December 2021

[Allsnow]

1 hour ago, snowman19 said:

It did yes, but the late November through mid-late December very cold/snowy prediction has been a bust as has the very weak SPV prediction 

I’m not sure why someone would forecast a weak SPV when it typically gains strength in December. Typical Niña climo usually has December the best month for cold/snow. But lately none of these typical base state normalities seem to be working out 

[MJO812]

6 minutes ago, Allsnow said:

I’m not sure why someone would forecast a weak SPV when it typically gains strength in December. Typical Niña climo usually has December the best month for cold/snow. But lately none of these typical base state normalities seem to be working out 

Alot of forecasts were for a snowy and cold December and a warmup 2nd half.

That might be the opposite just like you said

[psv88]

60 now. 

[qg_omega]

Down to 59 from a 64 high 

[LibertyBell]

27 minutes ago, donsutherland1 said:

Although it was mostly cloudy throughout the region, daily record high temperatures were matched or broken in many parts of the region. Those records included some dusty 19th century antique marks. Record temperatures through 7 pm included:

Allentown: 63° (old record: 61°, 1952 and 1979)
Atlanta: 75° (tied record set in 2007)
Baltimore: 70° (old record: 66°, 1971)
Buffalo: 67° (old record: 61°, 1899)
Harrisburg: 68° (old record: 63°, 1897)
New York City-LGA: 67° (old record: 62°, 1971)
New York City-NYC: 66° (old record: 64°, 1879)
Newark: 68° (old record: 65°, 1966 and 1971)
Philadelphia: 68° (old record: 65°, 1899 and 1971)
Poughkeepsie: 64° (old record: 63°, 1966)
Rochester: 64° (tied record set in 2015)
Scranton: 64° (tied record set in 1979)
Syracuse: 64° (old record: 62°, 1979)
Toronto: 64° (old record: 56°, 1979)
Trenton: 65° (tied record set in 1911)
Washington, DC: 70° (old record: 68°, 1897, 1971 and 1979)
Wilmington, DE: 67° (old record: 66°, 1971)
Wilmington, NC: 80° (old record: 79°, 2007)

Baltimore's 70° temperature was that city's record 189th such day. The previous record was 187 days, which was set in 2017.

A cold front will move across the region this evening and tonight. It could bring some heavy showers and thundershowers, damaging winds, and perhaps some hail. This cold front will bring a transient shot of somewhat cooler air to the region. Another warmup is possible beginning next week.

No Arctic blasts appear likely for the foreseeable future. Overall, through December 20th, there will likely be only some relatively short-lived cool shots. Afterward, the AO could go negative, increasing the opportunity for colder outcomes.

In the Midwest, Chicago has yet to receive its first measurable snowfall through December 10. Only five prior years saw their first measurable snowfall on December 10 or later:

1. December 20, 2012
2. December 16, 1965
3. December 14, 2001
4. December 12, 1946
5. December 10, 2003

The base case is that the closing 10 days of December could turn cooler, though not necessarily cold. Since 1950, there have been 7 cases where the AO averaged +2.000 or above during the first week in December, as has been the case this year. The mean December 21-31 temperature in New York City was 40.2°. The median temperature was 41.5°. The coldest was 35.3° (1951) and the warmest was 44.0° (1979). In short, this historic experience would suggest that there will be no severe Arctic outbreaks in the East this month. It also suggests that New York City will likely have an average temperature of 40° or above this month.

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 -1.1°C and the Region 3.4 anomaly was -0.9°C for the week centered around December 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.87°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 +14.79 today.

The preliminary Arctic Oscillation (AO) figure was +1.368 today

On December 9 the MJO was in Phase 6 at an amplitude of 2.539 (RMM). The December 8-adjusted amplitude was 2.194 (RMM).

Based on sensitivity analysis applied to the latest guidance, there is an implied 88% probability that New York City will have a warmer than normal December (1991-2020 normal). December will likely finish with a mean temperature near 42.4° (3.3° above normal).

 

Don what was the high at JFK? I don't see it listed here, thanks!

 

[donsutherland1]

2 minutes ago, LibertyBell said:

Don what was the high at JFK? I don't see it listed here, thanks!

 

59. It was well short of its daily record due to a persistent onshore wind.

[LibertyBell]

Just now, donsutherland1 said:

59. It was well short of its daily record due to a persistent onshore wind.

how disappointing, I figured the warmth of the airmass would overcome the coolness of the ocean since the ocean isn't very cool this year.

[hudsonvalley21]

63 is still holding here.

[bluewave]

The other problem is that there are forecasts using analogs from a much colder era than we have now. Cold analogs from the 70s to even the mid 90s have not worked out. But we still see forecasts trying to use those colder analogs without success in recent years.  76-77 was the last top 10 coldest winter in our area and nothing has come close since then.

[Brian5671]

6 minutes ago, bluewave said:

The other problem is that there are forecasts using analogs from a much colder era than we have now. Cold analogs from the 70s to even the mid 90s have not worked out. But we still see forecasts trying to use those colder analogs without success in recent years.  76-77 was the last top 10 coldest winter in our area and nothing has come close since then.

