2013 Fall Medium Range Discussion

[Isotherm]

The 1951-1980 base period is an accumulation of 3 decades worth of years in which a -PDO/-AMO was dominant (cold in both the Atlantic and Pacific). This has a significant effect on global climate, and since 2012 is only several years into the latest -PDO phase, and still very warm AMO, I think the 1980-2010 base period is much more applicable for right now. You cannot take a 30 year slice of time in which the world's natural forcing mechanisms favored cold and then compare it to a time where you're still in a warm period in terms of the natural cycles.

[skierinvermont]

Where'd you pull that map from, national doomsday database (NDD)? Www.endofworldbyfire.com? Hansen's closet?

Take your denier nonsense to the climate forum. GISS is a legitimate reputable and well documented scientific source and there is every justification for posting it in this thread as factual data relevant to the topic of discussion. These are basic scientific facts and there should not be any debate of them (except perhaps some details of methodology) on a forum that claims to be about science. Do you really think all of the mathematical and scientific experts in the world, and the best smartest posters on this forum (like Don S.) have been duped by what is really a very simple publicly available methodology?

If you spend a little time in the climate forum, you will find there is very little debate regarding the usage of GISS even from self-identified skeptics like tacoman or ORH.

[Isotherm]

Take your denier nonsense to the climate forum. GISS is a legitimate reputable and well documented scientific source and there is every justification for posting it in this thread as factual data relevant to the topic of discussion. These are basic scientific facts and there should not be any debate of them (except perhaps some details of methodology) on a forum that claims to be about science.

That comment was entirely in jest. I just found it funny that you chose the base period that would look the warmest globally.

[skierinvermont]

That comment was entirely in jest. I just found it funny that you chose the base period that would look the warmest globally.

No I did not. There are much colder base periods. 1941-1970, 1931-1960, 1921-1950, 1911-1940, 1901-1930, 1891-1920, 1881-1910 are all colder base periods. And that includes +PDO+AMO periods (even though we've been in a -PDO period for 5 years now which has been dominated by La Ninas).

[Isotherm]

No I did not. There are much colder base periods. 1941-1970, 1931-1960, 1921-1950, 1911-1940, 1901-1930, 1891-1920, 1881-1910 are all colder base periods. And that includes +PDO+AMO periods (even though we've been in a -PDO period for 5 years now which has been dominated by La Ninas).

Ok - fine, but now we're beginning to move away from the question that brought this topic up originally - whether the CONUS is likely to continue torching, or will we see some of the colder anomalies much of the world has experienced over the past year. I still believe the 1980-2010 base is most relevant to this discussion, as it indicates there are plenty of temp anomalies colder than our most recent period globally. The Late 1800s through the mid 1900s don't have much relevance to the discussion regarding temp anomalies for this winter.

[Ottawa Blizzard]

I agree with this comment whole heartily. The short term climate has changed and it is very hard to get below normal months anymore. You are correct that it seems to have begun with March 2010 and in fact that whole warm season was insanely mild in 2010...then winter 2010-11 was very good in the northeast. Then last winter hit and in the my 35+ years of following winter in upstate NY/far northern PA, I have NEVER seen such a mild AND snowless winter. I remember some of the more mild ones... 1982-83 (18" in January) among other big snowstorms, 1988-89 (average temps but snowless), 1989-90 (a real december to remember!!!), 1990-91 and 1991-92 poor winters but at least some cold...then the rocking mid 90s began. even the mild 1994-95 ended up pretty good February on. 1997-98 was very mild but we had two major snowstorms of 12-18". 1998-99 was mild too but March we got record snows of 36"!! 2001-2002 was very very mild but we got a 13" dump of snow. winters 2002-2003 thru 2004-2005 were cold and snowy but not the same league as some of the winters of the 60s and 70s. Then 2005-2006 sucked pretty bad except december was cold. 2006-2007 started late but became awesome by the end of January (the pattern actually changed after a mild December...imagine that!).

