jwilson

Well, we have a massive -EPO showing up within the 7-10 day range now.  I have a friend that lives in Alaska and she got two feet of snow yesterday, and usually downstream that's bad news for us (at present).  Obviously, we haven't had much winter weather.  But the Alaskan Ridge can change things.

Question is whether we can shake that -PNA this month.  A big ask, I suppose.  Even closer to neutral is better.  Very end of Euro (200+ hours) is setting something up, but the GFS looks even a little better maybe.  We'll see whether these looks hold into next week.

Keep in mind, models tend to exaggerate pattern changes, even transient flips.  They move too quickly.  I said it earlier that the change might be appearing too soon in model land.  It's more likely to be a gradual shift with lull days in-between.

If we get to the 15th or 20th and the better looks still aren't established under 7 days, then it's probably fair time to wonder if a change will happen at all.  Though you still need to see how the indices adjusted in that period.

Basically, if the pacific hasn't improved in the last few days (and it hasn't), then the long-term better looks will keep getting pushed back.  Really, this is typical for a Nina December (-PNA).

I admit I'm not too focused on discrete storms or threats just yet.  Mostly watching the upper atmosphere and seeing if it cooperates.  Getting something on the front-end of a potential pattern change would be a big win, however.

For now I think we're simply in a holding pattern.  These are OP runs so the usual caveat, but the 0Z Euro from yesterday compared to today are starkly different in developing a better pacific (incoming -EPO versus positive and a more natural +PNA look).

Mid-month we transition to a neutral or +PNA, usher in a big -NAO block, and seem to keep the -EPO and -AO.  Those are the good things.  It's possible we're breaking the pattern down too quickly and delay by a week or so, which for the white Christmas lovers wouldn't be a bad thing, necessarily.

The issue for me is whether that -NAO manifests as too strong and acts as a true block over 40N.  That would be great if you live in Raleigh, but for us it's potentially bad news.  The placement retrogrades west enough to entice us.

December of 2010 wasn't bad here at 12.2" total.  It's a top analog.  It would require more research, though, to determine how exactly we got that snow over the month.  Was it synoptic or just lots of little lake events?

Long-term, I don't think any pattern is locked-in.  We're in a volatile situation where La Nina corrodes and leaves us with a sort of bouncing atmosphere.

19 hours ago, TimB said:

Other than 2020, when was our last good December? And by good, I mean even average.

Well, our average has skewed up a tad because of two years ago, which happened to be the 2nd best December ever (behind 1890).  If you look at patterns, I'd guess we're due for another single-digit total next month.  Perhaps even another dud.  The only instance of snowfalls snapping back that quickly were across 2010 to 2012, where you had a bad year sandwiched by two better-than-average years.  Granted, this is weather and quite literally anything can happen, but historical trends don't suggest a big total this December.  For whatever that's worth - and to be fair that may not be worth much.

Average December snow since 1989 is 8.12" and it was 7.73" before 2020 happened.  That's a pretty big jump for one season.  We've only hit the average twice since 2014 (2017 was 13.3").  Before that mini-drought we had actually had a strong run of good Decembers.  In the preceding seven-year period, we hit the average five times, four of those in double digits.

On 11/28/2022 at 12:37 PM, Rd9108 said:

I will say that I wouldn't get too wound up if the costal guys are freaking out about the pattern. If the current NAO and depiction on the GFS plays out we should see enough cold air in our area for snow. I'll be curious is we start seeing good snow storms start showing up. 

I would agree.  It's quite rare for all of Pennsylvania to win in a single snowstorm together.  Usually it's one section of the state that wins while other sections miss out entirely.  Most common I'd say are eastern sections, then central, then western (for the big ones).  Erie is its own climate because of lake effect, thus they win the most.  For synoptic setups, though, 2010 is the rare example of Pittsburgh and Philly both winning on the same storm.  Pittsburgh seems to do better when the coastal sections do worse - meaning more inland tracks.  A marginal La Nina isn't necessarily as bad for us here.

I think the +PNA is the dominant driver anymore.  Spotting that ridge in the right location allows everything downstream to flow into the right place.  Too much of a -NAO pushes storms away from us, either south or into the coastal plain.  A +NAO isn't as negative for us because of our inland and more mountainous orientation.  Lows riding the spine of the Appalachians are ideal in many ways.  Cold air sources are easier to come by locally.  Basically all the same reasons we do better with clippers.  The PNA can also influence earlier development down into the southern states or Gulf of Mexico.  That's important for us because we don't do Miller B's here.  They strengthen too late.

