And we're off - first threat for a few mangled flakes

[Edge Weather]

GFS Ensembles

Keep getting better each run. WOW.

[supermeh]

GFS Ensembles

Keep getting better each run. WOW.

Getting there.

[eduggs]

The last few days' runs of the global models kind of resemble a single suite of ensemble members. And that doesn't really surprise me. Each subsequent run of a model changes the initial conditions a little bit from the previous run. But in the medium range, the sequence does not necessarily converge toward the result.

We've seen a few recent "hits" from the Euro, UK, JMA, Nogaps, and several more misses and near misses from the GFS, NAM, and intermittent runs of the others. Until or unless a narrow consensus solution is identified in the modeling, I would expect the ensemble populations to continue to reflect the overall spread in the model suite at large.

[tornadojay]

The Low P. on the GEFS did shift northwest somewhat by about 25-50 miles, if you compare 0z and 12z, but yes, the major shift west in precip was likely due to some amped up members. Should be interesting to see when E Wall comes out with the individual members.

it looks like the 500 charts are coming out.. some of them do looked amped up

[Alpha5]

it looks like the 500 charts are coming out.. some of them do looked amped up

Yeah always a red flag when the OP run is SE of the ensembles. I checked out the individuals and it looks like there are 5 or so big hits with the rest scraping the coast. Definitely some wiggle room on this one

[eduggs]

GFS Ensembles

Keep getting better each run. WOW.

Looks like approx. 4 good hits (including a few high precip solutions), 4 moderate hits with primarily coastal impact, and then another 4 grazers or misses. That pretty much suns up the state of the globals - between the JMA, Euro, UK, GFS, and Nogaps - over the past 24 hours.

[TheTrials]

WOW

[TheTrials]

This is taking on the classic model progression of what we see tracking winter storms.

[eduggs]

None of the models show an airmass capable of producing accumulating snow along the coast or in NYC, even if the perfect track/intensity verifies. But they all would support snow above 1000ft, and possibly continuous snow.

Forecast soundings are plenty cold aloft - downright winter-like. But they are springlike below 900mb. That means flakes could be possible almost anywhere, but surface temperatures would be slow to drop below about 38 near sea level. A highly elevationally depending snowfall would result, with a few valley locations possibly getting a lucky dusting of white with a transient dynamically induced surface temp drop.

[Alpha5]

None of the models show an airmass capable of producing accumulating snow along the coast or in NYC, even if the perfect track/intensity verifies. But they all would support snow above 1000ft, and possibly continuous snow.

Forecast soundings are plenty cold aloft - downright winter-like. But they are springlike below 900mb. That means flakes could be possible almost anywhere, but surface temperatures would be slow to drop below about 38 near sea level. A highly elevationally depending snowfall would result, with a few valley locations possibly getting a lucky dusting of white with a transient dynamically induced surface temp drop.

If you look at soundings for the close suburbs, the freezing level is hovers somewhere between 925-950, thats enough for it to snow...maybe not stick...but you'll see snow, especially considering how cold 850's are supposed to be.

[TheTrials]

None of the models show an airmass capable of producing accumulating snow along the coast or in NYC, even if the perfect track/intensity verifies. But they all would support snow above 1000ft, and possibly continuous snow.

Forecast soundings are plenty cold aloft - downright winter-like. But they are springlike below 900mb. That means flakes could be possible almost anywhere, but surface temperatures would be slow to drop below about 38 near sea level. A highly elevationally depending snowfall would result, with a few valley locations possibly getting a lucky dusting of white with a transient dynamically induced surface temp drop.

This is Bridgeport CT at 84 hours from the GFS. It's damn cold above and plenty of room to wetbulb at 950 and below (-5 dew point at 950) and I wouldn't say springlike at the surface either. Throw in a good CCB and its snowing, probably not accumulating but def. snowing and at night all bets are off in a really well put together system like some of the ensembles and the euro from yesterday was showing.

http://vortex.plymouth.edu/cgi-bin/gen_grbsnd.cgi?id=KBDR&mo=gfs_avn_us&pl=out4&ft=3.5day&cu=latest&pt=parcel&size=640x480

[Alpha5]

http://vortex.plymouth.edu/cgi-bin/gen_grbsnd.cgi?id=KHPN&mo=gfs_avn_us&pl=out4&ft=3.5day&cu=latest&pt=parcel&size=640x480

For HPN off the GFS. Freezing level is at 930 with dews below 0 at the surface

[Neblizzard]

I would just like to see some flakes here in the NYC metro area, a coastal storm is a bonus anyway. 12z Euro will be key...

[earthlight]

None of the models show an airmass capable of producing accumulating snow along the coast or in NYC, even if the perfect track/intensity verifies. But they all would support snow above 1000ft, and possibly continuous snow.

Forecast soundings are plenty cold aloft - downright winter-like. But they are springlike below 900mb. That means flakes could be possible almost anywhere, but surface temperatures would be slow to drop below about 38 near sea level. A highly elevationally depending snowfall would result, with a few valley locations possibly getting a lucky dusting of white with a transient dynamically induced surface temp drop.

Agree with most of this, but disagree in the sense that there is no way the snow gets to the lower elevations. The way for this to happen would be for the Euro solutions from yesterday to verify. The euro text soundings show exactly what's occurring even as far south and east to the coast as KEWR. The boundary later is warm to start, but the system is extremely cold for this time of year. As the CCB develops, dynamic cooling is more than sufficient (and by more than sufficient I mean by several degrees in the snow growth layers and a degree or two even down to 925mb) for snow formation and precipitation.

