AMO,PDO,ENSO,QBO,NAD,AO,PNA. What the Hell does it all mean?

Yes, each one of those little acronyms have something to do with how cold, how hot, how many storms, and ect we will get during the upcoming Winter Season.

These factors derive from both the Oceans and the Atmosphere and they both have a major role in determining weather patterns across the world. One of the big misconceptions out there in the world of the internets is what effects the lack of, or presents of El-Nino', and what it means to the pattern in the South. You hear people comment about the lack of El-Nino' coming on as predicted, the colder and wetter forecast are a bust for this year. That is all hog wash if you ask me. There are way to many other factors that play a much more important role in determining these factors. Lets go over a few...

The entire equation begins in the oceans.

ENSO: El Niño–Southern Oscillation

ENSO is a quasiperiodic climate pattern, not a storm, that occurs across the tropical Pacific Ocean roughly every five years. The Southern Oscillation refers to variations in the temperature of the surface of the tropical eastern Pacific Ocean (warming and cooling known as El Niño and La Niña respectively) and in air surface pressure in the tropical western Pacific. The two variations are coupled: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the western Pacific. Mechanisms that cause the oscillation are currently not completely understood, (as in many things with science ) and remain under study.



The extremes of this climate pattern's oscillations, El Niño and La Niña, cause extreme weather (such as floods and droughts) in many regions of the world. Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected. In popular usage, the El Niño–Southern Oscillation is often called just "El Niño". El Niño is Spanish for "the little boy" and refers to the Christ child, because periodic warming in the Pacific near South America is usually noticed around Christmas.



Current analysis.

While we saw a brief bump in the warming and we continue to see some subsurface warm water it most likely will not be enough to push us into what I believe a significant enough weak el nino to see the classic weak el nino effects on the pattern. When you look back there arent many years that had a multiyear nina event that went warm neutral without going into full blown weak el nino territory. That leaves one to wonder, will we be able to push to near the 1.0 point or does this year buck the trend. Personally I beleive we max out in the .5-.7 range possibly sneaking up to .8.

PDO: The Pacific Decadal Oscillation

The Pacific Decadal Oscillation (PDO) is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20° N. During a "warm", or "positive", phase, the west Pacific becomes cool and part of the eastern ocean warms; during a "cool" or "negative" phase, the opposite pattern occurs.





IPO or ID; Interdecadal Pacific oscillation


The interdecadal Pacific oscillation (IPO or ID) display similar sea-surface temperature (SST) and sea-level pressure (SLP) patterns, with a cycle of 15–30 years, but affects both the north and south Pacific. In the tropical Pacific, maximum SST anomalies are found away from the equator. This is quite different from the quasi-decadal oscillation (QDO) with a period of 8-to-12 years and maximum SST anomalies straddling the equator, thus resembling the ENSO.

Current Analysis;

After seeing a record negative PDO September we saw the PDO rebound quite a bit during the month of October, however it continues to remain negative and out of phase with ENSO which is a negative factor for building/sustaining a nino. Given that these PDO warming bumps are quite common in the grander scheme I doubt that we will see a monthly positive PDO for DJF though we may sustain closer to normal before starting to fall off again as we head toward spring. The negative anomalies in the GOA certainly is one that will favor seeing more troughing in this area through the winter, while the current ridge in the aleutians may warm the SST's and create an aleutian high.

AMO: Atlantic multidecadal oscillation

The Atlantic Multidecadal Oscillation (AMO) is a mode of variability occurring in the North Atlantic Ocean and which has its principal expression in the sea surface temperature (SST) field. While there is some support for this mode in models and in historical observations, controversy exists with regard to its amplitude, and in particular, the attribution of sea surface temperature change to natural or anthropogenic causes, especially in tropical Atlantic areas important for hurricane development.



Analysis;

Warm. Not really a lot we can say here, its in the sae warm phase we have been in since we started looking at weather on the internet. That said the warm SST anomalies are certainly a positive and one that is found in many -NAO years. I would like to see a little more cold water near NF, however, given the passage of Sandy and the Noreaster that followed, we may have seen these areas cool.

From the skies above, ATMOSPHERIC

MJO: The Madden-Julian oscillation

The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30–90 days) variability in the tropical atmosphere. It is a large-scale coupling between atmospheric circulation and tropical deep convection. Rather than being a standing pattern (like ENSO) it is a traveling pattern, propagating eastwards at approximately 4 to 8 m/s, through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself in various ways, most clearly as anomalous rainfall.

