November 2017 Discussions & Observations Thread

[SACRUS]

Record lows 

Place : 11/10; 11/11
 

NYC: 24 (1976) / 27 (1914)
EWR: 27 (2004) / 25 (1956)
LGA:  31(1956) / 29 (1956)
JFK: 28 (2004) / 28 (1973)
TTN: 23 (2003) / 25 (1987, 1956)
PHL: 23 (1976) / 23 (1961)
 

 

[SACRUS]

Dep thru 11/7
 

TTN: +5.0
PHL: +4.8
EWR: +4.5
LGA: +4.3
JFK: +4.0
NYC +4.1: 

[WeatherFeen2000]

Cold day 43 degrees under mostly cloudy skies

[Drz1111]

2 hours ago, SnowGoose69 said:

I'm almost sure December 2010 had that exact pattern and was quite cold 

This time of year with the very stable atmosphere. that can be a particularly cold pattern.  Less so in Feb or March.

[Isotherm]

It appears to me that the upcoming NATL block initiation is due - at least in part - to the circum-global propagation of upper divergence associated with the prior MJO forcing. We recently had a robust phase 8 disturbance, which, while it weakened significantly into the COD on the CPC diagrams, one can still track the eastward propagation of the -VP through the Atlantic and into Africa October 30-Nov7th. This signal induces planetary wave propagation usually resulting in sufficient turbulence to influence the NAO modality approximately 7-10 days later - which, to no surprise, seems to be initiating circa the 13th-15th of November. The forcing for the -NAO is certainly there, but does it have the maintenance power of some of our impressive early blocking stretches such as 2010, 2009, 1995?

[SnowGoose69]

27 minutes ago, Isotherm said:

It appears to me that the upcoming NATL block initiation is due - at least in part - to the circum-global propagation of upper divergence associated with the prior MJO forcing. We recently had a robust phase 8 disturbance, which, while it weakened significantly into the COD on the CPC diagrams, one can still track the eastward propagation of the -VP through the Atlantic and into Africa October 30-Nov7th. This signal induces planetary wave propagation usually resulting in sufficient turbulence to influence the NAO modality approximately 7-10 days later - which, to no surprise, seems to be initiating circa the 13th-15th of November. The forcing for the -NAO is certainly there, but does it have the maintenance power of some of our impressive early blocking stretches such as 2010, 2009, 1995?

The SST configuration in the Atlantic if you ask me is the best this late in the fall in ages.  It's not perfect but way better than the last 3-4 years 

[Stormlover74]

Looks like a decent rainmaker for Monday

[nzucker]

4 hours ago, snowman19 said:

The EPS continues to show a west based -NAO in the long range. However, it is also showing a GOA vortex. If that GOA vortex has staying power, anyone hoping for cold here better pray for a persistent, predominant west based -NAO or you are going to have problems....big problems 

It's typical when you get big Aleutian ridge patterns with a -NAO to see a piece of the vortex left behind over Alaska. This isn't necessarily a bad thing, as long as those low heights aren't the dominant feature on the map, but rather a result of the strong poleward block over the Aleutians.

Dec 2010 was -4F at NYC with 20"+ of snow, and look at 500mb:

 

[snowman19]

33 minutes ago, nzucker said:

It's typical when you get big Aleutian ridge patterns with a -NAO to see a piece of the vortex left behind over Alaska. This isn't necessarily a bad thing, as long as those low heights aren't the dominant feature on the map, but rather a result of the strong poleward block over the Aleutians.

Dec 2010 was -4F at NYC with 20"+ of snow, and look at 500mb:

 

Yes, that’s the question, is the GOA vortex that’s modeled to develop a transient feature? Or is it the beginning of a semi-permanent response we are going to see this winter to the combo of La Niña forcing along with a -QBO (i.e., the relationship Anthony Masiello found in the article I linked from a few years ago)? That’s something we really won’t get a better idea of until late this month....

[MJO812]

10 minutes ago, bluewave said:

The new EPS weeklies and ECMWF monthlies went all in on the MJO induced blocking initiating a long term pattern change. 

 1) Record MJO induced blocking ridge develops near Alaska with near record +500 mb anomalies and record cold here.

2) Heights build across the pole to Greenland and drop the -AO  day 6-10/11-15...vortex pulls back near Alaska and a new trough develops near Northeast under Greenland block

3) Beyond day 15 a +PNA/-EPO ridge develops and continues to build across the pole to Greenland

4) December features a -EPO/+PNA/-AO block extending across the pole to Greenland and a trough over the Northeast 

5) January has a strong Aleutian ridge extending across the top to Greenland...-PNA drops and a "bowl of cold trough" develops near the Great Lakes like February 2014

6) February has a strong -PNA/+AO vortex with strong SE ridge

 

 

Big front loaded winter on the monthlies

[PB GFI]

6 minutes ago, Snow88 said:

Big front loaded winter on the monthlies

They are great In Dec and Jan , a little better than front loaded.

[MJO812]

Strong west based -NAO on the GEFS moving forward.

[PB GFI]

Just a beautiful day 10 - 16 at 500 on the GEFS / matches the EPS.

 

[NJwx85]

Watch Monday, that's a sharp shortwave in an ideal position to produce a miller B.

