My Official Winter Forecast for 2011-2012

After spending several weeks of planning, researching, typing, and creating maps, I have finally managed to compile my findings and present to you all my winter outlook for the upcoming 2011-2012 winter season. It's been a long and tough road but I am glad to finally share my ideas with you all on what I think could set up as we progress through the DJF period. A lot of things were taken into consideration, but I will go over the main points to support my idea of how the winter pattern will set up. With that said, here's the following:

ENSO:
Taking a look back at the previous winter season, many folks were banking on the traditional La Nina conditions that were expected across the country, with the usual warm and dry pattern establishing itself over the Southern States with most of the cold and snow well to the north for areas such as the Midwest and Great Lakes region. However, despite being one of the main drivers of the winter season, it has been proven that Ninas can be dominated by another factor: The NAO (which I will discuss next). Despite the difference in the strength of the Nina, we will once again go through another Nina in a back-to-back scenario, as many of us have expected. Based on current conditions in the Pacific, it looks as though we are in the weak category right now but it may strengthen into a moderate Nina for the rest of the year. Personally I believe that the Nina will remain weak but being on the strong side (Strong Weak Nina basically). On the chart below, you can see what guidance is prediction from here on out (ending period is ASO):

It appears it suggests that modeling wants to take a dive toward the borderline weak/moderate Nina category. I'm leaning more toward a weaker scenario but I am keeping, in consideration, the possibility that this can very well get stronger than what models give it credit for but again, I would expect moderate at best and nothing like the previous year where it was quite strong. The CFS has this as developing into a pretty strong Nina but I don't think it has the right idea at this moment. We will need to continue to watch how things unfold out there from here on out. I expect the Nina to position itself more East or East-central per current trends in the SST anomalies.

NAO:
Being one of the most trickiest of oscillations to predict, especially outside 2 weeks, none can guarantee how strong and what phase it will be in, although for this winter chances are increasing for yet another dominantly-negative phase of the NAO. The overall North Atlantic SST anomaly setup, developing negative QBO, and low solar activity leads me to believe that this will be the case once more. Due to variability in this particular index, there is just no telling exactly how this will setup regarding position and strength so things can change over the next month toward December. In recent years (and going back in the late 50s, 60s, and late 70s as well), it appears as if the negative phase has been more common than the neutral or positive phase, which is an indication that we may be entering a decadal period where more often than not the negative phase will take over. However, as many will tell you, there are times where we will be in either of the other phases which would then increase chances for stronger ridging east and troughing west especially during a winter where La Nina is the ENSO state. Signs are pointing that this should continue for the next several years but with positive spikes among them but for now, colder is the word and will be the case again for the 2011-2012 winter. I expect a moderate West-based -NAO to take form but not as strong as it was during the 2009-2010 winter where it was record strong. Remember that if strong enough, the -NAO can override what would be a Nina pattern and since this Nina, as it stands now, appears to be weak for the most part, the -NAO should likely dominate the pattern but relaxing periods will also be in the mix, likely sometime in either mid-January or early February. If the predicted blocking sustains itself longer and remains strong enough, then February may end up being colder than forecasted so keep that in mind as we progress through the season.

AO:
Observing the above normal snowcover across Eurasia, this favors an increase in stratsopheric warming due to the thermal effect from enhanced snowcover. This also strengthens the Siberian high and allows it to control the Arctic, affecting the jet stream by causing it to dig further south resulting in the usual Arctic air outbreaks that the US typically sees every now and then. As winter progresses, higher pressure anomalies can be found in the Arctic while lower pressure anomalies are present along the mid-latitude oceanic regions. While this is occurring, there is an increase in energy transfer from the lower to upper levels of the atmosphere, causing the polar vortex to weaken and allow a more north-south flow instead of the east-west (when less energy transfer is occurring). Warmer air is then able to enter into the polar stratosphere. All of this and the fact that it is strongly correlated with the NAO (0.82 to be exact so it's high) leads to yet another dominately-negative AO for the winter.