Then last winter hit which was surreal in my books...then March 2012 was 12 degrees above normal with the whole warm season until November very warm. It is like I am in southern PA or even MD! November cooled down and was 2 degrees below normal. But compared to the +3 to +6 departures and the occasional +7 to 12 we have seen the past few years...the below normals are rare and if they occur they are just 1-3 below for the most part. This December is running 8 degrees above normal so far, so unless we get blasted with arctic air and below zero temperatures before the end of the month...it will be above normal to make for the warmest year on record around here since records began in 1950. I am NOT saying that CO2 and all the highly uncertain AGW stuff is the reason but at least in the short term we are in a very mild pattern across much of the eastern U.S. Most of the cold is not on our side of the hemisphere...although it is in AK and western Canada at least. Plus the southeast ridge won't go away and thus we are seeing this darn reverse PNA pattern which is killing us and wasting nice blocking north of us. I hope it will change but as has been stated.... the models keep changing the pattern beyond 7 or 8 days and it keeps getting pushed back...just like last year. I posted on this forum that this year was looking eerily similar to last winter and they pulled the thread!!! My credentials of a meteorologist were being questioned. A real meteorologist knows that longer range forecasting is a crap shoot. Analogs are all bias to the cold of the 1960s and 1970s when we had negative NAOs and a negative PDO so most winter forecasts end up calling for cold. Analogs are tenuous at best for forecasting winter. They don't even work very well for real operational meteorology where we have to forecast storms etc.

I am a skiier and last year was terrible. I was hoping for an early start to this season...but it is looking like last season all over again. I don't care about getting snowstorms anymore...these are a pipe dream at least for now...but all I am hoping for is temperatures in the 30s and 20s so they can make snow and get the ski resorts in upstate NY open by Christmas break!!!! All I am asking for is just 3-5 degrees above normal...is that too much?

This hits the nail on the head.

[skierinvermont]

Ok - fine, but now we're beginning to move away from the question that brought this topic up originally - whether the CONUS is likely to continue torching, or will we see some of the colder anomalies much of the world has experienced over the past year. I still believe the 1980-2010 base is most relevant to this discussion, as it indicates there are plenty of temp anomalies colder than our most recent period globally. The Late 1800s through the mid 1900s don't have much relevance to the discussion regarding temp anomalies for this winter.

Oh sure the U.S. is not going to continue torching relative to modern normals, although it will tend to remain on the warm side even of the very warm 1981-2010 normals. The last 12 years have averaged .5F above the 1981-2010 base period globally. Will it remain 4F above the 1981-2010 base as it has been this year? Of course not. But the next 10 years (and the next 10 winters) will probably average around 1F warmer than the 1981-2010 base, possibly even more.

I was just disagreeing with some posts claiming the globe had gotten colder. The globe continues to warm, although at a slower pace over the last 15 years because of increased La Ninas and the decline in solar activity.

[am19psu]

Guys, this is medium range thread, not a long range or climate thread. Take that stuff elsewhere.

[Srain]

The next in a series of strong upper air (500mb) low/trough enters the picture on Sunday to our W over Arizona/New Mexico. The GFS is quicker and drier with this feature passing over Kansas while the Euro and its ensembles suggest a much further S track and 'hint' at a closed cold core upper low meandering E across the Southern Plains. A strong blocking pattern over the Hudson Bay Region of Canada tends to favor a more southern/slower track suggesting a potent Winter Storm yet again crossing New Mexico/Texas/Oklahoma. Confidence is very low in the medium range forecast so expect changes in this progressive pattern.

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0355 AM CST TUE DEC 11 2012

VALID 141200Z - 191200Z

...DISCUSSION...

