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December 2020 General Discussions & Observations Thread


bluewave
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1 minute ago, uncle W said:

these are the years with at least one day having a -5sd AO...since 1950...

1959-60.....11/18...11/19...

1962-63.....01/21...

1965-66.....01/28...

1968-69.....02/13...02/15...

1969-70.....03/04...03/05...03/06...03/07...03/08...03/09...03/10...

1976-77.....12/28...12/29...11/11...11/12...11/13...11/14...11/15...11/16...11/17

1977-78.....02/05...02/06...

1984-85.....01/18...01/19...01/20...

2002-03.....10/18...

2009-10.....12/20...12/21...12/22...12/23...12/24...12/25...01/03...01/04...01/05...01/06...02/06...02/14...

2010-11.....12/18...

2012-13.....03/19...03/20...03/21...03/22...

Would be happy to keep company like this.  The race for -5SD is on!

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On 12/21/2020 at 1:23 AM, LibertyBell said:

I have a strong feeling that you believe the coast will have to wait for January for the pattern to benefit us.

 

The block starts out too far south next week on the latest EPS. So the EPS doesn’t leave room for a cold 50/50 low pattern. It looks like milder temperatures this run in the 6-10 day period.
 

DC3B45F5-BAE9-4623-972C-DE1005F7D5B3.thumb.png.520c9378771d2979c115455260a92a0b.png

 

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5 hours ago, Allsnow said:

Niña is dead 

 

 

I completely disagree. This is the strongest trade wind surge we have seen since October. Nino 3.4 is going to drop. Also as Don already pointed out, this is the lowest SOI we’ve had since 2012. Region 3.4 SSTs are solidly in moderate territory. Oceanic and atmospheric indicators certainly show a healthy Niña, not a dead one. It’s also showing that this is very likely to be a slow fade in late winter, not a sudden shift into Neutral/La Nada

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1973-74 is a good analog for this winter so far...that year had the ice storm on 12/16-17...snow and ice on Jan 3rd-4th and 9th-10th...Big thaw the last week in January...Feb starts with frequent light sleet and snow...a surprise 6" snowfall on the 8th...snow on 2/25 is heavy south of the city...surprise snowstorm on 3/29...parting shot on April 10th...snowfall is way ahead of that year so far...10.5" to 2.8"...all we need is the same totals 73-74 had the rest of the way to get to 30" for the season...

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2 hours ago, uncle W said:

1973-74 is a good analog for this winter so far...that year had the ice storm on 12/16-17...snow and ice on Jan 3rd-4th and 9th-10th...Big thaw the last week in January...Feb starts with frequent light sleet and snow...a surprise 6" snowfall on the 8th...snow on 2/25 is heavy south of the city...surprise snowstorm on 3/29...parting shot on April 10th...snowfall is way ahead of that year so far...10.5" to 2.8"...all we need is the same totals 73-74 had the rest of the way to get to 30" for the season...

how much in that 4/10 event?  and what was the biggest event that season and on what date did it occur?  thanks

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3 hours ago, uncle W said:

these are the years with at least one day having a -5sd AO...since 1950...

1959-60.....11/18...11/19...

1962-63.....01/21...

1965-66.....01/28...

1968-69.....02/13...02/15...

1969-70.....03/04...03/05...03/06...03/07...03/08...03/09...03/10...

1976-77.....12/28...12/29...01/11...01/12..01/13...01/14...01/15...01/16...01/17

1977-78.....02/05...02/06...

1984-85.....01/18...01/19...01/20...

2002-03.....10/18...

2009-10.....12/20...12/21...12/22...12/23...12/24...12/25...01/03...01/04...01/05...01/06...02/06...02/14...

2010-11.....12/18...

2012-13.....03/19...03/20...03/21...03/22...

.....................................................................

dates..................-AO

1...01/15/1977.....-7.433...

2...01/16/1977.....-7.331...

3...01/14/1977.....-7.311...

4...01/13/1977.....-6.520...

5...03/05/1970.....-6.365...

6...01/19/1985.....-6.226...

