Central PA - Winter 2020/2021

[MAG5035]

Nice burst of snow currently, too bad it doesn't look like it's going to last too long. 

[Itstrainingtime]

1 hour ago, canderson said:

That’s true - it’s been incredibly dry (again.)

 

37 minutes ago, pawatch said:

Don't think we have truly recovered from the drought last year.

Here we are half way through January and Yuck.

It's been kind of a sneaky dry spell - we're so focused on what might be coming at the end of the month that we've been caught off guard how dry it's been.

Anyway, just about .25" in the gauge. Nice, steady light rain has fallen all evening. 

[MAG5035]

21 minutes ago, pawatch said:

Don't think we have truly recovered from the drought last year.

Here we are half way through January and Yuck.

It's been dry so far this month, or essentially the last two weeks. But we were coming off a very active period with the big mid-December winter storm, the significant Christmas rainstorm/flood, and the New Years and Jan 3rd systems that delivered various types of precip (and another decent snow up your way). That's a pretty busy 15 day period. Drought monitor only has a small D0 area in a portion of the Mid Sus Valley, likely dealing more with the short term dry conditions of the last couple weeks and dead vegetation drying out. We had seen solid improvements in the drought conditions in the late fall going into last month and the aforementioned active period pretty much eliminated it completely with no part of PA having actual drought conditions. North-central had been dead center for the worst of the drought conditions this fall and that very deep snowpack from the snowstorm was a big part in helping eliminate it. 

[Blizzard of 93]

The EPS & CMC ensembles are still loudly signaling for snow opportunities during the last week of January.

The 6 inch snow line again gets to the LSV on both!

 

[paweather]

14 minutes ago, Blizzard of 93 said:

The EPS & CMC ensembles are still loudly signaling for snow opportunities during the last week of January.

The 6 inch snow line again gets to the LSV on both!

 

Thanks Blizz! Keep us positive. It will be a month and a half since we saw accumulating snow. I’ll try to remain hopeful. The Januarys seem to be the most boring months around here anymore. 

[showmethesnow]

The models (EPS, GEFS, CMC) are hitting pretty hard on the fact that the next 8/9 days will be for the most part uninteresting in the snow department in the east. Basically we have a shredding machine setting up to squash and rip apart any energy that moves into the east. But take heart, after this period things actual start looking more upbeat on the models.

Below we have the 5 day mean on the GEFS day 3-8 (All models agree on this general setup). What we have setting up is a PV and 50/50 couplet overtop central and eastern Canada. Around this feature we have energy rotating around the PV towards the 50/50 helping to reinforce it. Note the fairly impressive low pressure anomalies for a 5 day mean through the Lakes and through the NE. This is pretty formidable suppression which would take a lot to combat. What is attempting to push back against it is the cutoff low/lower latitude troughing in the SW and the responding forcings it is creating in the lower latitudes for ridging in the southern states. This really is not a good setup for a general snowstorm in the east and as we have generally seen on the models, everything moving eastward in the mid-latitudes fizzles out. Doesn't mean some won't see snow. Those who typically enjoy lake enhanced snow as well as those up in New England can do quite well as the PV energy rotates around and then amplifies as it hits the coast off of the NE and Canada coast.

Now I wouldn't call this a shutout pattern through this period for a general snowstorm outside of the areas mentioned above. But it isn't pretty. The models have been having a rough time in the Southwest with the energy so maybe we see something actually there that has more oomph. Or we could possibly see a short lapse in the suppression which a system could take advantage of. But even in these cases I think we would be hard pressed to get anything meaningful above 40N in the East, west of the Apps.

 

 

 

Now to give you a better idea of what systems are encountering as they move eastward look at the closeup map below. I think the anomalies tell the story here. Not only that but look at the angle of these anomalies. The isobars tell the story as we are seeing a significant downhill look into the east for a 5 day mean. This is an impressive, suppressive look.

 

But I did say take heart (or at least as much as you can for 10+ day projections). As many are aware and have been talking about, the models have started hitting on a potential storm roughly around the 26th. If the models are somewhat correct with some of the major features and how they handle them then this is actually a legit window IMO and not just another fantasy threat we see at 10+ days all to often. 

