SnowGoose69

The GEFS/EPS still strongly disagree on virtually every indice. GEFS likes more of a -AO/NAO/WPO/PNA whereas the EPS is way less negative on the AO/NAO and same story on the WPO/PNA

I mentioned 2/8/94 earlier for a different reason but this storm may resemble it in one way in that 80% of the accumulation may occur in the first 4 hours where some places might see 2 inch per hour rates at points. After 9-10pm it could be very light spotty type stuff with even a chance of some mixing in areas that largely stayed N of the mix line during the peak of the event.

2/7/94 was insanely mild down in the TN Valley/SE. ATL I believe hit 80 that day...might be closest match but February is a different story than Dec. Its way easier for those places to get that warm in early February than late Dec

I still think NYC ends up with a solid period of sleet with this. We're seeing the typical correction back south now we often see at this range but then inside the final 18-24 ticks back to the N tend to occur once again and sometimes verification still ends up even further N by 15-20 miles on what your game time start guidance has. There will likely be 2 big time areas who get smashed here. One will be the typical just NE of the changeover which might run from like CNTRL LI NW up through Fairfield Co and roughly SWF/POU. The 2nd will be a frontogenesis/dry air subsidence induced area somewhere in ERN CT probably up into SRN-CNTRL MASS. Overall the good news is the 3K does not agree with the 12K but given where the RGEM has been consistently and the 3K at 18Z I like a 30 or so mile shift to the NE on this roughly. I am in Flagstaff so I'll be missing the whole thing.

EPS/GEPS at 00Z long range were close, GEFS not much but at 06Z GEFS was closer to those 2. Seems main difference is GEFS though stronger on the negative side on the AO/NAO is more + on the EPO and - on the PNA than the EPS/GEPS. But if we go with history as GA has posted a few times, odds favor the +PNA in January in these similar winters.

Its sort of a SWFE behaving event, I guess its an overrunning storm, but yeah very few historical matches to this

Comes in as the 6th closest match. Closest according to CIPS is 12/14/95, overall this setup has more of the NW-SE dive though, 1995 the low tracked well north so the results of that to me are not a good match. 12/19/79 looks like by far the closest match on track but this system is more juiced and more broad. https://www.meteo.psu.edu/ewall/NARR/1979/us1219.php

It also went insanely north with yesterday's event at about 48-60 hours out too. Given nothing else at 00Z did that I'd not really change any ideas yet. The RRFS/RGEM at this range have recently tended to have slight suppression/amped biases respectively so something near what the GFS shows is what I'd go with now

Up here I could see it, down there a 40 mile shift they'd be mainly sleet or freezing rain

We'll see over the next 12-24 but this may be the start of the 40 or so mile push NE I expected could happen, thats every 18z model minus the ICON more or less.

2/8/94 did that down here. Overrunning events tend to do that, it often comes right at the beginning where it goes gangbusters or somewhere mid-end while the in between periods are light.

ATL seems to have missed 79 but I would imagine they beat it easily either tomorrow or on the 27th more likely based on temps aloft. 84-85 is reachable on the 27th I think

GFS will always underdo mid-level warmth though in that scenario the flow aloft at the warmest level is like from 280, not as bad as it being from 230 but probably still verbatim underdone a bit. Its why I said before you'll see ratios near 10:1 eventually, even if its 25F at the surface if you're -1C at 750 or 800

There's been many. 97-98 and 01-02 never had one for the 5 boroughs but may have had them NW but there's been quite a few winters with none. Obviously forecasts 30-40 years ago were so poor we had many storms with WSWs issue that today never would have been out.

We have had more legit threats overall though than we did in that stretch. In hindsight 3/14/99 and 1/25/00 both should have had WSWs out but model hiccups and some gaffs by the NWS led to neither being forewarned.

I think there was one since December 2020 I just don’t remember when. March 96 to December 29 2000 without one though still remains the most insane thing ever.

Surprised they left E Suffolk out but these days they rarely put areas in they are not highly confident reach 6 or will have both snow/mixed precip

Yeah it’s why often times on coastals Long Island does well but so does Passaic and Orange. That may be due to elevation at times as well but so frequently on benchmark track storms there is a secondary max up in that area

You'll end up as always here with someone on the far NE edge getting smoked while what you thought would be a jackpot zone gets less than forecast and places SW of that zone doing as well as was expected. You always sort of want to be 20-40 miles NW/N/NE of where at 24 hours out the biggest snows are likely because often times the zone expected to do best gets fronto/banding screwed by an area to their N.

It does seem the SER is worse now and the 50/50 region trofing is not there as much. Here are 2 setups from the 80s which nowadays I would bet result in much more massive SERs than they did back then. Notice in both cases the low heights in the NW ATL, now it seems that feature is there less. https://www.meteo.psu.edu/ewall/NARR/1989/us0205.php https://www.meteo.psu.edu/ewall/NARR/1985/us0204.php

The GFS is not bad with northern stream dominant systems and or where there is not a whole lot of complications in the setup like a phase/cyclogenesis. This was a setup I warned people a couple days ago do not toss the GFS even if it becomes an outlier.

The hope was it would be better than the NAM at 48-84 and the HRRR at 48 but so far its been as bad or worse than the NAM in that range. Its best feature is its been handling the mid levels as good as the 3km NAM or better and worlds better than the HRRR. I still think that the NWS will let the NAM run for several years with no upgrades as they did the NGM because people will want access to its MOS product. The RRFS will have no MOS product due to its resolution evidently which would make it overly sensitive to microclimate features so we'd be down to just the GFS MOS and that is all once the NAM is DFA'd

This is about as good a shot as you're getting in a pattern like this for 4 at NYC, thats for sure. I think this is mainly 3-5 or 3-6 with some places in banding seeing more but I'd be wary of going 5-8 or 6-10 with this as I see some mets doing, even if we get 12 or 13:1 which is possible for awhile but given the 750-850 layer probably approaches -1 or so, even in the prime accumulation locales we'll fall back closer to 10:1 even with SFC temps in the low 20s

Models did really suck on thermals the last 2 snow events but for totally different reasons and also the bias was largely bad beyond 24-30. The first event the fact we had sun all day hurt us, the 2nd the SW flow is always something you have to account for and until the final 24 models overlooked how far DPs would rise. This time we have 23/6 and 28/8 as spreads when snow starts with a 010-030 wind. We are good even if we have a bit of a cool error at this range.

The RRFS has had severe suppression biases so far on every system I have used it for this season beyond 48-60. Its a bit concerning for sure, but once inside 48 its blown away the HRRR as far as thermal profiles...if anything its been a bit too warm but I'd rather that than the HRRR bias of always being 1-2C too cold aloft.