December 2017 Discussions & Observations Thread

[MJO812]

18z gfs looks great for a storm near Xmas

MJO supports that outcome

[bluewave]

The most interesting weather statistic today was one of the lowest  negative 500 mb height anomalies on record for December at OKX.

 

 

 

 

 

 

 

 

 

[qg_omega]

5 minutes ago, bluewave said:

The most interesting weather statistic today was one of the lowest  negative 500 mb height anomalies on record for December at OKX.

 

 

 

 

 

 

 

 

 

Very deep trough but no true artic air with it

[bluewave]

15 minutes ago, qg_omega said:

Very deep trough but no true artic air with it

NYC generally gets its best cold on a NW to N flow down the Hudson Valley and strong Arctic high pressure. These strong W flow days across the Great Lakes often have better cold departures aloft than at the surface.

[coastalplainsnowman]

It's quiet here - is that not snow on our doorstep to the southwest closing in fast?  Just checked forecast.  1-3", Long Island under a Winter Weather Advisory?  Had to make sure my browser pages weren't cached.  

Edit: to the southwest

[MJO812]

5 minutes ago, coastalplainsnowman said:

It's quiet here - is that not snow on our doorstep to the southwest closing in fast?  Just checked forecast.  1-3", Long Island under a Winter Weather Advisory?  Had to make sure my browser pages weren't cached.  

Edit: to the southwest

It's almost here

[NorthShoreWx]

On 12/12/2017 at 11:13 PM, Morris said:

Cheap midnight low incoming, saving today's departure.

Actually, yesterday's (Tuesday's) low here was doubly cheap.  It was 31 at 12:01AM before warming to over 40 by sunrise, then was 31 again at 11:59PM.

Ironically, today's (Wednesday's) high was 31 at 12:01 AM and then again 31 a little before 1PM.

A low of 31 occurring twice the same day and then a high of 31 occurring twice the following day.  I'd put everything on 31.

 

 

[AfewUniversesBelowNormal]

6 hours ago, qg_omega said:

Very deep trough but no true artic air with it

Only 7-8mb from lowest today

[Eduardo]

4 hours ago, bluewave said:

FWIW, there is pretty good EPS and GEFS agreement through the 23rd. We have to monitor the MJO and NAO  to know exactly where the pattern is going after the 23rd. Small changes can have a big impact on the exact location of where the gradient sets up beyond day 10.

Chris, I would think that, were that raging EPO to verify and hold for a bit, even some transient, bootlegged NATL ridging would put us in a good spot at this time of year, no?

Models will flip back and forth over the next few days but overall, I like where we sit: -EPO, favorable MJO and cold close by.  I'll take my chances, cross my fingers and hope that we stay on the good side of the gradient. 

[Paragon]

17 hours ago, donsutherland1 said:

I don't want to say that they were more favorable, but that a number had big potential including but not limited to 1995-96. The coefficient of determination was .62. Of course, a lot of other variables are involved (and it's encouraging to see the GFS showing a stormier pattern in the medium-range and beyond).

I used the NWC's seasonal snowfall chart, which shows 33.2". Of course, the chart has at least one typo, as winter 2015-16 had 32.8" snow, not 32.1".

Like you, I suspect Central Park underreported during the Blizzard of 1996.

Don, is there a way of calculating which winter in NYC history had the most potential and what its likely range was?  Perhaps a winter in the 1800s- I think you mentioned that David Ludlum wrote an account of a winter just prior to when records started being kept at Central Park when over 90 inches of snow fell in New York City?

 

[Paragon]

18 hours ago, snowman19 said:

As depicted, any storms, if cold enough in the low levels, would be an ice storm/freezing rain setup, not a snowstorm setup, isentropic event, at least through Christmas. I hope not, ice storms are the worst

This would be a snowier pattern if it was late January or February, but this early in the game, it's a mix set up.

 

[Paragon]

17 hours ago, donsutherland1 said:

Some snow flurries are falling in the Bronx.

It's been snowing nicely tonight, I wonder if that second batch gets here in time for the morning rush?

[Paragon]

13 hours ago, EastonSN+ said:

That's why it gets me so upset when Bridgeport is used for all CT shoreline references in historical snowfall. What's worse it has a lower snowfall average than NYC which is of course off due to said measurement shortfalls.