Below we have shortly before this period of interest. What is occurring is the PV and 50/50 couplet is now in the process of separating. The PV lobe is rotating up towards the pole and the 50/50 is migrating eastward (Good timing of the 50/50 low moving eastward and relaxing its influences for a possible storm). Between these two features we now how the higher heights over the NAO domain nosing southward between them. This is effectively cutting off the NS energy rotating around these features and along with it the suppression through the Lakes and into the NE. With this relax in suppression the ridging in the south is taking advantage of it. Ridging that is created by the general troughing in the west. That general troughing/energy in the west the models have been having a hard time handling recently.  So what actually verifies could have somewhat significant influences on the evolution of any system in the East. But for now we really have to leave this and any possible influences as a question mark. 

Now I mentioned I felt that this may be a legit threat and not just another phantasy one. Let me explain why. Generally, many of our 10 day threats revolve around smaller scale features (more MESO scale in nature) and some intricate timing between them to force the pattern for a storm signal. Expecting the globals to get all that right at such ranges is asking a hell of a lot. So typically we see a storm show up for a few runs or even a day or two and then it disappears as the models then start picking up on different timing of these smaller scale features. But this is not what we are seeing here. What is forcing the pattern in the East and hence the storm signal, are the major players (larger scale features). It is all revolving around the NAO/PV/50/50 and how they evolve and the globals have a better handle on these features at longer ranges. What is comforting as well, is seeing all three models in unison with this evolution. And despite what some may think, the models have done a pretty good job in the longer ranges with how they have handled the Greenland/Eastern Canada/N Atlantic domain where these features are located.  So short of the SSW/split impacting this negatively as it works its way down through the atmosphere I believe chances are good we see a semblance of this look verify despite being 9/10 days out. ***Word of caution, there is always a possibility we could see something cut to the west to a certain point before moving/transferring east. What form of troughing and strength we see in the West could play a big part in that.***

 

 

 

Thought I would also make a quick mention on what we would see any post day 9/10 storm. Even there we are now seeing some positives through the day 11-16 period. Though you may #$%#@ when you look at the isobars and see the same steep downhill look in the east that we saw in the above example they really are not the same. The difference here is the lower pressure anomalies extending from the 50/50 have now shifted south from targeting NE and are now targeting the mid-Atlantic. What this is implying is that we are more then likely seeing systems moving through the mid-Latitudes and amplifying as they move off the coast (the prior example we were seeing NS energy running the border and amplifying as it hit the coast). In this look below, generally the NW sector of the low pressure anomalies (circled) is where you want to be. 

 

[pawatch]

Mag here is rainfall map for this year.

Blizz and SMTS Thanks!

[paweather]

GFS says the 25th-26th is the ticket. Miller B. Ohio then transfer. 

[paweather]

Just to get some hopes up:

[Blizzard of 93]

3 hours ago, paweather said:

Thanks Blizz! Keep us positive. It will be a month and a half since we saw accumulating snow. I’ll try to remain hopeful. The Januarys seem to be the most boring months around here anymore. 

It’s been 1 month since our top 5 December winter storm that still has everyone in our region above normal in the snow department through today’s date.

Most of our great winters have slow periods.
Some people in other threads have mentioned the great winter of 09-10. That season we also had a great December storm that delivered a similar amount of snow in the Harrisburg area that this year’s storm brought. Then, there was NOTHING in the snow department all of January. Thankfully we were then treated to one of the greatest weeks of winter weather of all time with our 2 February blizzards. After that, we just missed the great storm later in February that retrograded in off of the coast that crushed NJ into upstate New York and New England. We got a few inches of snow from that storm, but it could have been much more with a slightly more west track. March of that year brought Nothing in terms of snow to CTP.

My point is that even our great memorable Winters can have long periods of down time. This year, if we get another good winter storm late this month, another good one in February or March, plus a few small events mixed in, we would remember this winter as a great one and forget about the 5 weeks of down time.

