Medium Range Discussion Winter 2011-12

[donsutherland1]

Don, what do you think of JBs thoughts for a cold February?

From his twitter page:

http://www.weatherbe...january-28-2012

Ottawa Blizzard,

I believe my biggest area of difference from JB (at least from the video) is the assumption that the changes taking place will lock in. Indeed, the AO information I cited earlier and the relevant February cases paint a picture of even more widespread warm anomalies than my February guess (top image). A comparison is below:

Much of Canada would also be milder than normal in the February 1952, 1954, 1986, 2003, and 2005 composite.

Having said this, my February thoughts do not preclude at least some cold, even a colder than normal period during February. Also, as is the case with any long-range forecast, there is significant risk of error.

[donsutherland1]

Most of those years show up quite dissimilar to this one, in progression. I've liked the colder February idea this year due to systematic progression coherent with the Sun, while contrary to statistically based methods, I feel it probably could have been seen above the fray if systematic progression had been weighted higher than dissimilar analogs were weighted.

2005/06, 2006/07, 1967/68, and 1898/99 have followed a similar progression broad scale, in my eyes. 3/4 of those were -ENSO, and all had low geomagnetic activity by a big margin.

Aside from the indication of February's AO probably averaging negative, this information is not the basis of my February forecast. It is interesting to note that the February cases I cited were also generally mild ones and the composite featured even more warmth than my thinking.

[Chris L]

Most of those years show up quite dissimilar to this one, in progression. I've liked the colder February idea this year due to systematic progression coherent with the Sun, while contrary to statistically based methods, I feel it probably could have been seen above the fray if systematic progression had been weighted higher than dissimilar analogs were weighted.

2005/06, 2006/07, 1967/68, and 1898/99 have followed a similar progression broad scale, in my eyes. 3/4 of those were -ENSO, and all had low geomagnetic activity by a big margin.

February 1899? The King of all February(s)?

[donsutherland1]

February 1899? The King of all February(s)?

Chris,

During January 1899, almost all of the Arctic region was covered by below to much below normal readings. A large body of exceptional cold was available and the pattern that unfolded allowed it to flood into the U.S. In contrast, during the January 1-23, 2012 period, much of the Arctic has been covered by above to much above normal readings. Even if the same synoptic pattern evolved in the same fashion as 1899 this coming February, the outcome would be much more moderate in terms of the magnitude of cold.

[Chris L]

Chris,

During January 1899, almost all of the Arctic region was covered by below to much below normal readings. A large body of exceptional cold was available and the pattern that unfolded allowed it to flood into the U.S. In contrast, during the January 1-23, 2012 period, much of the Arctic has been covered by above to much above normal readings. Even if the same synoptic pattern evolved in the same fashion as 1899 this coming February, the outcome would be much more moderate in terms of the magnitude of cold.

Yes, that's what I believed, Don; tremendous cold.

I am surprise that he (BethesdaWX) would used that analog.

[BethesdaWX]

Aside from the indication of February's AO probably averaging negative, this information is not the basis of my February forecast. It is interesting to note that the February cases I cited were also generally mild ones and the composite featured even more warmth than my thinking.

Why do you suspect the changes won't lock in? The +PNA looks legit as would be favored with a progressing MJO wave, and atmospheric components to La Nina had already been weakening [atmospheric wind/pressure budget change precedes change in SSTAs].

Also to mention, weak to barely moderate La Ninas tend to favor colder Februaries in the East anyway, especially in years like this with a +PNA average

[uncle W]

with the AO at -3.230, how does it stack up with winters since 1949-50...is it the low for this winter?...I hope not... I hope it continues the downward trend...

lowest daily winter ao value since 1950.....

season.......value.....date.....

1949-50......-2.854.....3/15/50.....

1950-51......-4.353.....12/27/50...

1951-52......-3.805.....3/4/1952...

1952-53......-3.766.....12/27/52...

1953-54......-3.495.....1/30/54......

1954-55......-3.064.....1/4/55........

1955-56......-4.564.....2/15/56......

1956-57......-4.473.....2/21/57......

1957-58......-4.030.....3/11/58......

1958-59......-4.026.....1/7/59........

1959-60......-4.108.....1/28/60.......

1960-61......-2.719.....1/10/61.....

1961-62......-4.417.....3/4/62.........

1962-63......-5.010.....1/21/63.......

1963-64......-4.470.....12/20/63....

1964-65......-3.973.....1/26/65.......

1965-66......-5.130.....1/28/66......

1966-67......-4.147.....12/13/66.....

