January 2017 Discussion & Observations

[MJO812]

2 hours ago, snowman19 said:

The ensembles (GEFS, CMC, EPS) are showing yet another repeat of the same pattern we've had all winter long, over and over again, cold for 5 days then back to an extended warmer than normal period again right after. DT just pointed this out on twitter:  https://mobile.twitter.com/DTVaWeatherman/status/824342583275098112

Eps looks very nice moving forward. The first 2 weeks of February should offer snow.

[PaEasternWX]

11 minutes ago, Snow88 said:

Eps looks very nice moving forward. The first 2 weeks of February should offer snow.

could* fixed. Don't jinx it.

[leo1000]

2 hours ago, bluewave said:

The wild card for the February pattern will be the major Kara PV split that the ensembles are showing. If a piece ends up near Japan like the

ensembles have, then it may allow the SE ridge to actually flatten out for more than just a few days at a time. We will see. The strong Kara PV

has been stuck in place all winter so far.

 

 

 

If a major Major Kara split does in fact happen doesn't it have a lot of staying power?. Allowing the cold air to have staying power. 

[snowman19]

2 hours ago, PaEasternWX said:

could* fixed. Don't jinx it.

If you had to pick two major factors out up until this point of the winter that have been a big fly in the ointment for any prolonged high latitude blocking it has been the strong positive QBO and the modoki type La Niña. Everytime a block forms it doesn't last more than a week before it gets torn apart

[Isotherm]

I continue to like the second week of February (centered around the 6th) for reasons mentioned heretofore. Should be a southwest flow event which could produce a moderate snow event w/ sufficient energy infused via the Pacific jet. Neutralization of the geopotential height field in the Arctic will occur, but whether we induce a genuine, protracted NAO/AO domain block will be a function of stratospheric progression. The latest ECMWF now removes the official SSW event w/ mean zonal winds remaining positive through D10, with subsequent re-intensification. As I mentioned in a prior post, I've thought that we're going to need another wave-1 or preferably wave-2 follow up to truly induce a real / efficacious SSW w/ downward propagation. If we accomplished that, later February into March could become quite interesting. If we don't, we're probably going to continue to need to rely on Pacific poleward ridging into the Arctic. Regardless, the vortex is substantially weaker which will allow for an increased propensity of higher geopotential heights in the NAM domain. The takeaway from me continues to be our most conducive pattern of the winter thus far (not saying much), but in an objective sense, not a great pattern for the coast through week 2 (although a snow event is likely the second week of feb).

[Isotherm]

The precursor pattern is quite conducive for a follow up robust wave-2 as well. So if the vortex rebounds post this initial attempt (which I believe it will), I think there's a decent chance it could be fully destroyed in mid February with a more effective warming.

[pazzo83]

Looks like we'll have two days of 50+ highs.  51F at the midnight hour in Central Park.

[CPcantmeasuresnow]

53 minutes ago, pazzo83 said:

Looks like we'll have two days of 50+ highs.  51F at the midnight hour in Central Park.

50 miles away encased in sleet and snow I'm 33

[nzucker]

56 minutes ago, pazzo83 said:

Looks like we'll have two days of 50+ highs.  51F at the midnight hour in Central Park.

It's 50F here in the Bronx at 1am on Jan 26 with mostly clear/broken skies. That's kind of frightening. A cool May/early June night in the middle of winter.

[nzucker]

3 hours ago, snowman19 said:

If you had to pick two major factors out up until this point of the winter that have been a big fly in the ointment for any prolonged high latitude blocking it has been the strong positive QBO and the modoki type La Niña. Everytime a block forms it doesn't last more than a week before it gets torn apart

The +QBO/low solar couplet makes it really hard to see blocking. A lot of the colder Nina winters like 70-71 had more negative QBOs. 10-11 had a lower QBO in a solar minimum which produced a lot more blocking. This probably has to do with the strength of the stratospheric polar vortex Also, a lot of the 60s cold/snowy Ninas were east-based...the warm west ENSO/cold east ENSO produces a much better MJO cycle and hence PAC pattern than the cold west/warm east couplet like this year. 

