November 2021

[MJO812]

13 minutes ago, LibertyBell said:

January is our most reliable month for cold and snow

 

Cold but not snow 

[bluewave]

9 hours ago, LibertyBell said:

why do so many ignore the nao in their forecasts?  long range forecasts are USELESS because nao forecasting isn't reliable.

astrology is more accurate-- the point being how accurate a long range forecast is is no higher than one would expect from randomness 

 

They didn’t ignore the NAO in their forecasts. But a forecast issued on November 8th for the 22-29 is going to miss a few things. Notice how good a job it did with the colder signal for the end of the month. So I would consider that EPS forecast very good for such a long range forecast. Just understand that it underestimated the big +EPO trough in Alaska.  So if  we don’t have a -NAO and the long range EPO verifies more positive, then the temperatures could beat expectations to the upside. That’s why you have to be careful when dealing with a record Pacific Jet and long range forecasts. Maybe someday the models will have AI built in and the forecast limit near 2 weeks can get extended further out in time. 

[SnoSki14]

On 11/1/2021 at 8:55 AM, snowman19 said:

As long as you have troughing over AK and the GOA (+EPO), you aren’t getting arctic cold. That has to change. All -NAO/-AO would do is bring down PAC maritime junk air in that setup. I think we end up with yet another above normal month 

Fail

[BxEngine]

17 minutes ago, SnoSki14 said:

Fail

Listen. Im all for pointing out snowman’s incessant lack of humility for someone who is constantly wrong. But im no so sure YOU should be the one doin it, my dude. Back to the weather. 

[LibertyBell]

36 minutes ago, bluewave said:

They didn’t ignore the NAO in their forecasts. But a forecast issued on November 8th for the 22-29 is going to miss a few things. Notice how well a job it did with the colder signal for the end of the month. So I would consider that EPS forecast very good for such a long range forecast. Just understand that it underestimated the big +EPO trough in Alaska.  So if  we don’t have a -NAO and the long range EPO verifies more positive, then the temperatures could beat expectations to the upside. That’s why you have to be careful when dealing with a record Pacific Jet and long range forecasts. Maybe someday the models will have AI built in and the forecast limit near 2 weeks can get extended further out in time. 

thats a great reason to keep it at 2 weeks until we get that next big technological paradigm shift (AI, like you mentioned.)  Actually the best type of AI is AGI and if that ever happens, it would be a real game changer in every aspect of society (not just science and technology.)

https://www.zdnet.com/article/what-is-artificial-general-intelligence/

 

What is artificial general intelligence?

An Artificial General Intelligence (AGI) would be a machine capable of understanding the world as well as any human, and with the same capacity to learn how to carry out a huge range of tasks.

 

[LibertyBell]

59 minutes ago, MJO812 said:

Cold but not snow 

it actually has been evolving in that direction, it used to be February but our largest snowstorms have been happening in January over the past few decades (with a couple of exceptions- but the largest snowstorms that covered the widest area- like Jan 96 and Jan 16 were, as labeled, in January lol.)

 

 

[bluewave]

17 minutes ago, LibertyBell said:

thats a great reason to keep it at 2 weeks until we get that next big technological paradigm shift (AI, like you mentioned.)  Actually the best type of AI is AGI and if that ever happens, it would be a real game changer in every aspect of society (not just science and technology.)

https://www.zdnet.com/article/what-is-artificial-general-intelligence/

 

What is artificial general intelligence?

An Artificial General Intelligence (AGI) would be a machine capable of understanding the world as well as any human, and with the same capacity to learn how to carry out a huge range of tasks.

 

A recent study improved MJO forecasts out to four weeks using deep learning.

https://www.nature.com/articles/s41467-021-23406-3

Producing accurate weather prediction beyond two weeks is an urgent challenge due to its ever-increasing socioeconomic value. The Madden-Julian Oscillation (MJO), a planetary-scale tropical convective system, serves as a primary source of global subseasonal (i.e., targeting three to four weeks) predictability. During the past decades, operational forecasting systems have improved substantially, while the MJO prediction skill has not yet reached its potential predictability, partly due to the systematic errors caused by imperfect numerical models. Here, to improve the MJO prediction skill, we blend the state-of-the-art dynamical forecasts and observations with a Deep Learning bias correction method. With Deep Learning bias correction, multi-model forecast errors in MJO amplitude and phase averaged over four weeks are significantly reduced by about 90% and 77%, respectively. Most models show the greatest improvement for MJO events starting from the Indian Ocean and crossing the Maritime Continent.

