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Midweek Storm DISCO


DomNH

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Wasn't the Euro last night like a 6-8'' snowbomb before changing to rain N of Rt. 2?

Yeah, the euro had a nice snowbomb north of rt 2, but it almost had an inv trough like signature. In had the main low way east of the benchmark, but a small secondary kept trying to form near the Cape.

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Scott just scolded me for not putting this in this disco - haha

anyway...Folks, if things break right we end up with a warning criteria icing event (who would have thunk during a La Nina...) on Tuesday+, followed by a larger mass field differential event on D7-9.

Don't count on appropriate boundary layer resolution ioutside of 60 hours, even by the superior resolved NAM. I have seen this many times in the past for intervals 60 to 84 hours, warm run, warm run, warm run, a little cooler, cold at 24-36. High pressure north is pinning polar-arctic hybrid air mass in place, and the great damming signature in the PP up and down the eastern seaboard at hour 60 is telling that there is probably more resistance there than would be normally expected for an eastward retreating high. Such that, most importantly a weak gradient low coming up underneath LI would definitely excite more ageostrophic drain than the even the NAM is seeing at this time range. Also doing so over anomalously large snow pack rim to rim from CAR to ALB. No guidance I saw off the 00z cycle was taking this thing truly west of SNE - though some were non-commital with a secondary appeal. I see the 31F isotherm lining up from NW CT to BED, with pockets of 32 strugglers with static ice from just N of HFD to NW RI, to the southwest 'burbs of BOS. Probably starts as snow everywhere before the character of the event flips to this description - even on the coast, but they go from snow to cold rain inside of I-95 down to PVD.

I also leave room open here for more discerned coastal cyclogenesis should the S/W coming on-board over the WC around 60 hours be somewhat weaker, thus allowing the lead (Tuesday dynamics) to be less damped. As far as total impact, it depends on the QPF but the Euro was pounding 1+" liq equiv, and now the 12z NAM is as well. Also , the Euro last night tried to commit more fully to secondary, and also has a nose of damming in the PP extending SW from NW GOM to ALBish, which signals that you'd be unwise to be 850 thermal field reliant for your surface p-type. [Edit: Oh yea, and *IF" said 60 hour S/W coming in out W is substantially stronger, the lead is less impactive and we're then monitoring a Miller A potential - not yet modeled)

I have less issue now with a more surpressed solution than was depicted earlier yesterday(s) because the overnight recalculations at CDC and CPC have the NAO slipping negative in increments beginning presently and leading to next weekend... Which leads nicely to the possible biggie out there in time.

The PNA is concertedly nearing +1 SD in the well-clustered 21 member GFS for multiple nightly EOFs at CPC, now the CDC is at least picking up on this in the initializaitons (showing a clear negative bias in the D4-7 lead predicitons). Taking these into account, we have strong PNA with negative differentiating NAO. Do not discount that deep amplification into a quasi-closed N stream low in the vicinity. It would not take much of a nudge to have all that evolve similarly to the KU even a few weeks ago. Stay tuned...

One last thing, I am also noticing a subtle trend the retard the displacement east of the polar high up N leading into mid week..

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And a little advisory event with the follow up low past hr 108..lol.

There's actually a tussle in the large scale flow regarding which S/W is dominant. They are about equal, though one coming on board out west is slightly stronger at hour 60ish. If that comes on weaker, than the lead is less damped and may get more defined with coastal cyclogen - that would change the landscape of this from ice to more of snow-rain-snow deal. If it comes in stronger, than the lead probably become less impactive altogether and then that 2nd one goes nuts.

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LOL, John....it just makes it easier for peeps to look for disco.

Anyways...good points John. It does seem like a signal for a good icing event in the interior...perhaps more sn/ip if coastal cyclogenesis can get going quicker..such as the gfs..and even the euro. The euro actually had an inv trough like signature...not far from the NAM depiction.

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I know this is a mid week thread ... But, there is a nice right entrance jet max rapidly approaching the area with some pretty impressive dynamic lift taking place from ALB-BUF... There are some moderate low visibility snow bursts taking place in that area, in a general light snow envelopment... This will translate across SNE later this afternoon and evening. 1-3 signaled by the GGEM 3 days ago is spot on. This type of cold air mass can lower visibility more than rad returns would suggest.