The MJO is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian Ocean and Pacific Ocean. The anomalous rainfall is usually first evident over the western Indian Ocean, and remains evident as it propagates over the very warm ocean waters of the western and central tropical Pacific. This pattern of tropical rainfall then generally becomes nondescript as it moves over the cooler ocean waters of the eastern Pacific (except over the region of warmer water off the west coast of Central America) but occasionally reappears at low amplitude over the tropical Atlantic and higher amplitude over the Indian Ocean. The wet phase of enhanced convection and precipitation is followed by a dry phase where thunderstorm activity is suppressed. Each cycle lasts approximately 30–60 days. Because of this pattern, The MJO is also known as the 30–60 day oscillation, 30–60 day wave, or intraseasonal oscillation. While we all think as MJO as strictly and tool to forecast the enhanced Tropical Cyclone activity, it has is place in what may occur during the non-tropical seasons also.




Analysis;

While I do think its fairly difficult to predict the MJO, in the extended I am a firm believer that the MJO can be used to predict the long term pattern if we are in a stable MJO circuit. That said, I think we will be able to get more help from the MJO this year given the warm neutral enso conditions not being a detriment to any approaching kelvin waves. So basically watch the MJO forecasts and see where we are.

QBO; Quasi-biennial oscillation

Yet another Oscillation. The quasi-biennial oscillation (QBO) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km (0.6 mi) per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found.

Analysis;

I am and have always believe the QBO does at least have some effect on the overall level of blocking ( we will talk more about this ) that we see across the Northern Hemisphere. With the QBO strongly negative now and near its peak the weakening over the winter we should see patterns that are ripe to set up with blocking, not dissimilar to what we have seen the entire fall.

NAO: North Atlantic Oscillation

The North Atlantic Oscillation (NAO) is a climatic phenomenon in the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level between the Icelandic low and the Azores high. Through east-west oscillation motions of the Icelandic low and the Azores high, it controls the strength and direction of westerly winds and storm tracks across the North Atlantic. It is part of the Arctic oscillation, and varies over time with no particular periodicity.

The NAO is the dominant mode of winter climate variability in the North Atlantic region ranging from central North America to Europe and much into Northern Asia. The NAO is a large scale seesaw in atmospheric mass between the subtropical high and the polar low. The corresponding index varies from year to year, but also exhibits a tendency to remain in one phase for intervals lasting several years.

Westerly winds blowing across the Atlantic bring moist air into Europe. In years when westerlies are strong, summers are cool, winters are mild and rain is frequent. If westerlies are suppressed, the temperature is more extreme in summer and winter leading to heatwaves, deep freezes and reduced rainfall.

A permanent low-pressure system over Iceland (the Icelandic Low) and a permanent high-pressure system over the Azores (the Azores High) control the direction and strength of westerly winds into Europe. The relative strengths and positions of these systems vary from year to year and this variation is known as the NAO. A large difference in the pressure at the two stations (a high index year, denoted NAO+) leads to increased westerlies and, consequently, cool summers and mild and wet winters in Central Europe and its Atlantic facade. In contrast, if the index is low (NAO-), westerlies are suppressed, these areas suffer cold winters and storms track southerly toward the Mediterranean Sea. This brings increased storm activity and rainfall to southern Europe and North Africa.

Especially during the months of November to April, the NAO is responsible for much of the variability of weather in the North Atlantic region, affecting wind speed and wind direction changes, changes in temperature and moisture distribution and the intensity, number and track of storms.

Although having a less direct influence than for Western Europe, the NAO is also believed to have an impact on the weather over much of eastern North America. During the winter, when the index is high (NAO+), the Icelandic low draws a stronger south-westerly circulation over the eastern half of the North American continent which prevents Arctic air from plunging southward. In combination with the El Niño, this effect can produce significantly warmer winters over the northeastern United States and southeastern Canada. Conversely, when the NAO index is low (NAO-), the eastern seaboard and southeastern United States can incur winter cold outbreaks more than the norm with associated snowstorms and sub-freezing conditions to visit us here in Florida, in summer, a strong NAO- is thought to contribute to a weakened jet stream that normally pulls zonal systems into the Atlantic Basin, thus contributing to heat waves.

Positive Phase



Negative Phase



Analysis;

As stated above I do like the fact the QBO is negative and rising. A negative QBO has in general supported a -AO/NAO couplet through most analogs. This combined with the decadal trend of a -NAO, warm SST's around Greenland and what looks to be an upcoming PV split. I, along with many other Mets, believe we are heading into a steady negative phase of the NAO for the Winter.