I think "higher lows" is the more expectant result of climate change, overall.  Regularly hitting new highs and maintaining hotter temps isn't necessarily the most measurable change.  More humidity, higher wet bulbs at a more consistent rate is also an extension of that.  There are a few places on Earth that are actually becoming inhospitable to humans because of their increased and dangerous humidity levels (like locales in Pakistan, for example).

52 minutes ago, Ahoff said:

I thought June was our peak?

Maybe my memory has failed me, but I remember a tweet from the NWS that said July averaged more thunderstorms than any other month, though I was looking at the severe climatology and you appear correct.  June has more tornadoes and hail reports, at least.

I can't find historical data on severe watches/warnings or t-storms, overall.  Guess I'm a doofus lol.

July is usually our peak severe month.  Been pretty quiet, overall.  I'm assuming we're going to pay for this later with a soggy fall or something.

What's with the security bubble over Allegheny county recently?  The storms keep dodging us to the north and south.  

Who wants highs in the 40s and 50s the first weekend of June?  I sure hope the GFS is cracked.

This two-month winter definitely overperformed, maybe somewhat location dependent (as is every winter, really), but I didn't expect to even approach normal in this La Nina.  Really, though, it was a half-and-half winter.  December and February behaved as is tradition.  Then March went nuts as it tends to do from time to time.

10 minutes ago, TheClimateChanger said:

Smelling the rain never works here because the warm tongue always wins out - if not at the surface, aloft. We do much better staying all snow and potentially exceeding forecasts when we're on the western fringe of a storm forecast to dump 12"+ in central PA. The precipitation shields often seem to expand further west or at least linger out this way longer than expected.

Respectfully disagree somewhat, although I understand your point.  it all depends on the orientation of the baroclinic zone and the development of the low itself.  We smelled the rain yesterday and got to see some of the biggest snowflakes ever, which also led to the overperformance.  When storms are pushing in from our southwest or south and running due north or NNE it's one thing, but in a progressive flow, we'll only be borderline for a brief period with the cold pushing in quickly.  Thus there's no threat to changeover.  This isn't a case where the system continues to deepen as it gets too close to us.  In this case, the low deepens only as it gets further away.

You need to be close to that rain-snow line in such a fast moving system or you miss the best snowfall rates.  Granted, you'd be right if the low intensifies too quickly in the south and is then pulled too far west along the boundary, but for now that doesn't look like the issue we're facing.

GFS has been pretty stable in placement, but right now that's the high end event and it's "only" 3-6" for most of the area.  CMC is similar.

The NAM came back a bit west from its highly progressive 6Z run, but the changes at 500H are quite subtle.  Really we just need that s/w to dig further west/south earlier.  The timing of that intensification is the only thing that's really going to matter in this fast flow.  I think the NWS went a little too high with their initial estimations, we've seen that before.  If I was the NWS, I probably wouldn't have issued a total yet at all.  The NAM is too jumpy right now to be reliable and a 5-7" call doesn't have much support at mid-day.

The issue is the best frontogenesis stays east of Pittsburgh from the beginning on current model runs.  If the best rates manage to slide east of us at the onset, that's when you know it's going to be a low-end event.  We gotta smell the rain.  It's such a progressive storm there's no room for error if you want to see a higher total.  But right now pretty much everything is on the table.  After yesterday, as well, we can't discount a surprise in either direction.

I haven't been tracking tightly lately but today's event came as a bit of a surprise.  Where's all that mix and rain?

Since today overperformed, I have to imagine we're looking at a similar occurrence this weekend.  Either that or we get plain rain instead.

The flakes this morning, especially, were massive.  Dinner plates. 

I might be drunk but I'm looking forward to that first thunderstorm. 

If winter and cold is what you're still after, you can sort of hold out hope for now.  There's no more 50 degree days in the long-term until around March 5th.  It barely touches 40 over the next two weeks.  That warm-up is also like the others: two days and then back into the freezer, with ample cold dumped into the U.S. (likely due to that strengthening -EPO).  That could change, of course, but for now, as long as cold is around, it leaves an opportunity for snow.

I'm personally ready for an early spring, but it looks like we're going to hold onto winter for a while longer.  If we can't eek out more snow in the pattern, that would have to be considered a disappointment.

