AO Forecast to Plunge

[donsutherland1]

Today, the AO was -3.065. December 2010 set records for December blocking during La Niña events. Records included the lowest daily AO reading, lowest monthly average, and most days with an AO figure of -3 or below.

Moreover, it should be noted that the AO is likely moving into a long-term negative cycle.

The 10-year moving average bottomed out in 1966 (-0.423 10-year average) and then peaked in 1995 (+0.253 10-year average). It has generally been falling since that time. The chart does not include 2010, as the data is not yet final. Based on the preliminary figures, when this year's data is in, the 10-year moving average will have fallen further to around -0.125, the lowest 10-year figure since 1988 (-0.224 10-year average). In addition, 2010 will finish with an annual average of just below -1.025. That would break the record of -0.959 set in 1960. The record high annual average is +1.024, established in 1990.

[nynjpaweather]

Today, the AO was -3.065. December 2010 set records for December blocking during La Niña events. Records included the lowest daily AO reading, lowest monthly average, and most days with an AO figure of -3 or below.

Moreover, it should be noted that the AO is likely moving into a long-term negative cycle.

The 10-year moving average bottomed out in 1966 (-0.423 10-year average) and then peaked in 1995 (+0.253 10-year average). It has generally been falling since that time. The chart does not include 2010, as the data is not yet final. Based on the preliminary figures, when this year's data is in, the 10-year moving average will have fallen further to around -0.125, the lowest 10-year figure since 1988 (-0.224 10-year average). In addition, 2010 will finish with an annual average of just below -1.025. That would break the record of -0.959 set in 1960. The record high annual average is +1.024, established in 1990.

Now that's interesting! How well does this match up with the solar cycles? I got to dig that up next week!

[Yes_Probably_Maybe_No]

Strat cooling says hi

[okie333]

Strat cooling says hi

Not for long

[NJwinter23]

Yeah "carrying less weight" wasn't really a good way to put it. I think you and NJWinter said it better by saying that it was easier to overlook given all the other signals that strongly suggested blocking. If it is as big of a factor as it now appears it may be, it was big last year too but was easier to overlook with all the other stuff going on.

Given the orientation of the warm water though, even that favored blocking. It was as textbook of a setup as you could get IMO.

Exactly VA. I can tell you in my case, it wasn't until this past Summer into Fall with the continued streak of -NAO when the alarm went off in my head. I mean at that point I'm looking at the persistence back to 08-09 compared to any other point in records, and I really started to lose any skepticism in the theory and accepted that something else BIG like the extended solar min had to be at play in forcing this to the extreme. But like HM said, how long can you run with something because of persistence before you finally get burned? I credit the forecasters who tried to foresee the end to the crazy NAO period for various logical reasons. It may not work out in the end this winter, but fwiw it made logical sense I thought.

And credit to Okie for making an excellent NAO call so far.

[Yes_Probably_Maybe_No]

Not for long

Perhaps but the negative anomalies are propagating down which could lead to a worse pattern then some are believing for week 2-3 of Jan.

[Desnowlover]

Kudos Mr. Sutherland! Happy New Year

Area Forecast Discussion

Issued by NWS Mt. Holly, NJ

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MOUNT HOLLY NJ

238 AM EST SAT JAN 1 2011

LONG TERM /TUESDAY THROUGH FRIDAY/...

OVERALL IT REMAINS AN ATYPICAL OR THROW BACK NINA WINTERS FROM THE

EARLY 20TH CENTURY ACROSS OUR CWA. MR DON SUTHERLAND`S RESEARCH

INDICATES THAT THROUGH TODAY THE ARCTIC OSCILLATION (THE NORTH

ATLANTIC OSCILLATION IS PRETTY CLOSELY TIED TO IT) WILL SET A

BLOCKING (NEGATIVE) DECEMBER RECORD FOR ANY NINA WINTER SINCE 1950.

WITH BLOCKING WEATHER PATTERNS TOWARD THE POLE, THE COLD AIR IS

FORCED SOUTHWARD. THIS HAS PRETTY MUCH MADE THE TYPICAL LA NINA

CLIMATOLOGY OF RECENT NINA WINTERS DEAD IN THE WATER. THIS DECEMBER

FOR PHILADELPHIA WILL BE THE COLDEST DECEMBER SINCE 2000 AND THE

COLDEST MODERATE OR STRONG LA NINA SINCE 1955.

http://forecast.weather.gov/product.php?site=NWS&issuedby=PHI&product=AFD&format=CI&version=1&glossary=1&highlight=of

[anomalous]

Oymyakon in eastern Siberia , according to Weather Underground, will have a low of -92F Wednesday. If that occurs, that would beat the previous NH low of -90. Oh yeah, Narsarsuaq in western Greenland will be 53F today with rain.