As you can see, compared to last year, the NAO has been negative





AO: The Arctic oscillation

The Arctic oscillation (AO) or Northern Annular Mode/Northern Hemisphere Annular Mode (NAM) is an index (which varies over time with no particular periodicity) of the dominant pattern of non-seasonal sea-level pressure variations north of 20N latitude, and it is characterized by pressure anomalies of one sign in the Arctic with the opposite anomalies centered about 37–45N.[1] The AO is believed by climatologists to be causally related to, and thus partially predictive of, weather patterns in locations many thousands of miles away, including many of the major population centers of Europe and North America.



AO Warm



AO Cool



However, the correlation between sharply negative Arctic Oscillations and excessive winter cold and snow in regions vulnerable in that way to these negative AOs should not be overstated. It is by no means a simple, one-to-one equivalence. An extreme Arctic Oscillation does not necessarily mean extreme weather will occur. For example, since 1950, eight out of the 10 coldest Januarys in New York did not coincide with the 10 lowest January AO values. And the fourth warmest January there since 1950 coincided with one of those 10 most negative AOs.[8] So, although many climatologists believe that the Arctic Oscillation affects the probability of certain weather events occurring in certain places, the heightened chance of a phenomenon by no means assures it, nor does the lessened likelihood exclude it. Further, the precise value of the AO index only imperfectly reflects the severity of the weather associated with it.




PNA: Pacific/North American Pattern

The Pacific/North American Pattern, or PNA, describes the variation of atmospheric circulation patterns over the Pacific Ocean and North America. Like other atmospheric circulations, the PNA has the most impact on climate variables during the winter. There are two phases of the PNA, a positive phase and a negative phase. The positive phase usually relates to El Niño and the negative phase to La Niña, however there is a weak connection between the PNA and ENSO.



During the positive phase of the PNA, ( shown above )the Aleutian low in the Gulf of Alaska strengthens and the high pressure ridge over the Rocky Mountains also strengthens. This is similar to the strong phase of the North Atlantic Oscillation and increases the pressure gradient between the two centers of circulation. This causes an increase in wind speed which steers more storms into the Pacific Northwest.

The positive phase of the PNA leads to above average temperatures in the western United States. These above-average temperatures are because of the upper-level ridge over the Rocky Mountains. (Recall that surface high pressure areas are located within ridges and are accompanied by sinking air and clear skies.) This ridge is stronger than under normal conditions, increasing the temperatures at the surface and preventing the development of thunderstorms over the mountains which could provide rainfall or snow. The winds off the Pacific are pushed northward because the ridge is blocking the air from continuing the normal track from the west. When this happens, the southwestern United States sometimes experiences drought conditions with decreased precipitation totals due to the blocked flow.

Also during the positive phase of the PNA, deepening troughs of low pressure exists over the Northern Pacific Ocean and the Southeastern United States. These troughs help bring colder air down farther into the South from the northern latitudes, increasing the winter storm activity for these regions. This helps cause below average temperatures across the south-central and southeastern US and above average precipitation in these areas as well. The deepening trough over the eastern US shifts the jet stream and the storm tracks farther south. This causes below average precipitation to fall throughout the Ohio Valley and the Mississippi Valley down into the northern part of the southeastern states.

The Pacific/North American Pattern involves changes in atmospheric pressure between the Aleutian Low and the high pressure over the Rocky Mountains.



The negative phase of the PNA ( above) is essentially the reverse pattern of the positive phase. The upper-level ridge over the Rocky Mountains becomes weaker than normal during the negative phase corresponding to cooler than normal air. The Aleutian low also weakens, reducing the pressure gradient between the two circulation centers. This results in below average temperatures across the western US. Above normal precipitation is also likely for the western United States as winds off of the Pacific Ocean will bring storms farther south into this region.

Over the eastern United States, the upper-level trough is weaker than normal and warmer temperatures persist throughout this area. This shifts the jet stream and storm tracks northward into the Ohio Valley and the Mississippi Valley. This creates areas with above average precipitation in these valleys. Warm air masses from the Gulf of Mexico now have the potential to move farther north and cause temperatures to be above average in the states surrounding the Gulf. Above average precipitation will also be a factor in the northeastern United States with these below average temperatures. Florida and the southern parts of the southeast US, however, will be experiencing a dry spell during a negative phase in the winter months, accompanied with warm temperatures.

All in all I expect the PNA to remain negative through the winter given the -PDO, GOA cold anomalies and cold water down the west coast. That said, this can be counteracted by the MJO. As the MJO orbits through favorable PNA phases we may see 1-2 week periods of +PNA conditions and potentially cross polar flow given the higher than normal potential for AO polar blocking. This was my thinking a few weeks ago when I was talking about it was going to get cold then go through a warm spell and then deep arctic cold heads South bound.