ALTHOUGH MODEST SPREAD PERSISTS AMONG THE VARIOUS MODEL ENSEMBLE

DATA...CONFIDENCE IN THE DEVELOPMENT AND TRACK OF A SIGNIFICANT

SURFACE CYCLONE ACROSS THE CENTRAL PLAINS TOWARD THE GREAT LAKES

REGION THIS COMING FRIDAY/SATURDAY IS FAIRLY HIGH. HOWEVER...AT

LEAST IN PART DUE TO SIGNIFICANT GULF MOISTURE ONLY BEING IN THE

PROCESS OF RETURNING AS THE SYSTEM EVOLVES... JUXTAPOSITION OF THE

MORE FAVORABLE FORCING FOR UPWARD VERTICAL MOTION AND WARM SECTOR

BOUNDARY LAYER DESTABILIZATION REMAINS FAR FROM CERTAIN. EVEN

SO...THE RISK FOR SEVERE STORMS MAY NOT BE OUT OF THE

QUESTION...PARTICULARLY IN A CORRIDOR FROM WEST CENTRAL THROUGH

NORTHERN TEXAS AND PARTS OF SOUTHERN OKLAHOMA LATE FRIDAY...THROUGH

ARKANSAS/NORTHERN MISSISSIPPI/NORTHERN ALABAMA AND WESTERN MIDDLE

TENNESSEE BY LATE SATURDAY. HOWEVER...THE MAIN IMPACT OF THIS WAVE

MAY BE TO HELP ESTABLISH SUFFICIENT MOISTENING...ACROSS THE

WESTERN/NORTHERN GULF OF MEXICO AND GULF COAST REGION...TO

CONTRIBUTE TO A MORE SIGNIFICANT SEVERE THREAT WITH THE NEXT

VIGOROUS SHORT WAVE IMPULSE...WHICH MAY SUPPORT STRONG SURFACE

CYCLOGENESIS ACROSS THE SOUTH CENTRAL U.S. NEXT MONDAY/TUESDAY. THE

SPREAD AMONG THE MEDIUM RANGE MODELS AND ENSEMBLE DATA...THOUGH...IS

STILL MUCH TOO LARGE TO CONFIDENTLY ASCERTAIN THE POTENTIAL FOR A

REGION SEVERE WEATHER EVENT...AND GRAPHICALLY DELINEATE AN AREA.

..KERR.. 12/11/2012

[tacoman25]

Really? Last 12 months on a 1951-1980 base. Almost no areas of earth are below normal, and none substantially so. This year will rank as one of the warmest on record on all temperature sources (UAH, RSS, GISS, Had4, NCDC, BEST). This is despite the majority of the year being under the influence of a La Nina (remember 3 month lag from ONI->Temps for surface temps, 5 months for satellite temps).

Your map just backs up what I said...that the U.S. has been the warmest place in the mid-latitudes this year, regardless of baseline.

What I said is that the rest of the mid-latitudes have been cooler than the U.S., not necessarily cooler than whatever normal you want to use.

[tacoman25]

It does appear that model consensus is now strong for the development of a very west-based -NAO in the mid range.

[SnowGoose69]

The Euro has now tried to put that AK Vortex up there about 10 days in a row at 240 hours...hopefully it does not eventually end up being right...thus far its been wrong and just keeps trying to put it back there at the end of most runs.

[tacoman25]

You mean weak west based blocking. Doesn't mean much when the PAC is shearing everything out.

I didn't mean it was strong -NAO, just very west-based.

[Wow]

SOI still holding strongly negative. It's pulled the 30 day avg into neg territory.. a first since summer.

http://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/30daysoivalues/

[LakeEffectOH]

Thanks. Nice description. The Pacific jet killed us last year and looks like it is cranking up again. SSTs change very slowly and we know we are in a negative PDO....could be a long winter for us. Let's hope not.

I just checked the SOI and it has really crashed in the past few days. It is at around -45 today and was around -48 yesterday. I wonder if that's going to affect the Pac pattern.

http://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/30daysoivalues/

[donsutherland1]

Hints of Change to a Colder Pattern Growing Stronger...