Fyi. Fairfield officially had 27 for the 96 blizzard

I believe JFK also underreported that storm, no way it was only 20".  

PD2 which they reported 26" had visibly less snow than Jan 1996.

The only storm that measures up to and exceeds Jan 1996 here was Jan 2016 and they were closer than the measurements seem to indicate.

If Jan 2016 was 31-32 inches here, than Jan 1996 was more like 28, and PD2 was 26, with Feb 1983 in the same general range.  Those are all the 20+ storms I've experienced.

 

[Paragon]

11 hours ago, Morris said:

31/20 today. -13

Pros, when is our average first day with a max below freezing?

For NYC?  Never lol

NYC's lowest average high temp is like 36.  I suppose you could calculate an average first date below freezing based on the years that have them but it doesn't mean anything because the average high never gets to freezing or below.

 

[Paragon]

10 hours ago, bluewave said:

Last December it was the 16th. No highs below freezing in 2014 and 2015. December 12th in 2013.

Yeah but Chris these are all below normal days, if you go by average high temps per date there isn't an "average" below freezing high because the average high never gets that low- a high below freezing is anomalous regardless of the date.  Besides there is no way to calculate an average date for something which in some years doesn't happen at all.

 

[CIK62]

Next 8 days averaging 36degs., maybe 1deg. BN.

[Ralph Wiggum]

I think the combination of the recent MJO 7 transit and the +NAO will favor a cutter storm track through the Great Lakes around the 23rd. Beyond that, I don't want to speculate yet. It's important to verify the 6-10 details before trying for 11-15 and beyond where the holiday period falls. 

 

 

Agreed. EPS/GEFS both took another step back last night with a classic Nina look trying to lock in the LR. Trof anchored in SW, strong signal for SE Ridging, +NAO. This isnt a horrible setup with energy ejecting out of the SW trough and riding up along the SE Ridge axis every other day which looks stationary. Plenty of cold HP along the Canadian border....nice gradient pattern setting up. With a look as such locking in, whoever ends up on the cold side of the boundary is probably going to have one heck of a stretch of active wintry weather. Boundary is displaced too far North and West right now on the ens (except GEPS) but plenty of time to adjust. I dont like the way the GEFS and EPS keep ticking the boundary farther N and W though as lead time is shortening. Need to see how next week pans out tho first.

 

 

 

[PB GFI]

7 minutes ago, Ralph Wiggum said:

Agreed. EPS/GEFS both took another step back last night with a classic Nina look trying to lock in the LR. Trof anchored in SW, strong signal for SE Ridging, +NAO. This isnt a horrible setup with energy ejecting out of the SW trough and riding up along the SE Ridge axis every other day which looks stationary. Plenty of cold HP along the Canadian border....nice gradient pattern setting up. With a look as such locking in, whoever ends up on the cold side of the boundary is probably going to have one heck of a stretch of active wintry weather. Boundary is displaced too far North and West right now on the ens (except GEPS) but plenty of time to adjust. I dont like the way the GEFS and EPS keep ticking the boundary farther N and W though as lead time is shortening. Need to see how next week pans out tho first.

 

 

 

2 M temps are BN everyday on the EPS on North day 10 thru 15.

There is a lot of HP in the pattern and plenty that will nose in.

We have a 3 day issue 18th - 21st where LP is cutting through W Canada so that will be a reset.

The MJO goes into 8 around the 21st time frame ,  so later in the period look for that weak SE ridge to get weaker 

[Ralph Wiggum]

2 M temps are BN everyday on the EPS on North day 10 thru 15.

There is a lot of HP in the pattern and plenty that will nose in.

We have a 3 day issue 18th - 21st where LP is cutting through W Canada so that will be a reset.

The MJO goes into 8 around the 21st time frame ,  so later in the period look for that weak SE ridge to get weaker 

As I posted, that cold HP along Canadian border is the caveat to all of this, so I do agree with that part. Still need to see that feature hold and start to see increased confidence it seeps South which I believe it will at times. Going to be a battleground setting up for sure. Areas on the cold side may end up looking like a battleground too if icing signal continues to pop up.

