Two Mdt to high impact events NYC subforum; wknd Jan 6-7 Incl OBS, and mid week Jan 9-10 (incl OBS). Total water equiv by 00z/11 general 2", possibly 6" includes snow-ice mainly interior. RVR flood potential increases Jan 10 and beyond. Damaging wind.

[bluewave]

11 minutes ago, Allsnow said:

That doesn’t answer the question…

 

yesterday morning you were using the ukmet illustrate a point because of its warm inland track. Now, it has since went to a cold snowy and you are cherry picking the 06z gfs with surface temps…

Because both sets of solutions are showing the same challenges with the warm air. The first challenge is a more wrapped up system which could correct NW under 72 hrs. The GFS has the 2nd challenge with a trough in the West pumping the ridge and temps in the mid 30s. But it takes longer for the system to consolidate so the surface low is weaker. While it’s still too early, the RGEM is weaker and more strung out with the low than the GEM near the end of it’s run. 

[Allsnow]

5 minutes ago, bluewave said:

Because both sets of solutions are showing the same challenges with the warm air. The first challenge is a more wrapped up system which could correct NW under 72 hrs. The GFS has the 2nd challenge with a trough in the West pumping the ridge and temps in the mid 30s. But it takes longer for the system to consolidate so the surface low is weaker. While it’s still too early, the RGEM is weaker and more strung out with the low than the GEM near the end of it’s run. 

But let’s ignore all the models getting snowier for the region? 

[bluewave]

4 minutes ago, Allsnow said:

But let’s ignore all the models getting snowier for the region? 

Why would you ignore a cold bias which has been showing up all season? 

[jm1220]

No ones ignoring anything. We’re still 3-4 days away and plenty can change. We’re in the Goldilocks area where the coast can stay snow and it’s heavy on models like the Euro. The GFS has light precip and an initial easterly flow which warms up the city and coast, and the lighter precip probably can’t cool the column enough. Other models yesterday (which we can easily go back to if the confluence starts to weaken and/or low strengthens) showed a further NW track which screws us that way. But there is that tiny Goldilocks track/outcome which most models went to yesterday. But I’m still far from confident that actually happens. I remember Dec 2020, March 2017 etc where they were too SE at this timeframe. 

[Tatamy]

1 hour ago, kdennis78 said:

What's well inland? I honestly would welcome snow or even ice over rain. My yard can't handle more rain.

I-84

[bluewave]

9 minutes ago, jm1220 said:

No ones ignoring anything. We’re still 3-4 days away and plenty can change. We’re in the Goldilocks area where the coast can stay snow and it’s heavy on models like the Euro. The GFS has light precip and an initial easterly flow which warms up the city and coast, and the lighter precip probably can’t cool the column enough. Other models yesterday (which we can easily go back to if the confluence starts to weaken and/or low strengthens) showed a further NW track which screws us that way. But there is that tiny Goldilocks track/outcome which most models went to yesterday. But I’m still far from confident that actually happens. I remember Dec 2020, March 2017 etc where they were too SE at this timeframe. 

It would be great if we had the cold airmass that we did in 2020 for this storm. Highs in the low 30s and lows around 20° have produced some memorable snowstorms for us. 
 

Data for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Date	Max Temperature	Min Temperature	Snowfall
2020-12-16	31	24	6.5
2020-12-17	33	24	4.0
2020-12-18	32	24	0.0
2020-12-19	32	20	0.0

[MJO812]

45 minutes ago, SnoSki14 said:

GFS looked like crap though. Not enough dynamics to overcome warm surface temps. 

It always does this with coastals 

[MJO812]

46 minutes ago, bluewave said:

It’s tough to rely on those 10:1 maps with marginal temperatures as the positive snow depth charts are much lower.

 

Snow depth charts haven't been accurate in the past. You can't deny the fact that the models are looking more colder and wintry even for the coast.

[bluewave]

2 minutes ago, MJO812 said:

Snow depth charts haven't been accurate in the past. You can't deny the fact that the models are looking more colder and wintry even for the coast.

I don’t trust those 10:1 charts in marginal temperatures. 

[MJO812]

18 minutes ago, bluewave said:

Why would you ignore a cold bias which has been showing up all season? 

Because not every storm is similiar . We have a a good cold air source up north providing enough cold air to our region.

Can it change? Sure but things are looking up right now. 

 

[MJO812]

3 minutes ago, bluewave said:

I don’t trust those 10:1 charts in marginal temperatures. 

I think 6+ isn't going to happen in NYC but a few inches might not be out of the question if we get a strong vort .

[jm1220]

7 minutes ago, MJO812 said:

Snow depth charts haven't been accurate in the past. You can't deny the fact that the models are looking more colder and wintry even for the coast.

We’re not getting 10-1 here. If temps are 32 or 33 it may be 8-1. We still have the problem of easterly flow off the water. If we get a good track and precip intensity it can be overcome, but there’s a very small window between too strong/NW or too weak/suppressed. Where we see models now probably isn’t the final answer. 

[bluewave]

1 minute ago, MJO812 said:

Because not every storm is similiar . We have a a good cold air source up north providing enough cold air to our region.

Can it change? Sure but things are looking up right now. 

 

A good cold air source wouldn’t have highs in the upper 30s. Marginal air masses leave less leeway for significant snowfall from short term model changes. 

