MAG5035

And wow, Winter storm watches up already for everywhere, literally. I don’t think I ever saw such a large expanse of watches.

Looking over the 0z ensembles, they continue to be more supportive of an all snow outcome in all of C-PA despite the Euro and especially Canadian op creeping that mix line into southern PA. 

Here’s the Canadian ensemble members and p-type. Note that none of the members really intrude into PA with the mix line. A couple get close, but snow is predominant regardless. That factors pretty heavily into what your seeing on the NBM maps, as it blends all these ensembles. 

0z Euro ensemble is fantastic

Here’s the multi-run trend for MDT (Euro ensemble), you can see how this has really escalated the last couple days. 

27 minutes ago, canderson said:

0z GFS is running and contains new data from the hurricane hunters. 

They can keep that data coming haha. It doesn’t get much better than that for a well timed and positioned handoff to the coastal low to put PA in the best snows. 

8 minutes ago, Blizzard of 93 said:

I think the NBM factors in ratios.

It does, I know reading into the updates of the new version that it mainly applies the Cobb method for snow ratios. I think the current version does to a degree as well, not sure. But the NBM snow maps do factor in variable ratios. 

2.5” so far this evening here, what a nice surprise. Was down at our camp in NW Huntingdon Co earlier and about the same there as well. Roads are a mess.

I’ve been busy enough watching the weekend that I missed being advised for 1-3” earlier this afternoon for tonight. Snowing sideways and 26ºF currently. 

20 minutes ago, Eskimo Joe said:

He seems to love dunking on snow chances. I can understand his reticence on not seeing some sleet nose into the Lower Susquehanna Valley, but he consistently seems to be the first person to rain on the parage of snow lovers.

Yea I mean I’m not going to argue his points, they’re valid. I’ve posted a couple times about his point #2 (western ridge alignment) the last couple days, why not air the skepticism he had when some guidance had this buried in the Carolinas as recently as yesterday at 12z?

With that said, there’s only so much this storm is going to punch up into that cold air mass. It’s still fairly progressive in nature. Any PA mixing issues would likely be relegated to mainly sleet and not after a pretty large amount of snowfall. That strong of CAD isn’t going to get dislodged below 850mb by this. MDT is in the low teens for most of this event. 

7 minutes ago, Itstrainingtime said:

Don't read MU's thoughts. At least if you want a snowstorm at home.

Is he bailing on the first sign of a mix? haha

0z Euro ensembles continue to look better for heavier snows in PA, probs for 6”+ in a 24 hour period (at just the 10:1) are 80% or higher for about the southern third of the state now.

0z Euro ensemble snowfall mean

1 hour ago, canderson said:

That N trend still has a hundred or so miles to go imo. I wonder if sleet makes it into the DC metro area. 

Possibly, I certainly think further down in VA may mix with this. I’ve not really sweated us missing out if the phasing scenario came to fruition, because of the pattern setup as I alluded to yesterday. 500mb ridge axis is west along the Pac Coast (classic for C-PA is Boise, ID ridge axis), height’s build in the SE US ahead of this system. Still relatively progressive though even with the phase, so I think that and the very anomalous cold air mass in place are what make this potential event go. A more typical cold airmass in place probably would have us under the gun for yet another messy winter storm that we’ve had too many of the last several years. 

Models have been more consistently showing some surface low reflection west of the Apps as well, which given the depth of the cold air mass and strong high pressure in place should be a good thing for us in terms of enhancing the snowfall across all of PA. Most of our classic big ones (96, 03, etc) have that signature. Comparison wise it’s tough, no storm is ever the same. Some shades of 2003, but that one didn’t have the prolific ice/snow zone the whole way back to Texas that this one’s forecast to have. The Baja low component of this reminds me of 2010, but this is a way colder setup and probably a weaker low that will keep moving. Antecedent cold air mass comparable to 1996 or even colder, but that was a much more amplified 500mb setup in the classic positioning. I personally don’t think the top end accum potential is going to get near any of those 3 in the Mid-Atlantic/PA but we’re not in NAM range yet haha. The overall impact and the sheer area of the US that is going to get significant snow/ice out of this though, is going to be biggest story with this. 

Crushed.. the difference between this run and the 12z today is hilarious.

I’m at 114 here with the GFS and it’s looking better than the 18z run with expanse of heavier snows deeper into PA, it’s gonna be a good one. 

Here’s Euros total QPF, trying to separate the storm QPF from the event Thursday thats going to deliver several more inches of snow in NW PA. 

Also, surface temps for this are insane. Here’s the 135 hr frame, which was basically the best 6hr precip frame for our area.

Temps are like that the entire event. Normally you see temps like that and would think one would be smoking cirrus.  I know ‘96 started with temps that cold, but I don’t think temps stayed there the entire event. Even if we don’t see the best QPF the whole column is essentially in the ideal snow growth temp range. 

Man the Euro is a hammer. Snowing the whole way into Monday evening with an upper low passage and everything. 

