December 2023

[SnowGoose69]

3 minutes ago, Brian5671 said:

That's true in January-you don't need a crazy cold airmass like you do in shoulder months like Dec/Mar

You can see that on the 12Z Op run...snow verbatim nearby or overhead in what is really a 2009-2010 type air mass.

[binbisso]

14 minutes ago, Brian5671 said:

That's true in January-you don't need a crazy cold airmass like you do in shoulder months like Dec/Mar

Yeah I don't get it. By January 1st were starting to get to peak climo. Who wants 15° for a high temperature and 0 for a low? We don't need that. We need a favorable 500 mb Pattern with storm sliding on  south of us, which is exactly What guidance is showing. Otherwise it's congrats Richmond.

[Stormlover74]

4 minutes ago, binbisso said:

Yeah I don't get it. By January 1st were starting to get to peak climo. Who wants 15° for a high temperature and 0 for a low? We don't need that. We need a favorable 500 mb Pattern with storm sliding on  south of us, which is exactly What guidance is showing? Otherwise it's congrats Richmond.

Pretty much. Jan 2010 was quite cold but everything was suppressed. Feb wasn't very cold but just cold enough for us to get slammed twice and almost a third 

[Rjay]

58 minutes ago, Stormlover74 said:

And here's snowman to tell us why it's bad news

I see the same issue Nittany and snowman do. 

[40/70 Benchmark]

3 hours ago, bluewave said:

This may be the first time that we had a +PNA -AO in early December with a weak Southeast ridge. 
 

Wouldn't the huge +EPO have something to do with that? I feel like that was more anomalous than the early month NAO, just like the PNA was more anomalous than the NAO last year. And yes, I am sure some of it maybe due to CC, but its more than that IMO.

[NittanyWx]

22 minutes ago, binbisso said:

Yeah I don't get it. By January 1st were starting to get to peak climo. Who wants 15° for a high temperature and 0 for a low? We don't need that. We need a favorable 500 mb Pattern with storm sliding on  south of us, which is exactly What guidance is showing. Otherwise it's congrats Richmond.

There's a large temperature spread between this December anomaly and the number's you're talking about.   However, historically we do better when there's a source airmass in W Canada.

 

I'm pretty clear in that I think the PNA is 'favorable' for a stormier solution, source is not favorable for a decent cold air supply and that leaves us with chances for snow, but less room for error.

[Dark Star]

22 minutes ago, binbisso said:

Yeah I don't get it. By January 1st were starting to get to peak climo. Who wants 15° for a high temperature and 0 for a low? We don't need that. We need a favorable 500 mb Pattern with storm sliding on  south of us, which is exactly What guidance is showing. Otherwise it's congrats Richmond.

Except you don't want Pacific air to our north either...

[EastonSN+]

1 hour ago, North and West said:

Explain this to me like I'm five.

Alaska heights are better, as well as slightly better in Greenland. The more the trough moves west the better.

[Allsnow]

17 minutes ago, EastonSN+ said:

Alaska heights are better, as well as slightly better in Greenland. The more the trough moves west the better.

We probably see that as we get deeper into January. As the mjo wave emerges into p3 imo..

[EastonSN+]

35 minutes ago, NittanyWx said:

There's a large temperature spread between this December anomaly and the number's you're talking about.   However, historically we do better when there's a source airmass in W Canada.

 

I'm pretty clear in that I think the PNA is 'favorable' for a stormier solution, source is not favorable for a decent cold air supply and that leaves us with chances for snow, but less room for error.

If I am not mistaken, we obviously need a track to the south/east of us (i.e. overrunning snow to rain is unlikely) as well as decent intensification and rates. 

[NittanyWx]

Just now, EastonSN+ said:

If I am not mistaken, we obviously need a track to the south/east of us (i.e. overrunning snow to rain is unlikely) as well as decent intensification and rates. 

Missing Canadian HP from your equation.

[jm1220]

33 minutes ago, EastonSN+ said:

If I am not mistaken, we obviously need a track to the south/east of us (i.e. overrunning snow to rain is unlikely) as well as decent intensification and rates. 

In 97-98 we had plenty of storms track SE of us and it was still rain because of the putrid airmass. It should improve as we head into Jan and I’m not saying this is 97-98 again but especially on the coast we’d like a colder airmass nearby to be wrapped into any storm. A good track doesn’t guarantee snow near/east of the city. 