1967-68......-3.490.....2/7/68.........

1968-69......-5.282.....2/13/69......

1969-70......-6.365.....3/5/70.........

1970-71......-2.821.....2/6/71.........

1971-72......-1.490.....1/1/72.........

1972-73......-2.044.....12/17/72.....

1973-74......-2.792.....12/19/73...

1974-75......-1.695.....12/18/74...

1975-76......-3.262.....1/24/76.......

1976-77......-7.433.....1/15/77.......

1977-78......-5.291.....2/5/78.........

1978-79......-4.387.....1/25/79.......

1979-80......-3.705.....1/24/80.......

1980-81......-4.318.....3/4/81.........

1981-82......-3.804.....12/30/81....

1982-83......-3.410.....2/6/83.........

1983-84......-3.706.....3/13/84......

1984-85......-6.226.....1/19/85......

1985-86......-3.894......2/6/86.......

1986-87......-3.507.....3/9/87........

1987-88......-2.314.....2/28/88.......

1988-89......-0.318.....3/4/89........

1989-90......-3.482.....12/10/89....

1990-91......-3.381.....3/9/91........

1991-92......-2.597.....12/4/91.....

1992-93......-2.228.....3/2/93.......

1993-94......-3.503.....2/24/94.....

1994-95......-3.116.....3/9/95.......

1995-96......-4.353.....12/19/95..

1996-97......-3.377.....12/30/96.....

1997-98......-4.269.....1/10/98......

1998-99......-3.856.....3/10/99.....

1999-00......-2.118.....2/18/00.....

2000-01......-4.854.....2/25/01....

2001-02......-3.293.....12/28/01..

2002-03......-3.575.....1/22/03....

2003-04......-4.387.....1/17/04....

2004-05......-4.337.....2/26/05....

2005-06......-3.569.....12/5/05....

2006-07......-2.184.....2/4/07......

2007-08......-2.468.....1/2/08......

2008-09......-3.178.....2/3/09.......

2009-10......-5.821.....12/21/09...

2010-11......-5.172.....12/18/10..

2011-12......-4.441.....1/29/12

[BethesdaWX]

Yes, that's what I believed, Don; tremendous cold.

I am surprise that he (BethesdaWX) would used that analog.

There was more in the way of Sea Ice then, but atmospheric progression large scale has been similar, raging + AO in December and January, PAC NW got cold in January with a SE ridge present, February developed the -AO/-NAO.

It was also a weak Nina, -PDO, +AMO, and similar solar magnetic state.

[Chris L]

There was more in the way of Sea Ice then, but atmospheric progression large scale has been similar, raging + AO in December and January, PAC NW got cold in January with a SE ridge present, February developed the -AO/-NAO.

It was also a weak Nina, -PDO, +AMO, and similar solar magnetic state.

Fair points, I have seen your forecast, and I hope you do very well in terms of snowfall amounts; and February, can be a very fun month for us all if we can get a decent -NAO... I think February 10-15 time frame is ripe for us.

[donsutherland1]

Why do you suspect the changes won't lock in? The +PNA looks legit as would be favored with a progressing MJO wave, and atmospheric components to La Nina had already been weakening [atmospheric wind/pressure budget change precedes change in SSTAs].

Also to mention, weak to barely moderate La Ninas tend to favor colder Februaries in the East anyway, especially in years like this with a +PNA average

A number of reasons:

1. Even if details remain to be resolved, retrogression is showing up on the ensembles

2. The MJO forecasts are suggesting that a no single or small group of phases will predominate in the extended range

3. The La Niña probably will fade slowly in February (decent model agreement)

[BethesdaWX]

Chris,

During January 1899, almost all of the Arctic region was covered by below to much below normal readings. A large body of exceptional cold was available and the pattern that unfolded allowed it to flood into the U.S. In contrast, during the January 1-23, 2012 period, much of

the Arctic has been covered by above to much

above normal readings. Even if the same synoptic pattern evolved in the same fashion as 1899 this coming February, the outcome would be much more moderate in terms of the magnitude of cold

The lack of surface cold in the arctic doesn't constitute the same effect in the mid latitudes, the LT over the arctic has warmed about 0.94C since 1979, which is when most of the warming took place. [up in the atmosphere --- mixing]

Higher up in the atmosphere is where to look as the profile is well mixed dynamically, local albedo enhancement effects in the arctic are usually confined there.

[donsutherland1]

I think February 10-15 time frame is ripe for us.

