December 2016 Discussion & Observations

[Brian5671]

13 minutes ago, SnowGoose69 said:

People forget how close that month was to being a shutout despite being something like 3-5 degrees below normal.  I think NYC had 0.8 on the month going into that storm, and that storm came close on a couple of occasions inside day 5 to not happening. 

and the night before forecasts on that storm busted hard. Storm was supposed to track over LI or something like that...instead it developed later and further northeast  and took a further northeast track....   The storm took a track into RI and changed Boston to rain and of course anyone SW of Philly saw nothing.   Forecast for the NYC area was a change to rain, but the storm was all/mostly snow and the region got b/w 10-20 inches on average.

[Paragon]

20 minutes ago, bluewave said:

 

The 12-30-00 snowstorm kicked the whole snowy pattern off. That one broke the long snow drought following the historic 95-96 winter.

Some of the best snowstorm swells for the surfers with that storm.

I was doing some calculating in my head and I think in the period from 00-01 to 15-16 we've had 15 historic snowstorms in 16 years.  Between 92-93 to 99-00 we had 5 in 8 years but all of those were prior to 96-97.  So that's 20 in 24 years even with the mini snow drought between 96-97 to 99-00 included.  I'm classifying a 10 inch snowfall at any of the four major metro reporting stations (NYC, EWR, LGA, JFK) as historic, which is pretty liberal, but such snowfalls were much more rare prior to 92-93.

[Paragon]

9 minutes ago, bluewave said:

 

We may have to wait until that pattern relaxes later on for our best snow chances since it's coast to coast high pressure with the -EPO.

 

 

 

When do you see the pattern relaxing? Around Jan. 20?  Before that I guess we have to look for a clipper or something similar to dust the ground lol.

[SnowGoose69]

2 minutes ago, Paragon said:

I was doing some calculating in my head and I think in the period from 00-01 to 15-16 we've had 15 historic snowstorms in 16 years.  Between 92-93 to 99-00 we had 5 in 8 years but all of those were prior to 96-97.  So that's 20 in 24 years even with the mini snow drought between 96-97 to 99-00 included.  I'm classifying a 10 inch snowfall at any of the four major metro reporting stations (NYC, EWR, LGA, JFK) as historic, which is pretty liberal, but such snowfalls were much more rare prior to 92-93.

The period from 2000 to now is as much an anomaly as the period from 1984 to 1993 was.  NYC had no 8 inch storms in that period.  I think they recorded over 7 both in the January 1987 and December 1990 storms but that was as close as they got.   I know my school district had no snow days from 1/23/87 to 2/9/94.  That was helped somewhat by several weekend events that would have shut us down but that's a hard streak to have for a school district in New York, even on Long Island 

[WEATHERBUFF]

8 hours ago, bluewave said:

The only below normal Decembers since 2000 were 2000...2002...2005..2009...2010. They all needed a strong -AO pattern to pull it off.

 

 

Which proves in December it takes kind of an extreme situation to get below the 1981-2010 averages.

[Paragon]

20 minutes ago, SnowGoose69 said:

The period from 2000 to now is as much an anomaly as the period from 1984 to 1993 was.  NYC had no 8 inch storms in that period.  I think they recorded over 7 both in the January 1987 and December 1990 storms but that was as close as they got.   I know my school district had no snow days from 1/23/87 to 2/9/94.  That was helped somewhat by several weekend events that would have shut us down but that's a hard streak to have for a school district in New York, even on Long Island 

The ironic thing was all we could muster with the Feb 1983 event was an early closing, because it hit on a Friday afternoon and midwinter recess started right after that.

There were a lot of 4-5 inch events where we either had delayed openings or delayed closings or were forced to look out the window wistfully watching it snow outside and wishing we were elsewhere and not in class.

It wasn't just the 8 inch events I don't think we had many 6 inch events either (either in the late 80s/early 90s drought or the late 90s drought).

[Paragon]

13 minutes ago, WEATHERBUFF said:

Which proves in December it takes kind of an extreme situation to get below the 1981-2010 averages.

Which makes the term "average" meaningless since "average" is supposed to (theoretically at least) give a balanced distribution of above and below.  Maybe we should be calculating median temps instead- and do the same with snowfall.

[Paragon]

16 minutes ago, bluewave said:

The EPS weeklies relax the pattern around mid-January.

Maybe we'll get into the kind of pattern where we have relaxations late in the month, so early to mid Jan and early to mid Feb (and maybe even early to mid March) will be like early to mid Dec (except you need to adjust for climatology) and late in each of those months we'll torch.

