Medium Range Discussion Winter 2011-12

[donsutherland1]

I'm going to bet against January turning out coldest relative to normal, in all proper analogs in the solar magnetic state (1967/68, 1978/79, 1989/90, 1999/00), All saw either a cold February and/or March. Knowing our distance from the 'true' max is 8-10 months away ((when the fields cross)) rather than the distance preceding a speedy change in more powerful cycles, this favors a brutal February in the Eastern US. I would put good money on this.

I think JB is maybe 10 days too early, based on lagged geomag activity index superimposed on current atmospheric kinetic momentum at all levels, followed by the challenge of forecasting the MJO. February should more than make up for a lackadaisical December and most of January. Call me crazy if you want.

Just so it's clear, I'm saying January would be the coldest month relative to normal in meteorological winter (DJF). March could well turn out colder than normal.

[ayuud]

Just so it's clear, I'm saying January would be the coldest month relative to normal in meteorological winter (DJF). March could well turn out colder than normal.

what about February?

[Srain]

post...

[HKY_WX]

post...

LOL definitely more than a hint of a pattern change. Jan starting to look exciting past day 7.

[Met1985]

Just wanted to say wow this looks like a big pattern change if it verifies. Thanks for all the info about the pattern really have learned a lot!

[donsutherland1]

what about February?

My current thinking is that February will be warmer, relative to normal, than January. The magnitude of the warmth will depend on the evolution of the La Niña and state of blocking (or lack thereof).

[BethesdaWX]

My current thinking is that February will be warmer, relative to normal, than January. The magnitude of the warmth will depend on the evolution of the La Niña and state of blocking (or lack thereof).

Is it a statistically based method or a direct state analysis method?

[donsutherland1]

Is it a statistically based method or a direct state analysis method?

A combination.

[Bob Chill]

My current thinking is that February will be warmer, relative to normal, than January. The magnitude of the warmth will depend on the evolution of the La Niña and state of blocking (or lack thereof).

Don, setting aside ENSO, when I pulled the 1+ AO Decembers and ran temp anoms for Jan and Feb, Feb stood out as the coolest month relative to normal by quite a bit. I don't have the maps on my PC at work but I'll dig them up sometime in the next couple of days.

It appeared that the strong +AO regime broke down over time. December being the warmest, Jan still warm but cooler relative to normal than December, and the Feb anom map looked the coolest by far. Not saying that will be the case this year but if I had to wager I would probably go with Feb being the coolest this winter.

This has been a weird Nina too. OND enso came in at .8 and the overall NA pattern seemed Nino'ish at times. I think it ends up being a barely moderate Nina when it's all said in done. Time will tell though. There are some cold looks on the models in the LR and we are off to a cool start so far. Maybe Jan AND Feb come in cold.......eh, who am I kiddin.

[winterymix]

This has been a weird Nina too.

Well...shall we look at the unbiased evidence? The evidence suggests a

sustained long-duration La Nina.

Water is a good insulator. Observe the volume of water that must warm a bit in

order to toggle the ENSO state:

[uncle W]

The cold La Nina February's after a warm start...I found four such cases since 1950...

1949-50...1971-72...1973-74...1974-75...out of the three 1970's analogs 1971-72 AO is closest...enso is similar...the four analogs had a December and January above average in the NYC area and a February and March that was below average...1975 barely but March and early April were cold...All four analogs had a cold period in April...There are many cases when there was a mild December and the following April had a cold period or snowfall...1984-85 and 1994-95 come to mind...The AO continues it's roller coaster ride from near +4 to just under zero...In 1971-72 it averaged slightly negative in February and March...1974-75 averaged positive in December and January but only slightly positive in February and March...1973-74's AO isn't a match...enso was stronger also...I still think 1971-72 is the best analog of the bunch...I like the idea of a colder February with some snow...Maybe March Madness...April fools cold...

[donsutherland1]

On 12/28 (#331), I speculated that because of a brief PNA spike--it reached +0.935 at its peak--that my initial thinking of widespread warmth could be incorrect. My argument was that the first 1-3 days could still start somewhat mild, but a push of cold would likely to assure that overall anomalies in the eastern third to half of the CONUS would likely wind up cooler than normal.