Solar Activity:
Despite the recent increase in activity, we are still on the low side of things and it looks to be that way for this winter. Research shows that throughout the years, during periods of low solar activity there seems to be an increase in frequency of -NAO episodes. This leads to the idea that lower solar activity equates to colder winters across the Eastern US due to its effects on blocking. I should also mention that during low solar activity, the decreased level of UV light can signal a developing -AO as well as recent studies suggest that the correlation does indeed exist and thus fits the idea, which makes monitoring this particular factor more importantly and carefully over the next several years. Again due to the uptick in activity, I do not see the -AO becoming as strong as it was during the 2009-2010 and 2010-2011 winters but would still be moderate at best. It's interesting to note that despite being low, we are actually nearing solar maxima and belive that it won't be reached until sometime between the years of 2012-2014.

QBO:
Another important factor to look into when it comes to analyzing blocking potential is the Quasi- Biennial Oscillation. To recap for those of you who aren't too familar or have not heard of this osciallation: The QBO is a stratospheric oscillation located above the equator. These winds can either blow west during the positive phase and east in negative. When taking a look at it through chart data, the 30-50 mb levels should be the areas to watch. The flow associated with this blows in one direction for a period of time and then eventually switches. For this winter, I am forecasting a weak to moderate -QBO to develop as data is suggesting the equatorial winds to flow more easterly, hence the developing negative phase. At the moment, based on the latest data, the 30mb zonal wind anomaly averages negative (-2.30) but the 50mb is positive (10.00), which leads me to believe that the QBO is currently weak but I expect it to strengthen further into the negative territory for the winter. During this phase, the polar vortex is weakened and increases potential for SSW (Sudden Stratospheric Warming: An event where sudden upward swing in temperatures occur in the stratosphere, causing the westerly winds of the polar vortex to slow or even reverse direction). This also increases high latitude blocking potential, and aid in the development of a -AO. It's opposite, the westerly (positive) phase promotes more positive zonal wind anomalies and strengthens the polar vortex, which makes it difficult to get cold air to drive south and thus decreases -AO potential. Still, we will need to continue to monitor it and see what the numbers are once we finish November.

30 mb: http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

50 mb: http://www.cpc.ncep.noaa.gov/data/indices/qbo.u50.index

Difference between the two regarding temperature and vorticity setup:

PDO:
Not much to say on this one other than that we will once more see the negative phase dominate and last for the next several years given its current cycle. You can see evidence of it based on the cooler anomalies located in the GoA as well as the warmer anomalies located west of that area.

AMO:
To recap for those of you not too familar with this: Known as the Atlantic Multi-decadal Oscillation, this index refers to SST anomalies of the North Atlantic region from the equator up to 70° N. It too has it fair share of warm and cool phases. It has been since the mid 1990s period that the AMO switched to positive and has stayed that way up until this point. The peak period of this index was back in 2005 when record Atlantic SSTs were observed and has since been on the decrease. In its warm phase, it affects the northern hemisphere by making it warmer than normal and cooler during negative. This warm phase also has an effect on Atlantic tropical activity, as it increases the potential for cyclonic development due to the presence of warmer waters. For this winter, the AMO is expected to continue in its positive phase (albeit weak), which will probably last sometime between 2015-2020 given the current rate.

Fall-Winter Pattern Correlation:

