January 28-30th Possible Nor'easter

[Rmine1]

Didn’t they do away with “Blizzard Watch”? Only warning? Think might be warranted for Suffolk tomorrow if everything holds serve

[HVSnowLover]

18 minutes ago, Jt17 said:

The winds aren't going to be nearly as intense on the northwest extent of the decent liquid equivalent. There WILL be ratios. People 100% exaggerate the OTHER direction on this too. If you get .8 inches of liquid and 12 inches of snow... just remember you don't get to be happy about it because you didn't get your 1 inch of liquid.  (I'm just playing)

I don't think people are saying no ratios but to assume about 12:1 ratios, maybe more like 15:1 on the western fringe of the decent snow.

[EasternLI]

7 minutes ago, Monmouth_County_Jacpot said:

eps????

Around 8pm

[winterwarlock]

25 minutes ago, wthrmn654 said:

almost exactly like the Mt Holly forecast map

[Blizzardo]

She's gonna come further west at the 2 minute warning

[HVSnowLover]

Just now, Blizzardo said:

She's gonna come further west at the 2 minute warning

I think the 0Z runs tonight are the 2 minute warning.  

[Yaz]

7 minutes ago, Rmine1 said:

Didn’t they do away with “Blizzard Watch”? Only warning? Think might be warranted for Suffolk tomorrow if everything holds serve

Yes

[nycsnow]

 

[Rmine1]

11 minutes ago, jdj5211 said:

 

better than a dirty pic from the wife

Let us decide 

[Blizzardo]

8 minutes ago, HVSnowLover said:

I think the 0Z runs tonight are the 2 minute warning.  

Tomorrow for me... seen too much wacky shit happen over the years...lol

[Doorman]

..Southern Appalachians through the Mid-Atlantic...
Days 2-3...

...Significant Nor'easter likely for the Mid-Atlantic and
Northeast...

Forecast confidence continues to increase in a significant snow
event, but the details of placement and amounts remains uncertain.

Dual shortwaves moving across the central part of the country are
progged to phase near the TN VLY and absorb into an amplifying
longwave trough across the East Coast. This trough is then likely
to tilt negatively and then close off as it approaches New
England. At the same time, a pair of jet streaks downstream of the
primary trough axis will intensify and become favorably coupled
(overlap of LFQ and RRQ of the subsequent streaks), in tandem with
the closing of the mid-level trough. All this is likely to occur
atop the natural baroclinicity offshore the East Coast, leading to
surface cyclogenesis off the NC/SC coast, which is then likely to
lift northeast while explosively deepening, potentially below
970mb as it moves somewhere near the Benchmark (40N/70W) Saturday
and then into the Canadian Maritimes Sunday. NW of the
surface-850mb low track, heavy snow is likely with deformation and
frontogenetical banding likely to enhance snowfall rates and accumulations.

https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfhsd

 

[jm1220]

That was a very encouraging run even back into NYC. I wouldn't go crazy over the precip output although it still shows a borderline MECS in the city verbatim. And yes it can still keep ticking west if the upper low closes off a few hours sooner as others pointed out. Trend is undeniable for the Euro since 6z to bring the heavy snow west. Interested to see the EPS and how many monsters it has that can bring crippling amounts into the city. Those are a possibility. Not high possibility but can't be ignored. 

But wow, central and eastern Suffolk are quite possibly in for an all out blizzard on Saturday. 2 foot amounts will be common there if the banding sets up like the Euro showed here. Could be 2/8/13-like where that happens, Euro showed roughly along Rt 112 over to the William Floyd for the death band. Latest NAM was a little east of there. 

And NW of NYC should be encouraged too at the heavier amounts inching west. Could probably be a warning event on this run out to western NJ, and there ratios will help. 

Again I wouldn't go higher than 12 or 13:1 ratios near the coast because of the strong winds. But the 1.2" liquid it shows on the Nassau/Suffolk border would still be 14-15".

Can't really talk all out blizzard for near NYC yet but trust me it isn't too far away from that with some minor added improvement. 

[USCG RS]

28 minutes ago, HVSnowLover said:

How can you tell when it is closing off? 

Below is a map of 500mb. The blue circle shows where the close off is and H5 (the black circle inside the blue circle). 

Soooo quick info about how the upper layers work. I wrote this before in here:

 

For reference anything with h/H in it is designating height in mb. For example, h925 is 925 mb where as h85/7/5 is 850mb/700mb/ and 500mb respectively. 

The governing physics of weather is such that the upper levels (h925 and above) are what govern sensible weather (ie what precip falls, how much, winds, etc). 

For winds, you want to look at h925. The winds here are what can mix down. Normally you take a 10-15% reduction, however, that is not always a hard and fast rule. 

For precip type, a good rule of thumb is to look at h85 and h925. If h85 is below freezing, there's a good chance the precip is frozen, and likely snow (there are exceptions when there are warm pockets above h85). If it is above freezing, it is likely liquid. Now if h85 is above freezing and h925 is close to freezing or below, there is a good chance you are looking at freezing rain. If h85 and h925 are above freezing, most likely it is plain rain. The exception here is if you have a very shallow yet very cold surface layer and/or the ground has been frozen for a good period of time (ie a cold spell for a few days) and sfc temps are just at or very slightly above freezing. Usually lighter precip helps to aid this exception as well. 