Instead, now that the cold shot is passing and milder air is returning, areas with cool anomalies will probably wind up even more limited than suggested, perhaps confined largely to parts of the Southeast in the Eastern third of the USA. For some ideas where things stand in the wake of the cold shot, here are the 1/1-4/2012 temperature anomalies in select cities:

Atlanta: Lowest Temperature: 22°; Anomaly: -3.5°

Boston: Lowest Temperature: 10°; Anomaly: +2.8°

Burlington: Lowest Temperature: 1°; Anomaly: +3.4°

Chicago: Lowest Temperature: 13°; Anomaly: +4.2°

Detroit: Lowest Temperature: 18°; Anomaly: +2.5°

New York City: Lowest Temperature: 13°; Anomaly: 0.0°

Philadelphia: Lowest Temperature: 14°; Anomaly: -0.1°

Raleigh: Lowest Temperature: 19°; Anomaly: -2.0°

Richmond: Lowest Temperature: 17°; Anomaly: -1.4°

Washington, DC (DCA): Lowest Temperature: 17°; Anomaly: -0.2°

In the end, as had been the case with the monthly December anomalies, the areas of warm anomalies are proving tyically larger than suggested by historic climatology (teleconnections/ENSO), while areas with cool anomalies are proving smaller than suggested by historic climatology.

[Lee]

Don, setting aside ENSO, when I pulled the 1+ AO Decembers and ran temp anoms for Jan and Feb, Feb stood out as the coolest month relative to normal by quite a bit. I don't have the maps on my PC at work but I'll dig them up sometime in the next couple of days.

It appeared that the strong +AO regime broke down over time. December being the warmest, Jan still warm but cooler relative to normal than December, and the Feb anom map looked the coolest by far. Not saying that will be the case this year but if I had to wager I would probably go with Feb being the coolest this winter.

This has been a weird Nina too. OND enso came in at .8 and the overall NA pattern seemed Nino'ish at times. I think it ends up being a barely moderate Nina when it's all said in done. Time will tell though. There are some cold looks on the models in the LR and we are off to a cool start so far. Maybe Jan AND Feb come in cold.......eh, who am I kiddin.

He's clearly weighing /counting more heavily on the strengthening Nina as his analogues suggest( ones with a +ao and late strengthening nina).

[BethesdaWX]

.

It appeared that the strong +AO regime broke down over time. December being the warmest, Jan still warm but cooler relative to normal than December, and the Feb anom map looked the coolest by far. Not saying that will be the case this year but if I had to wager I would probably go with Feb being the coolest this winter.

.

I agree with this 5 trillion times over, though my method isn't statistically based at all. But if I were to perform a statistical analysis, using the very limited sample size of strong +AO periods, in all sorts of PDO, AMO, QBO, and Sun Activity states seems risky. And knowing we've been in a +AO since mid/late August would further reduce my confidence level. I don't see how strong +AO periods aren't subject to the same forcings than moderate +AO periods are.

In -PDOs for example, the +AO periods do not last nearly as long as during +PDO periods, and there is a clear decadal scale correlation between the PDO and AO because they both are operated by the same mechanism. I haven't done anything with the QBO and the length of the +AO yet but I suspect there is something there.

So statistically speaking I don't see any reason to forecast a warm February even assuming my thoughts on the outcome of a Cold February are wrong.

[ORH_wxman]

Euro ensembles are showing quite a robust -EPO throughout most of the long range. However, they also form a -PNA which would likely limit the arctic air to the northern tier...esp the northern plains and norther Rockies...perhaps extending over to the northenr Lakes/New England at times.

The lack of any real -NAO and the -PNA will keep the SE ridge as a factor. There does look to be a transient north Atlantic ridge which would drive very cold air all the way down the eastern US around D9-10...but it doesn't last.

However, the strength of the AK ridge and having it bridge up with the northern Asia ridge suggests the AO may become negative in the long range despite the NAO staying generally positive.

[Isotherm]

This winter thus far has clearly proven, in no uncertain terms, that we are NOT dealing with your typical Nina progression temp wise. If we were, most of us would be sitting here with pretty decent winter outlooks up to this point. We have a few important factors arguing in support of a cold second half of winter: 1) The timing of the strong vortex/+AO event, early November through early January, is such that a continuation of the +AO regime is unlikely to occur. 2) Winds are switching easterly down to 45-50mb now, as the QBO shifts negative, and -QBO events are more supportive of the second half of the winter being blocky in the high latitudes as opposed to the first half, 3) Somewhat tying into #2, but the ongoing stratospheric warming will only be encouraged to propagate downward given the more conducive QBO modality evolving; we're already seeing indications of a perturbed tropospheric vortex, and its complete destruction is probable to occur given an intensifying strat warming event, 4) The Nina event is one that should continue to be hold > -1.0c in all ENSO regions, and may weaken even further over the next couple months if modelling is accurate. Since we do not have a moderate or strong Nina, it's going to be much easier to override the usual climo signature of warm East-Central / cold West for February. 5) The fall in solar values over the past month also bolsters the arguement for a more blocky second half of the winter