3 hours ago, Jns2183 said:

I think this storm is partly here due to la Nina breaking down. That increases volitilty significantly which is what we want for a big storm. The down side is the northern trend all winter has been due in part to the la Nina. I also feel, and I believe, studies have panned at that the northern trend that models do well above 50/50, isn't do so much to the teleconnection as it is data availability and it being much more available at lower latitude. If anything the prudent choice of action would be to see which models have had the better accuracy with high pressure placements at higher latitude both all winter and during the past month as that seems to be the hinge this storms depends upon

Sent from my SM-S731U using Tapatalk
 

I think in terms of the storm that could be at least partly true in terms of the Nina. More specifically it’s more of a function of the MJO in my opinion. It spent basically the whole month of December and the first 10 days of January in the null phase. So not much input from that, and we had northern branch dominated storm track that was very dry. Now there’s a pretty good pulse moving from 6-7-8, so I think that’s a driver in finally seeing a meaningful southern stream system show up on modelling. 

So the next question is what’s going to happen with it. I think as long as this thing comes out in one piece we will probably do well here. DT’s thoughts were posted a few pages ago saying about how important the MJO is and that it HAS to get into 8. Well for Richmond and that portion of the Mid-Atlantic, yea it probably does. Most deterministic guidance rapidly traverses 7 this week but doesn’t get there for this storm (close to 7/8 border). And this checks out with the 500mb pattern. 500 mb western ridge axis is in fact west of the classic positioning for C-PA. A more phased solution is going to build heights in the southeast as the storm comes out. It’s why I don’t particularly think a more phased and organized storm is going to get suppressed under us even with all the arctic air available. Now if energy is left behind and it comes out piecemeal, then sure… the heaviest precip will probably be to the south of C-PA. Even the improved 0z GFS run still left a lot of southern stream energy behind and there’s a big difference between that and the Canadian. Canadian phases it. 

Look at the height anomalies in the southeast even in the GFS case. If there wasn’t so much cold air in the pattern for this I would be more concerned about a more wound up system being some kind of a mixing event up into PA. But in this case I feel the more wound up scenario probably puts C-PA in the best snows. The key is going to be how these features come out and their interactions. 

Big improvement for PA on the 0z GFS vs 18z run and especially the 12z today, where there wasn’t even measurable snow anywhere near us. 

0z vs 18z

Early 0z stuff, regular NBM vs v5 NBM (newer version thats suppose to be fully operational in the spring). This has improved a tad for PA in the last couple runs. Right now I’m more watching this just for changes in the axis of the swath of heaviest snows vs any kind of amounts. But those kind of heavier amounts this far out is definitely a pretty strong signal considering the array of products that make up those NBM blends. 

I had to quick delete because I pulled a rookie move and posted/commented on what was last nights UKMET haha. I’ll be very curious if the Euro continues to move its heavy snow swath our way. Regardless, I’m not anywhere near sweating the too far south/north solutions. But this energy has to all come out and not have a portion of it left behind like what the GFS has been trying to do. I think as long as that happens I like our chances. 

Nice to see the snow hole the central counties shrink some with the more robust than expected snow shield developing back further last night. Unfortunately I was only the recipient of a light coating, or heavy dusting (whichever sounds better) with the 1-2” plus snows either falling a few miles away up on the Allegheny ridge to the west or the next county over to the east. So bit of a bummer. 

With that said, screw it I’m going all in on next weekend. For the first time this winter the southern stream looks involved with a shortwave coming out with Gulf moisture to tap and there appears to be plenty of cold air and decent high to attack. This has the look of a widespread and significant winter weather maker for a big chunk of the country. Whether that’s here or south/north of here is going to be the debate this week as models are changeable as per usual. 12z GFS buries this in the Deep South, Euro not quite as suppressed but still a C-PA miss to the south after the previous 0z run had the mix line in southern PA. Ensembles showed variability with some hits in the mix. Both 12z GFS and Euro AI’s are big hits that are backed up with their AI ensembles. So we’ll see, we’re way overdue for an actual big precip maker. 

Steady light to moderate snow here with a fresh coating, 29ºF. This has turned into an outright accumulating event for some folks that it really wasn’t in the forecast for. US 322 corridor from State College to Lewistown showing a lot of snow covered roads on the cameras. 

Pretty solid area of snow has blossomed up from WV over western and central PA the last couple hours. Something that the HRRR hasn’t really seen at all in recent runs where it doesn’t blossom precip til later over the Sus Valley. 0z 3k NAM looks to have seen that better as have the RGEM and globals. So I guess in other words, the HRRR is about the only thing that didn’t see that.

Snow falling here isn’t doing much currently, but it is accumulating up in the Laurels per 511 cams. 

9 hours ago, Itstrainingtime said:

MU Weather Center

@MUweather

The talk of the town is now Sunday’s potential storm. However, the main players remain unchanged from today’s system. With no blocking and no 50/50 low, I’m not biting on the nonsense shown on today’s GFS run. A flatter, weak wave and progressive system is most likely (EURO).