I believe there is a reasonable chance that the 2/10-15 time frame would fall within a period that is colder than normal in at least part of the East. As noted in Message #757, my initial look at the February 8-15 timeframe overall had more cold scenarios for the East than warm ones.

[BethesdaWX]

A number of reasons:

1. Even if details remain to be resolved, retrogression is showing up on the ensembles

2. The MJO forecasts are suggesting that a no single or small group of phases will predominate in the extended range

3. The La Niña probably will fade slowly in February (decent model agreement)

Thanks a bunch. I have a few questions?

1). Some ensembles show retrogression in the 11-15 day period, but most show a continuation of the +PNA, so I take it that you do not believe tbe MJO will be in octant 8 at that time?

2). RE: La Nina, I believe the models are referring to the ONI? I was referring to the atmospheric aspects which are more important in the near term?

[donsutherland1]

The lack of surface cold in the arctic doesn't constitute the same effect in the mid latitudes, the LT over the arctic has warmed about 0.94C since 1979, which is when most of the warming took place. [up in the atmosphere --- mixing]

Higher up in the atmosphere is where to look as the profile is well mixed dynamically, local albedo enhancement effects in the arctic are usually confined there.

A similar disparity existed at 850 mb and 500 mb. January 1899 had vastly more expansive cold anomalies than January 2012 to date. No matter how one slices it, surface to the lower- and mid-level troposphere, the Arctic in January 2012 is much warmer than it was in January 1899.

[donsutherland1]

Thanks a bunch. I have a few questions?

1). Some ensembles show retrogression in the 11-15 day period, but most show a continuation of the +PNA, so I take it that you do not believe tbe MJO will be in octant 8 at that time?

For all or most of February, certainly not. For a portion of February (probably 2nd week), that is the most likely scenario.

2). RE: La Nina, I believe the models are referring to the ONI? I was referring to the atmospheric aspects which are more important in the near term?

The SOI is not yet exhibiting the characteristics typically witnessed ahead of collapsing La Niñas. The ENSO guidance is fairly consistent with the SOI.

[Ottawa Blizzard]

Ottawa Blizzard,

I believe my biggest area of difference from JB (at least from the video) is the assumption that the changes taking place will lock in. Indeed, the AO information I cited earlier and the relevant February cases paint a picture of even more widespread warm anomalies than my February guess (top image). A comparison is below:

Much of Canada would also be milder than normal in the February 1952, 1954, 1986, 2003, and 2005 composite.

Having said this, my February thoughts do not preclude at least some cold, even a colder than normal period during February. Also, as is the case with any long-range forecast, there is significant risk of error.

Hey Don, I'm not sure if you saw my thread in the lakes subforum, but I find it intriguing that of the top 10 warmest januaries of the past century in Toronto, 7 of them were before 1945!

[BethesdaWX]

A similar disparity existed at 850 mb and 500 mb. January 1899 had vastly more expansive cold anomalies than January 2012 to date. No matter how one slices it, surface to the lower- and mid-level troposphere, the Arctic in January 2012 is much warmer than it was in January 1899.

I'm not confident the mid-tropospheric reconstructions are correct, especially given the diverging trends in sfc/vs/LT over the past 30yrs on UAH/RSS vs GISS [at the surface]. There isn't a quantitative method to reconstruct the tropospheric profile back to the 1800s. If it is modeled reconstruction, then I would throw it out now.

[BethesdaWX]

For all or most of February, certainly not. For a portion of February (probably 2nd week), that is the most likely scenario.

The SOI is not yet exhibiting the characteristics typically witnessed ahead of collapsing La Niñas. The ENSO guidance is fairly consistent with the SOI.

1) Ok, thanks. So a wave progressing from octant 8 to octant 3 is not something you see happening? I guess we'll disagree there but time will tell, good luck

2) I agree, I was more referring to the GLAAM, but the MJO forcing upcoming is another detrimental factor in my opinion.

[Harry]

Ottawa Blizzard,

I believe my biggest area of difference from JB (at least from the video) is the assumption that the changes taking place will lock in. Indeed, the AO information I cited earlier and the relevant February cases paint a picture of even more widespread warm anomalies than my February guess (top image). A comparison is below:

Much of Canada would also be milder than normal in the February 1952, 1954, 1986, 2003, and 2005 composite.

Having said this, my February thoughts do not preclude at least some cold, even a colder than normal period during February. Also, as is the case with any long-range forecast, there is significant risk of error.

My only gripe with those analogs is the fact that 1952, 2003, and 2005 for starters were El'Nino. Maybe it is me but yeah i would be very cautious with using such analogs. Both 54 and 86 i do believe were neutral. I understand the data set is limited but yeah these analogs do not inspire much confidence to say the least.

