ORH_wxman

We had White Tday and White Xmas in 2002....good double whammy there. 1990s were kind of shitty, but 1995 was great. Cold and snowy all December pretty much. 1992 had the leftovers of the Dec 11-12, 1992 storm over the interior....it got a bit glacial because we had a cutter about a week before Xmas, but it wasn't enough to melt it out. 1991 had decent snow cover too...Dec '91 was actually not bad over the interior....and then winter went to total shit after that. 1993 was saved by a band of SN- that dropped an inch overnight 24th into 25th after we lost our snowpack from a grinch storm on 12/23. 1994 was a disaster, 1996 got wiped clean by epic Xmas Eve grinch storm....1997 of course was the infamous 12/23/97 bust that dumped a ton of snow....'98 and '99 were dogshit but '98 did give a white Xmas to far SE areas....the Cape had like 6-10". I think the cutoff was just south of BOS.

The lead TPV lobe continues to trend eastward (it's doing it again on the 18z NAM as I type).....it will move with perfect precision to ruin any interesting wind component, but not enough for any front end thump.

Somehow Leo got his weenie tag grandfathered in or something.

Seems like a lot of destructive interference on that look. There is a temp ridge spike out west on 12/26 though, so not impossible to try and sneak a system in there, but it's unlikely.

Some of the biggest errors I see in the CC discussions are trying to disentangle underlying longterm anthropogenic climate warming from natural variability over shorter time spans. The northern plains to northern Rockies have a cooling trend in winter since the late 1990s. Does that mean climate change is causing it to be colder there in winter? No of course not. It's natural variability there temporarily overriding the underlying warming trend. Same thing can happen in reverse....somewhere can warm faster than what CC is responsible for, but usually that is natural variability working in the same direction as CC. However, in the latter case, I usually see it all assigned to CC because it's easier to explain that way. The other big errors are often in attribution studies. These are studies that try and show if certain types of events will become more frequent or less frequent in the future. The error most often seen is that the study may have like 4 or 5 emissions scenarios, and the one that makes headlines is the RCP 8.5 scenario which is unrealistic to begin with. But that scenario has the most drastic changes so it makes for a good story. Other times, I've also seen weird stuff where severe arctic outbreaks are blamed on CC like in 2014 in the midwest....when empirical evidence shows that arctic outbreaks are becoming less common.

I ran the frequency of snow events by decade for ORH by size....and it's pretty noisy. The conclusion is that 12"+ def increasing, nickels are decreasing (but again very noisy) and moderate events slowly increasing. The 1980s were a shit decade for all types of snow.....

Agreed

They'll get rain, but the amount of residence time of the warm sector could be minimal up there if the 12z trends keep up....so hopefully the pack doesn't take a big hit.

You aren't a credible arbiter of pattern recognition though....

More and more CAD showing up on these 12z runs....prob will start reducing the wind risk over the interior (esp like CNE) if that keeps up.

12z guidance so far is pushing more and more of the TPV lobe eastward.....it's not going to help most of us, but it will help reduce the amount of time the warm sector parks in New England....so it may be beneficial for ski areas.

Here's ORH top December snowfalls.....the Hudson Bay block is pretty consistent across most months. It's one reason I really liked the 12/16 look at one point when it was pushing the whole ULL under us with the big Hudson Block in place.

That's also a composite of all months....December is going to look different because wavelengths are a bit different....I'll see what the top December snowfall composite looks like

Several of the top NESIS storms missed us or just gave us a glancing blow. That looks idealized for the Mid-Atlantic. That looks pretty suppressive for New England as a whole....maybe not bad for far southern areas. When I redo the composite for top snowfalls at ORH, it def looks a little different.

That looks too wrapped up that far west to be a KU....ULL nuclear over Detroit isn't great. On a hemispheric scale, you can see though how close we were to a great look. The longwave pattern there is excellent....but there are never any guarantees to success in favorable longwave patterns.

Maybe we can all lose power for a week so that we don't have to see the model solutions until early January.

The warmer winters from those years had really crappy patterns for the most part just like our warmest winters now have crappy patterns for the most part. Analogs are very useful. Just don’t take the temps verbatim…which you shouldn’t do anyway in analog forecasting. The anti-analog crowd has never explained how they know what a good or crappy pattern looks like…and if they cannot explain that, then they have zero ability to give an informed opinion.

Yeah it’s too early to punt first half of Jan. Post-Xmas looks useless though for now. Most guidance has AK pig retrograding back toward Aleutians in early January which matches some of the tropical stuff so it’s possible we get into a good pattern sometime in early January, but obviously no guarantees.

Ukie is actually a decent front ender…esp for CNE/NNE

He’s trying too hard even for his low-bar standards. Unless he’s just exponentially more ignorant than I gave him credit for back when he was nor’easter27.

Watch this feature (TPV)…we want it as Far East or southeast as possible…right now it kind of stalls in Ontario and then lifts back north and north west and allows the shortwave behind it to cut up to our west

Analogs are really to be used as probabilistic tools. I know most people just have their eyes glaze over at that term but it’s unfortunately the reality of long range forecasting. Check Jan 1969 and Feb 1969. The patterns aren’t all THAT different but the snowfall and sensible wx was extremely different….and those were one month apart…nevermind years or decades. Think of it I’m these terms: 1. pattern is really good…so we have a 40% chance of a decent snow event in the next 7-10 days 2. pattern is kind of mediocre/average. We have a 25% chance of a decent snow event in the next 7-10 days 3. pattern sucks donkey balls. We have prob a 10% chance at a decent snow event over the next 7-10 days. There are no guarantees in any of those statements. But you’d much rather have the higher percentage pattern. But if two shortwaves don’t phase properly or there’s a random over-phase and we get a cutter, then it still won’t work out. Doesn’t really change anything empirical about the longwave pattern either.

RGEM looks like its reverting back to parakeets if extrapolated. So we prob aren’t going to see the GGEM come east against like 00z did. OTOH, the Icon looks more interesting. Def more confluence up north this run but it’s still not quite enough.

A 30 hour snowfall will need to have a minimum of 2 measurements even if you are doing it the lazy way. You must measure at least once in a 24 hour period. 30 hour snowfalls aren’t that common anyway unless you live in upslope land.

If we didn’t use analogs, we’d be forecasting like voo-doo methods back in the early 20th century. The reason we know a western ridge is good for us is because historical analogs tell us how many large storms we got from western ridges. Are western ridges supposed to no longer good for snowfall because it was colder by 0.7C in 1975 than it is now? You can easily adjust for that too in a long range forecast….”normally I’d go -2 to -4 temperature departures but maybe I’ll go -1 to -3 instead because of underlying warming.”