January 2017 Discussion & Observations

[bluewave]

12 minutes ago, PB GFI said:

 

 

Happy New Year Chris , 

Day 11 12 13 are BN at 2M  on the GEFS and the ridge is gone .

It should be .

Day 10 Euro is N with another HP pushing back thru the UMW.

I am not even sure that day 10 ridge is even there , but its gone 11 thru 13 on the GFS.

Happy New Year Paul.  The CMC and Euro ensembles continue to be less aggressive on the blocking near Greenland than the GFS.

The older Euro run had more ridging over it and now it's backing off. The GEFS longer range have been overdone with blocks there

since late November and back off the closer we get. Hopefully, we change this tendency as the winter goes on.

 

Old EPS more blocking near Greenland

 

New run less blocking

 

 

[PB GFI]

3 minutes ago, bluewave said:

Happy New Year Paul.  The CMC and Euro ensembles continue to be less aggressive on the blocking near Greenland than the GFS.

The older Euro run had more ridging over and now it's backing off. The GEFS longer range have been overdone with blocks there

since late November and it starts backing off the closer we get in time. Hopefully, we change this tendency as the winter goes on.

 

Old EPS more blocking near Greenland

 

New tun less blocking

 

 

 

The press of the ridge is -EPO/-WPO HP.

 

I am never concerned about the Atlantic,  the Pacific is always the bigger player.

 

[WEATHERBUFF]

1 hour ago, Animal said:

Morning afd from mt holly nws is calling for a non event. Fish storm/non event.

Mt Holly has been way too cautious in recent years.

[WEATHERBUFF]

23 minutes ago, PB GFI said:

 

The press of the ridge is -EPO/-WPO HP.

 

I am never concerned about the Atlantic,  the Pacific is always the bigger player.

 

Yes we have gotten by the last few year without much help from the Atlantic.

[bluewave]

42 minutes ago, PB GFI said:

 

The press of the ridge is -EPO/-WPO HP.

 

I am never concerned about the Atlantic,  the Pacific is always the bigger player.

 

You need to be concerned about the Atlantic if you want to extend the cold shot longer than the 10 days we got back in December.

Either a strong ridge over the top to Greenland or a flip to +PNA will be necessary to have a longer duration cold period like

we saw during the 13-14 or 14-15 winters. Otherwise, we stay in the rinse repeat pattern since the beginning of December.

[donsutherland1]

Despite some encouragement on some of the guidance (not the latest run of the GFS), I'm not very optimistic about the prospects for a snowstorm Thursday night and Friday. While there could be some impact on the area as the storm moves offshore well south of the region, the synoptic pattern argues that any such event would probably be a light one. The Arctic Oscillation (AO) is forecast to be positive, while the PNA is forecast to be negative.

I took a look at 136 storms that impacted the northern Mid-Atlantic/southern New England areas in January (1950-2016). Based on that sample, significant snowfalls (6" or above) were markedly higher only when the AO was negative. The most favorable set-up was an AO-/PNA+ pattern. That pattern accounted for two-thirds of the 6" or greater snowfalls in January in New York City and all of the 10" or greater snowfalls.

The following were the statistics from the 136 storms that were divided based on the AO and PNA:

% of Storms with 6" or More Snow/Biggest Storm:
AO-/PNA-: 9% (9.1")
AO-/PNA+: 24% (27.5")
AO+/PNA-: 0% (5.8")
AO+/PNA+: 10% (9.8")

Sample Sizes:
AO-/PNA-: 32 Storms
AO-/PNA+: 49 Storms
AO+/PNA-: 25 Storms
AO+/PNA+: 30 Storms

Total: 136 Storms

Assuming the teleconnection forecasts are reasonably accurate (and there is still a lot of uncertainty concerning the AO), the following would represent the sample of storms I examined:

 

[bluewave]

1 hour ago, WEATHERBUFF said:

Yes we have gotten by the last few year without much help from the Atlantic.

We had plenty of help from the Atlantic last winter with the -4.8 January -AO drop setting us up for the historic blizzard.

14-15 didn't have a -PNA to worry about so the -EPO/+PNA block was all that was necessary. 13-14 had a combination

of Atlantic and Pacific blocking to get the job done. When the PNA went negative in February, the block over the pole 

held the cold in place.

