Late December miracle early next week!?

[SR Airglow]

Sort of interesting that the warm layers are in totally different places on the GFS and CMC -- on the 0z GFS the warm layer is around 850, while on the 0z GGEM 850 is much colder and it's up around 700-750 that it's warmer. 

[40/70 Benchmark]

The limiting factor for snow south of the pike especially is that the antecedent airmass in the mid levels never gets overly cold. It does north of the pike and especially CNE northward. But the cold becomes shallower the further south you go. There's a pretty tight gradient at about 800mb before the onset of the event over New England.

Still 84h to start time so trends can happen. But this is why right now you are very unlikely to see one of those events that front end thumps SW CT with 7-8".

This doesn't mean no frozen though. Sleet and some icing are a high threat.

Good post, that is what Steve was looking for.

[Ginx snewx]

I already busted on the one in Novie that I thought would get nne.

I am very knowledgeable about my swfe climo but have been presently surprised the last 2. It all depends on how intense that initial thump is. We will get a much better handle on that Sunday. Seen it go both ways where warm air floods in before UVVs take off and seen it dump and wash out warm tongues. Intensity will be key. I believe we had a similar discussion last year which ended as a snowier outcome for even NWNJ.

[HIPPYVALLEY]

The limiting factor for snow south of the pike especially is that the antecedent airmass in the mid levels never gets overly cold. It does north of the pike and especially CNE northward. But the cold becomes shallower the further south you go. There's a pretty tight gradient at about 800mb before the onset of the event over New England.

Still 84h to start time so trends can happen. But this is why right now you are very unlikely to see one of those events that front end thumps SW CT with 7-8".

This doesn't mean no frozen though. Sleet and some icing are a high threat.

 

Outside of some fantasy Christmas wishes after yesterday's 18z runs I would hope nobody was actually expecting that.

[CoastalWx]

The GFS seems disturbingly woeful with 2m temps. No way in hell is it warming above 32 well into SNH with that high as shown verbatim. That is terrible.

[ice1972]

0z GFS is such garbage.....no way it's that warm bro.....

[ORH_wxman]

The GFS seems disturbingly woeful with 2m temps. No way in hell is it warming above 32 well into SNH with that high as shown verbatim. That is terrible.

It's amazing that even with the much higher resolution it has vs 6-7 years ago, it still sucks with CAD.

[CoastalWx]

It's amazing that even with the much higher resolution it has vs 6-7 years ago, it still sucks with CAD.

I mean, how is that possible? That's just awful.

[OceanStWx]

The GFS seems disturbingly woeful with 2m temps. No way in hell is it warming above 32 well into SNH with that high as shown verbatim. That is terrible.

 

But they fixed it!

 

Although in seriousness, I'll sacrifice 2 m temps if that means it correctly forecasts the upper levels. But that's not always a guarantee either.

[ORH_wxman]

But they fixed it!

Although in seriousness, I'll sacrifice 2 m temps if that means it correctly forecasts the upper levels. But that's not always a guarantee either.

I think all of us would make that sacrifice. Sfc temps are the easiest variable that a good human forecaster can crush the NWP guidance on.

But of course, we know it will screw up other levels too from time to time. I do believe the GFS has gotten better in winter storms vs 5 years ago but it still is lagging most other guidance on those events. Just ask Ekster what he thinks of the GFS when all the chips are down.

[Ginx snewx]

At this time,.8 precipitation has fallen. This is Lincoln RI, sort of what I alluded to. Thats snow and thumping too.

[dendrite]

Maybe Steve, but H65 temps that warm scare me wrt nucleation.

[OceanStWx]

I think all of us would make that sacrifice. Sfc temps are the easiest variable that a good human forecaster can crush the NWP guidance on.

But of course, we know it will screw up other levels too from time to time. I do believe the GFS has gotten better in winter storms vs 5 years ago but it still is lagging most other guidance on those events. Just ask Ekster what he thinks of the GFS when all the chips are down.

 

Dry humping the Euro.

 

It's tough being on short term now and having to give this storm up to the long term guy, but thanks to a swap with Ekster I'll be on short term right through this system.

 

[OceanStWx]

At this time,.8 precipitation has fallen. This is Lincoln RI, sort of what I alluded to. Thats snow and thumping too.

 

Playing with fire. Another degree and that isn't so nice, plus when you shove the DGZ up that high (500 mb) you aren't maximizing lift and snow growth potential.

 

[USCAPEWEATHERAF]

The 00z GFS continues the theme with giving me 5-8" of snow.