[EastonSN+]

19 minutes ago, jm1220 said:

In 97-98 we had plenty of storms track SE of us and it was still rain because of the putrid airmass. It should improve as we head into Jan and I’m not saying this is 97-98 again but especially on the coast we’d like a colder airmass nearby to be wrapped into any storm. A good track doesn’t guarantee snow near/east of the city. 

Yeah, I must admit I have been raising 97/98 wayyy too much. I BELIEVE that 97/98 had a stronger El Nino but I may be mistaken.

 

[bluewave]

1 hour ago, 40/70 Benchmark said:

Wouldn't the huge +EPO have something to do with that? I feel like that was more anomalous than the early month NAO, just like the PNA was more anomalous than the NAO last year. And yes, I am sure some of it maybe due to CC, but its more than that IMO.

Had stronger +EPOs in early December 1952 and 1959. But were still able to manage an Eastern trough with the -AO +PNA patterns. Keep seeing some version of the Southeast ridge with teleconnection combos that it was usually absent in during the past.
 

 

[MJO812]

Ensembles looking good moving forward after the New Year.

[snowman19]

No argument from me about stormy (all strong/super El Niños are) and a changing pattern. Here is my issue, it is going to take SUSTAINED cross-polar flow to get arctic cold into Canada. All of the arctic air is on the other side of the pole in Eurasia, that’s not debatable, record low snowcover and record low sea ice on our side of the pole too, also fact, not my opinion. If anyone thinks we are getting arctic cold by the start of January, they are going to be very sorely mistaken. Do we cool down? Sure. I think a seasonal cool down at best into the start of January, not “cold” by any means until Canada changes in a very big way

[Brian5671]

You know the pattern is terrible when the storm goes by and the "cold air" after the storm drops the temp to 50.

[brooklynwx99]

6 minutes ago, snowman19 said:

No argument from me about stormy (all strong/super El Niños are) and a changing pattern. Here is my issue, it is going to take SUSTAINED cross-polar flow to get arctic cold into Canada. All of the arctic air is on the other side of the pole in Eurasia, that’s not debatable, record low snowcover and record low sea ice on our side of the pole too, also fact, not my opinion. If anyone thinks we are getting arctic cold by the start of January, they are going to be very sorely mistaken. Do we cool down? Sure. I think a seasonal cool down at best into the start of January, not “cold” by any means until Canada changes in a very big way

we don't need Arctic air to snow... you just need near normal, and ensembles have us near or below normal by the end of the month. Canada can be +10 and it doesn't really matter for our intents and purposes down here

[brooklynwx99]

also that's a bit of a strawman. who is advocating for Arctic cold? I haven't seen anyone say that

[snowman19]

3 minutes ago, brooklynwx99 said:

we don't need Arctic air to snow... you just need near normal, and ensembles have us near or below normal by the end of the month. Canada can be +10 and it doesn't really matter for our intents and purposes down here

Did I say it wasn’t going to snow?

[brooklynwx99]

Just now, snowman19 said:

Did I say it wasn’t going to snow?

based on how strongly you feel about the lack of Arctic air in Canada, yes, I would believe that you'd find it harder for us to snow. I don't think that's a stretch

[brooklynwx99]

the temp anomalies in Canada are a bit overrated IMO. look at Feb 2022. Canada was an icebox, but it didn't matter because the 500mb pattern sucked and the mean storm track was to the west. I would much rather have an above normal Canada if the 500mb pattern leads to coastal storms

 

[Allsnow]

I think the higher hgts in AK wait until we enter p3. Todays eps backed off a bit in the 11-15 day of higher hgts in that area 

[binbisso]

17 minutes ago, brooklynwx99 said:

the temp anomalies in Canada are a bit overrated IMO. look at Feb 2022. Canada was an icebox, but it didn't matter because the 500mb pattern sucked and the mean storm track was to the west. I would much rather have an above normal Canada if the 500mb pattern leads to coastal storms

 

A 100% agree. Just get us to near normal temperature wise on January 1st and I'll roll the dice with that 500 MB pattern the ensembles are showing 

[kingbaus]

Might have day 10 storm to track. Even though it's looking like rain as of now.

[Dark Star]

2 hours ago, brooklynwx99 said:

we don't need Arctic air to snow... you just need near normal, and ensembles have us near or below normal by the end of the month. Canada can be +10 and it doesn't really matter for our intents and purposes down here

>95% you won't get snow with Pacific air...

