December 2019

[LibertyBell]

58 minutes ago, bluewave said:

Now the Euro is going even more extreme than the GFS with the -EPO block near Alaska next week.This looks like something out of the winter 13-14 and 14-15 playbook.

 

 

14-15 was a lot better (it was colder and snowier) than 13-14.  How was the evolution different between those two winters?

14-15 would have been ideal if the peak of the storms was a bit further to the south and to the west.  It went from a lackluster first half to near historic second half.

 

[CIK62]

I am noticing that the GFS brings the hammer down hard starting the 10th. in a place like Minneapolis et al, with all sub-zero days for the duration of run.    

I believe big things could happen between the 10th---18th even here.

Of course this extreme output can be caused by noise and hash data being ingested.        The analogy of a room full of people, bunched into  various groups, all but one of which  is engaged in some sort of inane palaver.       Can the eavesdropping equipment zero in on the salient group, while filtering the others out---thus learning something of general import, that can be used to make a prediction.   

[forkyfork]

1 hour ago, bluewave said:

Now the Euro is going even more extreme than the GFS with the -EPO block near Alaska next week.This looks like something out of the winter 13-14 and 14-15 playbook.

 

 

the EPS still has a ridge north of alaska on day 10 so that might trend colder too

[Gravity Wave]

45 minutes ago, LibertyBell said:

14-15 was a lot better (it was colder and snowier) than 13-14.  How was the evolution different between those two winters?

14-15 would have been ideal if the peak of the storms was a bit further to the south and to the west.  It went from a lackluster first half to near historic second half.

 

The trough was a little too far east in 2014-15. I remember because I was in Ithaca as it experienced its coldest February in history while SNE was getting repeatedly crushed by storms.

[ForestHillWx]

2014-2015 winter was very cold. The first in our Chester house. I distinctly remember what the gutters looked like loaded with ice/snow and monster icicles. 

[EasternLI]

Here's a very interesting tidbit from the twitterverse. I could be wrong, but I still think this winter is going to be a fun one. 

 

[LibertyBell]

12 minutes ago, ForestHillWx said:

2014-2015 winter was very cold. The first in our Chester house. I distinctly remember what the gutters looked like loaded with ice/snow and monster icicles. 

the ocean temp was 31 lol first time in my life I've seen freezing drizzle because of a sea breeze.....

 

[donsutherland1]

Overall, my forecast for the recent storm was a bad one. The worst outcomes were in the southern and western edge of the snowfall (Allentown and Philadelphia). Later and farther east development of the upper-level low contributed to this outcome. The historic tendency related to the PNA held true for the greater New York City area with 4" or more snowfalls during the first half of December being uncommon when the PNA is negative, as was the case this time around.

Snowfall estimates and verification:

Albany: 12"-18"; Total snowfall: 20.1"
Allentown: 4"-8"; Total snowfall: Trace
Binghamton: 8"-16"; Total Snowfall: 10.7" (within range)
Boston: 5"-10"; Total Snowfall: 7.1" (within range)
Bridgeport: 2"-4" (high uncertainty); Total snowfall: 2.8" (within range)
Hartford: 6"-12"; Total snowfall: 16.4"
Islip: 1"-3"; Total snowfall: 1.9" (within range)
New York City: 3"-6"; Total snowfall: 1.6"
Newark: 3"-6"; Total snowfall: 2.4"
Philadelphia: 3"-6" (high uncertainty); Total snowfall: Trace
Providence: 4"-8"; Total Snowfall: 5.5" (within range)
Worcester: 8"-16"; Total snowfall: 17.0"

In the wake of yesterday's snowfall, brilliant sunshine accompanied by a cold breeze prevailed. Overnight and tomorrow, a weak disturbance could touch off a few snow flurries and snow showers.

The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20.

The SOI was +9.08 today.

Today, the preliminary Arctic Oscillation (AO) figure was +3.059. That is the highest figure since March 29, 2019 when the AO was +3.149.

Daily MJO data has continued to be unavailable. Model initializations can provide a general idea of the MJO's progression and amplitude.

After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. However, the third week of the month could turn colder. There has been growing consensus toward a return of colder air on the guidance.

When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.3" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

[MJO812]

Wow

 

[SnoSki14]

I'm not that impressed going forward. 

The -EPO will deliver transient cold shots but the positive AO/NAO will cause any system to cut and torch us unless we see a very strong -EPO/+PNA pattern like 2013. 

Currently models aren't showing anything that strong. EPS wasn't very good either and models are already backing off any major arctic blast. 

The MJO is another question mark, some models show it moving into the warmer phases but there might be resistance so we'll have to see. 

Best chance at something more favorable will be 3rd week of December.

Overall the month should overall average AN on temps. 

[Tatamy]

Light snow now falling.  Ground covered 33*

[CIK62]

The next 10 days are averaging 41degs., or 2degs. AN.

35* here at 6am.      36* at 7am.    38* by 11am.

btw:     In the 1993 blizzard, the models got everything right 120 hours out, except for the 10"-20" along the southern periphery in the Deep South.       That's a decade of snow for them, in one day.

[MJO812]

6 hours ago, SnoSki14 said:

I'm not that impressed going forward. 

The -EPO will deliver transient cold shots but the positive AO/NAO will cause any system to cut and torch us unless we see a very strong -EPO/+PNA pattern like 2013. 

Currently models aren't showing anything that strong. EPS wasn't very good either and models are already backing off any major arctic blast. 