If one examines the ECMWF forecast for the MJO, the MJO is forecast to move into Phase 1 by late December. The composite anomalies are cold across much of the nation when that happens in December with ENSO Region 3.4 anomalies similar to where they are today (second map for ENSO Region 3.4 Anomalies of -0.25°C to +0.50°C in December with the MJO in Phase 1 and Amplitude 1 or greater).

The 12/11/2012 18z run of the GFS ensembles (from RaleighWx's model page) shows widespread cool anomalies at 300 hours not dissimilar to what one would expect were the MJO forecast to verify.

Some guidance is also hinting that the EPO could go negative in the extended range. That could bolster prospects for the development of a cold pattern.

Finally, with the SOI remaining strongly negative, there remains a growing prospect that the development of the cold pattern could coincide with an increasingly active subtropical jet. If so, prospects for snow could increase during the closing 10 days of December.

[LakeEffectOH]

Thanks Don, I look forward to reading your discussions.

[Ginx snewx]

I don't see enough cold air to get that look, certainly the 12Z Euro or it ens mean don't support that much cold prior to the D+11, in fact the euro ens mean is warmer than normal along the east coast at 240 hrs. Of course, I may be influenced by the fact that I basically don't see this as being a particularly cold pattern with there being no real riding across western Canada to bring cold into our area.

Man Wes have the Ens flipped

[Ottawa Blizzard]

Much of Canada seems to torch with this outlook. Reminds me of 2009-2010 which was a miserably boring winter up here in Ontario. Is this becoming the new norm- high latitude blocking and lack of sea ice forcing below average temperatures well south, with the further north you go, the greater above average your temperatures will be? If this is the future, then it does indeed appear bleak for winter in a large portion of Canada.

[Srain]

Much of Canada seems to torch with this outlook. Reminds me of 2009-2010 which was a miserably boring winter up here in Ontario. Is this becoming the new norm- high latitude blocking and lack of sea ice forcing below average temperatures well south, with the further north you go, the greater above average your temperatures will be? If this is the future, then it does indeed appear bleak for winter in a large portion of Canada.

The CFSv2 suggest otherwise...

[usedtobe]

Man Wes have the Ens flipped

Your quote was from the 8th and the the cold air won't really get into the east until after the storm around the 8th so the call was not as bad as implied though I still was probably slow to call for the change towards colder. On the 11th I wrote this

http://www.washingtonpost.com/blogs/capital-weather-gang/post/new-storm-to-watch-as-pattern-points-to-colder-weather/2012/12/11/ac196066-43ba-11e2-9648-a2c323a991d6_blog.html#pagebreak

Last night's euro is the coldest look yet at and beyond day 10 as it finally builds a nice surface high. The ens also have flipped colder at 240 but the pattern also looks on the dry side on the euro ens mean. One caution, if you look at the 120 hr GEFS ens members, their handling of the low on that panel is all over the place attesting to how little predictability there is in the pattern.

[VAwxman]

There is a window of opportunity for some eastern chill as the "floating ridge" (the NAO ridge) gets pulled back west owing to added subtropical flow, but the Pacific side I don't think will be very helpful for awhile. There can be a reflection of MJO 1-2 that helps get the window of opportunity going, but if this is a true MJO event (unclear on this yet), the Pac will again be less than favorable as we close the month, and I'm not sure there is much support to maintain much of a -NAO either.

There are hints of a warming stratosphere at the end of the month, and that MIGHT coincide with a more favorable tropical forcing position once into the New Year (maybe middle third of Jan?)

[donsutherland1]

Much of Canada seems to torch with this outlook. Reminds me of 2009-2010 which was a miserably boring winter up here in Ontario. Is this becoming the new norm- high latitude blocking and lack of sea ice forcing below average temperatures well south, with the further north you go, the greater above average your temperatures will be? If this is the future, then it does indeed appear bleak for winter in a large portion of Canada.

In terms of the current blocking regime, that will likely be the case as the block slowly retrogrades westward. However, southern Canada, including cities such as Toronto, Ottawa, and Montreal will likely be colder than normal.