[donsutherland1]

The powerful storm responsible for bringing record daily rainfall amounts to the Southeast and parts of the Middle Atlantic region, including a possible 24-hour state rainfall record in South Carolina, brought heavy rain to the region overnight into this morning. Gumboro, DE (5.74"); Butler, NJ (5.53"); and, Stockley, DE (5.52") were among locations receiving rainfall of 5" or more today.

A number of 19th century daily rainfall records, including Concord's and Central Park's records from 1876, were broken.

Regional rainfall amounts included:

Albany: 2.13" (old record: 1.52", 1887)
Atlantic City: 2.27" (old record: 1.10", 1986)
Bangor: 2.19" (old record: 0.68", 1975)
Binghamton: 2.06" (old record: 0.90", 1990)
Boston: 1.64" (old record: 1.44", 1951)
Bridgeport: 1.87" (old record: 1.14", 1951)
Burlington: 2.02" (old record: 0.85", 1954)
Concord: 2.28" (old record: 1.60", 1876)
Hartford: 2.17" (old record: 1.95", 1986)
Islip: 1.65" (old record: 1.41", 2012)
Manchester: 2.46" (old record: 1.29", 1954)
New Haven: 1.77" (old record: 1.24", 1961)
New York City-Central Park: 2.21" (old record: 1.30", 1876)
New York City-JFK Airport: 1.47" (old record: 1.32", 1986)
New York City-LaGuardia Airport: 2.13" (old record: 1.29", 1961)
Newark: 2.75" (old record: 1.22", 1951)
Philadelphia: 2.19" (old record: 1.72", 1977)
Poughkeepsie: 2.23" (old record: 1.52", 1887)
Providence: 2.42" (old record: 1.46", 1954)
Scranton: 2.16" (old record: 0.93", 1961)
Trenton: 2.17" (old record: 1.80", 1887)
White Plains: 2.64" (old record: 1.51", 2000)
Worcester: 2.82" (old record: 1.79", 1954)

In the warm sector of the storm, parts of the region also experienced daily record high temperatures. Daily records included:

Bangor: 61° (old record: 53°, 1954 and 2000)
Boston: 63° (old record: 61°, 1915 and tied in 1928 and 1990)
Caribou: 57° (old record: 54°, 2000)
Concord: 62° (old record: 59°, 1928)
Hartford: 64° (old record: 58°, 1954)
Islip: 61° (old record: 59°, 1984)
Manchester: 64° (old record: 54°, 1954)
New Haven: 62° (old record: 54°, 1966 and 2006)
New York City-LaGuardia Airport: 63° (old record: 62°, 2006)
Newark: 64° (tied record set in 1937)
Portland: 59° (old record: 53°, 1996)
Poughkeepsie: 64° (old record: 55°, 1954)
Westfield, MA: 63° (old record: 54°, 1928)
Westhampton: 62° (old record: 56°. 2012 and 2015)
White Plains: 63° (old record: 61°, 2006)
Worcester: 61° (old record: 57°, 1928)

Behind the storm, it will turn colder, but not severely cold. Tomorrow could see variably cloudy conditions with some passing snow flurries or snow showers, generally well north and west of New York City and Newark.

No Arctic air appears likely through the remainder of December. A transition to a colder pattern could commence during the first week of January. Severe cold appears unlikely early in the transition.

The ENSO Region 1+2 anomaly was +1.5°C and the Region 3.4 anomaly was +2.0°C for the week centered around December 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +1.85°C and the ENSO Region 3.4 anomaly has averaged +1.95°C. A basinwide El Niño event is ongoing. El Niño conditions may strengthen somewhat further this month.  

The SOI was +7.42 today.

The preliminary Arctic Oscillation (AO) was +2.835 today. Strong blocking in the final week of November, as occurred this year, has often been followed by frequent blocking in December and January.

On December 16 the MJO was in Phase 7 at an amplitude of 1.737 (RMM). The December-adjusted amplitude was 1.617 (RMM).

Based on sensitivity analysis applied to the latest guidance, there is an implied 95% probability that New York City will have a warmer than normal December (1991-2020 normal). December will likely finish with a mean temperature near 42.5° (3.4° above normal).

 

[brooklynwx99]

1 minute ago, Dark Star said:

>95% you won't get snow with Pacific air...

that's not Pacific air. the source region is out of northern Canada

[the_other_guy]

2 hours ago, Brian5671 said:

You know the pattern is terrible when the storm goes by and the "cold air" after the storm drops the temp to 50.

it’s gonna be quite the cold week. Just let’s have some patience. 

