Typhoon Tip

Looks on rad as though the low must be rollin' up the Hudson/SE NY ... now N of NYC.. looks like 4" inches here, ... but that's an estimate. I unfortunately didn't get a measurement before this flipped to rain at around 5 or so. Not sure if there was an IP interval before that happens. We'd been mild and rising ...now mid 40s, so whatever fell is soft oatmeal at this point.

Talked about that all day yesterday and the 00z runs did little to help unfortunately... wave space contentions plague the late mid/ext range, muddling/obscuring whatever signals are out there. The best fit is still the 24th... but, the 22nd is still in play. There is an ambrosia of different aspects that leap out for me: -- typically in a two+ wave contention scenario out in time, one or the other will emerge as the main player in future cycles. This is more complex than just that, because the 22nd has different causal roots than a would-be 24th. -- the evolution of the flow from south the Alaska to the Maritime of Canada evolves to be gradient rich. The compression that implies is not allowing anything to manifest from the NP-OV-MA/NE-Maritime of Canada, per the 00z cycle, in either of the operational Euro/GFS. I am not sure that is right ... it may be. This is a separate matter to the first bullet above. It represents a large scale vs smaller scale, negative interference ... a commonly found attribute in recent winters frankly but won't get into that - ... I have found that events can "hide" in the hurried maelstrom of those types of latter mid range flow constructs, but start emerging over future cycles as fast movers. -- yet, I will add another aspect... Those are top down, the EPS, GEFS and GEPS means, and they mature coherent +PNA --> +PNAP flow structure, a modulation that typically precedes storm genesis over eastern N/A. The reason I've been leaning more 24th is that timing above lands on 23rd, and the next day in all these, that trough subtending through the Lakes amplifies pretty smartly down stream of that obvious +PNA flex. The scaffold of the hemisphere is thus favoring the 24th - however, there are small systems that can materialize that are not anchored in such larger scaled modalities. The 00z Euro's 22nd is one such suggestion... it more than less squirts out ahead of that larger cog work. Those are trickier to gauge out in time, particularly in fast flows that are compressing below an elephant's ass of an SPV.

Snow sky set to a butterscotch glow over a town immersed in cold. Moon no longer visible … feels it. Not surprising the late cool trend/models - matches the obs I was commenting on earlier

Can y’all include location

Oh so it’s saying we all get 42” ?

The short answer is no… It’s not usual to go from 22 with a dewpoint of 10 to above freezing and rain. It doesn’t make it impossible though … The dew points are very low north of the pike here in the interior… When that saturates it’s going to hygroscopically cool the surface layer considerably … I’m also noticing that the surface synopsis right now it looks like the high-pressure is a little bit more resistant to leave than some of these global models had suggested - …just a little but maybe the Euro was onto something? We’ll see … But the storm is moving so fast I think that these factors may last long enough to get us under the occlusion boundary i.e. shut off before we get a huge huge rain out of this - I’m wondering now … there was a storm similar to this back in 1986 I wanna say in late January early February was forecast to be a small amount of snow going over to rain from a coastal storm set to cut up across the area and what actually happened is the models underestimated the cold … trip point squeezed under as it snowed very heavy for about four hours and we amassed 8 to 10 inches and then it flipped drizzle and ended. Of course this is not 1987 and the tech is a lot more sophisticated… But given those obs above together with the speed of this thing one may to wonder

Might be worth mentioning, .. the hours don't line up perfectly ( staggered by 1:30 ~ ) but the 22:27 analysis by WPC gives the impression that the GFS may have been slightly too aggressive in lowering surface pressure over eastern/central NE... Their analysis is 22:27, featuring 2 mb > than the GFS' 18z fix for 00z over western Ma. Looks also as though the center of the high pressure is modeled east of where it is now of 00z. Don't have any sfc source that land right on the top of the hour unfortunately..

