psuhoffman

It was giving me 8” along the PA line yesterday. Trend.

No this setup is bleeding the wrong way. Has been for the last several days honestly but somehow the gfs continued to amplify the h5 way more then all other guidance anyways. But the trough in front is slowing down more and more, that tpv in Canada is diving south more each run and the combination is compressing the flow a lot more. Frankly had the h5 flow looked the way it does now when I got excited 10 days ago I probably wouldn’t have. Imo the bigger failure is the wave Monday. The progression sped up. That wave is happening during our best window wrt the Rex block and trough retrogression. But frankly the pathetic lack of cold F’d that up. No nice boundary for the wave to focus along, and that’s hey because it’s a surface driven not upper level wave. So it’s washing out and we weren’t even cold enough anyways if it hadn’t to maintain heavy snow. But simply from a pattern progression that was our best shot to get a simple overrunning snow in DC. The timing has changed for the next wave. The trough amplifies too much off the east coast and the ridge stops retrograding behind it. The wave after has a better chance to amplify but by then what pathetically little cold there is has eroded even more since the polar source is cut off. Imo the root of the fail was we had 5 days of epo ridge that opened a direct air feed off the Arctic straight down into southern Canada and the northern US...but that air quickly modified and mixed to become just an average blah airmass. That limited the potential of EVERY discreet threat within the blocking window. Created the double bind. Less potential energy from a weaker boundary. Made us need more suppression to stay cold. But less likely to get amplified waves. It’s not 100% over. Weirder things have happened. But I’m past the point of expecting it.

If this fails the lingering of the early week system which decreases the spacing and prevents ridging from really going up behind it is probably the biggest culprit. It’s the biggest change in the overall pattern from when I looked at it a week ago and really like it. The spacing isn’t as good now. Of course as the system approaches we are barely on the cold side and temps crash as the coastal forms...so whose to say had ridging gone up more this doesn’t cut and jump to the coast too far north like a lot of the gefs members that rained on us the other day. Our “win zone” with every storm is so narrow with the current temperature profile.

Another run that’s close enough not to give up. If it’s going to make a move my guess is we start to see it in the next 24 hours.

....falls apart just as it gets to us. I want off this loop

Storm after the storm....(ducks and runs)

The bombing Atlantic low combined with the blocking suppressed attempts to ridge out in the east. I’m still skeptical we get a big snow threat in the Feb 4-10 window but I could see some mix/icy scenarios and that look towards mid February is potentially very good.

Geps as predicted lost that weird split wave look. Back to looking like other guidance. It’s south of the gefs and significantly weaker though. But at least it’s back to the right progression. Targets central VA.

Stop judging runs by snow maps. Cmc was an improvement.

@Ralph Wiggum dug this up...that gfs track and intensity was pretty identical to a previous storm with similar strong blocking. This doesn’t have the same upside because it’s moving faster and doesn’t have the same stj juice but this gives an idea of what the precip representation for a storm of that amplitude and that track should look like. Some differences. The primary was a little stronger to the west initially and after that point above the Feb 2010 storm gained SLIGHTY more latitude but by then it was occluding and the precip was sinking southeast anyways. I would obviously scale back the qpf a lot here and I would shift the northern fringe south maybe 20 miles. But just saying if that gfs track and intensity was correct the results into southern PA would be a lot better. But there would be a brick wall somewhere not far north of Philly.

Typical model error. You know how this works. There is never that slow gradual tapering like that. The guidance never sees that enhanced lift area on the north fringe banked up against the confluence to the north. Happens time and again. If this run was correct wrt surface and h5 track and intensity this would be the real result. Somewhere near that red like would be a sharp cutoff with south of that line getting more then what is depicted there and closer to the Max down in VA.

here we go again down the next rabbit hole. Why not. So this time the TPV is actually on our side and the coldest air in the N Hemisphere is in N America. -NAO. WPO ridge. Cooler SSTs in Feb. Ok might as well try EVERY possible variation of a good pattern just to prove we’re fooked no matter what lol

Don’t ask questions you won’t like the answer too.

