Typhoon Tip

Me old favorite FOUS grid ( NAM) has an impressive .5+" liq equiv in one 6-hrly period, between 48 and 54 hours at Logan, and all temperature sigma levels are -1C ( 980, 900, 800 mb). There may or may not be an elevated warm layer; if not, that's a wall of S with at least an hour or two embedded where approaches S+. Gotta figure west of the city out along say Rt 9 and the Pike out to Springfield would pound for a time given these grid interpretations.

Looks like what the generalized perspective offered on this last Saturday. Deposited all interpretive peregrinations since … still a 2-4 or 3-5 scenario. That should be advisory in headline scale. However WAA bursts can sometimes overperform …

I’ve been mentioning this but in a sense the speed of this thing moving through appears to outpace the drag/‘scour out’ rate. That said … if a meso or preform beta low forms and moves under that would then put the kabosh on warming the interior before it’s all in the books

No problem from me. I said 2 weeks ago when this started looking encouraging via the various methodologies ... that we are being enabled in our hiding from the truth - so to speak. 'All winter ... ' 'everything's the way it should be'. yeah, riiight. Despite anyone's personal belief, the objective reality is that CC has claimed enough of our tendency vectors, that as soon as we close down the cold source into mid latitude N/A the NE Pacific circulation mode - I even annotated charts to show, "...As long as this feature is there, winter is within reach" - it's perpetual autumn. While it is there, it is easy for people to either not be aware, forget, or just flat out deny that we blow torch ( relative to normal...) at a higher pitch than prior climate generation, and do so more and more dependably. And it shows... Those weirdly extraordinary heat bursts in February and March since the earlier 2000's, taking place regardless of antecedent established long and short telecon correlation biases, ... are a part of that. etc etc. Just as much as the "cold" January turns out to not even be appreciably below normal across the total subforum - somewhere in that reality is a cold pattern that can't quite get it done. Oblivious though... So, hey ... as long as we're dumping -25 C 850 mb plumes through NW Canada and spreading them out to 45 N, we can bury our head in the winter sand of it all, like a cat hiding their head in a brown paper bag while their tail and ass sticks out thinking that is their world and they are all safe. LOL ...seriously, my cat used to do that when it gets scared. It's pretty funny

The weekend is less clear for the southern 1/3 to 1/2 of this sub-forum. Yesterday it was more clear; that clarity has been disrupted overnight by a trend to push the low track farther N. It's right on the door stop at this point from being a full breach warm intrusion for MA/CT/RI; but for now, we we're narrowly escaping with minoring mix ending as liquid rain S of VT/NH. In fact, with 552 dm thickness, and initially a WNW flow ahead of the cold front Sunday morning that I'm seeing in the Euro and GGEM... if the sun comes out in that region there's going to be awesome rise/appeal to the air mass for several hours as it is. Up there you'd have to correct this - by the way - weak to middling system more so before this becomes a problem for you. We'll see if the things settle back S -

Notice how that took place in a relaxed deep tropospheric, lateral gradient in the non-hydrostatic heights too - there's a 975 mb low under that. We can't seem to get this over on our side of the hemisphere in recent years. If/when it is cold enough for winter events, the cold itself seems it cannot evolve to middle latitudes without compression/velocity saturation. Cold seems to always arrive with base-line negative interference. What we need is for more of the gradient to be in the hydrostatic heights (the "thickness"). Not the other way around...

Again … very similar in size and duration as this event on the 6th.

Ha... that's an interesting thought. I was haven't considered them in aggregate. I've see that only once around here, though ...way back in the late 1980s. There was a nondescript icing event and then it got cold. I remember still hearing that crinkling sound when the wind would blow through the trees like 4 days later. Then, there was a nor'easter brewing and there was concern for wind and snow loading on the ice but it didn't actually become an issue.

Unfortunately ..this event isn't likely to produce much of either. 5" of snow is likely tops. .35" glazing where/if all ice.

That's a nice comparison to 1994 ... I think we must've talked about it before as memory serves, but one of those systems was an IP carpet bombing while heavy blowing and drifting OEs banding was pummeling underneath. Strange. It even came out as far as Acton where I was living then, and I remember at one point we had 1/4 mi vis from breezy 20:1 shattering snow, while the sound of hail on the car tops. I'd never seen that combination of ptypes and haven't really since.

The Euro's 12z, 120 hour layout is right out of a mid March winter storm set up... HUGE thickness dipole across the eastward extension of the polar boundary - March's and even latter February's this gets to be interesting. Here we are signaling why storms at that time of year can once in a while, massively over-achieve. The only limitation to this one is likely to be the attending S/W is probably being attenuated for moving through a very compressed field, otherwise, in principle, that could be a very dangerous set up. As is, it probably means that it would likely over produce where ever it is precipitating as the storm formulates through that gradient pathway -

Not quite as cold as the GFS but damn close ... Close enough that I suspect we could be coalescing a consensus. GFS has moved maybe 70 total miles in 3 days of guidance. The Euro's getting away with not moving as much as it's just cooling everything off - reluctantly getting to a similar result. The surface PP in the Euro solution looks more like it's bending around BL cold forcing than "admitting" the GFS is right about a low down there... haha sumpin' li' ghat

agreed ... I add it's also on the table, too.

