January 2017 Discussion & Observations

[bluewave]

22 hours ago, Allsnow said:

I'm not sure how long the +pna lasts. The gefs break it down by the start of February and by then we need to hope for good placement of the pv lobe. 

 

 

The EPS and CMC are also retrograding the ridge back toward the Aleutians instead of holding it in the +PNA position over Western Canada.

Just not quite as fast as the GEFS are. So this could be our first indication that this will follow the seasonal trend and not be an extended 

colder pattern but shorter. We may need to cash in on snowfall while we still have a favorable pattern like the last two.

 

 

 

 

[Allsnow]

23 minutes ago, bluewave said:

 

The EPS and CMC are also retrograding the ridge back toward the Aleutians instead of holding it in the +PNA position over Western Canada.

Just not quite as fast as the GEFS are. So this could be our first indication that this will follow the seasonal trend and not be an extended 

colder pattern but shorter. We may need to cash in on snowfall while we still have a favorable pattern like the last two.

 

 

06z gefs bring back the trough in the west and southeast ridge by the end of the run. Going to come down where that pv settles after the displacement. 

[CIK62]

Next 8 days, including today, figure to average a Dec. 2015 busting, +14.5degs.   I estimate a positive surplus of 186 degrees by the morning of the 27th.,  or +7.2degs.

[psuhoffman]

43 minutes ago, Allsnow said:

06z gefs bring back the trough in the west and southeast ridge by the end of the run. Going to come down where that pv settles after the displacement. 

It does but it may not be a long lasting thing. I know many were happy with the last euro weeklies. Day 18 matches day 15 of the EPS well. From there the PV drops into north of Hudson Bay and heights rise in Greenland creating a neutral or slightly neg nao by day 21. Then that trough coming into the west swings through and the pna ridge builds again but partially in response to the changes on the Atlantac side.  As the effects of the mjo diminish we will need that to hand off to or we go right back to the base state we have been stuck in most of winter.  I'm not sold we get that help but things aren't off pace yet. The relaxation of the pna in the feb 2-5 period was predicted. 

[Allsnow]

15 minutes ago, psuhoffman said:

It does but it may not be a long lasting thing. I know many were happy with the last euro weeklies. Day 18 matches day 15 of the EPS well. From there the PV drops into north of Hudson Bay and heights rise in Greenland creating a neutral or slightly neg nao by day 21. Then that trough coming into the west swings through and the pna ridge builds again but partially in response to the changes on the Atlantac side.  As the effects of the mjo diminish we will need that to hand off to or we go right back to the base state we have been stuck in most of winter.  I'm not sold we get that help but things aren't off pace yet. The relaxation of the pna in the feb 2-5 period was predicted. 

Thanks. With the southeast ridge and pv placement we could have some fun in the east. Going to be gradient like with that look. Hopefully we can produce something with the Pna spike to start Feb 

[SnowGoose69]

1 hour ago, Allsnow said:

06z gefs bring back the trough in the west and southeast ridge by the end of the run. Going to come down where that pv settles after the displacement. 

The GFES has more or less had half its members doing that for the last 5-7 days at Day 15-16, then 2-3 days later at Day 12 its a raging +PNA again.  This particular run just had more members doing it.  The GFS just wants to break that pattern down immediately.  It probably breaks down but I would not expect it til maybe 2/12-2/15.

[psuhoffman]

18 minutes ago, SnowGoose69 said:

The GFES has more or less had half its members doing that for the last 5-7 days at Day 15-16, then 2-3 days later at Day 12 its a raging +PNA again.  This particular run just had more members doing it.  The GFS just wants to break that pattern down immediately.  It probably breaks down but I would not expect it til maybe 2/12-2/15.

I posted earlier the day 15-16 EPS and gefs actually match up well with the day 18 of the euro weeklies that everyone loved so much.  But it's a temporary relax. A ridge bridge forms over the top between AK and northern Greenland (as is already starting day 16 on gefs) then the PV is pressed down enough that the trough reforms in the east. That sets up a pretty good look feb 6-14 or so. We get another relax then reload late feb into match. I'm not saying I buy that progression 100% but this relax showing up is not alarm bells going off to me. It was expected. The first warning shot were in trouble would be if we see the PV going right back up to Greenland. 

[donsutherland1]

January 1-18, 2017 Summary:

This is a summary, not a forecast verification. This summary illustrates that the January 1-16, 2017 outcomes are remarkably consistent with what a composite EPO-/PNA-/AO+ pattern would typically produce (500 mb and surface temperature anomalies). There was a difference, namely the trough across Canada did not extend across much of Greenland. As a result, unlike the composite pattern, January 1-16 was warmer than normal across Eastern Canada and much of Greenland.