Accumulations are an entirely different story and likely would be reserved to higher elevations no matter how you slice it. But if the Euro solutions from yesterday are correct, and this thing tucks in near the coast and is strong, I think we could get snow falling for a few hours during heavy deformation/frontogenesis even into the immediate suburbs of NYC.

[Edge Weather]

The Euro already looks more amped up to me at 48hrs.

[eduggs]

This is Bridgeport CT at 84 hours from the GFS. It's damn cold above and plenty of room to wetbulb at 950 and below (-5 dew point at 950) and I wouldn't say springlike at the surface either. Throw in a good CCB and its snowing, probably not accumulating but def. snowing and at night all bets are off in a really well put together system like some of the ensembles and the euro from yesterday was showing.

http://vortex.plymou...el&size=640x480

That degree of warmth right near the surface in a saturated column and northerly winds looks very springlike to me. I've seen it many times. When you've maxed out the in-situ cooling mechanisms and there's no more cold air to advect in, temperatures will be very stubborn to drop. I definitely think wet snow flakes would mix in everywhere, but if you're below - say - 400ft, you're going to have trouble accumulating anything on a wet, warm ground.

Accumulating snow could occur right to sea level. The airmass north of the cold front could be slightly drier/colder than modeled. Cooler air aloft could be transporter to the surface temporarily. And of course snow can accumulate at 35F with large aggregates and high intensity. But it's unlikely. The models show very significant elevational dependence (within some latitude dependence as well) for any potential snow accumulations.

[TheTrials]

That degree of warmth right near the surface in a saturated column and northerly winds looks very springlike to me. I've seen it many times. When you've maxed out the in-situ cooling mechanisms and there's no more cold air to advect in, temperatures will be very stubborn to drop. I definitely think wet snow flakes would mix in everywhere, but if you're below - say - 400ft, you're going to have trouble accumulating anything on a wet, warm ground.

Accumulating snow could occur right to sea level. The airmass north of the cold front could be slightly drier/colder than modeled. Cooler air aloft could be transporter to the surface temporarily. And of course snow can accumulate at 35F with large aggregates and high intensity. But it's unlikely. The models show very significant elevational dependence (within some latitude dependence as well) for any potential snow accumulations.

It's not even close to being saturated on that sounding bro.

[TheTrials]

The Euro already looks more amped up to me at 48hrs.

yes, through 60 very ukie like.

[Edge Weather]

Definitely more amped up at 60 hrs.

[Edge Weather]

precip into south Jersey at 66 hrs.

[Edge Weather]

precip on the doorstep of NYC at 72 hours.

[LocoAko]

Agree with most of this, but disagree in the sense that there is no way the snow gets to the lower elevations. The way for this to happen would be for the Euro solutions from yesterday to verify. The euro text soundings show exactly what's occurring even as far south and east to the coast as KEWR. The boundary later is warm to start, but the system is extremely cold for this time of year. As the CCB develops, dynamic cooling is more than sufficient (and by more than sufficient I mean by several degrees in the snow growth layers and a degree or two even down to 925mb) for snow formation and precipitation.

Accumulations are an entirely different story and likely would be reserved to higher elevations no matter how you slice it. But if the Euro solutions from yesterday are correct, and this thing tucks in near the coast and is strong, I think we could get snow falling for a few hours during heavy deformation/frontogenesis even into the immediate suburbs of NYC.

I didn't see the euro text soundings (jealous!) but wouldn't our very low-level wet bulb temperatures still be above zero? With heavy enough precipitation I agree that we could still get the snow down but it is still so marginal even in the best situation.

[TheTrials]

Ukie and Euro are really cousins, its scary. They look identical at 72 hours.

[tornadojay]

I wish the euro 500 plots showed vorticity, but I guess you can just imagine it.. anyhow... this run looks interesting.

[Edge Weather]

This is going to be WAY better than the previous run

[eduggs]

It's not even close to being saturated on that sounding bro.

The wetbulb temp is well above freezing.

Then you can knock off a few tenths for latent heat of melting and you still need to transport in more cold air - presumably with vertical motions or transient cold pockets advecting laterally.

[supermeh]

This is going to be WAY better than the previous run

about to go BOOM!

[eduggs]

Agree with most of this, but disagree in the sense that there is no way the snow gets to the lower elevations. The way for this to happen would be for the Euro solutions from yesterday to verify. The euro text soundings show exactly what's occurring even as far south and east to the coast as KEWR. The boundary later is warm to start, but the system is extremely cold for this time of year. As the CCB develops, dynamic cooling is more than sufficient (and by more than sufficient I mean by several degrees in the snow growth layers and a degree or two even down to 925mb) for snow formation and precipitation.

Accumulations are an entirely different story and likely would be reserved to higher elevations no matter how you slice it. But if the Euro solutions from yesterday are correct, and this thing tucks in near the coast and is strong, I think we could get snow falling for a few hours during heavy deformation/frontogenesis even into the immediate suburbs of NYC.

Oh I agree it could snow or mix everywhere - at least in the overnight. Everything is cold except right near the surface. Heck, with steep lapse rates it can snow above 40F. I just meant that overall a perfect track is not sufficient to get near freezing temps in the City for example.

[TheTrials]

Euro is still well east of where we want it. With no closed 500 the surface low slips east of the BM which means no CCB and light to moderate rain with whatever falls.

The trough doesn't go negative enough to push to low further up the coast.

We won't have an mid-level lows remotely close enough (if they are closed off at all) to give us a CCB

[earthlight]

the ccb misses to the southeast by 50 miles on the euro.