Nonsense or not this is the third run GFS in a row today that has shown a fairly impactful event running the whole way up.. starting all the way down in New Orleans with accumulating snow. Still not impacting C-PA or most of the LSV, but this is way more wound up than anything else. 

0z vs 18z GFS. I’m using a 10:1 map so I can do the 48 hr total and separate out the other LES and light snows leading up to this. 

18z Euro did try to come toward this scenario a bit, having a snow swath down to the Gulf Coast (starting in FL panhandle) but not as robust and mostly offshore. I dunno, progressive and positive tilt along with a lack of phasing probably argues towards the Euro end of things. On the other hand, could argue this has room to come west given axis of what is now a massive western ridge is along the Pacific Coast. New RGEM and Canadian don’t dig the responsible shortwave anywhere near as far down as GFS/Euro and it comes out faster and fires the coastal by Sunday morning off the Mid-Atlantic coast. This actually does impact C-PA with lighter snows but really impacts New England, pretty much a late blooming coastal solution for us with no snow anywhere near the Deep South. Certainly a lot of differences for an event that’s already starting in the outer reaches of NAM range. 

5 hours ago, mahantango#1 said:

DT: WILL DO A NEW SHORT VIDEO THIS EVENING ABOUT JAN 15-16.

 

The last few runs on the operational GFS continued develop a huge snowstorm for the middle I thank New England coast. the model not me but the model is showing something like the January 2016 blizzard or Something like the 1909 or 1922 blizzards on the Mid-Atlantic coast. it's a very extreme solution. it's not out of the question but most of the data is against that kind of massive system.

 

 on the other hand the upper level energy on the 12z Saturday midday European model has taken a big step towards the GFS idea of a big Mid-Atlantic winter storm on January 15

It’s certainly a bit of a long shot but the big storm option is definitely on the table. There’s a lot of energy dropping in amplify this trough and it’s darn near an all out phase and explode type east coast storm. I have the 18z solutions below and you can see the distinct shortwaves lined up, but still on a positive trough axis. The trough eventually goes negative but it’s takes time and doesn’t seem to phase features cleanly/completely, which still yields some kind of event but not a storm of the nature that has occasionally been thrown out by mainly the GFS. 

Some things to consider, regardless of any eventual storm evolution this looks to be a fairly potent trough and closed 500mb low that develops over or just under PA. I think that alone will probably generate a swath of snows somewhere in central and/or eastern PA as the trough goes negative. 

Another thing to consider is temps. Tomorrow will be cold and windy but this is a quick cold shot that moderates rapidly for the first half of the week. Temps will likely be mild (5-10ºF above normal) first half of the week right up to the early stages of this digging trough and associated coastal potential. If we do get a storm it will be preceded by mild to marginal temps, esp in the Sus Valley. So when it’s probably 50ish there the day before, don’t be surprised. 

3 hours ago, GrandmasterB said:

From a met in the NE forum. Sign me up! 

“Seems a pretty straightforward setup for back half Jan, rebuild source region in western Canada late next week/weekend, likely leaking cold into the northast at times with GOA ridging (-EPO) beyond.  Chances for coastals during transition periods, and perhaps a more active southern stream from MLK and after.”

One thing to keep an eye on is the MJO, which has been in the null phase for most of the last few weeks (not a major influencer). Models are forecasting it to finally strengthen, with most sending it solidly into Phase 6 later next week (esp GEFS). Euro guidance was more toward the border of Phase 6/7. Phase 6 is more often than not one of the eastern US torch phases with a high degree of corellation. Given some lag time this would generally suggest another warm period coming at some point possibly late month. Ensembles are definitely NOT showing much signs of that today temp-wise in the D10-15 range.

So this will all be interesting to watch evolve. EPO/WPO are forecast to go pretty negative in that 10-15 day range along with a -AO/NAO. One of the few more recent examples of it not mattering much being in the warm phases was 2014 and 2015, and the main drivers of the cold those winters were in fact a persistently strong negative EPO/WPO.  

The timeframe around the 15th or so has fairly consistently looked like it could be the best attempt at amplification we’ve seen so far this winter, which is definitely not saying much. Whether or not we can get some better phasing of features there remains to be seen, and probably will for a good while yet considering the range and model performance lately. There’s some potential there though, and during a period next week which should be at least seasonably cold. But in the meantime while we’re warmer and occasionally raining the next few days, 30 year anniversary of the Blizzard of 96 highlights might have to fill the void. 

Regarding the lack of bigger coastal snowstorms as of late in our neck of the woods, the Northeastern US apparently hasn’t had a RSI (NESIS) rated event since March 12-16th, 2023 (I had to do digging just to remember what that one did). There’s a slight chance the event right after Christmas might’ve snowed enough over more populated areas (NYC) to be a minimally rated one and hasn’t been added yet, but the point still stands. The last major rated NE storm was the Jan 31-Feb 2, 2021 storm.