December 2023

[powderfreak]

Just now, STILL N OF PIKE said:

That is where you get to then show your weenie nature or not 

Ha, yeah I guess my point was do most here look at a snow map and expect that amount?  I certainly don’t.  I like to post them because it’s showing the most likely spot to get the most QPF to fall as snow.  That’s it.

3km NAM shows 15” I’m think cool, 1.50” QPF falling as wet snow.  Maybe we can grab 8-9” of actual accumulating snow.

[weatherwiz]

2 minutes ago, powderfreak said:

Ha, yeah I guess my point was do most here look at a snow map and expect that amount?  I certainly don’t.  I like to post them because it’s showing the most likely spot to get the most QPF to fall as snow.  That’s it.

3km NAM shows 15” I’m think cool, 1.50” QPF falling as wet snow.  Maybe we can grab 8-9” of actual accumulating snow.

Very fair 

[ORH_wxman]

7 minutes ago, CoastalWx said:

Gfs drops part of the PV due to that AK block @ORH_wxman

Yeah I made a post in the main El Niño thread this morning about it with @WxUSAF…there’s def a chance for come colder outcomes in that period. I don’t know if it will be able to save the 12/17 threat, but it could make the week leading into Xmas more interesting. 

[CoastalWx]

1 minute ago, ORH_wxman said:

Yeah I made a post in the main El Niño thread this morning about it with @WxUSAF…there’s def a chance for come colder outcomes in that period. I don’t know if it will be able to save the 12/17 threat, but it could make the week leading into Xmas more interesting. 

That’s the time I’m thinking that would help. Think 12-17 probably in and up if it happens. 

[40/70 Benchmark]

4 minutes ago, powderfreak said:

Ha, yeah I guess my point was do most here look at a snow map and expect that amount?  I certainly don’t.  I like to post them because it’s showing the most likely spot to get the most QPF to fall as snow.  That’s it.

3km NAM shows 15” I’m think cool, 1.50” QPF falling as wet snow.  Maybe we can grab 8-9” of actual accumulating snow.

Eh....like I said, case-by-case. They can be better qualitative tools than qualitative, but when your method will fail is in a big coastal with potent deformation areas....having the mid levels be a prolific driver of snowfall is an entirely different ballgame because the models greatly struggle with mid level dynamics....you will see the vast majority of QPF focused with the low level deformation when the heaviest amounts actually fall near the modeled NW gradient, underneath the best mid level CSI.

[OceanStWx]

Say you have a warm nose that change ptype over to sleet and that's about +2C. 

Kuchera would be ratio = 12 + 2(271.16-max temp). In this case 12 + 2(-4) or 4:1. Obviously much better than 10:1 sleet accumulation. Still to high but, better.

But at Dendrite's place the warm nose is only -4C. Still warm enough to make some iffy snow growth, but cold enough to keep it all snow. 

Kuchera would be ratio = 12 + (271.16-max temp). In this case 12 + 2 or 14:1. And for each degree cooler than that you add an inch to the ratio. So you can see how it gets out of hand fast in cold environments with poor snow growth.

[OceanStWx]

5 minutes ago, 40/70 Benchmark said:

Right...thanks. I literally had that a$$ backwards. Like I said....middle age and the offseason are a bad combo. I think the proprietary NARCAN maps from F5 are some sort of modified Kuchera product.

There are a few instances when Kuchera can be fairly accurate when snow growth is ideal in a deformation zone, but that is not frequent...that is what I was thinking of.

We're also trying to move models towards more explicit snowfall output. Like the NBM is going to start doing snowfall as a percentage of ptype. So if rain and snow is a 50/50 probability in the NBM, only half the QPF will be used as snow, multiplied by a forecast snow ratio.

[40/70 Benchmark]

3 minutes ago, OceanStWx said:

Say you have a warm nose that change ptype over to sleet and that's about +2C. 

Kuchera would be ratio = 12 + 2(271.16-max temp). In this case 12 + 2(-4) or 4:1. Obviously much better than 10:1 sleet accumulation. Still to high but, better.

But at Dendrite's place the warm nose is only -4C. Still warm enough to make some iffy snow growth, but cold enough to keep it all snow. 

Kuchera would be ratio = 12 + (271.16-max temp). In this case 12 + 2 or 14:1. And for each degree cooler than that you add an inch to the ratio. So you can see how it gets out of hand fast in cold environments with poor snow growth.

At Kevin's house it's easy....go sleet.

[dendrite]

Corn Cobb pipe and a button nose

https://meteor.geol.iastate.edu/~ckarsten/cobb/cobb.php

[OceanStWx]

1 minute ago, dendrite said:

Corn Cobb pipe and a button nose

https://meteor.geol.iastate.edu/~ckarsten/cobb/cobb.php

Which uses some combination of temp, RH, and lift in the DGZ. My preferred method, and available in Bufkit as an accumulation option.

I believe the Max Temp in Profile would be Kuchera, Cobb has two study versions, and then there's the straight ratio slider bar option.

[weatherwiz]

2 minutes ago, OceanStWx said:

We're also trying to move models towards more explicit snowfall output. Like the NBM is going to start doing snowfall as a percentage of ptype. So if rain and snow is a 50/50 probability in the NBM, only half the QPF will be used as snow, multiplied by a forecast snow ratio.