[snowman19]

The powerful storm responsible for bringing record daily rainfall amounts to the Southeast and parts of the Middle Atlantic region, including a possible 24-hour state rainfall record in South Carolina, brought heavy rain to the region overnight into this morning. Gumboro, DE (5.74"); Butler, NJ (5.53"); and, Stockley, DE (5.52") were among locations receiving rainfall of 5" or more today.
A number of 19th century daily rainfall records, including Concord's and Central Park's records from 1876, were broken.
Regional rainfall amounts included:
Albany: 2.13" (old record: 1.52", 1887)
Atlantic City: 2.27" (old record: 1.10", 1986)
Bangor: 2.19" (old record: 0.68", 1975)
Binghamton: 2.06" (old record: 0.90", 1990)
Boston: 1.64" (old record: 1.44", 1951)
Bridgeport: 1.87" (old record: 1.14", 1951)
Burlington: 2.02" (old record: 0.85", 1954)
Concord: 2.28" (old record: 1.60", 1876)
Hartford: 2.17" (old record: 1.95", 1986)
Islip: 1.65" (old record: 1.41", 2012)
Manchester: 2.46" (old record: 1.29", 1954)
New Haven: 1.77" (old record: 1.24", 1961)
New York City-Central Park: 2.21" (old record: 1.30", 1876)
New York City-JFK Airport: 1.47" (old record: 1.32", 1986)
New York City-LaGuardia Airport: 2.13" (old record: 1.29", 1961)
Newark: 2.75" (old record: 1.22", 1951)
Philadelphia: 2.19" (old record: 1.72", 1977)
Poughkeepsie: 2.23" (old record: 1.52", 1887)
Providence: 2.42" (old record: 1.46", 1954)
Scranton: 2.16" (old record: 0.93", 1961)
Trenton: 2.17" (old record: 1.80", 1887)
White Plains: 2.64" (old record: 1.51", 2000)
Worcester: 2.82" (old record: 1.79", 1954)
In the warm sector of the storm, parts of the region also experienced daily record high temperatures. Daily records included:
Bangor: 61° (old record: 53°, 1954 and 2000)
Boston: 63° (old record: 61°, 1915 and tied in 1928 and 1990)
Caribou: 57° (old record: 54°, 2000)
Concord: 62° (old record: 59°, 1928)
Hartford: 64° (old record: 58°, 1954)
Islip: 61° (old record: 59°, 1984)
Manchester: 64° (old record: 54°, 1954)
New Haven: 62° (old record: 54°, 1966 and 2006)
New York City-LaGuardia Airport: 63° (old record: 62°, 2006)
Newark: 64° (tied record set in 1937)
Portland: 59° (old record: 53°, 1996)
Poughkeepsie: 64° (old record: 55°, 1954)
Westfield, MA: 63° (old record: 54°, 1928)
Westhampton: 62° (old record: 56°. 2012 and 2015)
White Plains: 63° (old record: 61°, 2006)
Worcester: 61° (old record: 57°, 1928)
Behind the storm, it will turn colder, but not severely cold. Tomorrow could see variably cloudy conditions with some passing snow flurries or snow showers, generally well north and west of New York City and Newark.
No Arctic air appears likely through the remainder of December. A transition to a colder pattern could commence during the first week of January. Severe cold appears unlikely early in the transition.
The ENSO Region 1+2 anomaly was +1.5°C and the Region 3.4 anomaly was +2.0°C for the week centered around December 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +1.85°C and the ENSO Region 3.4 anomaly has averaged +1.95°C. A basinwide El Niño event is ongoing. El Niño conditions may strengthen somewhat further this month.  
The SOI was +7.42 today.
The preliminary Arctic Oscillation (AO) was +2.835 today. Strong blocking in the final week of November, as occurred this year, has often been followed by frequent blocking in December and January.
On December 16 the MJO was in Phase 7 at an amplitude of 1.737 (RMM). The December-adjusted amplitude was 1.617 (RMM).
Based on sensitivity analysis applied to the latest guidance, there is an implied 95% probability that New York City will have a warmer than normal December (1991-2020 normal). December will likely finish with a mean temperature near 42.5° (3.4° above normal).
 

Extremely likely now that this El Niño peaks as a “low-end” trimonthly super event for NDJ. As per @Gawx the official ERSST that NOAA uses has been running even warmer than the OISST. We probably see something like a +2.1C for the trimonthly average