All in all, it depends how quickly the January pattern change evolves, but it wouldn't surprise me, in fact at this point I'd expect February to be the coldest month relative to normal in the Eastern US. The second half of January should be much colder / more wintry nationwide, but I think February has a chance to be front to end colder than normal for much of the northern tier. We'll see how it plays out, but this winter is going to be a very interesting case study. Definitely one of the more difficult winters to forecast long range wise in several years, IMO at least.

[Geos]

This winter thus far has clearly proven, in no uncertain terms, that we are NOT dealing with your typical Nina progression temp wise. If we were, most of us would be sitting here with pretty decent winter outlooks up to this point. We have a few important factors arguing in support of a cold second half of winter: 1) The timing of the strong vortex/+AO event, early November through early January, is such that a continuation of the +AO regime is unlikely to occur. 2) Winds are switching easterly down to 45-50mb now, as the QBO shifts negative, and -QBO events are more supportive of the second half of the winter being blocky in the high latitudes as opposed to the first half, 3) Somewhat tying into #2, but the ongoing stratospheric warming will only be encouraged to propagate downward given the more conducive QBO modality evolving; we're already seeing indications of a perturbed tropospheric vortex, and its complete destruction is probable to occur given an intensifying strat warming event, 4) The Nina event is one that should continue to be hold > -1.0c in all ENSO regions, and may weaken even further over the next couple months if modelling is accurate. Since we do not have a moderate or strong Nina, it's going to be much easier to override the usual climo signature of warm East-Central / cold West for February. 5) The fall in solar values over the past month also bolsters the arguement for a more blocky second half of the winter

All in all, it depends how quickly the January pattern change evolves, but it wouldn't surprise me, in fact at this point I'd expect February to be the coldest month relative to normal in the Eastern US. The second half of January should be much colder / more wintry nationwide, but I think February has a chance to be front to end colder than normal for much of the northern tier. We'll see how it plays out, but this winter is going to be a very interesting case study. Definitely one of the more difficult winters to forecast long range wise in several years, IMO at least.

I looked at SOI daily values measured between Tahiti and Darwin and they've been falling since the 29th of December. There staying consistently low over the past 8 days.

I would expect the second half of January - March to be wintry/below normal temperatures-wise for the east of the Rocky's too. Maybe something similar to what happened with the 2006-2007 winter. February 2007 was very cold here: -9.6° departure from normal!

[SnowGoose69]

Yeah, but that was a El Nino. This isn't. I think the problem is the longer ranges of the models/ensembles overestimate the -EPO thus fails to deliver its long range promise. If the -EPO doesn't develope............................the pattern stays 'warm'.

The 93-94 mentioning is bad too. That would also be a weak El Nino. The -EPO/-PNA/-AO dominated most of that winter, but the fact there was not a La Nina likely suppressed the SE ridge factor somewhat and it was still evident as shown by the fact little snow fell in the MA that winter. The same pattern now would probably shift everything 100-200 miles north.

[mahk_webstah]

The 93-94 mentioning is bad too. That would also be a weak El Nino. The -EPO/-PNA/-AO dominated most of that winter, but the fact there was not a La Nina likely suppressed the SE ridge factor somewhat and it was still evident as shown by the fact little snow fell in the MA that winter. The same pattern now would probably shift everything 100-200 miles north.

Hmmmm...I'm kinda liking my 43.3N.

Didn't I read somewhere that this nina has an unusually strong stj though?

The SE Ridge is an interesting factor. I should get beaten down from time to time and give you guys down there some good shots. You have to figure the NAO exerts at some point. Also 93-94 was just a barrage of storm after storm. I was in CC Philly and it was torture, constant changeover events while NYC and SNE were getting destroyed. Stood in a cab line in NYC in Jan that year at -5 and though I would die in my suit and dress shoes. Brutal cold.