How's the NBM performance with temperatures at PWM compared to MET/MAV? I've noticed many times the NBM is on the lower side (especially with high temperatures). I did recently see you can now check NBM performance on Iowa State which will be fun to dig into.

[bwt3650]

I’m headed up to Jay peak soon so I’m happy to see this. 

Almost whole mountain open today; though it’s very soft. It’s been an incredible start.


.

[Hazey]

The 20-25th period has legs. I think conditions will be favourable with marginal airmass and several s/w’s in the flow. Period to watch. You guys might grab the 17th. To warm here on that one

[OceanStWx]

7 minutes ago, weatherwiz said:

How's the NBM performance with temperatures at PWM compared to MET/MAV? I've noticed many times the NBM is on the lower side (especially with high temperatures). I did recently see you can now check NBM performance on Iowa State which will be fun to dig into.

Since it's a blend of everything, it has the same biases as the models. So bad in CAD for instance. 

But it's bias correct individually at every grid point, so day to day it is quite good.

[powderfreak]

20 minutes ago, 40/70 Benchmark said:

Eh....like I said, case-by-case. They can be better qualitative tools than qualitative, but when your method will fail is in a big coastal with potent deformation areas....having the mid levels be a prolific driver of snowfall is an entirely different ballgame because the models greatly struggle with mid level dynamics....you will see the vast majority of QPF focused with the low level deformation when the heaviest amounts actually fall near the modeled NW gradient, underneath the best mid level CSI.

Yeah for sure, I guess that’s why I keep saying it as QPF falling as snow.  Not jackpot actual snowfall on ground or anything.

In a big coastal, it’ll still show you were the most QPF will fall as snow.  It’s up to you to figure out the ratios.

And ratios drive the deformation bands.  Not QPF.  That’s on the user to adjust the ratio to QPF.

Its a very crude tool.  Like when I see a snow map, the second image is what I see.

 

[mreaves]

2 hours ago, CoastalWx said:

Kevin is anxiously awaiting Stowe pics. He appreciates them. 

Not as much as Ray does though. 

[STILL N OF PIKE]

3 minutes ago, mreaves said:

Not as much as Ray does though. 

I beg to differ 

[jbenedet]

The El Niño is already amplifying +NAO conditions and deamplifying -NAO conditions. It’s a mystery to most bc this doesn’t show up in the index. 
 

[Layman]

3 hours ago, dendrite said:

950mb winds…w.t.f.

 

2 hours ago, Ginx snewx said:

This is insane. Inland CT misses the brunt due to LLJ strengthening 

Collectively, do these look like a reasonably accurate depiction of what to expect Sunday night into Monday?  

The 950mb winds look to have a super tight gradient right over my head.  Would a shift west strengthen the winds here or is that determined by the coast regardless?

The NAM 10-meter looks really mundane at my location if I'm interpreting it correctly.

[OceanStWx]

6 minutes ago, Layman said:

Collectively, do these look like a reasonably accurate depiction of what to expect Sunday night into Monday?  

The 950mb winds look to have a super tight gradient right over my head.  Would a shift west strengthen the winds here or is that determined by the coast regardless?

The NAM 10-meter looks really mundane at my location if I'm interpreting it correctly.

What matters is where the mid level front is. The low level jet won't penetrate inland if the mid level front is parked right on the coast like some of the NAM runs are showing now. The farther west you can get that front, the higher the wind potential.

[Damage In Tolland]

Feels dewy out there today . She’s cutting west. 

[HIPPYVALLEY]

45° and overcast in Northampton.

I’m pouring beer samples at an event that is going to have six wine and three whiskey reps also pouring.  I’m going to need to pace myself.

[STILL N OF PIKE]

53 in Reading Mass. Holiday party soon after I just had AYCE sushi . We torch and we full

[Damage In Tolland]

8 minutes ago, HIPPYVALLEY said:

45° and overcast in Northampton.

I’m pouring beer samples at an event that is going to have six wine and three whiskey reps also pouring.  I’m going to need to pace myself.

 

[dendrite]

35.5°

Finally some clearing as the sun is setting. There’s still some snow in the trees and near 3” depth away from the trees. I’m not liking my odds of warm sectoring tomorrow night. 

[weathafella]

Lol.....there’s a difference in the euro op in clown range from 0Z to 12z.

[weatherwiz]

13 minutes ago, dendrite said:

35.5°

Finally some clearing as the sun is setting. There’s still some snow in the trees and near 3” depth away from the trees. I’m not liking my odds of warm sectoring tomorrow night. 

I read this...then look at the time.

DEPRESSING 

[weatherwiz]

A nice TDS in Tennessee. Forgot what severe weather looks like its been so dead

[ORH_wxman]

11 minutes ago, weathafella said:

Lol.....there’s a difference in the euro op in clown range from 0Z to 12z.

I like the way the northern stream has been looking on some of the extended guidance around 12/20. So if the longshot of 12/17 doesn’t work out, there may be another window shortly after where there’s more cold to work with. 

[weathafella]

20 minutes ago, ORH_wxman said:

I like the way the northern stream has been looking on some of the extended guidance around 12/20. So if the longshot of 12/17 doesn’t work out, there may be another window shortly after where there’s more cold to work with. 

It could make for a fun night at Clarke’s!