As we've seen over the previous month, there have been plenty of troughing scenarios with much cooler temperatures for highs with cold lows, including our widespread frost/freeze that took place during the late part of the month. It was quite impressive to see such a significant amount of snow fall across the northeastern states, let alone areas back across the TX Panhandle and OK where both areas are seeing snow before Halloween. This, as well as the above normal snowcover that took place across Eurasia (as explained earlier), seems to clue in on what could be a winter similar to the last two where lots of troughiness takes place across the East with storm systems traversing across the South and up the coast. The amount and strength of CAD events were fantastic as well (especially our most recent one) and would suggest that we MAY be getting back into a period where CADs will become more common than they have been in the past. However, this would also mean an increased chance for a significant icestorm of some sort and unfortunately many would agree that we are overdue for a nasty one to take form at some point, and this winter holds that threat though not guaranteed. We'll see. Also the currently highly amplified pattern experienced across the northern hemisphere is another thing to consider in the back of your mind, as that too could possibly mean that we will see such a pattern take shape for at least the first half of the winter. As I was typing this, models are indicating a developing blocking signal in the latter part of this month and supports the idea of establishing Greenland blocking with much chillier temperatures for the mid-month period. Whether or not that feature stays there is uncertain but just the idea of getting blocking like that so soon before meteorological winter begins is interesting. This kind of correlation doesn't always guarantee what happens in the following winter but it is another useful "tool" to use when attempting to forecast in the long-range.

ANALOGS:
I went and chose the best ones that I could find matching the current Fall pattern and how it evolved in the latter for the winter. Mostly based on second year weak Ninas that were weak to around moderate (except 1995-1996), -PDO (except 1995-1996), -QBO (except 2008-2009 and 2010-2011), and low solar activity (except 1967-1968). I also put beside each one which one I put more weigh on. As you can see, 1962-1963 seems to be a perfect match regarding the potential setup overall for the upcoming winter. The rest featured something that is not present with the current developing pattern. Despite that, I have put my thoughts on which years deserves more or less weigh when it comes to thinking about which ones would work out the best.

1962-1963- Weak Nina, -QBO, -NAO, -PDO, low solar activity (more)
1967-1968- Weak Nina, -QBO, -NAO, -PDO, near solar maxima (more)
1995-1996- Weak Nina, -QBO, -NAO, +PDO, low solar activity (less)
2008-2009- Weak Nina, +QBO, +NAO, -PDO, low solar activity (less)
2010-2011- Weak-Moderate Nina, +QBO, -NAO, -PDO, low solar activity (more)

Temperatures:

I expect conditions to be similar to the previous winter but not as brutal with the cold so I am going for colder than average across the Midwest, Great Lakes, the MA and NE. Slightly below temperatures can be found for areas further south for places such as the northern section of the Southeast, parts of the TN Valley, stretching northwest across southwestern MO, KS, southwestern NE, NE CO, parts of WY, and parts of ID. I expect average temperatures (though they can fluctuate) across the Central Rockies down to the parts of the Southern Plains, and through the central portion of the Southeast. I have included the PNW as well, but I believe they can easily become cooler than average considering my thoughts for their overall winter. Slightly warmer than normal temperatures are in store for areas from northern CA, southeast to most of LA, and eastward along the Gulf Coast through much of FL. The warmest of temperatures will be experienced for the rest of the PSW and Desert SW to southern TX where I expect ridging to dominate and southern FL.

Precipitation: (Note: When I say precipitation, I'm referring to both wintry precip and rain potential)

There should be an abundance of precipitation for the PNW and eastward across the Midwest, Great Lakes, MA, and NE. Slightly above average will be featured for the Central Plain States and southeastward across parts of the Lower Ohio Valley and TN Valley, and through the northern section of the Southeast. Average precipitation is in similar place to where I had my temperatures except the PNW due to several storm systems arriving from the Pacific, taking favorable tracks to put down plenty of rain and snow for the higher elevations. Where I have the ridging situated, those areas should experience below average precipitation for the most part but I will not rule out a chance for them to at least reach their average. It only takes a storm or two to put them at average in both rain and snow so that was considered while making this forecast.

Snowfall:

Not much to mention with this map since this would match what I had with my other maps.  I will go over the percentage per area. (Note: I did not put the PNW in the above average snow due to the assumption that the mountainous regions will already see that happening and expect the lower elevations to see rain).

