd feel a little more confident to his northeast into ORH area, but if current guidance holds today, I'd prob take the over on 2-3". Obviously a NW tick again and that changes everything.

I'm prob taking the over on that for Kevin unless this shifts NW again today.

They will be taking those up a decent amount today unless there is a reversal in model trends.

18z euro tickled colder/SE. Also more dynamics this run. Hopefully that happens another tick or two

Many of our best Decembers had a solidly negative PNA (2007, 2008, 1970, 1975, etc)

Man, either GFS is gonna score a great coup or get embarrassed. This is less than 3 days out now and it’s way SE of other guidance. It often gags on coastals.

We'll see if it's full of crap...but theoretically the higher res models should be able to handle the BL better than the others. The warmth is from ground-up in this one....it's plenty cold at like 850-900 for a chunk of the time when heavy precip is falling.

I've expected the antecedent airmass to show up colder on guidance as we get closer....so yeah, I think the NAM would make some sense on that aspect. But the caveat is assuming no more NW ticks....if we're tracking the 925 low over interior SNE like the Euro did, that's not gonna cut it. We need it to track over or SE of LI to the Cape roughly to keep interior SNE mostly snow. But even on a Euro track, I'd still expect it to try and tick colder on the front end as we get closer. We just would flip to rain on the Euro even in a colder antecedent airmass.

3k is also colder than other guidance...only goes to 60h, but that is getting close to the onset of precip.

NAM tickled NW....it is still dumping good snow though over interior elevations. The antecedent airmass just is a lot better on the NAM than some other guidance.

Is there a pattern where cutters aren't a risk? They can happen in any pattern. I've seen them happen with a monster PNA ridge sitting over Idaho. A baffin/davis strait block does not strike me as a pattern where cutters are disproportionately represented. They can still happen though. But I'd give the nod to SWFE/redevelopers/Miller Bs when you have that type of Atlantic look with a mean trough over the central CONUS.

You also still have a large Baffin/Davis Strait Block there trying to pin part of the PV lobe under it.

Do we really care what the sfc low means are at 220 hours? I mean, 5-6 days ago, this friday's system was cutting into Ottawa and sending parakeets to Caribou....but the hemispheric pattern always said watch out for further SE solutions because when you have Baffin and Hudson Bay blocks, they usually do that. Plus, the GEFS looks like buckshot to me....lows in LAke Huron and lows over George's Bank.

I don't see this at all....it could cut if western trough digs and we lose confluence, but how do we get "storm will cut by a good amount" from that ensemble mean look? Here's the GEFS. Still waiting for EPS to come out far enough, but I doubt it looks super different.

Here's what I was talking about....look at the NAM whil it is still south of New England: Here is the Euro at the same time...note the lack of "curl" in the H5 heights south of NE. It's not really doing it until it's almost overhead which keeps us without good dynamics.

Most of SNE is under an inch of qpf through 84h....that isn't really going to do much outside of like the highest terrain well in the interior. We need that H5 protrusion to start curling back to the NW a bit earlier for the good dynamics like the NAM did.

Well that is a slight improvement from 00z....but not from 06z. Dynamics look kind of weak sauce this run

I have no idea....Ukie always just absolutely furnaces the low levels, so I don't really try and parse it outside of the synoptic tracks. Might have to do with how strong the lift is on the model at any given time, but usually I just completely toss the Ukie thermals and try and look at the track of systems on there if ptype issues are an issue with the storm.

Ukie def came SE some....still torching the low levels (what else is new for Ukie), but I like those ML tracks much better than 00z....850 going over the canal region now instead of over ORH at 00z.

You're in a good spot with elevation. I'll take the over on Templeton being more than 50/50 snow assuming we don't see a trend back NW.

GGEM tickling SE as well....still solidly NW of GFS though. But getting closer to a crusher for interior hills.

GFS coming in a bit colder than 06z as well...I'd like to see it a bit more dynamic like the NAM though.