7...01/17/1977.....-6.168...

8...03/06/1970.....-6.114...

9...03/04/1970.....-5.918...

10 11/18/1959.....-5.896...

 

11 12/21/2009.....-5.821...

12 01/12/1977.....-5.802...

13 01/18/1985.....-5.693...

14 03/20/2013.....-5.688...

15 01/20/1985.....-5.581...

16 12/23/2009.....-5.577...

17 11/19/1959.....-5.545...

18 01/03/2010.....-5.533...

19 03/07/1970.....-5.525...

20 03/09/1970.....-5.519...

 

21 12/22/2009.....-5.508...

22 01/04/2010.....-5.403...

23 03/21/2013.....-5.399...

24 01/02/2010.....-5.384...

25 12/20/2009.....-5.341...

26 01/11/1977.....-5.333...

27 03/08/1970.....-5.320...

28 02/05/1978.....-5.291...

29 12/29/1976.....-5.287...

30 02/13/1969.....-5.282...

 

31 12/18/2010.....-5.265...

32 12/24/2009.....-5.256...

33 03/22/2013.....-5.240...

34 12/28/1976.....-5.206...

35 02/06/2010.....-5.205...

36 03/19/2013.....-5.193...

37 01/05/2010.....-5.180...

38 02/14/2010.....-5.132...

39 01/28/1966.....-5.130...

40 03/10/1970.....-5.115...

 

41 02/15/1969.....-5.102...

42 10/18/2002.....-5.098...

43 12/25/2009.....-5.052...

44 02/06/1978.....-5.026...

45 01/21/1963.....-5.010... 

shocked 14-15 isnt in here

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40 minutes ago, LibertyBell said:

how much in that 4/10 event?  and what was the biggest event that season and on what date did it occur?  thanks

a half inch on 4/10 with a record low of 28...Feb 8th 1974 had the largest storm that was 6"...Freehold NJ scored a 11" storm on 2/25///

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Under partly sunny skies, temperatures rose into the middle 40s across the region. High temperatures included: Bridgeport: 46°; Islip: 45°; New York City: 46°; Newark: 47°; and, Philadelphia: 47°.

Across the Atlantic, it was even warmer. Record warmth prevailed in parts of western Europe. Daily record high temperatures included: Brussels: 57°; Chateauroux, France: 63°; Dresden: 59°; Grafenwoehr, Germany: 68° (new December record); Luxembourg: 54°; Paris-Le Bourget: 61°; and, Troyes, France: 61°.

A strong storm could pass to the west of the region on Thursday bringing a period of moderate to heavy rain, high winds, and unseasonably warm temperatures before colder air returns afterward.

In the wake of that storm, the unseasonably warm air will be driven into Atlantic Canada where record high temperatures are likely Friday and perhaps Sunday. Unseasonably cold air will push into Florida. Record low temperatures are possible in some parts of the state, especially along the Gulf Coast and southern portions of the Florida Peninsula, on Friday and perhaps Saturday.

The likely continuation of Arctic blocking into at least the first week of January will provide a higher than climatological probability for above normal snowfall for the December 21-January 10 period. The AO- is particularly important for moderate or significant snowfalls in the New York City and Philadelphia areas.

For the December 15-January 15, 1950-2020 period, the following percentages of select snowstorms have occurred when the AO was negative:

New York City:
4" or more: 66%
6" or more: 80%
10" or more: 86%

Philadelphia:
4" or more: 81%
6" or more: 85%
10" or more: 100%

Further, an AO-/PNA+ pattern is especially favorable for moderate or significant snowstorms during the first half of January. For the January 1-15, 1950-2020 period, daily snowfall reached or exceeded 4" on 1.7% of days in New York City and 1.2% of days in Philadelphia. During AO-/PNA+ patterns, those respective frequencies were 2.3% and 1.7%. In short, moderate or significant snowfalls were 37% more common in New York City and 42% more common in Philadelphia during AO-/PNA+ patterns.

The January 1-10 period likely has more potential than the days leading up to January.  