[wxmx]

Oymyakon in eastern Siberia , according to Weather Underground, will have a low of -92F Wednesday. If that occurs, that would beat the previous NH low of -90. Oh yeah, Narsarsuaq in western Greenland will be 53F today with rain.

And the 18z GFS wants to bring that air to our side of the world...wow at that -EPO... Models have been supportive of higher heights around AK for the mid range..but this run of the GFS is the extreme version...think vodka cold for most of the CONUS this run verbatim...things are supportive for a new wave which would again help pump ridges up north.

[ayuud]

[Srain]

And the 18z GFS wants to bring that air to our side of the world...wow at that -EPO... Models have been supportive of higher heights around AK for the mid range..but this run of the GFS is the extreme version...think vodka cold for most of the CONUS this run verbatim...things are supportive for a new wave which would again help pump ridges up north.

The 00Z and 06Z seems to agree, Jorge. It is becoming clearer that truly vodka cold is heading S and will sink deep into the Lower 48.

[Whacker77]

Is this plunge of arctic air likely to be a one off situation, or are setting the stage for several shots in a row as we head through January?

[A-L-E-X]

Oymyakon in eastern Siberia , according to Weather Underground, will have a low of -92F Wednesday. If that occurs, that would beat the previous NH low of -90. Oh yeah, Narsarsuaq in western Greenland will be 53F today with rain.

Ouch, we're headed towards Vostok, Antarctica territory!

[wxmx]

Bring it on! 1058mb (and pattern suggested by Euro indicates more in the way, with another near 1060mb entering AK)

[NaoPos]

Is this plunge of arctic air likely to be a one off situation, or are setting the stage for several shots in a row as we head through January?

[Snow Wizard]

Bring it on! 1058mb (and pattern suggested by Euro indicates more in the way, with another near 1060mb entering AK)

I almost guarntee you the 12z ECMWF is too far east with the blocking. There is no other model or even the 0z Euro ensemble to suport this solution.

[pcbjr]

I almost guarntee you the 12z ECMWF is too far east with the blocking. There is no other model or even the 0z Euro ensemble to suport this solution.

So, if the blocking is further west, how do you see it playing out?

[Nikolai]

So, if the blocking is further west, how do you see it playing out?

He's only saying that because the PNW gets warm. I'm sure he would see it playing out in a fashion more favorable to Seattle.

[A-L-E-X]

He's only saying that because the PNW gets warm. I'm sure he would see it playing out in a fashion more favorable to Seattle.

Actually, I would imagine if the block were further west it would be better for us too, because systems wouldnt be so suppressed.

[affytaffy]

AO @ -6? How sustained is this round likely to be?

[VAwxman]

Still early to see how it all plays out, but it's correct to say this pattern has the potential to be absolutely nuts with cold for almost all of the nation. A sick ridge over AK is THE signal you want to see to build up the strongest cold air masses in North America, and the fact that the NAO relaxes as this AK ridge gets cranked up actually helps build the cold. You would not want the NAO tanked too because if the Greenland ridge was too strong, it would actually connect to the AK ridge and effectively shut off cross polar flow. In the upcoming pattern, it looks like we keep that pathway open for awhile. Maybe the AO / NAO will tank anew after mid month, but by then the strong cold will be in place.

[JoMo]

Still early to see how it all plays out, but it's correct to say this pattern has the potential to be absolutely nuts with cold for almost all of the nation. A sick ridge over AK is THE signal you want to see to build up the strongest cold air masses in North America, and the fact that the NAO relaxes as this AK ridge gets cranked up actually helps build the cold. You would not want the NAO tanked too because if the Greenland ridge was too strong, it would actually connect to the AK ridge and effectively shut off cross polar flow. In the upcoming pattern, it looks like we keep that pathway open for awhile. Maybe the AO / NAO will tank anew after mid month, but by then the strong cold will be in place.

yeah, Norman/OKC mentioned this in their morning discussion.