The other issue you raise is more climate-related, so I'll limit my comments here. The continuing long-term warming trend in the Arctic could well result in greater warm anomalies relative to previous climatology across northern Canada.

Arctic amplification could also result in more prolonged periods of AO- and AO+ in part, due to some slowing of the jet stream. The prolonged and severe AO- regimes of 2009-10 and 2010-11 and the prolonged and strong AO+ regime of 2011-12 might be hints of what could lie ahead if that idea is right, but the sample size is far too small to be confident in that outcome just yet.

[tacoman25]

Much of Canada seems to torch with this outlook. Reminds me of 2009-2010 which was a miserably boring winter up here in Ontario. Is this becoming the new norm- high latitude blocking and lack of sea ice forcing below average temperatures well south, with the further north you go, the greater above average your temperatures will be? If this is the future, then it does indeed appear bleak for winter in a large portion of Canada.

It sure doesn't appear to be having that effect on Alaska.

[The_Global_Warmer]

Can anyone with more expertise comment on the building warm ssts in the North Central Pacific and any effect they might have???

[tacoman25]

Can anyone with more expertise comment on the building warm ssts in the North Central Pacific and any effect they might have???

-PDO regime. We had a very -PDO summer, and without a real +ENSO event to dislodge the regime, history tells us that -PDO and probably -PNA should dominate this winter.

[donsutherland1]

Some weekend thoughts...

The anticipated but slow transition to sustained colder weather in eastern North America is underway. I suspect when one looks back, the storm that brought daily record snowfall to Minneapolis-St. Paul on December 9-10, 2012 marked the very beginning of a slow, back-and-forth transition. Even as this week's events, excepting northernmost New England and parts of Quebec will likely see little frozen precipitation, they will mark the end game of the transition. By 12/20 +/- a day, the transition will likely be complete. The remainder of the month will generally be colder than normal in the eastern half of North America.

With a more active subtropical jet, there will be a risk of storminess. With the cold getting established, opportunities for snowfall in the Great Lakes region, Ohio Valley, Middle Atlantic States, New England, and southern Ontario and southern Quebec will increase. There could be a possibility of a moderate or even significant snowfall in part of that region.

Some guidance has even hinted at a brief outbreak of severe cold. For example, the 12/15 0z run of the GFS showed a low temperature of 3°F in New York City for 12/29. That would be the first December single-digit reading there since December 27, 1989. The 6z run showed a temperature as low as -32°C (-26°F) in Ottawa.

Given the generally positive EPO, I don't believe such an outbreak is likely this month (and the 12z GFS backed off on the extreme cold). One cannot rule out a day or two with low temperatures in the teens from Philadelphia into New England and a low temperature of -20°C to -15°C in Ottawa.

As the month ends, blocking is more likely than not to persist. Some ensemble members are hinting that the PNA, which has now been negative for 40 consecutive days, will go positive toward the end of December. That might set the stage for a bout of more significant cold in early January, but that's still too far out for one to have much confidence.

[Ottawa Blizzard]

Some weekend thoughts...

The anticipated but slow transition to sustained colder weather in eastern North America is underway. I suspect when one looks back, the storm that brought daily record snowfall to Minneapolis-St. Paul on December 9-10, 2012 marked the very beginning of a slow, back-and-forth transition. Even as this week's events, excepting northernmost New England and parts of Quebec will likely see little frozen precipitation, they will mark the end game of the transition. By 12/20 +/- a day, the transition will likely be complete. The remainder of the month will generally be colder than normal in the eastern half of North America.

With a more active subtropical jet, there will be a risk of storminess. With the cold getting established, opportunities for snowfall in the Great Lakes region, Ohio Valley, Middle Atlantic States, New England, and southern Ontario and southern Quebec will increase. There could be a possibility of a moderate or even significant snowfall in part of that region.