[MJO812]

3 minutes ago, jm1220 said:

We’re not getting 10-1 here. If temps are 32 or 33 it may be 8-1. We still have the problem of easterly flow off the water. If we get a good track and precip intensity it can be overcome, but there’s a very small window between too strong/NW or too weak/suppressed. Where we see models now probably isn’t the final answer. 

Of course not but people shouldn't downplay what the models are showing right now .

 

[Snowlover11]

we aren’t getting 10:1 ratios, so you can shit can that idea. probably more so 6:1-8:1.

[snowman19]

7 minutes ago, jm1220 said:

We’re not getting 10-1 here. If temps are 32 or 33 it may be 8-1. We still have the problem of easterly flow off the water. If we get a good track and precip intensity it can be overcome, but there’s a very small window between too strong/NW or too weak/suppressed. Where we see models now probably isn’t the final answer. 

The people using 10:1 ratio maps in a setup like this and thinking that’s actually going to verify are going to be shocked at the actual result. They are going to be grossly inaccurate. This is why the total positive snowfall maps are night and day different

[Brian5671]

9 minutes ago, bluewave said:

A good cold air source wouldn’t have highs in the upper 30s. Marginal air masses leave less leeway for significant snowfall from short term model changes. 

yeah urban areas would see white rain at best with those temps unless it's heavy

[SnoSki14]

8 minutes ago, MJO812 said:

Of course not but people shouldn't downplay what the models are showing right now .

 

Bluewave is just telling it like it is. I know many don't want to hear it but  the airmass is definitely marginal. 

He's just illustrating the challenges. I would honestly be surprised to see much for the coast. 

[Dark Star]

6 hours ago, SRRTA22 said:

Even half of that, Im sure all of us would be happy with 3-6" , hopefully we hold and can break the streak

Then again, if it is going to change to rain, or melt within 24 hours, may as well keep the streak going?

[BxEngine]

Maybe we need different storm threads for each subsection of this forum? 

[jm1220]

9 minutes ago, snowman19 said:

The people using 10:1 ratio maps in a setup like this and thinking that’s actually going to verify are going to be shocked at the actual result. They are going to be grossly inaccurate. This is why the total positive snowfall maps are night and day different

North and west where it’s colder is more likely to be 10-1 but anything like that here is a pipe dream. I’d be thrilled near the city with anything over a couple inches. North and west though, especially near/NW of 287 is likely sitting pretty. 

[EastonSN+]

57 minutes ago, bluewave said:

Because both sets of solutions are showing the same challenges with the warm air. The first challenge is a more wrapped up system which could correct NW under 72 hrs. The GFS has the 2nd challenge with a trough in the West pumping the ridge and temps in the mid 30s. But it takes longer for the system to consolidate so the surface low is weaker. While it’s still too early, the RGEM is weaker and more strung out with the low than the GEM near the end of it’s run. 

This is a good point, and a reason why it is USUALLY hard to get an all snow event in this region and why our areas yearly average is only approx 30 inches.

Look at all other years outside of 2000 through 2018 and 1955 through 1969, very hard to get all snow/KU events on a consistent basis. 

I remember getting amped up in February 1994 because I was FINALLY getting an all snow event without the risk of sleet! It was ALWAYS cutter, hugger or slider. 

Also, you can cut the country into three potential trough locations. East coast west coast and central/plains. That's a 1/3 chance right there. In addition, I believe that west coast troughing happens more often through history than east coast. 

We are in an RNA cycle unfortunately and we will have to thread the needle more often than not.

On a positive note, when it does happen it makes it that much sweeter! Getting a 6 inch event in the 80s and 90s was like getting a foot 2000 through 2018.

Leaving on another positive note. If it can snow in February 2018 in a sea of 60 and 70 degree days, it can snow this year. 

[MJO812]

25 minutes ago, Brian5671 said:

yeah urban areas would see white rain at best with those temps unless it's heavy

It's January , not March with the sun angle .

Gfs wouldn't work here anyway but Euro would for a few inches.

[SACRUS]

 

System has come ahore

 

 

[bluewave]

14 minutes ago, EastonSN+ said:

Leaving on another positive note. If it can snow in February 2018 in a sea of 60 and 70 degree days, it can snow this year

I never said that it couldn’t snow. Just that those 10:1 charts look overdone for such a marginal airmass. 

[Tatamy]

51 minutes ago, bluewave said:

I don’t trust those 10:1 charts in marginal temperatures. 

There is no law in the annals of physics that states that snow has to fall at a ratio of 10:1.  There seems to be a lot of people who believe that it does however that is not the case.

[Tatamy]

36 minutes ago, snowman19 said:

The people using 10:1 ratio maps in a setup like this and thinking that’s actually going to verify are going to be shocked at the actual result. They are going to be grossly inaccurate. This is why the total positive snowfall maps are night and day different

Do you know what variables are used to calculate this?

[WestBabylonWeather]

9 minutes ago, SACRUS said:

 

System has come ahore

 

 

Let’s see how todays models change now 

[Allsnow]

EPS snow mean went up this run at 06z with 6 at NYC 

snow depth 3-5 

[bluewave]

8 minutes ago, Tatamy said:

There is no law in the annals of physics that states that snow has to fall at a ratio of 10:1.  There seems to be a lot of people who believe that it does however that is not the case.

Yeah, two issues in play. The actual ratios and the raw model cold biases. But even the MOS numbers have been too cold at times this winter. That’s why I wouldn’t  even think about specific accumulations until under 72 hrs or even 24 hrs in a marginal situation like this.