NOTE THAT BOTH THE 00Z GFS AND THE 00Z ECMWF HAVE A 500-MB HIGH OF

AROUND 580HPA OVER ALASKA BY TUE 11 JAN. NOT A GOOD SIGN - NASTY

THINGS USUALLY HAPPEN IN TERMS OF COLD AND SNOW/ICE IN PATTERNS LIKE

THIS... NOT ONLY AROUND HERE BUT IN MANY PARTS OF THE LOWER 48. NEXT

WEEK MAY BE INTERESTING IN A NUMBER OF WAYS.

[Snow Wizard]

So, if the blocking is further west, how do you see it playing out?

I think the cold would start out further west and gradually invade much of the country. The vast majority of model runs have been showing that. The 12z ECMWF is an outlier at this point.

[Snow Wizard]

He's only saying that because the PNW gets warm. I'm sure he would see it playing out in a fashion more favorable to Seattle.

With how strong this Nina is, one would have to think the NW will score eventually.

[okie333]

yeah, Norman/OKC mentioned this in their morning discussion.

NOTE THAT BOTH THE 00Z GFS AND THE 00Z ECMWF HAVE A 500-MB HIGH OF

AROUND 580HPA OVER ALASKA BY TUE 11 JAN. NOT A GOOD SIGN - NASTY

THINGS USUALLY HAPPEN IN TERMS OF COLD AND SNOW/ICE IN PATTERNS LIKE

THIS... NOT ONLY AROUND HERE BUT IN MANY PARTS OF THE LOWER 48. NEXT

WEEK MAY BE INTERESTING IN A NUMBER OF WAYS.

I believe they mean 580 DM... MB is the same as HPA... so a 500MB HIGH OF 580MB? Doesn't make sense.

[A-L-E-X]

With how strong this Nina is, one would have to think the NW will score eventually.

How well did you do in 1966-67? I think that was a big winter for a large part of the country. That has been a close match since summer.

[A-L-E-X]

I think the cold would start out further west and gradually invade much of the country. The vast majority of model runs have been showing that. The 12z ECMWF is an outlier at this point.

that would be good for us (and probably you too) as we only want it marginally cold at this point and being near the boundary of different airmasses is a good place to be for big storms, probably snow in this kind of pattern.

[VAwxman]

LOL this would just be sick. (Map courtesy of MDA):

[JBG]

How well did you do in 1966-67? I think that was a big winter for a large part of the country. That has been a close match since summer.

Yes but the ENSO state was neutral-negative, not Niña on steroids. Granted teh summer of 1966 was a lot like the summer of 2010 in sensible weather but the December 1966 storm wa a piker compared to the Boxing Day Blizzard. And from the look of this and other threads January does not look to be a copy of the 1967 torch.

[Flexo]

Norman NWS is excited

MORE ATTENTION CONTINUES TO TURN TO THE POTENTIALLY SIGNIFICANT

TURN OF EVENTS NEXT WEEK. BIG RIDGE WILL BUILD N INTO ALASKA BY

LATE WEEKEND... SUPPORTING A SIZEABLE BUILDUP OF ARCTIC AIR OVER W

CANADA AND DOWNSTREAM HEIGHT FALLS INTO SW CANADA AND NW CONUS.

FORMATION OF A 500-MB 575-580 HIGH OVER AK... WHICH HAS BEEN

ADVERTIZED BY THE GFS AND ECMWF FOR SEVERAL DAYS NOW... GENERALLY

DOES NOT TURN OUT WELL - FOR MOST OF THE LOWER 48 MUCH LESS THE S

PLAINS. GFS SFC-T PROGS FOR NEXT TUESDAY ARE UNPRECEDENTED AS FAR

AS THIS FORECASTER CAN RECALL... AND IF TAKEN LITERALLY WOULD

IMPLY THAT PARTS OF MT/WY WOULD STRUGGLE TO REACH HIGHS OF -30F

NEXT TUESDAY. THAT SEEMS A WEE BIT EXTREME... BUT IN ANY EVENT THE

PATTERN CONTINUES TO SUGGEST A TURN TOWARD SIGNIFICANT AND

POTENTIALLY SEVERE WINTER WEATHER IN SOME WAY SHAPE OR FORM - THE

STUFF NATIONAL HEADLINES ARE MADE OF - BY SOMETIME NEXT WEEK.