For precip rates, you want to look at H7. H7 will show you where the model thinks the best forcing is going to be as well as the available energy for precip. H7 is about frontogenic forcing. 

Lastly, let's look at H5. I won't go into h3/250 as that is beyond the scope of this post. So for H5, this is where you look for phases and energies moving across the continent. So, the 0z GFS slipped east about 75 miles. If you just look at that, well.. Then to you all hope is lost. Yet if you look up at H5, you see that one of the energies phased slightly early, causing a slightly late capture of another energy, ie, phasing late. This allowed the surface low pressure to slip east. However, when you look through the energies at H5, you quickly begin to realize that a less than 3 hour difference in any one of the energies - and consequential phasing - would have changed the outcome (Ala 6z Euro). I'm not going to go too deep into H5 energies as if you have been following along, you would have seen this explained before. If you have not been, follow along from here and look out for what this post has pointed out. To go into h5 energies and orientations would be too long a post and likely confusing as each phase and energy act differently depending on location, speed, strength, etc. It's best to just observe for this moving foreward.

One last thing regarding upper levels. For a coastal storm (or in the Midwest when a storm explodes and runs up from the gulf), you want to be NW of the various closing off of lows at the upper levels. When low pressure systems develop, they develop from SE (at the sfc) to NW (through H5). This diagonal development with regard to height in the atmosphere allows each low pressure center at each level to vent (ie expel air up and outward so that the pressure can fall. Remember, in layman's terms, pressure is essentially a measure of how much air is in any given space at any given time). So as you always want to be NW of the sfc low pressure for frozen precip, you want to be NW of H85 for snow and NW of H7 for the best snowfall rates. When H7 moves directly over or West your area, this is when you can dry slot and when h85 moves over or west of your area, you have h85 temps which shoot above freezing and this changes your snow to other types of precip (remember we talked about upper levels temps earlier). 

On H5/7/85 maps, when a LP closes off a this level, it is represented through a close black contour (ie circle)

These are just some general rules to keep in mind with these types of storms and why the surface depictions on models are really the laziest type of forecasting and produces poor forecasting skills and verification. 

It is also why I am not writing this storm off at all. 

Last note - the Euro with its resolution tends to pick up on these rules the best. This is why it used to be the gold standard. 

[nycsnow]

Euro ensemble huge improvement and west I hear

[MJO812]

2 minutes ago, nycsnow said:

Euro ensemble huge improvement and west I hear

Yes sir

[nycwinter]

21 minutes ago, Rmine1 said:

Didn’t they do away with “Blizzard Watch”? Only warning? Think might be warranted for Suffolk tomorrow if everything holds serve

they did do away with a blizzard watch which is silly..

[Metasequoia]

Are ensembles of much use 24 hours before a storm? 

[MJO812]

There is a big cluster west of the Benchmark on the eps

[nycsnow]

Euro ens bring 1inch liquid to nyc wow impressive for a mean, let’s keep it going!! Nam soon

[EasternLI]

1 minute ago, MJO812 said:

There is a big cluster west of the Benchmark on the eps

[MJO812]

1 minute ago, EasternLI said:

Wow

[jdj5211]

That large western cluster can't be ignored!

[EasternLI]

That's nuts. 

[Franklin0529]

Tucky tucky tucky. Someone's gonna get lucky!! LFG!!

[Metasequoia]

Euro has been looking better each run as of late.

[USCG RS]

6 minutes ago, nycwinter said:

they did do away with a blizzard watch which is silly..

Yes and no. It streamlines advisories without it. 

Likewise, once a blizzard watch is issued, to 'drop' to a Winter Storm Warning makes the public perception of the forecasting office poor. They look at it as either hype, a lie, or poor forecasting. 

[MANDA]

Significant spread so close to event on EPS.

[psv88]

13 minutes ago, jm1220 said:

That was a very encouraging run even back into NYC. I wouldn't go crazy over the precip output although it still shows a borderline MECS in the city verbatim. And yes it can still keep ticking west if the upper low closes off a few hours sooner as others pointed out. Trend is undeniable for the Euro since 6z to bring the heavy snow west. Interested to see the EPS and how many monsters it has that can bring crippling amounts into the city. Those are a possibility. Not high possibility but can't be ignored. 

But wow, central and eastern Suffolk are quite possibly in for an all out blizzard on Saturday. 2 foot amounts will be common there if the banding sets up like the Euro showed here. Could be 2/8/13-like where that happens, Euro showed roughly along Rt 112 over to the William Floyd for the death band. Latest NAM was a little east of there. 

And NW of NYC should be encouraged too at the heavier amounts inching west. Could probably be a warning event on this run out to western NJ, and there ratios will help. 

Again I wouldn't go higher than 12 or 13:1 ratios near the coast because of the strong winds. But the 1.2" liquid it shows on the Nassau/Suffolk border would still be 14-15".

Can't really talk all out blizzard for near NYC yet but trust me it isn't too far away from that with some minor added improvement. 

Yea, we are solidly in MECS territory out here and only 25 miles from HECS. We have another 24 hours before go time, so we will absolutely see shifts that could get us into that sweet spot...or we could shift back to down. But if trends continue, the population centers could be in line for a big dog

[Doorman]

 

8 minutes ago, Metasequoia said:

Are ensembles of much use 24 hours before a storm? 

For posterity???

[MANDA]

Looking at individual EPS members there are 13 of 51 that IMO are big hits for this entire forum.