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The new GFS has us on (or just north) of the 0C 85H line much of that event with .75" qpf. I guess we are looking at snow..maybe goinng to sleet....or fluctuating. What is notable is how cold it keeps the low levels with the ageo flow staying more north probably due to that coastal wave. That is saying something when the GFS really hits that...a model not great with low level cold.

12z GFS still mild with a benchmark track. At hr 85. 0C 850 line along the ma/ct border extending ese.

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I know this is a mid week thread ... But, there is a nice right entrance jet max rapidly approaching the area with some pretty impressive dynamic lift taking place from ALB-BUF... There are some moderate low visibility snow bursts taking place in that area, in a general light snow envelopment... This will translate across SNE later this afternoon and evening. 1-3 signaled by the GGEM 3 days ago is spot on. This type of cold air mass can lower visibility more than rad returns would suggest.

Lets try to get a little more srly flow to advect some moisture in here. This could be one of those events that gives the Cape a nice 2" fluff.

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Yeah, the more I look at this I think colder solutions should be favored. The flow in the deep south and over Miami is highly highly compressible right now and leading prior to the lead S/W arriving to 100W. 576dm over MIA with nearly 400 naut miles between the geopotential isopleths, with 30KTs only of balanced geostrophic wind in the medium means that any S/W of even weaker caliber will have limit problems conserving strength (dynamics) upon passing through. The lead S/W turns negatively tilted down in GA, while we have nascent BL viscosity particularly in the N MA to New England...

Eh, that is not a warm result for us.

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Yeah, the more I look at this I think colder solutions should be favored. The flow in the deep south and over Miami is highly highly compressible right now and leading prior to the lead S/W arriving to 100W. 576dm over MIA with nearly 400 naut miles between the geopotential isopleths, with 30KTs only of balanced geostrophic wind in the medium means that any S/W of even weaker caliber will have limit problems conserving strength (dynamics) upon passing through. The lead S/W turns negatively tilted down in GA, while we have nascent BL viscosity particularly in the N MA to New England...

Eh, that is not a warm result for us.

It would be great if I could add even a few inches before a flip to ip or cold rain. I'll consider it a win if that happens. The trend over the last 24 hours, has been to really hit the southern stream vort hard.

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Actually, the anal analysis is technically a phase on this 12z GFS run... The S/W coming on board as of 12z this morning up over the Pac NW, phases with the current S/W over Old Mexico when the two marry over the N Gulf. That's trended heavily toward more coastal commitment on this run, which as Scott noted would pull back on ice and suggest more S/IP for the interior.

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Very informative discussion, Tip. Looking more and more like mostly/all frozen for inland NNE.

One minor quibble - the excerpt below:

Also doing so over anomalously large snow pack rim to rim from CAR to ALB.

That's undoubtedly true for the west half of that span, but CAR currently has a pitiful (for them in mid-Jan) 2", and the 8" IMBY in the W.Maine foothills ranks 9th of 12 yrs for 1/14 snow depth. Except for some of the higher mts, Maine north of Bethel/BGR/HUL is below normal for snowpack.

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Very informative discussion, Tip. Looking more and more like mostly/all frozen for inland NNE.

One minor quibble - the excerpt below:

Also doing so over anomalously large snow pack rim to rim from CAR to ALB.

That's undoubtedly true for the west half of that span, but CAR currently has a pitiful (for them in mid-Jan) 2", and the 8" IMBY in the W.Maine foothills ranks 9th of 12 yrs for 1/14 snow depth. Except for some of the higher mts, Maine north of Bethel/BGR/HUL is below normal for snowpack.

That's very interesting actually. I was discussing this with another Met by phone last night that it seems the behavior of last years layout is psueo playing out farther up the coast this year. Last year, SNE seemed to miss the bigger systems with at time comparatively lower snow depths compared to the MA.

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these are windy white-outy snow squalls folks -

post-904-0-11863300-1295110024.jpg

And this banded stuff extends N into southern Ontario, as well as E to near ALB and it is all charging E.

scott's gonna make you move it ...lol

we need a thread for today's "non threat" lol. it looks promising on the radar ...REV KEV Can you start a thread on today's stuff or better yet BOB!

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