Finally, I provided New York City’s numbers based on climatology, the composite pattern, and the January 1-18 outcomes (select temperature and snowfall data). Again, the numbers were not wildly different from what the composite pattern would have been expected to produce. If only forecasting the composite pattern with a great deal of accuracy were possible!

In sum, the outcomes to date reveal that those outcomes are not atypical with the synoptic pattern that prevailed. In fact, the composite EPO-/PNA-/AO+ pattern also saw 10% of days register high temperatures of 60° or above; the January 1-18, 2017 outcome was 11%, which is statistically the same.

Sample sizes were 600 dates for the climatology reference period and 73 dates for the EPO-/PNA-/AO+ pattern.

 

[nzucker]

15 hours ago, PB GFI said:

Accountability ....

 

This busted  3 degrees inside 24 hours and 7 degrees in only 48 hours .

 

Makes my 3 day period of a 2 degree bust from 12 days out taste good .

 

Amazing what a NE wind has done since 18z Friday,  just pinned temps in the upper 30s to a  max of  very low  40s 

 

This is the first time I have done this , maybe it will teach some not to throw stones .

This one  was a long time  coming .

 

 

Jan 5-18, which you forecasted to be below normal, has a cumulative surplus of +38. And today and tomorrow will bring the cumulative surplus close to +60, which means we will finish the Jan 5-20 period around +4F. You forecasted this period to be below normal...at verification time, you don't want to own your mistake. We had a torch when you forecast below normal.

The days with NE winds still had significant positive departures because of elevated nighttime lows. Regardless of "feeling chilly," lows in the upper 30s are still +15. As someone said, it should be frigid, it's mid January in the Northeast.

I am wearing my light fall jacket today, already 44F with a forecast high of 52F. Many places will approach 60F.

[pazzo83]

Yup, lows in the upper 30s/40 and highs in the low/mid 40s are January temps in parts of the Mediterranean on a cloudy day, not in the NE US.

[pazzo83]

We have entered an extended period of above-freezing temperatures - will be interesting to see how long it lasts.  The last reading below freezing was 8am on Monday, Jan 16th.

[PB GFI]

41 minutes ago, nzucker said:

Jan 5-18, which you forecasted to be below normal, has a cumulative surplus of +38. And today and tomorrow will bring the cumulative surplus close to +60, which means we will finish the Jan 5-20 period around +4F. You forecasted this period to be below normal...at verification time, you don't want to own your mistake. We had a torch when you forecast below normal.

The days with NE winds still had significant positive departures because of elevated nighttime lows. Regardless of "feeling chilly," lows in the upper 30s are still +15. As someone said, it should be frigid, it's mid January in the Northeast.

I am wearing my light fall jacket today, already 44F with a forecast high of 52F. Many places will approach 60F.

 

100 % of snow in only 10 days . 

 

The 5th thru 20 was took long .  Jan 5 - 18 KNYC + 2.64  BUST . Made 20 days ago - happens 

 

My torch call was Jan 17 - 24 . 

 

However you busted 3 DEGREES  in 1  DAY AND 7 DEGREES IN 2 DAYS

 

 

BUSTS happen , take your disaster like a man , I am . 

 

 

 

 

[bluewave]

11 minutes ago, pazzo83 said:

We have entered an extended period of above-freezing temperatures - will be interesting to see how long it lasts.  The last reading below freezing was 8am on Monday, Jan 16th.

We have taken this amazing extended monthly above normal temperature departure streak to 19 months now.

LGA monthly departures since July 2015:

7/15....+1.8

8/15....+3.0

9/15....+5.0

10/15...+0.3

11/15...+5.0

12/15...+12.6

1/16....+2.7

2/16...+3.1

3/16...+6.8

4/16...+0.5

5/16...+1.1

6/16...+1.4

7/16...+3.7

8/16...+5.3

9/16...+4.7

10/16...+3.1

11/16...+4.0

12/16...+2.1

1/17.....+4.8..... through the 18th

[psv88]

5 minutes ago, PB GFI said:

 

100 % of snow in only 10 days . 

 

The 5th thru 20 was took long .  Jan 5 - 18 KNYC + 2.64  BUST . Made 20 days away - happens 

 

My torch call was Jan 17 - 24 . 