Also, global temperatures were very low in some of the 1960s/1970s La Ninas. The build-up of cold and high sea ice during the 1973-1976 Strong La Nina event undoubtedly helped lead to the extreme cold of the 76-77 winter (which also had a -EPO/-NAO double block). Since global heights and global temperatures were quite low, and the polar regions MUCH colder, it was harder to see the type of extreme warmth common today in which Central Park gets 12 straight days of 40+ highs in mid January and no one looks askance. If global temperatures were 1C/2F lower, winter temperatures in NYC were probably 2-3C (3.5-5.5F) colder, esp including UHI changes.

1 hour ago, Isotherm said:

The precursor pattern is quite conducive for a follow up robust wave-2 as well. So if the vortex rebounds post this initial attempt (which I believe it will), I think there's a decent chance it could be fully destroyed in mid February with a more effective warming.

I think February will be back and forth with the Feb 1-7 period being cold with at least one snow event, then some warmth after. But I wouldn't be surprised if we had sustained cold from like Feb 25-Mar 20.

Can you explain the differences between a Wave 1 and Wave 2 response? I know they are both energy propagation that weakens the SPV/PNJ, but what is really each one doung?

[PB GFI]

15 hours ago, snowman19 said:

The ensembles (GEFS, CMC, EPS) are showing yet another repeat of the same pattern we've had all winter long, over and over again, cold for 5 days then back to an extended warmer than normal period again right after. DT just pointed this out on twitter:  https://mobile.twitter.com/DTVaWeatherman/status/824342583275098112

 

Non of the  guidance suggests this.

 

 

The guidance is active and we beat the ridge down at 500  after day 10 .

The change date has been the 27th , so once past it we enter into a final push towards winter weather .

February no doubt is the make or break month . If its another short window then its over . But the first half of the month looks to be good with more than 1 chance at accumulating snow .

 

 

[pazzo83]

8 hours ago, CPcantmeasuresnow said:

50 miles away encased in sleet and snow I'm 33

You guys are doing pretty well so far this year.

[pazzo83]

2 hours ago, PB GFI said:

 

Non of the  guidance suggests this.

 

 

The guidance is active and we beat the ridge down at 500  after day 10 .

The change date has been the 27th , so once past it we enter into a final push towards winter weather .

February no doubt is the make or break month . If its another short window then its over . But the first half of the month looks to be good with more than 1 chance at accumulating snow .

 

 

It's not like we haven't threaded the needle already this year.

[PB GFI]

23 minutes ago, pazzo83 said:

It's not like we haven't threaded the needle already this year.

 

Feb may offer a little longer event window than the terrible Dec and Jan windows did . Once past the 15th we may revert back to the same ole . The JMA weeklies are not pretty . 

I am looking for 2 snow events inside the period , with one being significant . 

But the 28 - 15 ish may be ok .  Will wait to see the weeklies post FEB 15  later for a clue . 

 

[PB GFI]

1 minute ago, PaEasternWX said:

Steve D did say early spring around Feb 15th.

 

Day 17 - 30 .

 

The period prior looks good . 

 

[donsutherland1]

In terms of the forecast teleconnections, the most recent GFS ensemble runs have been favoring an EPO-/PNA+ pattern. There is a split among the ensemble members regarding the AO’s evolution. One cluster takes it decidedly negative. Another cluster keeps it positive.

Considering the ensemble runs of the past 7-10 days, it appears likely that the first two weeks of February will likely see somewhat below normal to normal temperatures for the 2-week average. An EPO-/PNA+ pattern could provide opportunities for snowfall to average above normal, as it has typically been associated with an above average frequency of measurable snowfall events and above average 2” or greater snowfall events. Were the PNA to go negative, that development would suggest reduced snowfall prospects. During the second half of February, the gradual shortening of wave lengths would typically result in a PNA- being less hostile to snowfall prospects.

The 1981-2010 climate period was used for the “normal” baseline.

Below are the teleconnection states that have been forecast most frequently during the past week:

February 1-15 Pattern:

Oldest guidance:
EPO-/PNA-/AO+:  Temperatures near normal; below normal frequency of snowfall (previously modeled) – Very close to the February 1-15, 1989 pattern in terms of mean 500 mb height anomalies. This has also been the predominant pattern in the means for winter 2016-17 to date.

Most recent guidance:
EPO-/PNA+/AO+: Temperatures somewhat below normal to near normal; above normal frequency of snowfall, or
EPO-/PNA+/AO-: Below normal temperatures; above normal frequency of snowfall

These are general tendencies. The exact details of the synoptic pattern (ridge-trough positions, etc.) would be critical.