I think that we have much to look forward to in the next few weeks!

[MAG5035]

The two periods I have an eye on are D5-6 and D9-10 range. There's also going to be some weak shortwaves in the flow early this coming week but will likely primarily deliver periods of snow showers/light snow to the Laurel's and western PA. For the D5-6 (Thursday-ish) there's been some solutions that amp the northern branch just enough to generate a wave of precip to move across PA, esp on the Euro. This would probably be a light event if it occurred. Something's likely going to come out of this D10 range, but hard to say what at this point obviously. So far today the GFS and Canadian have something notable, but differ in the pattern somewhat. GFS dropped and phased a shortwave out of Canada making the huge storm it has. Canadian doesn't phase and also dumps the trough in the western US raising heights and making a more messy storm that tries to cut. 

[paweather]

EURO! Looks like we will have something to track next week....9 days away. 

[paweather]

I’ll take this

[Blizzard of 93]

13 minutes ago, paweather said:

I’ll take this

The storm is far from over at the end of the 12z Euro run at 240 hours. The storm is transferring at a great spot for us near the coast of North Carolina. I wish that we could see the next couple of frames!

 

[Blizzard of 93]

The GFS & Euro both have good agreement today with the position of the low for 9 days out. The GFS has the transferred low off of the Virginia coast while deepening as it heads north.

Here is the 12z GFS for comparison.

 

[Blizzard of 93]

The 18z GFS again brought CTP snow for the possible storm early next week. Hopefully we start to lock in on this threat potential over the next couple of days.

[MAG5035]

Heavy squall currently, getting everything whitened back up. 

[Blizzard of 93]

The 0z EPS still looked really good for the winter storm chance for early next week. The general low track cluster goes to the Ohio Valley and then transfers to the mid Atlantic coast.

Here are snapshots of one of the 6 hr precip panels early in the storm and then another map with the low clusters later in the storm on Monday night.

 

 

[Blizzard of 93]

Here is the 0z EPS snow map for just the 3 days near the time period of this early next week winter storm chance. 
This is a nice snow signal for over one week out. I like that on this map, CTP is right in the middle with some room to spare on all sides for inevitable adjustments.

 

[Blizzard of 93]

One final map for now, which is the 0z EPS overall 15 day snow map.

This is a great snow signal for our region. It is great to see the 6 inch snow line extend to the South of I-95 for the first time in a long time!

This is all mostly for next week, with the early week threat and then another chance later in the week.

 

[paweather]

Hopefully just one more week of DULL weather. I’ll take any type of storm to track. LOL

[Itstrainingtime]

Recorded a trace of snow this morning from a nice random snow shower. Wasn't expecting that!

[MAG5035]

This system in the longer range slated for early next week seems to be solidly in all guidance now in the general sense. All the op guidance last night tried to cut it to some degree, making messy solutions. Todays 12z GFS was more of the same with the Euro and Canadian now having a colder/weaker solution that does slide south and is all snow. GFS's deeper solution has more amplification and some northern stream interaction while Euro/Canadian run a weaker shortwave wave out with no interaction. One would have to worry more about suppression with the latter given the blocking. Either way big differences in the afternoon suite.

I've def been as optimistic as the next person with this upcoming pattern but i've soured a bit the last few days on some aspects. I'm not a fan of the evolution that has come about of retro-ing the pac ridge far enough west that it dumps the main trough into the western US (aka solid -PNA). Yea, with the strong NAO block the storm track will generally try to stay under us but I see limited phasing/amplification opportunity and if you do get it lined up/amped enough to get something like the stronger solutions from last night or today's GFS, they will try to cut. That brings me to the next problem, temps. Now if this potential system does try to cut into the block... it's likely going to weaken and/or transfer, and normally i'd favor a mostly frozen outcome even if the primary did get west of us. Problem is we currently don't have an actual solid cold air connection, and if that main trough dumps into the western US right when we finally see negative anomalies with some teeth building in Canada.. we're not going to be much colder than we are now as a lot of that cold will dump into the trough. So my worry with even the scenario of a stronger system with miller B evolution is we don't have strong enough antecedent cold to stave off a messy wintry mix type event over what normally could be a mainly snow event. Obviously a weaker system like the 12z Euro/Canadian wouldn't have the precip issues as we maintain colder temps, but the weaker system would be more apt to get outmuscled by the -NAO and only give us a lighter event or even a southern or suppressed one. 