[PB GFI]

3 hours ago, bluewave said:

You need to be concerned about the Atlantic if you want to extend the cold shot longer than the 10 days we got back in December.

Either a strong ridge over the top to Greenland or a flip to +PNA will be necessary to have a longer duration cold period like

we saw during the 13-14 or 14-15 winters. Otherwise, we stay in the rinse repeat pattern since the beginning of December.

 

I am only looking at the 15 day period , similar to Dec just with more snow .

 

I am not sure Jan 20 to 30.

I have been focused on the period and the possible snow late week and weekend which I like .

[mimillman]

I've never seen the GFS flip flop so much with forecasts under 168 hours so consistently as the past few days. Completely different representation in the 12z.

[nyblizz44]

4 minutes ago, mimillman said:

I've never seen the GFS flip flop so much with forecasts under 168 hours so consistently as the past few days. Completely different representation in the 12z.

Is it closer with the weekend storm?

[WEATHERBUFF]

1 hour ago, bluewave said:

We had plenty of help from the Atlantic last winter with the -4.8 January -AO drop setting us up for the historic blizzard.

14-15 didn't have a -PNA to worry about so the -EPO/+PNA block was all that was necessary. 13-14 had a combination

of Atlantic and Pacific blocking to get the job done. When the PNA went negative in February, the block over the pole 

held the cold in place.

It's all about timing, but being a Nina  sort of) it may be the cards that we are dealt with.

[WEATHERBUFF]

1 hour ago, bluewave said:

We had plenty of help from the Atlantic last winter with the -4.8 January -AO drop setting us up for the historic blizzard.

14-15 didn't have a -PNA to worry about so the -EPO/+PNA block was all that was necessary. 13-14 had a combination

of Atlantic and Pacific blocking to get the job done. When the PNA went negative in February, the block over the pole 

held the cold in place.

The pattern has not helped the coast much but away from the cities snowfall has been above average.

[mimillman]

4 minutes ago, UlsterCountySnowZ said:

You must not have followed it last year...lol... GFS is extremely pattern specific IMO, it does well in some and awful in others, i would rely on euro, then Nam/RGEM as we get closer... for next weeks events 

I lived in Chicago last winter so I didn't follow it much for east coast events. In the Midwest I believe it's medium range verification scores are higher.

[PB GFI]

4 hours ago, bluewave said:

Happy New Year to you also. The most impressive feature on the map this week is the very strong  -EPO drop. But the ensembles 

continue the theme of not much help from the AO as a piece of the stubborn vortex remains there. Any blocking on the Atlantic

side looks east based. After a mild start to the month, temps cool off for several days before they recover near of after day 10

closer to normal or maybe above.

 

Chris check the 2 M EPS anomalies day 11 thru 15 , they are BN .

 

I can't paste them from my phone , but take a peak .

[thunderbolt]

2 hours ago, donsutherland1 said:

Despite some encouragement on some of the guidance (not the latest run of the GFS), I'm not very optimistic about the prospects for a snowstorm Thursday night and Friday. While there could be some impact on the area as the storm moves offshore well south of the region, the synoptic pattern argues that any such event would probably be a light one. The Arctic Oscillation (AO) is forecast to be positive, while the PNA is forecast to be negative.

I took a look at 136 storms that impacted the northern Mid-Atlantic/southern New England areas in January (1950-2016). Based on that sample, significant snowfalls (6" or above) were markedly higher only when the AO was negative. The most favorable set-up was an AO-/PNA+ pattern. That pattern accounted for two-thirds of the 6" or greater snowfalls in January in New York City and all of the 10" or greater snowfalls.

The following were the statistics from the 136 storms that were divided based on the AO and PNA:

% of Storms with 6" or More Snow/Biggest Storm:
AO-/PNA-: 9% (9.1")
AO-/PNA+: 24% (27.5")
AO+/PNA-: 0% (5.8")
AO+/PNA+: 10% (9.8")

Sample Sizes:
AO-/PNA-: 32 Storms
AO-/PNA+: 49 Storms
AO+/PNA-: 25 Storms
AO+/PNA+: 30 Storms

Total: 136 Storms

Assuming the teleconnection forecasts are reasonably accurate (and there is still a lot of uncertainty concerning the AO), the following would represent the sample of storms I examined:

 

nice work Don 

[psv88]

47. Beautiful January day. 

I see alot of wishcasting on here. Until we see a real +PNA as opposed to a brief spike or a roll over ridge, we will be hard pressed to get any decent snows along the coastal plain. Inland of course is a different story. 