Some guidance has even hinted at a brief outbreak of severe cold. For example, the 12/15 0z run of the GFS showed a low temperature of 3°F in New York City for 12/29. That would be the first December single-digit reading there since December 27, 1989. The 6z run showed a temperature as low as -32°C (-26°F) in Ottawa.

Given the generally positive EPO, I don't believe such an outbreak is likely this month (and the 12z GFS backed off on the extreme cold). One cannot rule out a day or two with low temperatures in the teens from Philadelphia into New England and a low temperature of -20°C to -15°C in Ottawa.

As the month ends, blocking is more likely than not to persist. Some ensemble members are hinting that the PNA, which has now been negative for 40 consecutive days, will go positive toward the end of December. That might set the stage for a bout of more significant cold in early January, but that's still too far out for one to have much confidence.

Don, I noticed the record highs for today in Buffalo and Rochester were in 1894, so i went to Environment Canada's data site and found the December 1894 data for Toronto. Note the remarkable warmth that persisted for much of the month, then note the cold outbreak on the 27th and 28th. Kind of looks similar to what models are calling for in the immediate post-Christmas period this year. Also, take a look at the January 1895 data and all the snow that fell.

http://www.climate.weatheroffice.gc.ca/climateData/dailydata_e.html?timeframe=2&Prov=ONT&StationID=5051&mlyRange=1840-01-01|2006-12-01&cmdB1=Go&Year=1894&Month=12&Day=1

[blizzard1024]

Don, I noticed the record highs for today in Buffalo and Rochester were in 1894, so i went to Environment Canada's data site and found the December 1894 data for Toronto. Note the remarkable warmth that persisted for much of the month, then note the cold outbreak on the 27th and 28th. Kind of looks similar to what models are calling for in the immediate post-Christmas period this year. Also, take a look at the January 1895 data and all the snow that fell.

http://www.climate.w...&Month=12&Day=1

But remember this was when there was only about 300 ppm of CO2 in the atmosphere...now its almost 400 ppm....so forget it....winter's over!!! NOT!!!

[WXeastern]

Some weekend thoughts...

The anticipated but slow transition to sustained colder weather in eastern North America is underway. I suspect when one looks back, the storm that brought daily record snowfall to Minneapolis-St. Paul on December 9-10, 2012 marked the very beginning of a slow, back-and-forth transition. Even as this week's events, excepting northernmost New England and parts of Quebec will likely see little frozen precipitation, they will mark the end game of the transition. By 12/20 +/- a day, the transition will likely be complete. The remainder of the month will generally be colder than normal in the eastern half of North America.

With a more active subtropical jet, there will be a risk of storminess. With the cold getting established, opportunities for snowfall in the Great Lakes region, Ohio Valley, Middle Atlantic States, New England, and southern Ontario and southern Quebec will increase. There could be a possibility of a moderate or even significant snowfall in part of that region.

Some guidance has even hinted at a brief outbreak of severe cold. For example, the 12/15 0z run of the GFS showed a low temperature of 3°F in New York City for 12/29. That would be the first December single-digit reading there since December 27, 1989. The 6z run showed a temperature as low as -32°C (-26°F) in Ottawa.

Given the generally positive EPO, I don't believe such an outbreak is likely this month (and the 12z GFS backed off on the extreme cold). One cannot rule out a day or two with low temperatures in the teens from Philadelphia into New England and a low temperature of -20°C to -15°C in Ottawa.

As the month ends, blocking is more likely than not to persist. Some ensemble members are hinting that the PNA, which has now been negative for 40 consecutive days, will go positive toward the end of December. That might set the stage for a bout of more significant cold in early January, but that's still too far out for one to have much confidence.

Don..great post as usual!

I have very little doubt that the pattern is reacting to such a sustained deeply negative Arctic Oscillation and I know the Pacific has been working against sustained colder wx in the east since the first of Dec.. but does it usually take this long for a deeply AO- to fully drive a colder pattern change down into the lower latitudes or is this a rather unusual case?