Climo's on our side this time of the year with seasonable or marginal temps but we're going to get bit if we don't get some legit arctic air involved in the pattern. That goes double for the Mid-Atlantic region and the southern fringes of our region that can pretty much be an extension of the northern Mid-Atlantic climo. Current case in point... despite passage of a pretty deep trough where at 12z tomorrow morning there's sub 528 heights and sub 522 thicknesses across most of the state in mid-January, we're still going to be above average temp wise. That's something that normally could equate to a day that has highs in the teens to 20s-30ish NW to SE across the state with a run of the mill cold airmass. Harrisburg is forecast to still hit 41 tomorrow.  

 

 

[Blizzard of 93]

At this point, I would be good with the Euro or Canadian runs today with a weaker system that does not cut. I would take a nice all snow 2 to 4 or 3 to 5 inch all snow event.

 

[Blizzard of 93]

The 12z EPS offered a wide range of solutions from big hits to events similar to the Op run, to whiffs to everything in between. 
Here is the 12z EPS for the 3 day window around this storm chance early next week.

I like where we are sitting at this time.

 

[Blizzard of 93]

4 hours ago, Blizzard of 93 said:

The 12z EPS offered a wide range of solutions from big hits to events similar to the Op run, to whiffs to everything in between. 
Here is the 12z EPS for the 3 day window around this storm chance early next week.

I like where we are sitting at this time.

 

The 18z GEFS looks similar to the EPS for the early next week threat.

[MAG5035]

Had 0.8" overnight, mainly between 10-2am or so. I'm sure that'll be gone by lunchtime like Sat night's measured 0.9" snowfall was yesterday. 

Overnight guidance was meh on our potential longer range event. All the ops have the deeper system now which cuts. 0 and 6z GFS and 0z Euro have primary lakes cutters while Canadian tried to cut but forced a secondary (still a mix event). Ensemble guidance seems to look like it does something similar to the Canadian where front part of the storm cuts but secondary low takes over under PA. These are all mix event scenarios right now. This could trend colder to a more frozen event as it gets closer even if guidance still cuts the low, but I'm pessimistic on holding deep enough cold air for long for the reasons I discussed yesterday unless we force a secondary early enough. 

Longer range pattern just has not looked good on guidance to me. Moving the Pac ridge all the way to the Aleutians or even west of that and dumping a trough into the western US (also gone in the progs is the more sustained -EPO/-WPO) is going to screw up what was looking like a really good period if it comes to fruition..especially so if the -NAO relaxes but it's going to affect it either way when it comes to the storm track and cold air. Of course the longer range is highly changeable, but I am somewhat concerned this change in things may be right. MJO has quietly tracked into a low amplitude phase 4, looking like it may be arcing for a 4-5 run instead of being in the null phase. It's notable because model guidance is completely whiffing on it right now. The MJO site updates once a day with 0z guidance, and today's isn't in yet, but look at yesterday. You can see the big separation between the plotted point and where the ensemble guidance starts it's spaghetti plot. This is like this on NCEP guidance too. Models could be starting to adjust to where the MJO actually is, which would actually support what guidance has the Pac eventually doing. I hate to be pessimistic after being really confident on a very good winter period coming up last part of the month, but just don't like how things have evolved the last few days.   

[2001kx]

Wintry scene this morning (pic taken in Houtzdale)

Roads were horrible.

 

 

[Blizzard of 93]

The 0z EPS still looks good for the early next week winter storm chance. The mean still has the general idea of a low track to the Ohio Valley and then transferring off of the coast. There is still over a week to go until the event, so there is  lots of time for changes for the Op runs to lock in over the next few days.

[Blizzard of 93]

The 6z Para GFS also looks good for the possible event early next week. It does not cut the low into the lakes.