100% agree

[IrishRob17]

59 here at 8:20pm, 17 degrees above what should be the normal high, full on torch. 

[greenmtnwx]

1 hour ago, MJO812 said:

Alot of forecasts were for a snowy and cold December and a warmup 2nd half.

That might be the opposite just like you said

Anything longer than a few weeks forecast is garbage as we know. A lot of time is put in, but you may as well throw a dart. 

[IrishRob17]

21 minutes ago, IrishRob17 said:

59 here at 8:20pm, 17 degrees above what should be the normal high, full on torch. 

Up to 61, as expected, right before the front swings through. 

[RippleEffect]

world snow cover

[psv88]

Up to 61

[Stormlover74]

Warmest December day since Christmas eve 2015

[snowman19]

@donsutherland1 @bluewave One of the most well coupled Nina’s in history….

 

[SnoSki14]

40 minutes ago, snowman19 said:

@donsutherland1 @bluewave One of the most well coupled Nina’s in history….

 

Nothing Nina about this pattern.

[CIK62]

The next 8 days are averaging  46degs.(41/51), or +10 >>> +7 nowadays.

Month to date is  44.7[+2.7].       Should be about  45.3[+4.5] by the 20th.

Reached 64 at various times here yesterday.

Today: 46-49, wind nw. and breezy early, m. clear.     There is no BN in sight any longer---just closer to Normal and more frequent accidental leakages of cold.

CFSv2 has the last 5 days of the month at 10BN  and Jan. at 20BN!......but how can you accept the January outlook--if it can't get the last 5 days of December correct?

44*(42%RH) here at 6am. {was 56* at Midnite}   43* at 8am.     50* at 3pm.      46* at 6pm.      43* at 10pm.

[snowman19]

11 minutes ago, bluewave said:

It isn’t our typical December La Niña pattern. But the full latitude -PNA trough in the West is more like what we get in a La Niña February. You can see the models still holding the -PNA trough over the next few weeks. This is generally a continuation of the fall record vortex in the NEPAC.

Recent La Niña February composite 

Forecast

The common theme through the end of the month on all ensembles (EPS, GEFS, GEPS) is the continuation of that -PNA, full latitude trough in the west

[bluewave]

17 hours ago, Allsnow said:

70’s in nj? Highest I see is 64 

Newark had a high of 69° which was the 6th highest December monthly maximum temperature on record.
 

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE NEW YORK, NY
121 AM EST SUN DEC 12 2021

...RECORD HIGH TEMPERATURE SET AT NEWARK NJ...

A RECORD HIGH TEMPERATURE OF 69 WAS SET AT NEWARK NJ YESTERDAY.
THIS BREAKS THE OLD RECORD OF 65 SET IN 1966.

 

Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Dec
Click column heading to sort ascending, click again to sort descending.

Rank	Year	Highest Max Temperature	Missing Count
1	1998	76	0
2	2001	74	0
3	2006	72	0
-	1982	72	0
-	1946	72	0
4	2015	71	0
-	2013	71	0
-	1984	71	0
5	1978	70	0
6	2021	69	20
-	1964	69	0
-	1956	69	0

 

[LibertyBell]

3 hours ago, SnoSki14 said:

Nothing Nina about this pattern.

Yall need to quit being obsessed with ninas and ninos, remember they only cover 20% of the weather here.  It's not like we're on the west coast.

 

[LibertyBell]

27 minutes ago, bluewave said:

It isn’t our typical December La Niña pattern. But the full latitude -PNA trough in the West is more like what we get in a La Niña February. You can see the models still holding the -PNA trough over the next few weeks. This is generally a continuation of the fall record vortex in the NEPAC.

Recent La Niña February composite 

Forecast

fyi this means rolling this pattern forward we may have an entirely different one come February and March if not January.

Do you remember the old axiom that's proven true time and again (with 06-07 being  a great example) that even the most stable of patterns can only last for a total of 8 weeks at most?  The great Chuck called that huge turnaround that winter.

 

[LibertyBell]

11 hours ago, bluewave said:

The other problem is that there are forecasts using analogs from a much colder era than we have now. Cold analogs from the 70s to even the mid 90s have not worked out. But we still see forecasts trying to use those colder analogs without success in recent years.  76-77 was the last top 10 coldest winter in our area and nothing has come close since then.

you're forgetting 2010-11 which I also referenced earlier which is exactly why enso only controls 20% of our weather.  2010-11 was a strong la nina and we got how much cold and snow that winter?  5 FEET!  Atlantic side blocking is way more important than anything else. Analogs like 1916-17 worked out well for 2010-11.

