December 2021

[bluewave]

14 minutes ago, Mr. Kevin said:

Do you really believe we get a legitimate -epo? I think the standing wave would have to break down to get a great propagation of mjo in phase 7 instead of a weak version. Just my opinion 

A west based -EPO with a -PNA and +AO is a warm pattern for us. This is what happened in February 2018. We want a -EPO to link up with a -AO like March 2018. So it may require a stratospheric warming event near the start of January to fully shift the pattern.

[rclab]

6 minutes ago, donsutherland1 said:

Cooler air will return tonight and tomorrow. Afterward, a system could bring light snow to parts of the region on Wednesday. A coating to an inch is possible even in Newark, New York City, and Philadelphia. Some pockets of 1"-3" amounts are possible. Eastern New England will likely see 1"-3" with some locally higher amounts.

No Arctic blasts appear likely for the foreseeable future. Overall, through December 20th, temperatures will likely be warmer than normal in the means with some short-lived cool shots.

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; 2021-22: November 28
Philadelphia: Normal: December 19; 2020-21: December 16

Out West, Denver has yet to see its first measurable snowfall through December 5. The previous record latest first measurable snowfall occurred on November 21, 1934. The progression of Denver's latest first measurable snowfall of the season is as follows:

November 11, 1882
November 16, 1894
November 19, 1931
November 21, 1934

The base case is that the closing 10 days of December could turn cooler, though not necessarily cold. Uncertainty is higher than usual. The evolution of the EPO and AO beyond mid-month will likely determine the outcome for much of the remainder of the month.

Although the MJO moved into Phase 6 at a very high amplitude in recent days, the sample size of cases where the MJO moved into Phase 6 at an amplitude of 1.75 or above during December 1-15 is very small (n=5). Moreover, just a single case occurred during a predominantly EPO+/AO+ pattern and none occurred during a La Niña. Among those five cases, two had a cold or very cold December 21-31 period, one saw near normal conditions, and two had warm conditions. In short, the current high amplitude MJO does not provide a clear signal where things are headed.

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 +16.66 today.

The preliminary Arctic Oscillation (AO) figure was +3.061 today

On December 4 the MJO was in Phase 6 at an amplitude of 2.199 (RMM). The December 3-adjusted amplitude was 2.280 (RMM).

 

Good evening Don. How often can one say that a mile high mountain cloaked city gets its first measurable snow later than a warm ocean hugging coastal metro… As always …

[EasternLI]

6 minutes ago, Mr. Kevin said:

I'm not as smart as you with charts, but what does this mean?

The basic explanation would be. The blue is anomalous trades associated with la nina (standing wave). You can see the warmer colors (MJO) Punch through the la nina standing wave. That's anomalous westerly wind.  At least on this chart from the 12z eps anyway. 

[donsutherland1]

34 minutes ago, rclab said:

Good evening Don. How often can one say that a mile high mountain cloaked city gets its first measurable snow later than a warm ocean hugging coastal metro… As always …

It’s rare. Denver has never had to wait so long for its first measurable snowfall, which should finally occur later this week. There is one winter where Washington, DC saw more snowfall than Denver (1910-11).

[CIK62]

Dec. 07-22      40/51 = 45 = +8, maybe +5 by today's standards for Decembers.        The best analog is 2001 which had a high of 71 today.       1998 analog was 66 today and 75 tomorrow.       We at least escaped that fate.       Both had some BN in the last week of the month.   

[rclab]

2 hours ago, donsutherland1 said:

It’s rare. Denver has never had to wait so long for its first measurable snowfall, which should finally occur later this week. There is one winter where Washington, DC saw more snowfall than Denver (1910-11).

Didn't DC out accumulate Boston one suppressed season? As always.

[MJO812]

The winds are intense here

[donsutherland1]

23 minutes ago, rclab said:

Didn't DC out accumulate Boston one suppressed season? As always.

That has occurred 10 times. The most recent winter was 2009-10 when Washington, DC received 56.1” of snow and Boston saw 35.7”.

[Rjay]

Severe thunderstorm warning for Suffolk 

[WeatherFox]

4 minutes ago, Rjay said:

Severe thunderstorm warning for Suffolk 

 Until 1015 PM EST.

* At 925 PM EST, showers producing damaging winds were located along
  a line extending from 10 miles south of Branford to near Captree
  State Park, moving east at 55 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and power lines.

* Locations impacted include...
  Islip, Riverhead, Centereach, Shirley, Medford, Southold,
  Hauppauge, Ronkonkoma, Manorville, Stony Brook, Patchogue, Middle
  Island, Port Jefferson, Wading River and Center Moriches.

 

[STORMANLI]

45mph gust

[Rjay]

Winds blew through and temps dropped 7 degrees in about 10 minutes.

[Rjay]

14 minutes ago, Rjay said:

Winds blew through and temps dropped 7 degrees in about 10 minutes.

Oops.  It's a malfunction.   Temp went right back up.   Not sure what happened. 

[Snowshack]

11 minutes ago, Rjay said:

Oops.  It's a malfunction.   Temp went right back up.   Not sure what happened. 

BNL shows it too 

https://wx1.bnl.gov/graph.html

 

[Rjay]

14 minutes ago, Snowshack said:

BNL shows it too 

https://wx1.bnl.gov/graph.html

 

Hmm idk lol 

[LibertyBell]

6 hours ago, rclab said:

Didn't DC out accumulate Boston one suppressed season? As always.