[donsutherland1]

Hints of a pattern change, with an EPO- and AO- are growing on the ECMWF and GFS ensembles and operational models. The PNA could turn somewhat negative, but not so negative that the trough locks into the West initially. One scenario based on historic teleconnection data coupled with ENSO data would be an area of cold anomalies that extends from Alaska/Western Canada through much of the Northern/Central Plains into parts of the Ohio Valley/East (exceptions being northern New England and eastern Canada) for the January 16-23 timeframe as a whole. The farther east one goes, the more moderate the cool anomalies would be. Under such a scenario, ridging would lead to the Southwestern U.S. being warmer than normal (a big change this winter).

A second scenario would keep the East generally mild with transient cold shots during the 1/16-23 timeframe. Cold anomalies would extend from Canada into the Northern Plains, but a more sustained period of cold could be delayed farther east. The 1/6/2012 0z run of the GFS favors this scenario.

Both scenarios keep eastern Canada (Newfoundland, New Brunswick, and Nova Scotia) along with northern New England warmer than normal. Both scenarios also show Alaska and Western Canada having below normal temperatures.

Such a pattern might last 2-3 weeks before the EPO goes positive, PNA- leads to the trough's relocating/locking in the west, and/or another AO+ regime sets in. That doesn't mean that the whole 2-3-week timeframe would wind up colder than normal as a whole in the East/Ohio Valley/southern Canada, but 1 or 2 weeks could wind up colder than normal. If so, there's a chance February could start colder than normal in that region. The ongoing strong PDO- regime suggests that the PNA- will likely lead to the trough's eventually heading west and then locking in there.

While I await more data before committing to either scenario, it should be noted that in a winter where the warmth has found a way to win out, even during the current week that saw winter's strongest shot of cold air delivered to the east, a dose of caution is in order. Hence, the second scenario might be somewhat more likely than the first one.

[BethesdaWX]

Such a pattern might last 2-3 weeks before the EPO goes positive, PNA- leads to the trough's relocating/locking in the west, and/or another AO+ regime sets in. That doesn't mean that the whole 2-3-week timeframe would wind up colder than normal as a whole in the East/Ohio Valley/southern Canada, but 1 or 2 weeks could wind up colder than normal. If so, there's a chance February could start colder than normal in that region. The ongoing strong PDO- regime suggests that the PNA- will likely lead to the trough's eventually heading west and then locking in there.

While I await more data before committing to either scenario, it should be noted that in a winter where the warmth has found a way to win out, even during the current week that saw winter's strongest shot of cold air delivered to the east, a dose of caution is in order. Hence, the second scenario might be somewhat more likely than the first one.

Why are you thinking the EPO and/or AO go back positive after late month? Not that it means anything, but I can't figure out how a warm east would persist at all past January 25th. Also curious, for what reason do you use the -PDO to forecast a western trough, when the +PNA has persisted this winter with a very strong -PDO, and while the -AO correlation to a -PDO happens to be higher than a western trough during the -PDO?

Wouldn't that be more MJO related? If the Long Range models are correct in what they're showing as far as stratospheric warmings towards the day 10-15 period at 10HPA, that could spell the end of the +AO by February which has been my thought.

[Srain]

Guidance is coming together suggesting a very active period beginning on Sunday. There are some hints of severe storms with gusty winds and small hail possible as a potent upper low slowly organizes in Northern Mexico and a stalled frontal boundary meanders near Central/SE Texas and a Coastal Low develops near the Lower/Middle Texas Coast. Rain and showers look to increase beginning from W to E on Sunday as the slow moving 5H low organizes and deepens near or just S of the Big Bend Region. While the exact track remains uncertain and this disturbance is now closing in on the Pacific NW, indications do suggest a stormy period is ahead.

This feature will enter the RAOB network Friday into Saturday as it moves onshore and drops SSE into the Great Basin/4 Corners Area. Winter Storm conditions may be expexted in New Mexico Saturday night into Sunday extending into W Central Texas. The early QPF forecasts suggest 2-3 inches of rain, mainly E of the I-35 corridor with isolated 4+ inch amounts possible just N of the Houston Metro area. Training of storms may be possible and Flash Flood criteria may be met.

As the closed cold core upper low treks E, cold air aloft could bring elevated storms with small hail as the upper levels will be very unstable. There are some indictions a trowal like feature will develop N of the U/L, and depending on track and profiles, wintry mischief may be possible. As the storm system passes, a strong push of cold Canadian air looks to be tapped as yet another Winter Storm winds up along the northern stream near the Great Lakes/Upper Mid West. A strong front appears likley Wednesday night into Thursday morning. Light snow may develop across the Southern Plains as this boundary dives S. Stay tuned as we appear to be heading into a very active period!