The MJO is another question mark, some models show it moving into the warmer phases but there might be resistance so we'll have to see. 

Best chance at something more favorable will be 3rd week of December.

Overall the month should overall average AN on temps. 

You weren't impressed with last week and some areas got snow.

The MJO isnt moving into the warm phases. 

[Dan76]

7 hours ago, JustinRP37 said:

Should we open a nostalgia thread? haha j/k

 

[IrishRob17]

3 hours ago, Dan76 said:

 

So if anyone wonders where their nostalgia posts went if they leave this thread check the Memory Lane thread. Good stuff all around. 

[bluewave]

Battle of many competing influences  coming up. Big East Asian Jet extension meets the -EPO. So the have a very fast split flow with an up and down temperature pattern. The question this month will be what happens with the MJO. All the models agree that it is headed for MJO 2. Longer range MJO forecasts are always poor. But every case of a MJO 2 in December since 1975 was followed by a move into phases 4-6. The only difference was the variation in amplitude of those phases.

Big temperature swings coming up

 

 

[Rtd208]

Snow flurries falling here. 

[uncle W]

the ao for 2016...

[ForestHillWx]

Still snowing out this way. Little pack freshener. Very fluffy stuff. 

[gravitylover]

Was it supposed to be flurrying this morning? 

[bluewave]

15 minutes ago, uncle W said:

the ao for 2016...

 

This looks like our first decade with the December AO reaching +3 or higher during 5 years. Ridiculous reversal following the record lows in December 2009 and 2010. Something really changed with the December AO and NAO  after 2010.

Years with AO reaching +3 or higher in December

2019

2016

2015

2013

2011

 

 

[SI Mailman]

Some light flurries here as I do my early morning parcel run. Thank you to everyone who shopped Cyber Monday.

[LongBeachSurfFreak]

Flurries on the uws. Looks like a little ocean effect snow right now on the east end with the return flow

[Brian5671]

1 hour ago, Snow88 said:

You weren't impressed with last week and some areas got snow.

The MJO isnt moving into the warm phases. 

check out Bluewave's post....it likely is, at least for a time.

[Dark Star]

27 minutes ago, gravitylover said:

Was it supposed to be flurrying this morning? 

Flurrying here also in Linden NJ (Tremley Pt.).  There was a slight chance of snow showers predicted for last night (but not by the NWS).

[MJO812]

6 minutes ago, Brian5671 said:

check out Bluewave's post....it likely is, at least for a time.

According to the euro , the MJO will stall out in 2. We will see if that was a hiccup. 

[uncle W]

50 minutes ago, bluewave said:

This looks like our first decade with the December AO reaching +3 or higher during 5 years. Ridiculous reversal following the record lows in December 2009 and 2010. Something really changed with the December AO and NAO  after 2010.

Years with AO reaching +3 or higher in December

2019

2016

2015

2013

2011

 

 

the ao is following the 1959 one...Hopefully the positive time is a s brief as 59...

[CPcantmeasuresnow]

12 hours ago, donsutherland1 said:

Overall, my forecast for the recent storm was a bad one. The worst outcomes were in the southern and western edge of the snowfall (Allentown and Philadelphia). Later and farther east development of the upper-level low contributed to this outcome. The historic tendency related to the PNA held true for the greater New York City area with 4" or more snowfalls during the first half of December being uncommon when the PNA is negative, as was the case this time around.

Snowfall estimates and verification:

Albany: 12"-18"; Total snowfall: 20.1"
Allentown: 4"-8"; Total snowfall: Trace
Binghamton: 8"-16"; Total Snowfall: 10.7" (within range)
Boston: 5"-10"; Total Snowfall: 7.1" (within range)
Bridgeport: 2"-4" (high uncertainty); Total snowfall: 2.8" (within range)
Hartford: 6"-12"; Total snowfall: 16.4"
Islip: 1"-3"; Total snowfall: 1.9" (within range)
New York City: 3"-6"; Total snowfall: 1.6"
Newark: 3"-6"; Total snowfall: 2.4"
Philadelphia: 3"-6" (high uncertainty); Total snowfall: Trace
Providence: 4"-8"; Total Snowfall: 5.5" (within range)
Worcester: 8"-16"; Total snowfall: 17.0"

In the wake of yesterday's snowfall, brilliant sunshine accompanied by a cold breeze prevailed. Overnight and tomorrow, a weak disturbance could touch off a few snow flurries and snow showers.

The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20.

The SOI was +9.08 today.

Today, the preliminary Arctic Oscillation (AO) figure was +3.059. That is the highest figure since March 29, 2019 when the AO was +3.149.

Daily MJO data has continued to be unavailable. Model initializations can provide a general idea of the MJO's progression and amplitude.

After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. However, the third week of the month could turn colder. There has been growing consensus toward a return of colder air on the guidance.

When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.3" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

Boston ended up with 5.9 inches for the three days, still within your range.

Albany ended up with 22.6 inches which is their 8th largest storm of all time.

[frd]

52 minutes ago, uncle W said:

the ao is following the 1959 one...Hopefully the positive time is a s brief as 59...

How was Jan and Feb 1960 in the East, do you recall?  ( silly question , right  ;-) 

  

[uncle W]

16 minutes ago, frd said:

How was Jan and Feb 1960 in the East, do you recall?  ( silly question , right  ;-) 

  

not great...March 3-4 1960 was the big blizzard...