[Ginx snewx]

Maybe Steve, but H65 temps that warm scare me wrt nucleation.

sand storms seem to be the swfe way lately, had one last year, stuff has a way of piling up though. Just making a point that the demarcation lines get blurred when you dig deeper. Orh soundings are similar even at 6 h.

[OceanStWx]

Out of curiosity, is the newer Euro similar to its current counterpart?

 

Late to the party on this question, but taking a peak at what little WeatherBell offers of the parallel it is warmer than the current op.

 

That's really just using the weenie snow map to infer where it has warmer mid levels temps. It shifts the plowable accumulation from the Pike to the NH border when you move from the op to the parallel.

 

[Ginx snewx]

Playing with fire. Another degree and that isn't so nice, plus when you shove the DGZ up that high (500 mb) you aren't maximizing lift and snow growth potential.

we always play with fire on swfes here. I will wait for SUN to get excited, this could be nothing but meh in 2 days or the models could sample the cold better and we switch up. I would only expect 2-3 max at this point. My point was that throwing out blanket statements about snow_sleet lines using a highway without looking at soundings, when we were discussing model outputs, can not always be correctly analyzed.

[OceanStWx]

we always play with fire on swfes here. I will wait for SUN to get excited, this could be nothing but meh in 2 days or the models could sample the cold better and we switch up. I would only expect 2-3 max at this point. My point was that throwing out blanket statements about snow_sleet lines using a highway without looking at soundings, when we were discussing model outputs, can not always be correctly analyzed.

 

Of course, but you typically keep your expectations in check because you know your climo.

 

Then again, you're east of 84 and south of the Pike, you're screwed.

[USCAPEWEATHERAF]

CMC would be about 6" of snow for CHH before the changeover to sleet and then rain.

[Ginx snewx]

Of course, but you typically keep your expectations in check because you know your climo.

Then again, you're east of 84 and south of the Pike, you're screwed.

Bufkit gives ORH 7.2 BDL 3.7 ,based on that only I would probably hit 4-5 if lucky. Being east in this setup helps some, being south hurts a lot.

[ORH_wxman]

CMC would be about 6" of snow for CHH before the changeover to sleet and then rain.

Nope gotta look above 850mb. Big warm layer on GGEM around 750 despite cold 850 temps.

[OceanStWx]

I still struggle sometimes digesting the information, but using the ensemble sensitivity forecasts from SUNY Stony Brook seems to indicate this is a northern stream forecast for the largest part of the variance (1/2).

 

The shortwave that sends the strong cold front through to set the stage seems to be one of the biggest drivers of uncertainty in this forecast  (12z runs from earlier today).

 

Not surprisingly, higher heights with that shortwave (weaker) would lead to a farther north and stronger low pressure in the Great Lakes. The shortwave that results in the low pressure we care about for Tuesday doesn't really carry a lot of weight there until 60 hours into the forecast or so.

 

Another large part of the variance (1/3) is related to the strength of the southwestern shortwave. Deeper and more ridging ahead of it creates more downstream confluence and higher pressures over New England. But that's also a poorer signal for secondary development.

[Ginx snewx]

I miss my SUNY MM5 out of Stony brook, nailed these inside 24 hours

[OceanStWx]

Do you think there is any potential of a small to middle sized ice storm out of this?

 

A true ice storm (0.5" or greater) is pretty tough to pull out of these set ups. It can be done if there is an exceedingly deep cold air mass in place (late Jan 1994 as an example).

 

That is the only SWFE that I found in 20 years of data that produced a half inch of ice. Temps eventually warmed to 50 at BAF and there was thunder with the cold front.

 

Ice storms are easier to achieve when overall forcing is weaker and more gradual. Think gentle upslope rather than an omega thump.

 

[weathafella]

Some tasty snow numbers on the mex.

[SR Airglow]

No major changes on the Euro so far through 66 -- maybe a hair cooler at the surface but pretty similar so far.

[ORH_wxman]

Looks really similar at 84h. Not much help this run for getting back to snowier. But it at least appears we are not getting a warmer solution.

High is actually stronger this run but the primary is deeper and further north too so the two basically offset each other

[SR Airglow]

78 hours almost identical to 12z -- precip shield is entering SNE at the same time the 0c line is at 700. 

[OceanStWx]

Those 00z GFS soundings are a bit of a red flag, even up this way. That DGZ is so high up that it's easy to lose saturation. Bufkit says +SN at GYX 18z Tuesday, but the DGZ is dry.

 

We would really want to make sure we have salt nuclei in there to get the dendrites growing at -6^oC.