I threw up an obs thread to save this one from becoming 370 pages deep LOL

19/7 Ayer, Ma. near calm wind. Moon dim vis/halo

Is it worth it to have a now-cast/Obs thread ? 19/7 ... near full moon dimly visible/halo Fwiw, the 22:27 analysis by WPC gives the impression that the GFS was slightly too aggressive in lowering surface pressure over eastern/central NE... That's 1:33 before 00z, which is perfectly comparative, but is close; it was 2 mb lower over western Ma, and had the center of the high considerable farther east of that ob position. Not sure if that's worth the mention...

well ... "confident in an event" ... It may be helpful for these long lead threads to put in bold italics that the goal is to nail down storm at all, when the purpose is for early awareness. Anyway, 512 asked about snow this or rain that, unfortunately ... that's a process of discovery that comes later on. I should also back-peddle on term usage in all honesty. I had "reasonably confident" in mind.

Hang in there ... Feel pretty confident in the 23/24th ... maybe 25, but this thread covers the front side and is entirely relevant. Not sure anyone saw my statement earlier, but having 1/3 (count) of the the total GEF members go from blase to couriering an import coastal from 00z through 12z, on top of a modest numeric +PNA persistence, is usually an omen for activity. I wanted to thread this too, but I was willing to wait on 'signal commitment' to either the 22 OR the 24th, not both. I suspect with the Euro dumping the previous, and it also in turn flexes it SPV to ( unrealistic) depths, is probably like the 'zygote' to modeling solution that relaxes said SPV and instead opens up the OV to less compression - not 100% but that's a likable correction for that source alone. May also be looking at a -AO tail end to winter

I dunno, I think the focus should be later 23 into the 24th... Half the GEF members carry a significant system along/astride the EC in that time range, an ~ 1/3 improvement in count comparing the 00z. Imho, the 12z Euro demos +PNAP over-expression from D5 into 7, a typical bias it does in that time range, such that it may be self-manufacturing unrealistically deep N. Ontario SPV toward later days. Wouldn't shock me if that ends up a bit shallower, while the southern extend of the total trough flow demos a bit more relaxed separation/identity in the OV.

I think Will's pointing out the key metric/wild card ... timing the exact retreat of the high is critical for timing p-type ... and cold resisting in general. It really really depends on that. Trust me... I am not "old" ...by I old enough and have experienced this sort of thing in the past, where synoptic turn around is truly extraordinary leaving one dazed in observance. I've described this in the past, so won't turn too much pen .. but Jan 1994 hosted an event that flipped 9 F, blue tinted snow grainy dawn, to 62 F southerly gales by 9 pm that same evening across SNE. That situation was had 0 high pressure N. The day prior, it did...and it was as stingy arctic air mass. That night, while decoupling and radiating off a snow pack, we zoomed into the single digits, but just above...the synoptic high pressure was quickly rolling out and receding east, leaving that cold at that dawn completely abandoned and exposed. It can happen. You can go from Dead Horse to the Del Marva in 9 hours given the right kind of face smacking. This does offer some +PP curvature ... more so than back whence ( as our virtual perfect pork job example LOL ). How much resistance is really dicey ... obviously some common sense convention knows that the southern half of CT-RI and SE Mass cook first. But the speed of erosion and all that. .. if the higher res models are in fact really belaying the high retreat east, our penchants for fighting off warm in the interior kicks in, in lockstep.

Ha, no by all means - go for it... I just wrote up about this in the Jan/obs thread. Paraphrasing... I feel confident the 20 -25th is an active interval, but there's an intra-modeling tussle with respect to which dates. I'd like a better handle ( personally..) on the 22nd or the 24th, as those are identifiable but are in some wave space contention, before taking ownership of a thread. But, I don't see any harm in having a thread running for interval for its own merit. Sure.