COLD AIR IS LIKELY TO BEGIN INVADING THE PACNW AND NORTHERN

ROCKIES/HIGH PLAINS OVER THE WEEKEND AND ROLL SE THEREAFTER. AT

THIS TIME WE ARE LEANING TOWARD THE ECMWF AND A FASTER INVASION OF

ARCTIC AIR INTO THE S PLAINS NEXT SUNDAY NIGHT. WHAT HAPPENS AFTER

THAT IS HARD TO SAY. BITTER COLD... SNOW AND/OR ICE... OR PERHAPS

ALL OF THE ABOVE. SUFFICE TO SAY NEXT WEEK LOOKS TROUBLESOME.

It's what national headlines are made of!

Dallas getting revved up:

/AND NOW A DISSERTATION ON A LIKELY COLD SPELL NEXT WEEK/

ALL THE MEDIUM TO LONG RANGE MODELS CONTINUE TO ADVERTISE A MAJOR

PATTERN SHIFT OCCURRING OVER THE NORTHERN LATITUDES...WITH BLOCKED

UPPER FLOW SETTING UP AND PERSISTING ACROSS CANADA. MODELS FORECAST

THE UPPER LEVEL RIDGE NOW OVER WESTERN CANADA TO BREAK DOWN AND BE

REPLACED BY A STATIONARY UPPER LEVEL LOW THIS WEEKEND. AS THIS

OCCURS...SURFACE TEMPS COOL AND PRESSURES GRADUALLY RISE. IN SHORT

THIS MEANS WESTERN CANADA WILL BE THE GENESIS REGION OF THE COLD

AIR MASS FORECAST TO ARRIVE IN 7 TO 8 DAYS.

THE ASTUTE OBSERVER WOULD NOTICE TEMPS ACROSS WESTERN CANADA AND

ALASKA ARE NOT THAT COLD NOW. I KNOW IT IS A HABIT FOR MANY OF US

TO THROW A MAP OF SURFACE TEMPS UP AND TRY TO SEE WHERE THE COLD

AIR IS AND WHERE IT IS COMING FROM. BUT THIS IS SORT OF A RULE OF

THUMB AND IS PARTIALLY FLAWED THINKING FOR A COUPLE REASON. FIRST

COLD AIR AT THE SURFACE IS NOT A CONSERVED QUANTITY...IT DEVELOPS

AND IS ALSO DESTROYED BY COMPLEX DYNAMIC MOTIONS ALOFT. THE SECOND

REASON IS AN ANALYSIS OF WHERE OUR PAST BIG ARCTIC OUTBREAKS

ORIGINATE USING BACKWARD TRAJECTORIES SHOWS US THAT THE NORTH POLE

REGION IS PREFERRED...BUT OUR SURFACE PARCELS HERE ACTUALLY

ORIGINATE AT LEVELS BETWEEN 500MB-700MB. THUS AN ANALYSIS OF

500MB-700MB TEMPS AND ANOMALIES IN THE NORTHERN LATITUDES CAN GIVE

US A GOOD PROXY TO COMPARE AND JUDGE THE STRENGTH OF FUTURE ARCTIC

EPISODES. THESE CURRENT MID-UPPER LEVEL TEMPS ARE CHILLY...BUT NOT

TOO UNUSUAL. SO THE FRONT THAT ARRIVES IN A WEEK MAY BE

SIGNIFICANT BUT NOT RECORD BREAKING...AT LEAST NOT INITIALLY.

WHAT IS INTERESTING ABOUT THE FORECAST UPPER PATTERN IS THAT BY

7-10 DAYS AN UNUSUALLY STRONG UPPER LEVEL HIGH IS FORECAST TO

DEVELOP OVER ALASKA...WITH A STRENGTHENING UPPER LOW ACROSS

NORTHERN CANADA. THESE POLAR LOWS ARE RESPONSIBLE FOR THE MAJOR

ARCTIC OUTBREAKS WHEN THEY MOVE SOUTH...AND THAT IS WHAT THE GFS

HAS BEEN FORECASTING TO OCCUR IN THE 10-15 DAY TIME RANGE. WHETHER

THIS ACTUALLY OCCURS REMAINS TO BE SEEN. REGARDLESS...THE BLOCKING

UPPER PATTERN WILL KEEP A PROLONGED FETCH OF CANADIAN/ARCTIC AIR

COMING INTO THE REGION FOR THE 2ND WEEK OF JANUARY. TOO EARLY TO

TELL WHETHER ANY MOISTURE WILL BE AVAILABLE...BUT NONETHELESS ITS

SHAPING UP TO BE AN INTERESTING WEEK WEATHER-WISE.