[Allsnow]

43 minutes ago, bluewave said:

 

We may have to wait until that pattern relaxes later on for our best snow chances since it's coast to coast high pressure with the -EPO.

 

 

 

I think we will have a chance with a wave along the artic front around the 5th then something better as it relaxes. Hopefully we can hold a high pressure to our north 

[dmillz25]

1 hour ago, Allsnow said:

Eps looks great to start January 

That has overrunning written all over it

[Allsnow]

Just now, bluewave said:

First 3-4 days of January look mild with the Euro trying to take on last run one 60 before it gets colder again.

 

Just now, bluewave said:

First 3-4 days of January look mild with the Euro trying to take on last run one 60 before it gets colder again.

You can see on the 18z gefs if we don't get a neg nao or blocking the se ridge will be around 

[Paragon]

Isn't one characteristic of La Ninas that we have a very narrow margin of error?  We need a bit of a SE ridge to keep a suppressed storm track at bay but too much of one and we get a cutter or runner.  Even that Boxing Day Blizzard we were talking about earlier had a very narrow margin- hence why it was so hard on the models.  Earlier in the month we had a possibility that ended up suppressed and out to sea.

[nzucker]

2 hours ago, pazzo83 said:

Dude how weird is it that Feb '15 was insanely cold here but it wasn't until the balmy 15-16 winter that we got Central Park finally below zero.  Some things just defy explanation.

Yes, amazing. I did hit -11F up in Putnam County in Feb 2015, and NYC had single digits on Feb 28, I believe, one of the latest occurences of single digits since March 1967. We had a great snowpack in both winter 13-14 and 14-15. The former had about 30" in Westchester in late mid-February, the latter had about 22" in early March. 

The cold outbreak last winter was one of only two in the 15-16 Winter. The first one was around January 5th, and it was around 0F in the Poconos. Jan ran a little over +1 last year, and Feb a little over +2, so the meat of the winter was not a total torch. It was the bookends that made it so notable for extreme warmth: the warmest December since the dinosaurs with 0 days below freezing (this month has like 10) and the 6th warmest March on record with magnolias and cherries blooming by 3/20, a full 3 weeks ahead of normal. Trees at 1600' at our house in NE PA had buds on 3/30, before being killed by record cold and several snowstorms in early April.

[SnowGoose69]

2 hours ago, pazzo83 said:

Dude how weird is it that Feb '15 was insanely cold here but it wasn't until the balmy 15-16 winter that we got Central Park finally below zero.  Some things just defy explanation.

That cold outbreak came almost straight from the north with little crossing of the Great Lakes.  I felt Central Park had a decent shot at below zero even though most of the MOS numbers had them just missing.  Most of the cold outbreaks the last 20 years either enter the US too far west or if they do come in to our north they end up crossing too far east into New England 

[nzucker]

3 hours ago, Isotherm said:

Going forward, remember our discussion awhile ago regarding analogs - you asked why I chose so many mod+  Nina years. Other indicators will continue to support the NW trough / SE ridge z500, from hemispheric torques, to tropical forcing and the NAM state. The result is a z500 that projects strongly onto the more robust Nina maps. Hopefully we can achieve something in that window.

I think the pattern will diverge a bit from the stronger Ninas, at least the warmer ones with collapsed Aleutian ridges, in the next few weeks. Years like 11-12, 99-00, 98-99 had a big AK vortex much of the season and little cold penetrated the US. I think going foward, January 1971, January 1972, January 1976, and Jamuary 1985 are good analogs; these months were snowy in New England, had severe cold snaps driven by favorable PAC patterns, and were decent, though far from great, on the coast. All delivered at least SOME snow to NYC. Most had colder Januaries and warmer Februaries, which seems to be the expected pattern progression.

One problem is it's hard to see what happens to the pattern after the -EPO/-NAO period from Jan 5-15. Will the whole thing break down and lead us back to the base state with low AAM, a tight vortex, and little blocking? Or will the ridging set off a chain reaction that warms the Arctic bottom up, in tandem with the weakening La Nina, extending the favorable pattern? Once EPO blocks began in 2014 and 2015, they seemed to recur more and more frequently. Like we had the one -EPO in mid Dec 2013, then Jan-Mar 2014 was all driven by the PAC. The background state suggests we revert to less blocking in the Jan 20-Feb 15 period, but who knows...