 

 

[LibertyBell]

11 hours ago, bluewave said:

The other problem is that there are forecasts using analogs from a much colder era than we have now. Cold analogs from the 70s to even the mid 90s have not worked out. But we still see forecasts trying to use those colder analogs without success in recent years.  76-77 was the last top 10 coldest winter in our area and nothing has come close since then.

also people around here really don't care about cold, they care about snow, regardless of average monthly temps...so based on that we should do analog forecasting based on snowfall patterns not average temps.  1976-77 was a mediocre winter for snowfall.  Wouldn't want to ever see that kind of winter ever again

 

 

[bluewave]

1 minute ago, LibertyBell said:

you're forgetting 2010-11 which I also referenced earlier which is exactly why enso only controls 20% of our weather.  2010-11 was a strong la nina and we got how much cold and snow that winter?  Atlantic side blocking is way more important than anything else. Analogs like 1916-17 worked out well for 2010-11.

 

 

While ENSO is a part of the pattern, we have been getting irregular expressions of those various ENSO states in recent years. The background warming pattern in December is independent of any ENSO state. 9 out of the last 10 Decembers have been warmer than average.

 

Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec
Click column heading to sort ascending, click again to sort descending.

Year	Mean Avg Temperature	Temperature Departure
2020	39.2	+1.7
2019	38.3	+0.8
2018	40.1	+2.5
2017	35.0	-2.5
2016	38.3	+0.8
2015	50.8	+13.3
2014	40.5	+3.0
2013	38.5	+1.0
2012	41.5	+4.0
2011	43.3	+5.8

[LibertyBell]

Just now, bluewave said:

While ENSO is a part of the pattern, we have been getting irregular expressions of those various ENSO states in recent years. The background warming pattern in December is independent of any ENSO state. 9 out of the last 10 Decembers have been warmer than average.

 

 

Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec
Click column heading to sort ascending, click again to sort descending.

Year	Mean Avg Temperature	Temperature Departure
2020	39.2	+1.7
2019	38.3	+0.8
2018	40.1	+2.5
2017	35.0	-2.5
2016	38.3	+0.8
2015	50.8	+13.3
2014	40.5	+3.0
2013	38.5	+1.0
2012	41.5	+4.0
2011	43.3	+5.8

absolutely, for December at least regardless of anything else forecasting above average December temperatures will get it right 90% of the time.

Here's a bigger challenge....can we change how we do analog forecasting to make it more fruitful?  How about we select analogs based on snowfall patterns, not monthly average temps.  It's easy to forecast above normal average temps nowadays, but there is a disconnect between that and what most winter weather fans care about which is snowfall.  Is there any way to do winter analogs independent of average monthly temperatures and strictly based on snowfall? It seems random at first glance, but there are definitely some patterns to be had, like the one which you mentioned where >3" of December snowfall (regardless of monthly avg temp) results in an above avg snowfall season.  It might be worthwhile to come up with analogs based on snowfall patterns going forward as opposed to temps.....what do you think, Chris?
 

[SnoSki14]

The western trough will be a problem until wavelengths change.

Wouldn't be surprised if March ends up as the coldest/snowiest month. 

[bluewave]

21 minutes ago, LibertyBell said:

absolutely, for December at least regardless of anything else forecasting above average December temperatures will get it right 90% of the time.

Here's a bigger challenge....can we change how we do analog forecasting to make it more fruitful?  How about we select analogs based on snowfall patterns, not monthly average temps.  It's easy to forecast above normal average temps nowadays, but there is a disconnect between that and what most winter weather fans care about which is snowfall.  Is there any way to do winter analogs independent of average monthly temperatures and strictly based on snowfall? It seems random at first glance, but there are definitely some patterns to be had, like the one which you mentioned where >3" of December snowfall (regardless of monthly avg temp) results in an above avg snowfall season.  It might be worthwhile to come up with analogs based on snowfall patterns going forward as opposed to temps.....what do you think, Chris?
 

Snowfall for our area really comes down to getting intervals of -NAO and -AO blocking. But this must be accompanied by a relaxation of the hostile Pacific patterns. While all our winters since the 15-16 Super El Niño have been warmer than average, the snowfall has been up and down. Even though  December warmth has been a winning bet for the last 9 out of 10 years, it’s tough to forecast seasonal snowfall correctly from October or November. 

[LibertyBell]

4 minutes ago, bluewave said:

Snowfall for our area really comes down to getting intervals of -NAO and -AO blocking. But this must be accompanied by a relaxation of the hostile Pacific patterns. While all our winters since the 15-16 Super El Niño have been warmer than average, the snowfall has been up and down. Even though  December warmth has been a winning bet for the last 9 out of 10 years, it’s tough to forecast seasonal snowfall correctly from October or November. 

It seems though if we could just nail that December snowfall forecast (the 3" marker you mentioned) we could at least make a pretty safe bet on whether the winter will be plus or minus snowfall wise.....let's for the sake of simplicity say average NYC snowfall is 30".....do you think it's a safe bet if we just use that one data point and project snowfall for NYC for an entire season just based on December we could say IF snowfall at NYC in December is less than 3" seasonal snowfall will be less than 30" IF snowfall at NYC in December is more than 3" seasonal snowfall will be more than 30"?  Maybe we could make the forecast around Thanksgiving which would maximize its accuracy and come up with a list of analogs around that time?