I don't love the trough alignment for the system next Friday.  The longwave pattern screams cutter to me.  Ridge too far west off the pacific coast.  Not that it can't change, but for now that would be the concern if you're still looking for snow.  The Euro and Canadian take a slightly different tact in not intensifying the central LP as deeply and it basically skirts a boundary nearby.  Seems much less likely than a cutter.

That said, the pattern looks a bit more conducive coming into March.  Pretty similar look to January.  The only issue is that's basically fantasy land.

Long-term, who knows.  OP GFS wants to sink the PNA and flood us with warmth, but a fairly strong -EPO may assist in continuing to push cold air down into the CONUS.

As soon as the groundhog saw his shadow, we knew it had to be over, right? 

I'm fine with an early spring.  January exceeded my expectations to some degree, and I never really expected some blockbuster, wall-to-wall winter.  March is always a wildcard, too.  You never know what might happen.

I'm good with some down time from tracking after January.  It was almost constant since New Year's.

At this point I'm chasing the big one and that's about it.  It's been at least six years since we've even sniffed the two-footer, same for places further east of us which seems like a semi-drought given recent climatology.  I don't have high confidence of one occurring this year.  We don't have the right kind of blocking setup.  I would say next year looks slightly more promising with a Nino prediction.

I have a friend that's a meteorologist in a southern market and did his thesis on public communication related to weather broadcasting and forecasting, etc.  It's pretty interesting how he approaches his forecasts, and I think it's something a lot of on-air mets (among others) miss.  There's not enough discussion about the nuance of storms, really.  And I realize the "general public" is overall kind of dumb so you can't wade too far into the minutiae, but I think a lot of mets skip over the grey-area talking points and focus too much on black-and-white numbers.

This does vary by forecaster, however.  We even see the local NWS has good discussions and bad ones.  I'm guessing there are not enough college-level courses on communication in this context, and some people are better communicators than others, naturally.  Regardless of how you felt about the last couple storms, there were obvious issues that some mets didn't really touch on or discuss enough.

I see some of the same things here on the board.  I wish we would ban Kuchera snowfall maps because those things fail to verify 99% of the time.  It only serves to create unrealistic expectations.  Actual precip forecasting requires multi-level and layer analysis.  Same with attempting to discern ratios.

(I'm being mostly facetious here with that Kuchera point, but I do think those maps should be largely ignored.)

At this point, I'm just hoping the models are under-developing surface warmth.  Looking at the NAM, for example, we'd be talking about significant icing.  The kind of ice that threatens power outages and tree damage, among other things.  12-18" of frozen precipitation and almost none of it is snow.  A fairly thick warm layer from 700-850 for most of the duration.  Maybe that dryslotting could help cut back precip totals, as well, but pretty much all the models have us approaching 2" of total precip.

With snow mostly off the table, I'd rather have plain rain.  The lower-res models show more of a sleet bomb.  Pretty rare to get measurably accumulating sleet.

2 hours ago, Mailman said:

Hard to be optimistic with this sort of setup. At least for me, anyhow.

I agree.  The cold air is moving in too late.  If we had that high about 12 hours earlier, we might be in the game, but there's a rather large sleet signature for anything that isn't rain.

The 12Z GFS, for example, shows 10" of sleet or ice.  That's the period where the 850 temps are still above freezing.  The GFS might be 3-6" of snow on the backend.  Big IF, though, and the GFS is the absolute best show for us right now.  Every other model is less generous.

The look at 500H isn't one of a "big snowstorm," either.  The trough alignment is awful.

I think our best hope is this system resets the trough for energy behind it giving us a better shot at snow.  The GFS tries to show this with a ball of energy on Monday, but even right now I'd say it's not quite right.  Goes negative too soon.  Won't analyze it further, though, because we have to wait for this FROPA to go through.

The GFS at the end of the run is pure "Goofus" territory.  A 36-hour ice storm for VA, NC, and SC.

That glorified frontal passage on Friday looks "meh" to me right now.  The setup doesn't typically result in deep snow drifts.  We'll see if anything changes.

It looked like the heavier bands really struggled to make it across the Delaware, for the most part.  My mom's place in Hatboro has like 4-6" but evidently it's quite windy and the light, powdery snow has been blown around easily.

With all these NS coastals and La Ninas, it might be time to get a shore place as a snow cabin.