 

[Brian5671]

26 minutes ago, SnowGoose69 said:

That cold outbreak came almost straight from the north with little crossing of the Great Lakes.  I felt Central Park had a decent shot at below zero even though most of the MOS numbers had them just missing.  Most of the cold outbreaks the last 20 years either enter the US too far west or if they do come in to our north they end up crossing too far east into New England 

unless the lakes are frozen, we need the blast to miss the lakes-my cold days here in CT winds are straight out of the north.   I remember a day in the mid 2000's where it was 8 or 9 at high noon with a due north wind....

[BombsAway1288]

54 minutes ago, Brian5671 said:

unless the lakes are frozen, we need the blast to miss the lakes-my cold days here in CT winds are straight out of the north.   I remember a day in the mid 2000's where it was 8 or 9 at high noon with a due north wind....

We had a day or two just like that in January 14'. I think it was on or around the 7th or 8th. I remember seeing 8 degrees under sunny skies at like 1:15 pm on wunderground stations and some area ASOS's. I believe there were some midnight highs on those days so what went down in the record books is deceiving 

[Isotherm]

3 hours ago, nzucker said:

I think the pattern will diverge a bit from the stronger Ninas, at least the warmer ones with collapsed Aleutian ridges, in the next few weeks. Years like 11-12, 99-00, 98-99 had a big AK vortex much of the season and little cold penetrated the US. I think going foward, January 1971, January 1972, January 1976, and Jamuary 1985 are good analogs; these months were snowy in New England, had severe cold snaps driven by favorable PAC patterns, and were decent, though far from great, on the coast. All delivered at least SOME snow to NYC. Most had colder Januaries and warmer Februaries, which seems to be the expected pattern progression.

One problem is it's hard to see what happens to the pattern after the -EPO/-NAO period from Jan 5-15. Will the whole thing break down and lead us back to the base state with low AAM, a tight vortex, and little blocking? Or will the ridging set off a chain reaction that warms the Arctic bottom up, in tandem with the weakening La Nina, extending the favorable pattern? Once EPO blocks began in 2014 and 2015, they seemed to recur more and more frequently. Like we had the one -EPO in mid Dec 2013, then Jan-Mar 2014 was all driven by the PAC. The background state suggests we revert to less blocking in the Jan 20-Feb 15 period, but who knows...

 

 

1975-76 was actually my secondary analog (1973-74 primary) for the winter, so I agree that we could see an interlude similar to that year coming up. 1973-74 and 1975-76 both featured some decent cold periods with not abysmal final snow totals along the coast. Regarding the upcoming period, I'm still unconvinced that we'll have NAO cooperation for more than 5 days. The wave break in the Atlantic could temporarily induce some higher geopotential heights up near Greenland, but given background conditions, it will be difficult to maintain. I don't see the hemispheric pattern as featuring close commonalities w/ 13-14 and 14-15, thus I'm not expecting that type of reversal. We are more likely to see a continuance of what we experienced in December -- some potent arctic outbreaks interspersed with 50-60 degree surges as the SE ridge burgeons northward.

[Morris]

40 at midnight in the park.

 

[JerseyWx]

3 hours ago, BombsAway1288 said:

We had a day or two just like that in January 14'. I think it was on or around the 7th or 8th. I remember seeing 8 degrees under sunny skies at like 1:15 pm on wunderground stations and some area ASOS's. I believe there were some midnight highs on those days so what went down in the record books is deceiving 

Absolutely, I think it was the 7th.  That whole afternoon stayed around 7 degrees here.  2013-2014 was one heck of a winter, tons of snow and extended cold.  2014-2015 had less snow here, but the cold was very sharp, especially in February.

[nzucker]

2 hours ago, Isotherm said:

 

1975-76 was actually my secondary analog (1973-74 primary) for the winter, so I agree that we could see an interlude similar to that year coming up. 1973-74 and 1975-76 both featured some decent cold periods with not abysmal final snow totals along the coast. Regarding the upcoming period, I'm still unconvinced that we'll have NAO cooperation for more than 5 days. The wave break in the Atlantic could temporarily induce some higher geopotential heights up near Greenland, but given background conditions, it will be difficult to maintain. I don't see the hemispheric pattern as featuring close commonalities w/ 13-14 and 14-15, thus I'm not expecting that type of reversal. We are more likely to see a continuance of what we experienced in December -- some potent arctic outbreaks interspersed with 50-60 degree surges as the SE ridge burgeons northward.