Scott already mentioned it but here's an example of how to get a duration event in a fast flow... you can see the elongation here is making up spatially for the rate of motion being so fast. Heh.. another way to look at it. D= R*T ... when the D is very large ( like ^ ), then the time ( duration of the event in this context...) becomes large. 100 MI/40 mph versus 1,000 mi/ 40mph

I'm at 15.5" for the season. I think my seasonal average is 58 here ? Will? someone knows...

yeah, can't disagree in principle. It's just physically not happening when the flow is so fast. Big systems require big curvature, which speed fights curvature in the purely Newtonian sense. It just exceeds the Corriolis parameter and blah blah blah you know what I mean but getting out there in time, there is signs of a relaxed EPO with a rising PNA ...sort of a reversal... It's vague for the time being but if it gets more coherent... probably favors more of a larger body event. you're right about the method for duration in a fast flow. You just need to get sort of luckily positioned in a dynamics series, and it becomes like 36 hours with a couple of waves going by just underneath. it's pretty much the only way to do it when a balloon ride competes with air line traffic velocity patterns. j/k

Yeah, not sure I agree tho - I get the excitement but the compression/speed is a huge limiting factor to big dawg constructed events. But that should be okay.. you load up enough nickle and dimes and have them succeed, you're getting there in the aggregate - and in terms of entertainment value it's probably better because of the constant dopamine heh. seriously though -

I know ... that solution would go a considerable distance toward mending broken hearts -

Yeah, the solution didn't really evolve S .. but either way, it's not been the snowier of guidance. no worries for snow mongering, considering the product and range -

Yeah, the problem with big events is that it's like cashing out an IPE bank account - "P" meaning planetary, so integrated planetary energy. There's a kind of "extratropical IPE budget" in a sense. You can be peppered by nickle and dimes, or use up the IPE in a go. That's why when you look at the days and sometimes weeks following historic big dawgs, you're typically waiting a while and enter a kind of post mortem dullard state of inactivity that protracts. So, "Big events" are tied to larger scaled mass field perturbations. Those don't come around that often, which means ... big events don't come around that often. Dated material at this point and getting old school, but that's really what the Archembault master's thesis was really useful for back in the day: exposing that, statistically. It used to get referenced quite a lot more frequently ... one can google it and read the paper and not get it because no one in society knows how to read and objectively intellectualize content any more ... but it is still out there. HAHA j/k (does seem like we're nearing a "stupifying idiot-zombie" crisis at a broadly scoped societal scale, though) It really can be described in a simple sentence. The atmospheric pattern remains the same until acted upon by a force that is sufficient to disturb the status quo. Borrowed from Newton's First Law of Mechanics? absolutely . For atmospheric phenomenon, the disruption is defined by a changing PNA, or EPO, or AO, or WPO ...or NAO, etc etc.. That's why we discuss d(PNA) and not PNA. Because the former is ( d = delta = "changing" ). You look at the PNA and says -1.00, then three days later it says -.5 ... that is a +d(PNA), or rising value. Rising PNA uuusuually = d-drip chances. Now, just imagine all these indices that are defined ( and in reality ...there are infinite domain spaces; there's no real boundary, but some regions do show better correlation in the statistics so boundaries are determined that will always be estimates) having their own changing modes. yeah ...

NAM appears to be coming in S ...but it's only out to 60 hours, and the model is piece of rhino dung at this range ... just sayin'

My fav 00z operational model run was the GGEM ... not for any predictive value ( of course ..haha ) but just the cinema. Given a small modulation, that was 3 events in a really beautiful temporal distribution - about every 3 days on the button. It's been a long, long time since we had a steady diet of nickle and dime potentials in an ensemble line modeled set-up. You could be enjoying a nice low end 6" warning event, and a half day later you're already in a winter storm watch. This happened in 2015, 1995, 1994 ... 2008 ( I think..) it's been that long as far as I recall.

Seemed like we bottomed out in temperatures during climo cold week, too - check that... but at least around here... I had multiple nights below 0 surrounding the 24th of January, with highs at 20 or less. It's been chilly overall..but that was kind of an embedded nadir

This event - to me - looks like it has the same circumstance of uncertainty at this range, that plagued ( and still does...) this D6 system in the foreground. It's evolving along a compressed/very fast flow. Excessive needle threading requires precision that's going to be hard to come by at a D5 or 6 lead... For now, the tracks seem to be N of the triple point lat/lon nexus we see for the 6th. All guidance I've seen from 00z have a low up NW of ALB, But like the 6th, the speed of the approaching wave/storm mechanics is so fast it outpaces the lower tropospheric ability to modulate/"scour out" the cold. This leads to the IB pulse snows that then go to pellets S and perhaps staying S N - circumstantially, this latter obviously favoring central and NNE if the track stays - not sure we can count on that, however. There seems to be a bit of hint to more secondary in the EPS and GEFs..which may be an indicator for a future correction but that's purely supposition for now.

It may snow pretty hard for a couple hours in NE Mass in that Euro solution. Even with Pivotal's 6-hourly cinema speed, it looks to me like there's a pretty good isentropic burst between hours 84 and 90, which probably means blossoms intensity on the ground up there. I'm not looking at any interpretive MOS-related graphics...just noting the QPF distribution/surge from Brian's to E of Boston axis that suddenly appears at hour 90. In fact, all the guidance I've seen now are doing something similar. Its a matter of when in the total system translation. The UKMET has the "in like a wall" look at 87 over western zone. Kind of like it's flurries to 1/4 mi vis in 5 to 10 minutes. GGEM is pure sleet event - bit of an operational outlier but possible... The GFS brings those 2.24" diameter jagged-edged cotton ball thumpers before flipping the Pike to drizzle.