[Ralph Wiggum]

Agreement

[qg_omega]

3 minutes ago, Ralph Wiggum said:

Agreement

Classic MJO phase 7 with a background Nina state, I wouldn't underestimate the SE ridge

[MJO812]

30 minutes ago, qg_omega said:

Classic MJO phase 7 with a background Nina state, I wouldn't underestimate the SE ridge

It is going to be a battle between the cold and warm air moving forward

[SnoSki14]

18 minutes ago, Snow88 said:

It is going to be a battle between the cold and warm air moving forward

That is not a battle you want to be a part of, 9 out of 10 times we lose and places further north do well. This screams 07/08 to me where New England wins and we lose. 

The only hope is the MJO.

However given what we've already seen snow wise and the amount of blocking, January could turn out pretty good. We're on the right side of climo/data.

I think most years that have had 5"+ in December did really well.

[Ralph Wiggum]

It is going to be a battle between the cold and warm air moving forward

Yep, and there is still some split on where this sets up. What I dont like is that as lead time is shortening, we are slowly losing the SW trof / SER being progressive and short-term and ticking more towards SW trof / SER anchoring in for a period. Where the axis sets up and whether the advertised pattern is brief or extended will likely be the next question if ens continue moving towards this look.

[dmillz25]

The higher North Atlantic heights in conjunction with a robust PNA/EPO should flood the northern tier of the United States in cold. Confluence and strong arctic highs will drain into the region and press the baroclinic zone south and east as the gradient provides a strong corridor for lift and convergence. These patterns ultimately suppress and counteract the se ridge in a fashion that is favorable for the northern middle Atlantic and New England. The models should adjust accordingly going forward. These are often some of the most challenging synoptic setups for them to compute. Don’t get to fixated on guidance variance over the next couple of days, it will eventually get ironed out. We know the global and large scale hemispheric pattern support such. Credit to BMC10 from elsewhere

Just wanted to drop this beauty here

[MJO812]

8 minutes ago, dmillz25 said:

The higher North Atlantic heights in conjunction with a robust PNA/EPO should flood the northern tier of the United States in cold. Confluence and strong arctic highs will drain into the region and press the baroclinic zone south and east as the gradient provides a strong corridor for lift and convergence. These patterns ultimately suppress and counteract the se ridge in a fashion that is favorable for the northern middle Atlantic and New England. The models should adjust accordingly going forward. These are often some of the most challenging synoptic setups for them to compute. Don’t get to fixated on guidance variance over the next couple of days, it will eventually get ironed out. We know the global and large scale hemispheric pattern support such. Credit to BMC10 from elsewhere

Just wanted to drop this beauty here

Swfe =)

[EastonSN+]

4 hours ago, Paragon said:

I believe JFK also underreported that storm, no way it was only 20".  

PD2 which they reported 26" had visibly less snow than Jan 1996.

The only storm that measures up to and exceeds Jan 1996 here was Jan 2016 and they were closer than the measurements seem to indicate.

If Jan 2016 was 31-32 inches here, than Jan 1996 was more like 28, and PD2 was 26, with Feb 1983 in the same general range.  Those are all the 20+ storms I've experienced.

 

Nice. My top 3 here are 96 with 27.

2013 NEMO with 22

Feb 2006 with 20.5

[Brian5671]

1 hour ago, SnoSki14 said:

That is not a battle you want to be a part of, 9 out of 10 times we lose and places further north do well. This screams 07/08 to me where New England wins and we lose. 

The only hope is the MJO.

However given what we've already seen snow wise and the amount of blocking, January could turn out pretty good. We're on the right side of climo/data.

I think most years that have had 5"+ in December did really well.

Agree there.  Gradient patterns where we win are rare-93-94 is a good example.     I do like the early blocking this year.    Otherwise I have worries we torch a good chunk of the winter based on Nina Climo which often favors December.

[MJO812]

EPO on the gefs is tanking off the charts just before xmas.

[Brian5671]

7 minutes ago, Snow88 said:

EPO on the gefs is tanking off the charts just before xmas.

EPO has saved us the last 4 years as we've had little to no help from the Atlantic...