The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.9°C for the week centered around December 16. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.57°C and the ENSO Region 3.4 anomaly has averaged -1.17°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +22.26 today.

Today, the preliminary Arctic Oscillation (AO) figure was -1.718. The AO has now been negative for 20 consecutive days.

On December 21 the MJO was in Phase 6 at an amplitude of 1.107 (RMM). The December 20-adjusted amplitude was 1.162.

Based on the latest guidance, the probability of a significant stratospheric warming event near or just after the start of January has increased. The highest levels of the stratosphere will warm during the closing days of December.

The recent snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. For now, blocking appears likely to continue into the start of January.

Based on sensitivity analysis applied to the latest guidance, there is an implied 69% probability that New York City will have a warmer than normal December. December will likely finish with a mean temperature near 38.2°.

 

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9 hours ago, uncle W said:

a half inch on 4/10 with a record low of 28...Feb 8th 1974 had the largest storm that was 6"...Freehold NJ scored a 11" storm on 2/25///

sounds like one of those typical 80s storms where Monmouth jackpotted on 2/25..do you have numbers for JFK from that storm?  I would expect something like 4"?

 

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9 hours ago, donsutherland1 said:

Under partly sunny skies, temperatures rose into the middle 40s across the region. High temperatures included: Bridgeport: 46°; Islip: 45°; New York City: 46°; Newark: 47°; and, Philadelphia: 47°.

Across the Atlantic, it was even warmer. Record warmth prevailed in parts of western Europe. Daily record high temperatures included: Brussels: 57°; Chateauroux, France: 63°; Dresden: 59°; Grafenwoehr, Germany: 68° (new December record); Luxembourg: 54°; Paris-Le Bourget: 61°; and, Troyes, France: 61°.

A strong storm could pass to the west of the region on Thursday bringing a period of moderate to heavy rain, high winds, and unseasonably warm temperatures before colder air returns afterward.

In the wake of that storm, the unseasonably warm air will be driven into Atlantic Canada where record high temperatures are likely Friday and perhaps Sunday. Unseasonably cold air will push into Florida. Record low temperatures are possible in some parts of the state, especially along the Gulf Coast and southern portions of the Florida Peninsula, on Friday and perhaps Saturday.

The likely continuation of Arctic blocking into at least the first week of January will provide a higher than climatological probability for above normal snowfall for the December 21-January 10 period. The AO- is particularly important for moderate or significant snowfalls in the New York City and Philadelphia areas.

For the December 15-January 15, 1950-2020 period, the following percentages of select snowstorms have occurred when the AO was negative:

New York City:
4" or more: 66%
6" or more: 80%
10" or more: 86%

Philadelphia:
4" or more: 81%
6" or more: 85%
10" or more: 100%

Further, an AO-/PNA+ pattern is especially favorable for moderate or significant snowstorms during the first half of January. For the January 1-15, 1950-2020 period, daily snowfall reached or exceeded 4" on 1.7% of days in New York City and 1.2% of days in Philadelphia. During AO-/PNA+ patterns, those respective frequencies were 2.3% and 1.7%. In short, moderate or significant snowfalls were 37% more common in New York City and 42% more common in Philadelphia during AO-/PNA+ patterns.

The January 1-10 period likely has more potential than the days leading up to January.  

The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.9°C for the week centered around December 16. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.57°C and the ENSO Region 3.4 anomaly has averaged -1.17°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +22.26 today.

Today, the preliminary Arctic Oscillation (AO) figure was -1.718. The AO has now been negative for 20 consecutive days.

On December 21 the MJO was in Phase 6 at an amplitude of 1.107 (RMM). The December 20-adjusted amplitude was 1.162.

Based on the latest guidance, the probability of a significant stratospheric warming event near or just after the start of January has increased. The highest levels of the stratosphere will warm during the closing days of December.

The recent snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. For now, blocking appears likely to continue into the start of January.

Based on sensitivity analysis applied to the latest guidance, there is an implied 69% probability that New York City will have a warmer than normal December. December will likely finish with a mean temperature near 38.2°.