[griteater]

Chris,

During January 1899, almost all of the Arctic region was covered by below to much below normal readings. A large body of exceptional cold was available and the pattern that unfolded allowed it to flood into the U.S. In contrast, during the January 1-23, 2012 period, much of the Arctic has been covered by above to much above normal readings. Even if the same synoptic pattern evolved in the same fashion as 1899 this coming February, the outcome would be much more moderate in terms of the magnitude of cold.

Any thoughts on why there is a lack of cold air over the Arctic specifically for this winter? I would have thought that a prolonged positive AO would favor a build-up of cold air around the pole, but maybe that's not necessarily the case.

[bluewave]

Today, the AO had fallen to -3.230. That is its lowest reading since January 12, 2011 when the AO was -3.297. The decline of the AO to -3.000 or below offers an indication that the AO will likely average < 0 in February. Since 1950, there have been 7 cases on which the AO fell to -3.000 or below for the first time in January on or after January 20. In 6/7 (86%) of those cases, the February AO averaged < 0. In 4/7 (57%) of those cases, the February AO averaged < -1.

Unfortunately, those outcomes do not necessarily indicate a cold February is in store for the East, much less across the U.S. and most of southern Canada. For five of those cases, the January AO averaged above -1. January 2012 will represent the sixth such case. Through January 28, the AO has averaged +0.231. The five prior cases in question were: 1952, 1954, 1986, 2003, and 2005. The composite for those five cases was milder anomalies across almost the entire CONUS and southern Canada.

Of course, a caveat is that the sample size is very small.

This time around the actual 500 mb anomalies are less impressive for the same AO reading.

[donsutherland1]

My only gripe with those analogs is the fact that 1952, 2003, and 2005 for starters were El'Nino. Maybe it is me but yeah i would be very cautious with using such analogs. Both 54 and 86 i do believe were neutral. I understand the data set is limited but yeah these analogs do not inspire much confidence to say the least.

My actual February forecast (top chart) doesn't use any of those analogs. The reference was only made with respect to the idea that the AO will probably average negative in February and that such an outcome does not assure a cold February.

[Srain]

The main weather headline in the medium range will be the potential EC trough and short wave energy diving into the Rockies/Plains. There remain many questions with the evolution of this storm system and two camps have development via the 29/00Z Operational output. We have witnessed some wild run to run swings, particularly with the 5H pattern from one to a SW low to a progressive off shore solution via the Euro/GFS. What have remained consistent are the GGEM/UKMet suggesting a stronger, more robust short wave near New Mexico. In a pattern that is transitioning to a +PNA/-EPO regime, difficulties often arise with the handling of the 5H pattern. It does appear that a shot of Arctic cold is ahead for the EC and with the feature mentioned above does warrant some attention as the week moves forward. Perhaps WSR will be tasked that could lead to less volatility with the Pacific energy in the next 24-48 hour. We will see.

[donsutherland1]

Any thoughts on why there is a lack of cold air over the Arctic specifically for this winter? I would have thought that a prolonged positive AO would favor a build-up of cold air around the pole, but maybe that's not necessarily the case.

Probably a combination of the longer-term warming (the Arctic has consistently been warmer than shown on composites using past data for similar patterns) and the cold air's having drained into parts of Eurasia.

[donsutherland1]

Thoughts for the 2/8-15/2012 Timeframe:

For the first time this winter, my medium-term forecast shows cold anomalies in the eastern U.S., southern Ontario, and southern Quebec. There is risk that a warmer outcome could still unfold and much will depend on the Arctic Oscillation. Currently, there is a huge spread among the ensemble members for the AO.

The following chart shows (clockwise):

1. The composite temperature anomalies for ENSO Region 3.4 anomalies in the -1.45°C to -0.65°C range, an AO in the -1.25 to -0.25 range, and the PNA in a +0.25 to +1.25 range.

2. The 1/29/2012 0z GFS Ensemble forecast of the Arctic Oscillation.

3. Composite temperature anomalies for MJO Phase 8 (Amplitude 1-2) during La Niñas in February.

4. The Objective Analogs centered on 2/9 rolled forward 3 days (GFS ensembles).

I'm pretty much in agreement with the chart based on the teleconnections (1st one). The only adjustment would be that Maine and possibly eastern Canada could be near normal to slightly above normal based on a combination of the blocking and decadal observed warming in that area for February.