2009-10

[LibertyBell]

5 hours ago, donsutherland1 said:

That has occurred 10 times. The most recent winter was 2009-10 when Washington, DC received 56.1” of snow and Boston saw 35.7”.

but DC didn't get more than Denver?

 

[LibertyBell]

4 hours ago, Rjay said:

Hmm idk lol 

its not a huge drop though

you can get that drop during heavy precip

 

[bluewave]

This start of December was a great example of models correcting warmer with an unfavorable -PNA and +AO pattern. The first week of December was originally forecast to be around -2. But the 5 station average is +4.5 through the 6th.

EWR….+5.9

NYC….+3.6

LGA…..+4.4

JFK…..+4.4

ISP…….+4.1

AVG…..+4.5

 

[CIK62]

The next 8 days are averaging 44degs.(38/50), or +6.

Reached 59 here yesterday.

Today: 43-46, wind w., variably cloudy.     No change thru the 23rd.  as of today.

38*(52%RH) here at 6am.{was 47* at Midnite}    37* at 7am.     39* at 9am.      40* at 10am.      42* at Noon.      43* at 1pm.     45* at 3pm.       40* at 7pm..

[donsutherland1]

3 hours ago, LibertyBell said:

but DC didn't get more than Denver?

 

Not in 2009-10. DC got more than Denver in 1910-11.

[donsutherland1]

Morning thoughts…

Today will be partly to occasionally mostly cloudy and noticeably cooler. High temperatures will likely reach the lower and middle 40s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 42°

Newark: 45°

Philadelphia: 45°

Normals:

New York City: 30-Year: 46.7°; 15-Year: 47.2°

Newark: 30-Year: 47.2°; 15-Year: 47.9°

Philadelphia: 30-Year: 48.4°; 15-Year: 49.1°

A system will likely bring some light snow or flurries to the region tomorrow. Little or no accumulation (0.5” or less) is likely in most of the region. Eastern New England could see 1”-3”.

[Roger Smith]

Yesterday, 2021 became a top ten wettest year for NYC ... this is part of a longer list I posted on Friday in this thread. I have copied only the years overtaken since Nov 1st, the full list includes all those passed in October.

NYC passed 2003 and then 1903 on Dec 6th to reach 10th place as shown ... 

Rank __ YEAR ___ TOTAL PRECIP 

_ 01 ____ 1983 ____ 80.56"

_ 02 ____ 2011 ____ 72.81"

_ 03 ____ 1972 ____ 67.03"

_ 04 ____ 2018 ____ 65.55"

_ 05 ____ 1989 ____ 65.11"

_ 06 ____ 2007 ____ 61.67" (needs 2.87"to tie)

_ 07 ____ 1975 ____ 61.21" (needs 2.41" to tie)

_ 08 ____ 1990 ____ 60.92" (needs 2.12" to tie)

_ 09 ____ 2006 ____ 59.89" (needs 1.09" to tie)

 

_ 10 ____ 2021 ____ 58.80" (.42" on Dec 6)

 

_ 11 ____ 1903 ____ 58.52" (passed Dec 6 at .14")

_ 12 ____ 2003 ____ 58.42" (passed Dec 6 at .04")

_ 13 ____ 1889 ____ 58.18" (passed Nov 22)

_ 14 ____ 1913 ____ 58.00" (passed Nov 13)

_ 15 ____ 1973 ____ 57.32" (passed Nov 12) 

[bluewave]

You can see why the models keep correcting warmer from the weekend going forward. They now how one of the deepest -PNA +EPO troughs near NW Canada on record for December. This is accompanied by a 6 sigma Jet max.  So a continuation of the fall record breaking +EPO and Pacific Jet pattern. 
 

[donsutherland1]

The preliminary December 1-7 average for the Arctic Oscillation (AO) is +2.570. Historically, that has been an ominous indication that seasonal snowfall in the major cities of the Northeast (from Philadelphia to Boston) would come in below to much below normal.

[MJO812]

 

[LibertyBell]

20 minutes ago, donsutherland1 said:

The preliminary December 1-7 average for the Arctic Oscillation (AO) is +2.570. Historically, that has been an ominous indication that seasonal snowfall in the major cities of the Northeast (from Philadelphia to Boston) would come in below to much below normal.

2011-12 now has to be the number 1 analog.  Makes sense you mentioned that with the rainfall pattern too and it's a second year la nina (typically la ninas right after el ninos give our best snowfalls of any enso state.)

 

 

[Great Snow 1717]

6 hours ago, LibertyBell said:

but DC didn't get more than Denver?

 

Speaking of Denver, Denver is currently experiencing its 2nd longest spans between last snowfall of the season and first snowfall of the season. As of today the span is 230 days and counting. 

No snow has fallen as of 12/7. This adds on to the latest snowfall on record. The previous record 11/21/1934. Three of the latest snowfalls on record have come within the last 11 years including 11/17/2016 and 11/15/2010. 

[Great Snow 1717]

20 minutes ago, LibertyBell said:

2011-12 now has to be the number 1 analog

 

So far the fall and early winter also remind me of 99-00.  Another non winter. 

[LibertyBell]

2 minutes ago, Great Snow 1717 said:

So far the fall and early winter also remind me of 99-00.  Another non winter. 

But just look at this pattern of awesome that repeats every 10 years lol.

2021-22

2011-12

2001-01

1991-92

1981-82