 

[SnowGoose69]

56 minutes ago, bluewave said:

They didn’t ignore the NAO in their forecasts. But a forecast issued on November 8th for the 22-29 is going to miss a few things. Notice how well a job it did with the colder signal for the end of the month. So I would consider that EPS forecast very good for such a long range forecast. Just understand that it underestimated the big +EPO trough in Alaska.  So if  we don’t have a -NAO and the long range EPO verifies more positive, then the temperatures could beat expectations to the upside. That’s why you have to be careful when dealing with a record Pacific Jet and long range forecasts. Maybe someday the models will have AI built in and the forecast limit near 2 weeks can get extended further out in time. 

It does seem that operational runs really struggle when there is a -NAO though in that D5-10 range.  Not that you can really trust Op runs that far out but they will tend to cut systems often and be too warm alot of the time at that range while the GEFS are showing a NAO OF -2 

[Brian5671]

1 hour ago, LibertyBell said:

January is our most reliable month for cold and snow

 

I think Feb might have higher snow fall averages even with a shorter month (28 days vs 31)?

[LibertyBell]

34 minutes ago, Brian5671 said:

I think Feb might have higher snow fall averages even with a shorter month (28 days vs 31)?

It has been traditionally, but I think that's changing.  Before 1996, big January storms ( > 10 inches) were few and far between.  I think if you compare double digit events we're seeing a transition towards them occurring in January more often, especially the really high end events ( > 20 inches).  Before January 1996, I can't find any 20 inch January events.

 

[nycwinter]

2 hours ago, LibertyBell said:

January is our most reliable month for cold and snow

 

in nyc i thought february was..

[psv88]

29 minutes ago, SnowGoose69 said:

I think there is some degree of downslope but it’s not unusual to see them or Nashville be colder than us.  Even in the 85 outbreak they got to like -9 or something insane in Atlanta while NYC was only -2

I went to college there for 4 years, they wedge pretty well and the higher elevations are more to their NE than the NW, so on a NW flow they dont downslope

[the_other_guy]

1 hour ago, psv88 said:

I went to college there for 4 years, they wedge pretty well and the higher elevations are more to their NE than the NW, so on a NW flow they dont downslope

It’s not consistent though. They’re talking about frigid outbreaks where the core is west of us unmoderated, but in general, they are much warmer than us

[donsutherland1]

Tomorrow will witness the return of a milder air mass, but its stay will be short-lived. Another strong cold front will move across the region tomorrow night. In its wake, an unseasonably cold weekend will follow. There is a small chance that a weak system could bring a period of light snow or flurries to parts of the region late Sunday into Monday.

First measurable snowfall statistics for select cities:

Allentown: Normal: December 6; 2020-21: December 9
Bridgeport: Normal: December 3; 2020-21: December 16
Islip: Normal: December 10; 2020-21: December 16
New York City: Normal: December 13; 2020-21: December 16
Newark: Normal: December 9; 2020-21: December 9
Philadelphia: Normal: December 19; 2020-21: December 16

The temperature anomaly for November 20-30 is on course to average below normal due to the development of AO blocking. The recent guidance has been correcting colder in response to this blocking. The Arctic Oscillation fell below -1.000 on November 23. Such strong blocking typically favors a period of colder than normal weather (November 20-30, 1991-2020 period):

Boston: Normal: 42.2°; AO cases: 38.4°
New York City: Normal: 45.5°; AO cases: 41.7°
Philadelphia: Normal: 45.4°; AO cases: 41.7°

The duration of the blocking remains uncertain. Should blocking dissipate, warmer conditions could develop near the start of December. Both the CFSv2 and EPS weeklies favor a return of warmer air at some point during the first week of December.

Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 23 4 pm is 16.28".

Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19.

The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter.

The SOI was +11.90 today.

The preliminary Arctic Oscillation (AO) figure was -1.749 today.

On November 22 the MJO was in Phase 4 at an amplitude of 0.733 (RMM). The November 21-adjusted amplitude was 1.027 (RMM).

Based on sensitivity analysis applied to the latest guidance, there is an implied 98% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.2° (1.8° below normal).

 

[lee59]

Down to 32 already.

[Rjay]

36 here

36 ISP

39 FRG

[Rjay]

Pretty damn cold in the NW surbs.  Already in the 20s at POU.  

[Rjay]

46 at LGA lol

[lee59]

Another quiet wind night creating vast temperature differences from place to place.

[LoboLeader1]

35 here

[the_other_guy]

37F in Hastings

[lee59]

Muttontown, the cold spot of Nassau County, already down to 29.7

[uncle W]

8 hours ago, LibertyBell said:

It has been traditionally, but I think that's changing.  Before 1996, big January storms ( > 10 inches) were few and far between.  I think if you compare double digit events we're seeing a transition towards them occurring in January more often, especially the really high end events ( > 20 inches).  Before January 1996, I can't find any 20 inch January events.

 

before January 1996 there weren't many 20" storms in any months...the blizzard of 88 in March and the Dec 1947...Feb 1961 had over 20" in a few spots but not in Central Park...but the Big Snow came in January 1836...possibly up to 3ft of snow fell...

1836 big snow...

http://chroniclingamerica.loc.gov/lccn/sn83030311/1836-01-11/ed-1/seq-2/

[CIK62]

Like a bad girl friend, the GFS has changed its mind again.      This is a model with no control or self-respect.       It belongs in the oven with your Thanksgiving Day's turkey.        Locking in an AN December now, as above.

 

[lee59]

Got down to 30 degrees here but clouds moving in so that may be my low.

[LibertyBell]

3 hours ago, uncle W said:

before January 1996 there weren't many 20" storms in any months...the blizzard of 88 in March and the Dec 1947...Feb 1961 had over 20" in a few spots but not in Central Park...but the Big Snow came in January 1836...possibly up to 3ft of snow fell...

1836 big snow...

http://chroniclingamerica.loc.gov/lccn/sn83030311/1836-01-11/ed-1/seq-2/

yeah I like to use LGA or JFK for snow measurements they seem to undermeasure the biggies both Feb 1961 and Feb 1969 were undermeasured at the Park and some would contend so was Jan 1996.

 

So Jan 1836 may have had more snow than March 1888?  Was that the below 0 snowstorm or was that a different one Uncle?

Maybe that was Jan 1857

[the_other_guy]

Another odd night of temps

37-39-30F at 630am

That is twice this week with the up and down temps.

Anyone know what is causing this?

Happy Thanksgiving

 

[RippleEffect]

10 minutes ago, jfklganyc said:

Another odd night of temps

37-39-30F at 630am

That is twice this week with the up and down temps.

Anyone know what is causing this?

Happy Thanksgiving

 

probably clouds

[CIK62]

The last 6 days of November are averaging 40degs.(35/45), or -3.

Month to date is  47.9[-1.0].         November should end near  46.3[-1.7].

Reached 49 briefly yesterday.

Today: 50-54, wind w., clear early, clouding up later.       Trace of Snow late weekend.      Big show is Dec. 06, the GFS claims.    Girlfriend shifts cold again and brings the snow{no sniffing},  I mean no kidding-----a 7" line. Lol!

40*(57%RH) here at 6am.      43* at 9am.        50* at Noon.      54* at 1pm.      56* at 2pm.      59* at 3pm.

[bluewave]

I know we talk a lot about El Niño and La Nina. But there seems to be another factor that has been influencing the pattern of our monthly departures. A monthly departure pattern that has been regularly repeating since 2010. We are all familiar with how warm September and a October has been over this period. But this turn to cooler has been a regular feature in November. Notice how closely this November has matched the 2010-2020 composite.