 

However you busted 3 DEGREES  in 1  DAY AND 7 DEGREES IN 2 DAYS

 

 

BUSTS happen , take your disaster like a man , I am . 

 

 

 

 

I dont understand the 100% of snow in 10 days part? The City is still below average for the year in terms of snowfall. 

[pazzo83]

2 minutes ago, psv88 said:

I dont understand the 100% of snow in 10 days part? The City is still below average for the year in terms of snowfall. 

He thinks he crushed his whole forecast bc Central Park got close to their Jan avg in the period referenced.  We are below avg at this point.

[PB GFI]

3 hours ago, psv88 said:

I dont understand the 100% of snow in 10 days part? The City is still below average for the year in terms of snowfall. 

 

NYC  monthly average for JAN is 7 inches for the 31 days .  NYC received 6.9 inches of snow in only 10 days .

 

The forecast was that between the 5 - 20 NYC would have AN snowfall . So the forecast was defined inside those 15 days .

 

If you receive a months worth of snow in only 10 days let alone 15 that`s AN for the period 

[donsutherland1]

3 minutes ago, psv88 said:

I dont understand the 100% of snow in 10 days part? The City is still below average for the year in terms of snowfall. 

I believe he means 100% of January snowfall. To date, January has picked up 6.9" (Central Park) vs. 7.0" normal monthly snowfall. JFK has 11.1" and LGA has 8.9".

[Brian5671]

already closing in on 50 here.  So much for no 50's Thursday or Friday of this week....

[psv88]

1 minute ago, Brian5671 said:

already closing in on 50 here.  So much for no 50's Thursday or Friday of this week....

45 here, was 31 this morning. 

[PB GFI]

14 minutes ago, pazzo83 said:

He thinks he crushed his whole forecast bc Central Park got close to their Jan avg in the period referenced.  We are below avg at this point.

 

Can`t crush the forecast if the temps forecast busted / the snowfall worked . 

 

I am on to late Jan into mid Feb .

 

We will see how that works . 

 

 

[pazzo83]

Fair enough

[qg_omega]

3 hours ago, bluewave said:

We have taken this amazing extended monthly above normal temperature departure streak to 19 months now.

LGA monthly departures since July 2015:

7/15....+1.8

8/15....+3.0

9/15....+5.0

10/15...+0.3

11/15...+5.0

12/15...+12.6

1/16....+2.7

2/16...+3.1

3/16...+6.8

4/16...+0.5

5/16...+1.1

6/16...+1.4

7/16...+3.7

8/16...+5.3

9/16...+4.7

10/16...+3.1

11/16...+4.0

12/16...+2.1

1/17.....+4.8..... through the 18th

Warm ocean temps?  JFK does much better with radational cooling despite being on Jamaica Bay

[bluewave]

16 minutes ago, qg_omega said:

Warm ocean temps?  JFK does much better with radational cooling despite being on Jamaica Bay

We are in good company. About 17% of the planet is running a 12 or more months above normal streak.

 

 

 

[ForestHillWx]

In all seriousness, what is normal? Normal as defined as the baseline between 1981-2010. Ok, then what happens? Being that its 2017, in 3 years, the baseline will be 1991-2020 and we lose the cold 1980's. Can anyone run the numbers on that? How far off are we from 1991-2020?

[uncle W]

1 hour ago, ForestHillWx said:

In all seriousness, what is normal? Normal as defined as the baseline between 1981-2010. Ok, then what happens? Being that its 2017, in 3 years, the baseline will be 1991-2020 and we lose the cold 1980's. Can anyone run the numbers on that? How far off are we from 1991-2020?

ten yr ave.temp....highest.....lowest.
1870's.........51.8..........53.6.........49.4
1880's.........51.6..........53.2.........49.3
1890's.........52.9..........54.6.........50.4
1900's.........53.1..........55.0.........50.7
1910's.........53.0..........55.0.........50.7
1920's.........53.1..........54.9.........51.2
1930's.........54.4..........55.8.........53.0
1940's.........54.3..........56.9.........51.9
1950's.........54.8..........57.0.........52.5
1960's.........54.2..........55.1.........53.0
1970's.........54.6..........56.1.........53.0
1980's.........55.1..........56.0.........54.0
1990's.........55.6..........57.2.........53.7
2000's.........55.1..........56.8.........53.4
2010's.........56.3..........57.3.........54.4

The 1870's and 80's had a steady 20 years averaging 51.7...
From the 1890's to the 1920's Central Park averaged a steady 53.0 for the 40 years... From the 1930's to the 1970's CP averaged a steady 54.5... The 1980's and 90's were warmer averaging 55.4...