Only problem is retreating high pressure.

[NJwx85]

Still going to be a nice rainstorm.

[NJwx85]

This won't be the final result, but for posterity.

[bluewave]

1 hour ago, PB GFI said:

They are great In Dec and Jan , a little better than front loaded.

I believe this was the fist run of the upgraded monthlies? The highest skill of the monthlies seems to be the PNA and EPO.

http://ak-wx.blogspot.com/2017/10/new-ecmwf-seasonal-model.html

[SnoSki14]

1 hour ago, PB GFI said:

They are great In Dec and Jan , a little better than front loaded.

Shades of 10/11 I see. I'm sure most of us would take that in a heartbeat. 

It would also be another extreme reversal from the record warm Sep-Oct pattern we've been in. 

[PB GFI]

Too bad that's a 10 day op of the Euro

Really great set up under that block.

 

[NJwx85]

7 minutes ago, PB GFI said:

Too bad that's a 10 day op of the Euro

Really great set up under that block.

 

What's wrong with the day 5 setup?

[PB GFI]

1 minute ago, NJwx85 said:

What's wrong with the day 5 setup?

For the rain and wind people looks good.

If you want a snowstorm day 10 is what you wana see on day 5.

[MJO812]

People are starting to mention 1995-1996 as an analog for this winter.

[NJwx85]

Just now, PB GFI said:

For the rain and wind people looks good.

If you want a snowstorm day 10 is what you wana see on day 5.

It's barely mid-November, putting on the snow blinders already?

 

 

[North and West]

2 minutes ago, Snow88 said:

People are starting to mention 1995-1996 as an analog for this winter.

How so? That's quite a claim to make (not you per se; just in general this far out)

[PB GFI]

8 minutes ago, NJwx85 said:

It's barely mid-November, putting on the snow blinders already?

 

 

For the purposes of looking at high lattitude blocking connecting from the Kara Sea to the Davis Straits with LP running off the Delmarva  then you want to discuss accordingly.

Thats part of the analysis ,  right or wrong.

The calendar doesn't play into parsing a map at 500 or the surface .

[NJwx85]

One big AO/NAO drop in mid-November and people have suddenly decided to throw out the most anomalously snowy Winters on record as an analog. 

While the EPS isn't exactly showing a warm pattern, the cold air seems confined to Northwestern Canada and the Western Atlantic Ridge is nearby the East coast, so a seasonable pattern seems reasonable for the rest of November, one in which shouldn't produce any significant Wintry weather in the East. 

[bluewave]

Dewpoints drop near 0 in NYC with the expected record cold just like November 18-19, 2014.

 

NEW YORK CITY-CENTRAL PARK
 KNYC   GFS MOS GUIDANCE   11/08/2017  1200 UTC                      
 DT /NOV   8/NOV   9                /NOV  10                /NOV  11 
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 
 N/X                    41          52          34          38    24 
 TMP  49 48 47 46 44 43 43 47 50 51 50 51 48 43 37 34 36 36 32 26 25 
 DPT  33 33 33 32 30 30 31 33 35 38 40 42 35 26 17  8  5  3  3  1  3 

NEW YORK CITY       
 KNYC   NAM MOS GUIDANCE   11/08/2017  1200 UTC                      
 DT /NOV   8/NOV   9                /NOV  10                /NOV  11 
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 
 N/X                    41          50          33          38    23 
 TMP  46 45 44 44 43 42 42 44 49 49 49 49 46 41 36 33 36 35 31 26 24 
 DPT  34 34 34 33 33 33 34 34 37 40 42 42 37 29 21 11  7  6  5  4  6 

[NJwx85]

Just now, PB GFI said:

For the purposes of looking at high lattitude blocking connecting from the Kara Sea to the Davis Straits with LP running off the Delmarva  then you want to discuss accordingly.

Thats part of the analysis ,  right or wrong.

The calendar doesn't play into parsing a map at 500 and the surface .

I think the calendar is relevant, because the setup early next week would have delivered a major snowstorm if there was any cold air to work with. Doesn't get much more classic than a strong shortwave driving into high latitude blocking and rolling over.

[PB GFI]

1 minute ago, NJwx85 said:

I think the calendar is relevant, because the setup early next week would have delivered a major snowstorm if there was any cold air to work with. Doesn't get much more classic than a strong shortwave driving into high latitude blocking and rolling over.

There's no blocking on day 5 at all.

There's nothing but LP between HB and Greenland 

Now look at the center of the height field over the D/S by day 10 and see the entire set up is night and day.

That short wave coming around the backside would exit underneath 

Thats a snowstorm for some . 

Again , the post preferenced it was day 10 , but if you see that set up on day 5 this board will be lit

 

[NJwx85]

1 minute ago, PB GFI said:

There's no blocking on day 5 at all.

There's nothing but LP between HB and Greenland 

Now look at the center of the height field over the D/S by day 10 and see the entire set up is night and day.

That short wave coming around the backside would exit underneath 

Thats a snowstorm for some . 

Again , the post preferenced it was day 10 , but if you see that set up on day 5 this board will be lit

 

I never claimed that the setup at day 10 wasn't great, however it's day 10.

If there is no blocking early next week, then what's causing that shortwave to roll over and close off?