I would thread for that Jan 21 thru 25th period, buuuut ... There are problems that I do not feel brave enough to go ahead with a thread, until I see another couple of cycles ( minimum..) to hopefully offer clarity. I suppose if the title of said thread is, "Watching the 20th - 25th, heightened potential for eastern U.S. " ...and then onward, it only discusses the frame-up from that black-box perspective, okay. We've been onto the 20-25th interval for days, yup. So some operational versions decided to go ahead last night, and formally turn on the d-drip within that time frame. For the record, the GGEM has been toying with this for several cycles, actually. Now with the Euro joining ( ...0z EPS trend notwithstanding um... 972 mb integrating polar-arctic air mass in CCB is almost scary ha!) they focus on the 22nd. Firstly, the previous GGEM was focusing the 23/24th, and is now 22/23... Meanwhile, the Euro is 23rd, by virtue of the fact that it's racing a cyclone past again; so if there is a windy white Euro dawn on the 23rd, the sun set may be visible that afternoon. Said previous 23-24th GGEM solutions were slower moving system characters, that appeared more keyed into a pattern morphology/H.A., implicating a longer duration event. But now this move toward a more 22/23rd Euro event is technically a continuity break. What's to be expected at D7+ Meanwhile, the GFS has neither the 22nd ...nor the 24th. It has vestiges of both, but neither has enough might to overcome the other, so yet again ...mm hm, negative interference is present in the 00z. The 06z has attempted to correct for the latter 24th event. The individual 00z GEF members are about split in which dates to emphasize. Putting all this together ... it seems we are about 50/50 by concept and synoptic recognition/ correction vectoring toward either the 22nd, or 24th... or .. if we want to be fair... it's more like 40/40/20, with the 20 being negative interference limiting. The numerical equivalent of the PNA shows a non-modulating positive regime through D10... I find that interesting, because every model and ens mean there is has a steep NW flow entering the NP leading the time span in question, which then looks to get a goose from some additional western ridge amplitude around D8... I'd like to see a 'hill' in the curve out there. Yesterday, there was...

Then you'll probably do well there... if this (presentation) isn't a lark. I've seen this happen before where the American cluster starts 'flashing' in warm intervals above the 50 hPa sigma level ( ..where they first materialize when real..), only to have them just not take place. ...plus, if it is an SSW that is going to be real and meaningful to present context, it ill will need to actually be a down-welling event, which cannot be ascertained at this very early detection... But Twitter personalities will certainly use it to poke their hornet nest constituency before making that determination, no doubt! ugh But, the 5 and 10 hPa sigma absolutely explode with very high standard deviation warm intrusion, over at the strat-trop monitoring division of CPC. ( https://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/ ) ...I like to use temperature detection as a first look.. But, that's clearly an intrusion event ( antecedent larger scaled planetary wave decay delivering thermal payload ..). The quickness in emergence, and the geometric morphology immediately ensuing, evinces that... And, although there was some excited solar activity since autumn, ...the longer term budget is still very much in a deep minimum, so ozone populations is probably high (enough). Well hell...okay, just looked and it does appear there are modest positive anomalies trapped within the mean PV aoa 100 hPa (ppm). ... one can see those at the same source ... Anyway, the QBO was entering a favorable late summer --> autumn negative phase, which is somewhat correlative with these warming stratosphere events, so... obviously you must be aware of that.. heh. We'll see. It fits.

Seems like the whole world is still in gawk mode over it but I’d like to know some of the geological statistics. Like how does it rank on the scale? Etc. What was the aerosol/plume concentration / assuming … what altitude was it shot to - judging by the satellite pictures it looks like it went all the way to the stratosphere.

I don’t know if it is though… Kinda depends on how many decades one’s suffered or celebrated. For those born later than 1990? This is an unprecedented bad streak. For those born before 1990 it just seems like maybe it’s cyclic. having said that… I do think there’s a problem with the models slowing the flow down too much in the mid range and then having to speed it back up to a reality; problem with gradient and velocity regardless of Enso or Teleconnectors - might be the tip off that there’s something more deeply systemically rooted that’s causing that. Whether that cc or just an emergent problem with these advances that they’ve been turning out with all these new versions – in fact they’re pumping them out too fast for me to trust them sometimes Oh … never mind. Thought you guys were talking about something else.

We may be seeing an onset of SSW before the end of the month. Early heads up

It’s warmer over Logan in the FOUS

That's what the system before this one look like, remember that - we joked because the spread was like a small country

Well I'm not totally serious either.. that's why said 'rant over'

I think you guys are confusing the usefulness of starting a thread for an active interval that host significant event, with whether said interval is in line with whatever it is that gets your rocks off. The active thread now? Looks to verify perfectly.. Jesus - ... the weather forecasting science/art is not here to placate your fantasies, and knowing "when" to launch a report based on whether a threat jives with that nudity is/was never part of its charge or reason for existing. Aside ..if it snows early Monday at all you'll like like an ass Rant over - you may not re-engage in your regularly scheduled programming-

ECMWF is out to get us free-loaders ... haven't seen the EPS since Thursday night as all my poach sites aren't updating LOL ...