More than likely, this cold period won't lock in. Instead, it will be similar to what happened a little earlier in January where periodic cold shots occurred over a 7-14-day period before the warmth regained hold. The magnitude of the cold shots might be similar and possibly somewhat less harsh. As a result, my February forecast continues to call for widespread warm anomalies.

The 1/29/2012 run of the CFSv2 is even more aggressive on the February warm anomalies (virtually all of the U.S. and Canada, including Alaska).

[Ottawa Blizzard]

Thoughts for the 2/8-15/2012 Timeframe:

For the first time this winter, my medium-term forecast shows cold anomalies in the eastern U.S., southern Ontario, and southern Quebec. There is risk that a warmer outcome could still unfold and much will depend on the Arctic Oscillation. Currently, there is a huge spread among the ensemble members for the AO.

The following chart shows (clockwise):

1. The composite temperature anomalies for ENSO Region 3.4 anomalies in the -1.45°C to -0.65°C range, an AO in the -1.25 to -0.25 range, and the PNA in a +0.25 to +1.25 range.

2. The 1/29/2012 0z GFS Ensemble forecast of the Arctic Oscillation.

3. Composite temperature anomalies for MJO Phase 8 (Amplitude 1-2) during La Niñas in February.

4. The Objective Analogs centered on 2/9 rolled forward 3 days (GFS ensembles).

I'm pretty much in agreement with the chart based on the teleconnections (1st one). The only adjustment would be that Maine and possibly eastern Canada could be near normal to slightly above normal based on a combination of the blocking and decadal observed warming in that area for February.

More than likely, this cold period won't lock in. Instead, it will be similar to what happened a little earlier in January where periodic cold shots occurred over a 7-14-day period before the warmth regained hold. The magnitude of the cold shots might be similar and possibly somewhat less harsh. As a result, my February forecast continues to call for widespread warm anomalies.

The 1/29/2012 run of the CFSv2 is even more aggressive on the February warm anomalies (virtually all of the U.S. and Canada, including Alaska).

Hey Don, do you think Toronto hasa chance of seeing an overnight temperature of -20C (-4F) this winter? That's usually the benchmark for me; a -20C night in Toronto and a -20C day in Ottawa/Montreal. Ottawa has been close at achieving the latter this January, the only problem being that the fronts have been going through overnight meaning that the official daytime high has usually been around -9C at midnight.

[donsutherland1]

Hey Don, do you think Toronto hasa chance of seeing an overnight temperature of -20C (-4F) this winter?

EC's data show that there were 3 days in January during which the temperature fell to -20°C or below. I don't know the hours involved.

As for February, it is probably more likely than not that Toronto won't have any days on which the temperature falls to -20°C or below. Such days in February have not been very common since 2000. The pattern that I expect in February would probably lower the probability of such days.

[donsutherland1]

This morning, the AO was -4.441. That is the lowest AO reading since December 19, 2010 when the AO was -4.695. Since 1950, there were 14 prior cases on which the AO fell to -4.000 or below in January. In 13/14 (93%) of those cases, the AO averaged < 0 in February. February 1959 was the lone exception. In 11/14 (79%) of those cases, the AO averaged -1.000 or below in February. In 6/14 (43%) of those cases, the AO averaged -2.000 or below in February. Hence, this latest data gives me strong confidence that the AO will average negative in February, and possibly -1.000 or below.

What is likely to be unprecedented for January 2012 is that none of the prior cases during which the AO fell to -4.000 or below in January had a January AO average > -1.000. The highest January average among those cases was -1.204 in January 1956. January 2012 has had an average AO of +0.069 (1/1-1/29). The month will likely finish with an average AO of -0.200 to -0.100. February 1956 had a monthly AO average of -2.029. Nevertheless, February 1956 saw the eastern portion of the U.S. have warmer than normal readings. Some of the data used for my February 2012 guess was based on February 1956.

[BethesdaWX]

Don,

What analogs are you using/weighting the highest right now? I'm curious how the large scale progression in those years compares to what we've seen this year.

[Scarlet Pimpernel]

Hi Don, haven't posted much myself in this rather lame winter, but I have followed some of the discussion. Great to hear your thoughts as always, even if the news hasn't been great for snow crows.

Anyhow, this may be a bit late in the thread but I've been meaning to thank you for posting this plot (a couple of times) of the MJO phases and relation to temperature anomalies over the U.S. Very helpful, as I'm not overly familar with the MJO but have heard many people talk about "circle of death", "Phase 8", etc. Now I have a better idea of what this is about and how it relates. I'll have to copy that image for myself for reference!