Where things might go in the second half of the month remains quite uncertain. The teleconnections that most typically favored much above normal readings were an EPO+/PNA-/AO+ pattern for that timeframe.  Movement of the teleconnections toward that state would indicate yet another shift away from winter-like conditions.

[uncle W]

the ao/nao/pna forecasts aren't so great this morning...this doesn't mean it can't snow...I'd like to see a good period with a -nao and -ao and hope we see something like that by the end of February...

[snowman19]

4 hours ago, PB GFI said:

 

Non of the  guidance suggests this.

 

 

The guidance is active and we beat the ridge down at 500  after day 10 .

The change date has been the 27th , so once past it we enter into a final push towards winter weather .

February no doubt is the make or break month . If its another short window then its over . But the first half of the month looks to be good with more than 1 chance at accumulating snow .

 

 

I guess we agree. I think the favorable period is February 1st - February 15th. I don't think it's overly cold though (most likely just normal) and I have serious doubts about any big coastal snowstorms during that period, more isentropic/SWFE, maybe a couple of clippers? After the 15th, there is pretty good evidence that we go back into a warm to possibly real warm pattern once again and that's most likely goodbye winter 16-17, fat lady singing 

[WEATHERBUFF]

11 minutes ago, snowman19 said:

I guess we agree. I think the favorable period is February 1st - February 15th. I don't think it's overly cold though (most likely just normal) and I have serious doubts about any big coastal snowstorms during that period, more isentropic/SWFE, maybe a couple of clippers? After the 15th, there is pretty good evidence that we go back into a warm to possibly real warm pattern once again and that's most likely goodbye winter 16-17, fat lady singing 

I think we see a wintry period late Feb thru mid March at least further north and west. The so called normal which is really the 1981-2010 averages are really below normal for recent years.

[dmillz25]

Looks like some snow sunday into monday?

[SnowGoose69]

I think if a big storm happens it's going to be after 2/15.  Prior to that as Don, bluewave and isotherm have posted its probably going to be SWFEs.  Doesn't necessarily mean areas down to the coast can't see 5-10 inches of snow in the next 15-20 days. 

[Stormlover74]

3 minutes ago, dmillz25 said:

Looks like some snow sunday into monday?

Gfs has an inch or so with something more substantial around the 6th, that's been showing up for a while now

[MJO812]

3 minutes ago, dmillz25 said:

Looks like some snow sunday into monday?

Yes

12Z runs looked great moving forward. Plenty of snow chances..

[MJO812]

30 minutes ago, snowman19 said:

I guess we agree. I think the favorable period is February 1st - February 15th. I don't think it's overly cold though (most likely just normal) and I have serious doubts about any big coastal snowstorms during that period, more isentropic/SWFE, maybe a couple of clippers? After the 15th, there is pretty good evidence that we go back into a warm to possibly real warm pattern once again and that's most likely goodbye winter 16-17, fat lady singing 

Pretty good evidence 1 month out?

[snowman19]

13 minutes ago, WEATHERBUFF said:

I think we see a wintry period late Feb thru mid March at least further north and west. The so called normal which is really the 1981-2010 averages are really below normal for recent years.

Once we get to March 1st you really start fighting against the clock for winter south of New England. I would certainly not want to hinge hopes of a "winter comeback" on the month of March

[snowman19]

1 minute ago, Snow88 said:

Pretty good evidence 1 month out?

Have you not seen how the last 3 months have gone or looked at the ensembles? It's the same pattern progression over and over again

[MJO812]

6 minutes ago, snowman19 said:

Once we get to March 1st you really start fighting against the clock for winter south of New England. I would certainly not want to hinge hopes of a "winter comeback" on the month of March

We have had snow into April

[winterwx21]

19 minutes ago, dmillz25 said:

Looks like some snow sunday into monday?

I mentioned a couple days ago that we have to keep an eye out for an inverted trough for Monday. Might be a longshot, but something to keep an eye on. GFS is hinting at it. 

[MJO812]

6 minutes ago, winterwx21 said:

I mentioned a couple days ago that we have to keep an eye out for an inverted trough for Monday. Might be a longshot, but something to keep an eye on. GFS is hinting at it. 

Cmc also

[Allsnow]

Should be the last day of the real torch. What a unreal stretch of warm weather in the heart of winter.