[donsutherland1]

PDO- winters have a higher frequency of PNA- than PDO+ ones (SSTAs being the driver). MJO can't be forecast that far out. Also the period of blocking that seems to be increasingly likely looks to be the result of the polar vortex's being displaced not split. Normal to somewhat below average Siberian snow cover also argues against an AO- winter. EPO is shown as returning to somewhat positive levels on some of the guidance e.g., 0z GFS ensembles.

[winterymix]

The early QPF forecasts suggest 2-3 inches of rain, mainly E of the I-35 corridor with isolated 4+ inch amounts possible just N of the Houston Metro area. Training of storms may be possible and Flash Flood criteria may be met.

How many of these rainy cycles will be needed in order to bust that drought?

[Srain]

How many of these rainy cycles will be needed in order to bust that drought?

We were -41 inches for departures from Oct 2010 through December 2011. It will take several cycles or a tropical system or two to erase our drought completely.

[bluewave]

One of the warmest looking Euro forecasts that I have seen in a while for January.

New all time record highs set yesterday for January.

... Record high temperatures set at Fargo and Grand Forks...

A record high temperature of 55 degrees was set at Fargo ND this

afternoon. This eclipses the old record of 40 set in 1984. This also

breaks the record for the highest temperature recorded in January at

Fargo. It was 54 degrees on January 20 1908.

A record high temperature of 47 degrees was set at the NWS office

in Grand Forks. The previous record was 42 degrees achieved in 1984.

Finally... the mark Andrews Grand Forks International Airport

featuring the Byron dorgan terminal broke New Ground in terms of

January warmth. The Mercury touched 46 degrees this

afternoon... beating the old mark for this date of 42 degrees... also

in 1984

. ... All-time January record high temperature set at Aberdeen SD...

At 310 PM CST this afternoon... a record high temperature of 63 degrees

was set at Aberdeen SD. This breaks the daily record of 46 set in

1935.

This is also the warmest temperature ever recorded in January in

Aberdeen SD. The previous record was 60 degrees... last set on January 24

1981. Records in Aberdeen date back to 1896.

[Srain]

Heh...

[BethesdaWX]

PDO- winters have a higher frequency of PNA- than PDO+ ones (SSTAs being the driver). MJO can't be forecast that far out. Also the period of blocking that seems to be increasingly likely looks to be the result of the polar vortex's being displaced not split. Normal to somewhat below average Siberian snow cover also argues against an AO- winter. EPO is shown as returning to somewhat positive levels on some of the guidance e.g., 0z GFS ensembles.

You don't think the pattern changes the SSTAs? Knowing ENSO precedes changes in the PDO? The -AO/-NAO pattern I'd think would enhance the -PDO North Pacific warm pool with the more poleward Aleutian ridge and -NAO block "feeding back" in flow, no? Maybe that is why the -AO is much more frequent in the -PDO, with long +AO periods rarely occuring except early in the -PDO phases. With the +PNA we have seen this winter [[and it looks to continue]] with the -PDO what would be creating that anomaly? The pattern over the North Pacific still argues to represent the -PDO "look" but the ridge is more elongated with the strong +AO which is why I think powerful +AO or strong Polar Vortexes usually do not coincide with a -PNA.

I don't disagree on the initial displacement of the Polar Vortex before the potential split, but how can a long range EPO or Polar Vortex config forecasts be used with any confidence right now? The SIberian snowcover count in October was near average overall, it was below average early on I think but towards the last week of October and into November it went above average if I remember correctly.

AO and PDO

[easternsnowman]

Why are you thinking the EPO and/or AO go back positive after late month? Not that it means anything, but I can't figure out how a warm east would persist at all past January 25th. Also curious, for what reason do you use the -PDO to forecast a western trough, when the +PNA has persisted this winter with a very strong -PDO, and while the -AO correlation to a -PDO happens to be higher than a western trough during the -PDO?

Wouldn't that be more MJO related? If the Long Range models are correct in what they're showing as far as stratospheric warmings towards the day 10-15 period at 10HPA, that could spell the end of the +AO by February which has been my thought.

It sound like that is analog related and it has not worked well in the last couple of years.

[hurricaneschwartz]

Heh...

Nice map, but the EURO ensembles show no such thing (much more zonal). This is 2 days in a row with that nice 240 hour tease from the operational EURO.

Glenn