 

thats why many are gungho on the first third of January, there are plenty of historic examples to choose from

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The next 8 days are averaging 37degs.(29/44).        Making it 32degs., or -2.0.

Month to date is  39.3[+0.5].           Should be 37.3[-0.1] by the 31st.

All models are ZIPPO with any snow for their durations.       As I noted weeks ago, Tampa's 32 straight months w/o a BN one, would end.   As indicated by others, this applies to all of Florida.

38*(54%RH) here at 6am.       37* at 7am.

 

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Morning thoughts...

Today will be partly to mostly sunny. It will remain mild. Temperatures will likely top out in the lower and middle 40s across most of the region. Likely high temperatures around the region include:

New York City (Central Park): 44°

Newark: 45°

Philadelphia: 45°

A strong storm will impact the region tomorrow into Friday. A general 1.00”-2.00” rainfall with locally higher amounts, along with high winds and unseasonably mild readings is likely. Colder air will return later Friday.

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14 hours ago, LibertyBell said:

thats what I was expecting.... we'll have our shot after New Years

We just need the trough out West to shift east under the block after New Years. But you can see how the models are showing more ridge in the East now than 3 days ago to close out the year. The wave break and record block south of Greenland is too south based next week with no room for  cold 50/50 low pattern.

New run

797C6156-F6E1-45DB-A220-7256B4B5E48D.thumb.png.8e15005cb9a210398c66f5729917f21b.png

Old run

 

8A57D9CE-9D46-48BC-A7FC-6D36EB64B11F.thumb.png.5dc5d7521f727d21956729d290172324.png

 

 

 

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45 minutes ago, LongBeachSurfFreak said:

A surprising amount of snow remains on the ground here in south wantagh with 100% coverage. 32 currently has locked the pack back up. This really shows the staying power of ice. 

still full coverage here almost a week later.   I expect today and tonight to get rid of alot of it....

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48 minutes ago, bluewave said:

South Florida and New England will have similar temperatures for a time Christmas morning.

9664B020-A48A-4E03-95E5-DB2722ECB702.gif.8d862d6e2052c3a89e97520cd44264cd.gif

 

Extremes seem to be the current climate standard. Portland say hello to Miami. “and they tell me over and over again my friend that .....” As always 

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1 hour ago, LongBeachSurfFreak said:

A surprising amount of snow remains on the ground here in south wantagh with 100% coverage. 32 currently has locked the pack back up. This really shows the staying power of ice. 

also big snows in December have staying power because of low sun angle and short days.  as long as it doesn't rain lol

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3 hours ago, CIK62 said:

The next 8 days are averaging 37degs.(29/44).        Making it 32degs., or -2.0.

Month to date is  39.3[+0.5].           Should be 37.3[-0.1] by the 31st.

All models are ZIPPO with any snow for their durations.       As I noted weeks ago, Tampa's 32 straight months w/o a BN one, would end.   As indicated by others, this applies to all of Florida.

38*(54%RH) here at 6am.       37* at 7am.

 

looks like the coldest xmas for florida since 1995?  Dec 1995 would be a nice analog ;)

Orlando chances of hitting 32 ?

 

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14 hours ago, jfklganyc said:

There is still snow outside your window. Did we already revert back to the winter is over mentality we had the first week of December?

Yes - same garbage as 2019. Last winter I remember checking my weather app and always seeing cold and snow in the unrealistic 10 day forecast but it never came. 

Oh wait, I had snow and cold in April and May which at that point we are all tired of winter.

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2 hours ago, mikem81 said:

These look really good. Models dont seem to match these

MRF Ensemble North Atlantic Oscillation outlooks

ao.sprd2.gifpna.sprd2.gif

The Pacific is really bad til 1/1 which is partly why but models, especially Op runs can show patterns at day 7-10-14 that don’t look anything like the indices and ultimately correct as you get in closer.  We saw that in recent winters where MJO was raging phase 5 and the AO positive and the GFS of Euro Op run at D10 thinks you’ll have -20 850s with a trof in the east 

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