Tom, your posts are amazing, thank you. I think New England/Upstate NY had some excellent snow totals and cold anomalies in January 1976. I believe the cold was strongest near the Great Lakes and Canadian border. Feb 1976 was pretty bland, however. The same thing was true in 1971 and 1985, as well as 2009; January had a potent arctic shot, but that led to a much warmer February. Jan 28, 2009 had 6.5" in Dobbs Ferry, and Maine hit -50F...1985 had the Reagan Inauguration Outbreak...1971 was famous for cold and snow in New England.

The one commonality many of these La Nina winters had is that the cold and snow were short-lived and often did not continue into February. 75-76/73-74/70-71 were slightly below average snowfall winters in NYC, 08-09 around average. I think 20-25" is reasonable for Central Park this year.

I think the pattern is a little better than December. That EPO block looks more long duration, it is combined with a -NAO, and climo is near ideal. You may be shortchanging the pattern a bit though it is hard to pile up a lot of snow at KNYC with SWFEs and clippers, and I don't see the PNA going positive with the EPO block so far west. We want that over Fairbanks, not the Aleutians. Could be a gradient pattern.

Also agree that we don't see a full reversal like 13-14/14-15. There was stuff going on those years that hinted at a pattern change. This year we have a record cold stratosphere with low ozone, so the NAO dip may fade fast once the effecr of the Thursday storm bombing negative tilt is over.

[bluewave]

20 hours ago, pazzo83 said:

The leaf drop was late again this year - we still have some lower level brush and a few trees with leaves.

Yeah, you can still see NYC running cooler than the other sites.

Highs yesterday:

NYC....60

LGA....62

JFK.....62

ISP.....62

EWR...62

[dWave]

52 minutes ago, bluewave said:

Yeah, you can still see NYC running cooler than the other sites.

Highs yesterday:

NYC....60

LGA....62

JFK.....62

ISP.....62

EWR...62

I had to get across the Park yday and didnt want to take a bus so I walked, I went right by the site, I've seen pics but never in person before.  Yeah even with the trees bare not much sun gets there and the ground is still coated with leaves. Its worse than I thought.  

The fact that it still can put together 17-18 straight above normal months is even more remarkable. 

[Brian5671]

that explains why KNYC was a degree cooler in December than surrounding sites....

[CPcantmeasuresnow]

It's now official, all 6 reporting stations in the upton area are above normal for the month including Central Park by 0.4 to 1.8 degrees. With the last 4 days of the month to be near or above normal we should easily continue the above normal streak at 18 months and counting. If it wasn't for June 2015 when Central Park was a mere -0.2 degrees below normal the streak would be at 21.

Almost two years in a row of above normal temperatures. Forgive my frustration but when does it F'n end.

[bluewave]

34 minutes ago, dWave said:

I had to get across the Park yday and didnt want to take a bus so I walked, I went right by the site, I've seen pics but never in person before.  Yeah even with the trees bare not much sun gets there and the ground is still coated with leaves. Its worse than I thought.  

The fact that it still can put together 17-18 straight above normal months is even more remarkable. 

Thanks for the update on the situation with the vegetation there. It's been a while since I saw updated photos from the site.

You can see how the daily highs for December at NYC are averaging the coolest among the local sites.

 

December average high so far

NYC....44.1

LGA....45.9

JFK.....45.8

EWR...44.7

 

 

[CPcantmeasuresnow]

24 minutes ago, bluewave said:

Thanks for the update on the situation with the vegetation there. It's been a while since I saw updated photos from the site.

You can see how the daily highs for December at NYC are averaging the coolest among the local sites.

 

December average high so far

NYC....44.1

LGA....45.9

JFK.....45.8

EWR...44.7

 

 

Or are airports just a bad spot to be taking temperature readings? Some of  the highs, especially at Newark during the warmer months are way high compared to surrounding non urban areas.

[bluewave]

24 minutes ago, CPcantmeasuresnow said:

Or are airports just a bad spot to be taking temperature readings? Some of  the highs, especially at Newark during the warmer months are way high compared to surrounding non urban areas.

The local airport sites don't have anything blocking the sun reaching the sensors like trees or buildings. They are in open areas.

Central Park used to have highs just as warm or warmer than Newark did up until the 1980's. 

Famous July 1977 heatwave

NYC...7/18..100...7/19...102...7/21...104

EWR..7/19.100...7/21...102

[uncle W]

I'm afraid this winter will flounder until late February or March...could it end up severe like 1960?...twt...

[leo1000]

This sure looks interesting.  

 

Michael Ventrice ‏@MJVentrice  3h3 hours ago
The latest ECMWF Ens has trended much stronger with North Pacific "Date-line" ridge that is expected to set up shop late Dec-early Jan.