Without the +pna we go to a more thread the needle scenario which can produce. It's just much less likely. 

That being said, obviously the -EPO is helpful to keep the cold air around. But cold air is useless when the mechanisms for east coast amplification arent in place. 

So yea, the pattern will change. But its not clear if it will be a colder and snowier pattern, or just a colder pattern. 

My current view is the coast picks up 3-4" in the next 10 days. I don't think the pattern supports more than that based on current modeling.

[Stormlover74]

50. Starting the year off with double digit departures. Doubt we see any negative double digit departures this month.

[bluewave]

1 hour ago, PB GFI said:

 

Chris check the 2 M EPS anomalies day 11 thru 15 , they are BN .

 

I can't paste them from my phone , but take a peak .

The EPS 2M t's have been running too cold day 11-15 recently. So I am just looking at the teleconnections.

You can see how the cold just can't lock in for more than 5 to 10 days at a time with the unfavorable Atlantic and -PNA.

 

 

 

 

[pazzo83]

2017 starts off with mid 30s along the entire North Slope of Alaska.

Happy New Year!!

[EasternLI]

I don't hate this look on the 12z Euro. If the cutoff low off the west coast can end up a bit further west (more like a rex block under the ridge) it could allow higher heights on the west coast and maybe, maybe we could get something going. I'm NOT saying it happens, just something to look at. Of course we'll probably see a totally different look by tomorrow.

 

 

[PB GFI]

14 minutes ago, pazzo83 said:

2017 starts off with mid 30s along the entire North Slope of Alaska.

Happy New Year!!

 

-EPO

[nzucker]

1 hour ago, thunderbolt said:

nice work Don 

Yes, great stats, Don. Will be hard with the -PNA/+AO, but we can still get a storm if the EPO is significantly negative.

[PB GFI]

11 minutes ago, EasternLI said:

I don't hate this look on the 12z Euro. If the cutoff low off the west coast can end up a bit further west (more like a rex block under the ridge) it could allow higher heights on the west coast and maybe, maybe we could get something going. I'm NOT saying it happens, just something to look at. Of course we'll probably see a totally different look by tomorrow.

 

 

 

I agree . I like the period 

CMC is close 

JMA and UKMET have it .

 

That should come 

 

[pazzo83]

Just now, PB GFI said:

 

-EPO

Kind of ominous though, right?  I mean Barrow (sorry, Utqiaġvik) should not be pushing 40F in January.

[PB GFI]

40 minutes ago, bluewave said:

The EPS 2M t's have been running too cold day 11-15 recently. So I am just looking at the teleconnections.

You can see how the cold just can't lock in for more than 5 to 10 days at a time with the unfavorable Atlantic and -PNA.

 

 

 

 

 

My period is 15 days long and 5 days ago Some posted it was 5 days and done .

 

Its already 10 days in the guidance .

Check out the day 10 Euro OP , you can see the ridge pops for a day , and HP builds back in 

 

[PB GFI]

1 minute ago, pazzo83 said:

Kind of ominous though, right?  I mean Barrow (sorry, Utqiaġvik) should not be pushing 40F in January.

 

Deep anomaly for sure .

[Allsnow]

Sneaky torch day here. Up to 51. This awful winter continues 

[pazzo83]

1 minute ago, Allsnow said:

Sneaky torch day here. Up to 51. This awful winter continues 

52 in lower Manhattan.  Can't draw up many nicer January days unless it's 18F with 0.1 mile viz and heavy snow.

[Allsnow]

1 minute ago, pazzo83 said:

52 in lower Manhattan.  Can't draw up many nicer January days unless it's 18F with 0.1 mile viz and heavy snow.

i think we are in for more days like this. After next week we are going to get mild again 

[CIK62]

CFS as of today:    5-10  BN     11-14  AN       15-16  BN      17-25  AN (with a classic nationwide Jan. Thaw)    26-31  BN    Biggest improvement from last few days is at the end of the run.