SnowGoose69

Thankfully looks like maybe a 30-40 mile shift east in strongest 850-925 winds form yesterday. I think maybe SRN Queens/BKlyn could gust 40-45 for a time 19-21Z but the concern of 50-60 there or even things going to 22-23z looks out now. Nassau/Suffolk still a problem

The Op runs have been exceptionally wild lately but the GEFS/GEPS/EPS the last 2 weeks have mostly handled the pattern well, they've been a bit too fast with the changes as is often the case but they showed the cool down, moderation, brief cool down followed by the moderation and then likely shift again. They just have been about 3 days too fast on everything beyond D8-10 which is expected.

That was the most insane gradient I ever saw. Closest comparisons were 1/23/98 and 1/7/94 where in the first case NYC/N Queens had a massive ice storm and were 28-30 while the central and S parts of the borough and LI had rain. 1/7/94 some of the very far northern parts of LI like Lloyd Neck had 8 inches of snow while the south shore was entirely ZR with some sleet at times

GFS BUFKIT does not really mix winds down, even at JFK but I'm always suspect, even in winter on SSE flow about that

I still think in the end the month probably averages above normal, down in the southern MA/SE/TN Valley though a few places could see their first below December since 2010 since the period from 12/8-12/10 and 12/15-22 won't be as relatively torchy vs normal there as it will be here and in SNE, I think a few might have been below in 2020 in 2017 but a few sites averaged barely above those 2.

The last several cycles you see that D14-16 the GEPS/GEFS try to start moving the trof back into the Aleutians and building the ridge but the amount of members doing it is mixed so the signal is blunted on the mean. For the first time the EPS showed it last night at D15-16 you see subtle building of the ridge over BC and Yukon. As often happens the whole thing is probably delayed. Now we see a chance for a storm at 190 hours whereas 3-4 days ago 260 hours looked like a totally broken down pattern, we might see the warmup range around 12/14-12/22 and the final week of the month looks more like now

As I believe one of the Mets said here yesterday we don't want it anyway. It can sometimes mess with what may be a favorable setup by sending the PV to the wrong side of the globe. I believe in 20-21 or 21-22 that happened and it did in Jan/Feb 2012 too, we were about to see a favorable shift with a -EPO forming over AK and then the massive SSW sent the PV to Europe. Also near the solar max with this QBO phase SSWs are rare. One did happen though in Feb/March 1989 despite similarly bad background states so they can sometimes occur near the solar max but I think they more frequently happen later in winter vs earlier.

I think city west it could. East probably no as the SW flow has enough component off the water to warm the BL, the 3K NAM shows that well with snow in western queens but once you get east of there its rain. Looks like most areas will be sitting around 38/26-28 or so at the time so its close. We also are depending on that little area of energy generating that area of precip

Basically the last panel on the 12z ICON at 180 is what you want to see....drag the boundary far enough so that anything riding up on it after is snow. the 06Z GFS at 186 is simply too far west so the ensuing wave is rain.

Once we flip back to a +PDO it'll likely be less of a problem since you'd tend to have a +PNA more often

It may have something to do with the crazy Atlantic SSTs which is why we keep seeing those -NAOs with SE ridges

The 12z EPS was not as wildly bad as the 00Z was. I find it funny the EPS/GEFS basically switched places the last 2-3 days beyond day 10

We were trying to figure out in the MA forum last winter why that seems to happen all the time now whereas 20-30 years ago it never did

Yeah it did seem that way. I recall a couple during the day but they always seemed to come in like 3-4pm. It might be like the Gulf or SE coast hurricanes always hit the US at night though, when you check the stats many did hit during the day but we don't remember them.

It never made sense to drop it as far south as some models were doing based on the ridge/trof positioning

Even when you look at 1989 and 2000 which were 2 of the coldest recent Decembers your coldest weather was 12/20 and after. To even get lows of like 22 degrees the first week requires an impressive air mass.

It probably ends up colder than the model numbers are spitting out, there can be a tendency for the guidance to skew towards whatever climo norms are at day 5-6-7

Last winter I noticed the GEFS tends to overreact sometimes to the forecast MJO plots it has. In general the GEFS overdoes the MJO while the EPS seems to underdo magnitude on the plots but the actual EPS/GEPS runs do not seem to have the same issue the GEFS has.

The GEFS keeps thinking we are in a La Nina or that the MJO is running the show. Its been attempting to break the pattern or retrograde that ridge west but keeps kicking the can. It also has now moved towards the the GEPS/EPS from the 5th-9th whereas 3-5 days ago it was quite mild because it had the ridge too far east.

Its fairly patchy outside of a big area from BVY down to BED. Another area in CT near Hartford and south

This could just be the start of everything caving vs a crazy NAM run. The RGEM not having moved towards the Euro was surprising but the GFS in these situations has held out before til 24-36 and the NAM til 48.

This looks like it will fail to reach Nina territory anyway. We might get to -0.5 briefly some time mid to late December but it could easily stay neutral the rest of the way. We have very little track record in recent years in the new climo of a neutral after Nino. 92-93 and 03-04 are the only things close and both were neutral warm while this is neutral cold. 80-81 was really the last neutral cold following a nino

Yeah Just the Op and even that is just a transient upper low riding the western edge of the ridge and just gets booted due north. The GEFS some of its recent runs is semi concerning as its flattening the western ridge somewhat. The GEFS has tended to be better with the pac the last few winters so we need to see if that continues

Anytime we have a sustained ridge out west like this you can usually assume the GFS will be too flat. It only beats the Euro regularly in those more progressive setups

One thing is for sure. The NAM at 84 is closer to the Euro idea than anything else.