Ok what does this all mean. There is so much information to absorb. And one thing to note, back in the day, I hayed this teleconnection stuff. Guess I was more into woman and booze. ( But at least I did not sell myself for a quick 10 bucks like some on here )

When all things are thrown into the mix, this is what many feel that will be the end result.







Just keep in mind, the atmospheric warming in one part of the world effects the building of a blocking high over another part of the world, like Greenland. When there is blocking over Greenland, as was the case when Sandy was heading North, thing happen in the Eastern half of the County. Blocking is a contributor to huge East Coast snowstorms in three ways. First, blocking brings the cold air. Second, it helps to lower pressure off the Southeast coast to allow storms to form. Finally, it slows the eastward progression of storms, helping them to slow down, strengthen and dump heavier snow. Sandy gave us a preview of what can happen off the East Coast if we get phasing to take place. This is something we lacked last year.



Here is one video that shows some of the variables. Kinda a poor presentation at times but over all, describes and connects every thing together.



Stratospheric warming looks have begun, which should mean a tanking Arctic Oscillation and a possible deep freeze in December/January via the mid Atlantic and southeast!

This was from a couple weeks ago.



In response to the Stratospheric warming, the AO is responding and the GFS ensembles are showimg the high lat blocking in the AO and NAO regions! This in turn sends a deep trough over the SE US..Fun Times like occurred in 2009/10



I do have to admit, the models ( GFS and EURO ) have been junk as to consistency, and can not be trusted in the long term. But, the indexes we discussed above are very real and the outcome of what we are seeing has to be considered.

It means everything has cycles....and there is no Global Warming:) that was fun.

WOW !! Great blog, e !! Thanks for all the effort, you put into it......I'll have to read this one, several times......just to absorb, a bit of it!!

"( But at least I did not sell myself for a quick 10 bucks like some on here )"



Thanks E. Too much for me to absorb at once but well done sir.

sangria wrote:WOW !! Great blog, e !! Thanks for all the effort, you put into it......I'll have to read this one, several times......just to absorb, a bit of it!!

It's been 50 minutes since your post. How many times have you read so far san?

StAugustineFL wrote:"( But at least I did not sell myself for a quick 10 bucks like some on here )"



Thanks E. Too much for me to absorb at once but well done sir.

I see you caught that. Was making sure you read the blog. LOL

WARNING LANGUAGE.

StAugustineFL wrote:

sangria wrote:WOW !! Great blog, e !! Thanks for all the effort, you put into it......I'll have to read this one, several times......just to absorb, a bit of it!!

It's been 50 minutes since your post. How many times have you read so far san?

One and a half ........

GFS NOA Forecast. In the Negative

That's a substantial negative on the GFS E. To my eye things look relatively quiet for another week model wise before the NAO really dips. I'm curious to see what the first week of December brings.

We know who the dips are.....

One of the final pieces to the puzzle is falling into places now. Finally, the emergence of a solid +PNA will be of great importance to break this western trough poised to set up over the next week. With all this mess going on in the Pacific, nothing will go on, as far as storms in the East.



This, along with the -NAO all bets are off. With the blocking pattern projected to stay strong during this period.



The middle of December continues to be interesting. Must be something to do with Global Warming. The CO2 as really got everything screwed up.

Interesting. CLICK to animate;
http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

Looks like NYC in for some snow....

E, the -NAO has backed off (for today). It's headed weak negative after a brief dip. Honestly I get a little frustrated with all these "forecasts" from the CPC. Shizz changes direction like a fart in the wind.



The snowfall map you posted is on par with my thoughts in chat this morning.

Just for comparison..here is the current CPC AO ensemble forecast graph (Top) compared to this same time 2009 (Bottom)



Many Mets, believe the atmospheric conditions setting up is very very similar to the 2009 - 2010 winter. Now, you might ask why the Winter of 09-10 was so bad for Many across the globe. During the winter of 2009-2010 a rare combination of known factors (as we are seeing setting up now) in earth’s climate variability systems -- the Arctic Oscillation and North Atlantic Oscillation in the Atlantic. El Nino, the Pacific Decadal Oscillation and Pacific/North American Pattern in the Pacific and the Indian Ocean Dipole -- influenced the Northern Hemisphere winter from North America, across Europe to eastern Eurasia - as far east as Mongolia, China and Korea.



This has been a highly unusual northern hemisphere winter; extremely cold and snowy in some regions, stormy in others - yet Canada had its warmest winter on record, parts of the the Arctic and tropical sea temperatures were unusually warm. Now, to be fair, this year wee will NOT see a strong El-Nino' event as back in 2009-2010. Not even close.