[Paragon]

7 hours ago, ForestHillWx said:

In all seriousness, what is normal? Normal as defined as the baseline between 1981-2010. Ok, then what happens? Being that its 2017, in 3 years, the baseline will be 1991-2020 and we lose the cold 1980's. Can anyone run the numbers on that? How far off are we from 1991-2020?

The 1980s weren't all that cold- looks like they were about as warm as the 2000s.  The real accelerated warming that we have seen has actually started in this decade.

[bluewave]

Most local spots are running +4 or higher departures which will continue to climb into next week with the very mild January temperatures.

NYC...+4.3....LGA....+5.2...JFK...+4.4....ISP....+3.6...BDR...+4.7....EWR...+4.6

[CIK62]

Next 8 days will average +12degs.   I estimate a positive surplus of 178 degrees by the morning of the 28th. or +6.6degs.   This should keep going down now till final result for Jan. is known.

Making the last 4 days normal, would leave us at +5.7degs. for Jan.   This must be near 2SD's AN.

This would make the first two months of meteorological winter about +3.3 degs.  To get us to normal for all three months, Feb. would have to be near -7.3degs.

[donsutherland1]

My level of confidence in an EPO-/PNA+/AO+ pattern in which the EPO and PNA would offset the influence of the AO+ during the 2/1-15 period has diminished somewhat overnight. I have not yet given up on that idea, as pattern changes can sometimes be depicted in discontinuous fashion on the guidance in the extended range.

Nevertheless, it’s a risk that deserves some mention especially with a large cluster of ensemble members now indicating that the AO will rise to > +2.000 (one cluster is > +3.000) by the beginning of February.  So far, 24% of the first 51 days of meteorological winter have seen the AO at or above +2.000 and the AO would need to be positive for just one of the remaining 39 days of meteorological winter to have had 50% of days > 0. In short, the AO’s rising to +2.000 or above near the beginning of February would not be out of line with what has occurred so far this meteorological winter.

In any case, by the middle of next week one should have more confidence in what lies ahead for the first two weeks of February.

Should the AO+ take hold of the pattern and begin to dominate, the following sequence of events would be plausible:

1.    The trough that is forecast to develop in the East in the closing days of January (fairly high confidence outcome) would migrate northward, lifting toward or past the Canadian border.
2.    The EPO-PNA ridge would retrograde toward the Aleutians.
3.    The PNA would become weakly positive/neutral, or possibly even go negative.

The 6z GFS ensembles depict that sequence of events culminating in a PNA- pattern near the end of its forecasting range. The EPO-/PNA-/AO+ pattern has been the dominant pattern this winter so far, in the means (EPO- 56% days; PNA- 66% days; AO+ 86% days during the 12/1-1/19 period). So, the 500 mb pattern that is showing up on the GFS ensembles in the extended range is not dissimilar from the overall pattern for winter 2016-17 to date.

By hour 372, the forecast pattern on that guidance is quite similar to the mean 500 mb pattern that prevailed during the February 1-15, 1989 period with a trough that stretches from the Pacific Northwest across Canada toward Greenland and a burgeoning ridge across the Southern United States (ridge placement differs somewhat).

Overall, the February 1-15, 1989 pattern was not exceptionally warm in the northern Mid-Atlantic and New England regions. If one excluded the February 1-2 period during which the temperature spiked much above normal in the Northeast, the temperature anomaly was pretty close to normal. However, the 1989 pattern was not a particularly snowy one in such cities as New York and Philadelphia. Therefore, should the AO+ predominate and drive the pattern back toward the prevalent EPO-/PNA-/AO+ pattern for winter 2016-17, snowfall prospects for the first half of February could be markedly lower than what first appeared likely when the guidance was in consensus on an EPO-/PNA+/AO+ pattern with the EPO and PNA exerting a dominant influence on the pattern. In coming days, we’ll see where things stand.
 
All in all, it still appears that February will have a monthly anomaly that is cooler relative to normal than the January one. There remains a distinct possibility that the month could wind up somewhat cooler than normal as a whole in the Middle Atlantic and Northeast, but it’s too soon to be confident in such an outcome. Pattern persistence argues that the temperature would break above normal. For now, the odds of such an outcome remain somewhat more likely than not.

[SnowGoose69]

Warm as it's been I don't think NYC will end up in the top 10 warmest January's.  It's funny how when you look at the last 20-25 years, even some of the worst winters, January managed to avoid getting into that top 10.