If we’re really gonna do this...the tpv is in a better spot on the NAM then the gfs even. It’s south but west. Get that far enough west and it could end up pulling this north more. But that’s playing with fire (literally with our base state) so let’s not go there. The h5 is more amplified but it’s also a bit spread out with a southern and northern max. That’s not so good. I wouldn’t worry about the surface wave escaping that’s likely 84 hour NAM foolishness. Besides the primary will amplify in the TN valley in response to the upper feature then the secondary will form in response to that. Even if the initial wave escapes it might not matter.

My thoughts on the 84 hour NAM are that it’s the 84 hour Nam.

I remember at PSU in the late 90s when we had model diagnostic discussions in the weather station with Jon Nese and he didn’t trust that “new ETA model” and relied on the NGM. Then twice in a row the ETA schooled him/it and he changed his tune lol. Now I feel super old.

I was 90% snow in that event and got 10”. The bigger problem was the huge dryslot that punched all the way to central PA. But that was a result of a warm layer in the mid levels killing lift so it’s all related. Your points are correct though in general.

Let’s avoid the cause debate. It gets ugly and no one is changing anyone’s mind because nowadays everyone just dismisses things they don’t agree with anyways. So why risk upsetting people and killing relationships on here. But we have thermometers in lots of places and they aren’t all urban. We can confirm it’s getting warmer and it’s not all a result of the UHI. We don’t have to debate why or whose fault it is to talk about the effects on the weather which is what we’re all here for. The politics can go somewhere else.

Careful we’re slipping close to the part of the discussion I said we’re NOT having. But I have looked at the data and so I’ll simply answer from a purely numbers pov. Yes the UHI has made the heating and corresponding degradation of snowfall even more pronounced in urban recording stations. So yes urban centers are ahead of the curve. But non urban recording stations are warming also just not as fast. Now snowfall is tricky. Here seems to be the rub...because big ticket events due to increased potential energy due to warming, places north of a certain line or at high enough elevation are actually seeing their snowfall increase a bit but their variance also is going up. More big years and more duds. The average ends up a slight net increase. We (you and I) are literally right at the edge of that zone. Looking at coop data back to the 1800s our mean snowfall is actually up about 2” and our frequency of 10”+ events is way up but the chances of a sub 30” and sub 20” winter is also increasing. We’re getting more extremes. Places south of us without elevation are on the losing side of this equation. The slightly more frequent big storms are not offsetting the loss of snow in marginal setups. That’s logical since more of their snow was marginal temp wise to begin with. And that trend is true is non urban data points also but yes it’s more extreme in the UHI.

We could just move. God willing I’ll be in Colorado or New England ski country someday and not stressing model runs to get snow. I’ll still always do this...but it’s less stressful when you know even if this one misses there will be another and it will snow.

E/E rule?

Don’t do it y’all. The NAM always has that one run to get you excited just to make the fail hurt worse. I Don’t begrudge it, that’s the whole reason for its existence.

I noticed the same thing with the Brazilian But at least it looks good in a bikini

In 130 years DCs mean snowfall has gone from ~22” to ~14” in a very steady rate of decline. This (the fact it’s warning and snowing less) doesn’t seem debatable Imo. The cause may be but we’re not getting into THAT!

This is an anecdotal observation...I’ve not done an unbiased study or anything to confirm, but over the last few years I’ve found the geps to be unhelpful with medium range synoptic details. Often it will trend one way then jump back the next. Often when it differs from the op (in situations where the cmc op is in line with other guidance) the geps caves to the op. It just did that with the last 2 storms actually. Showed something vastly different then the operational and caved to the operational. So when the geps shows something “weird” not in line with the op OR other guidance I’ve learned to just toss it.