Above Average: 100%-200%
Average to Above Average: 100%+
Average: 100% (Could be slightly above or below)
Below Average to Average: 0%-100% (leaning more toward the low side for that area)

Storm Tracks:

I know it may look a tad confusing with all the lines drawn the way they are, but I will go over each starting with the primaries:

The first one I put down just off the West Coast.  Given the influence felt by the ridge and trough setup, it will travel just southeast of the PNW, throwing plenty of precipitation back their way and then head southeast from there.  Now there are three alternate paths that I think it could take at this point.  It can either jog to the southeast a bit and cut through the Ohio Valley and Southern MA before going OTS, take the same path but turn more northeastward once it's close to WV, or it can dive close to the Gulf Coast and then travel eastward through the Southeast and go OTS.

The next primary track is the Alberta Clipper, which we all should be familiar with.  This go around, however, I believe it can take a further south track due to influence from the -NAO troughing so areas that normally miss out can get in on the action.  There may also be moments where these clippers can get a bit of an attitude and actually pull additional amounts of energy from the south, though I would expect those amounts to be small at best.

The third primary is located down in the GoM where systems can develop and then travel along the coast, becoming the typical Miller A/Nor-easter kind of system.  We all should be familiar with this as well.

Moving on to the secondaries, you will notice I placed two on the map.  One of them is located in northern CA, which I expect tracks like that to take a direct northeastward direction spreading additional precipitation for the PNW and Northern Plains.  I predict this will happen a few times throughout the season.  The second one is down in eastern TX.  Here, a system would develop close to the Gulf and manage to pull plenty of moisture that may be nearby and then take either a direct east route and OTS, possibly jogging slightly northeast as well, head directly through the Carolinas or it may become an Apps Runner and potentially cause a Miller B setup with a coastal low developing nearby.  This particular track could happen a few times as well.

Conclusion:

Overall, this upcoming season is shaping up to be similar to this past winter. Lots of potential for an active Eastern US season even down across the Southeast with several storm threats to watch, not to mention the possibility of a major ice storm. It has been quite a long while since we last had such down here in NC and so we, as well as other areas that are favorable for this, are overdue for one and this winter just may bring it. When that would occur I can't be certain but I would guess it would have to be sometime in January or possibly February when the warmer air has a better chance to nose its way in during a CAD. Speaking of CADs, it's been amazing seeing them pop up so much like they used to years ago and could be a sign of us getting back into that pattern so I foresee periods where a wintry mix of snow, sleet, and freezing is possible across parts of the Carolinas. Going outside from here, I can see the PNW getting copious amounts of rain and snow back their way, keeping the area cool and wet for the most part while the mountainous regions get into the cold and snow. Areas across the MA, NE, GL, and Midwest should once more be in the jackpot for seeing plenty of blizzards and sustain periods of cold, perhaps some very brutal cold entering into those regions during December and again in January. The only area I see not being on the same page with them is the far northeastern corner of the US (mainly Maine) where they will be in their own kind of setup similar to what I expect for the areas in the light blue but with better chances for snow Down across the Southwest and Southern Plains, ridging looks to dominate that area with continued warmth and dryness. It's bad enough for them to have gone through the relentless drought during the summer and fall, and now unfortunately it looks to continue for winter. I'd like to see them be able to get some kind of massive southern storm system that develops and delivers tremendous amounts of rain for them (which I actually think would be possible though not likely); one that cuts directly through all of the Southern portion of the US. Winter, for them, will at least be calm with few chances for snow in the favored areas. I will not rule them out getting into a few periods of below average temperatures, which would be more likely as we progress through February since that's when I would expect the Southeast to finally be influenced more by the ridge and not the trough while the west experiences their pattern change. In short: This will be another exciting winter as we monitor storms, debate about how much snow someone will get, the bone-chilling moments when cold air strikes with vengeance, and most importantly: Your usual model drama and weenies doing their usual cliff dive when the models don't go their way LOL!

Anyway, I want to thank you all for taking the time to read my forecast. I know I'm not one of the best in the world but like I stated earlier, I have put a lot of hard work into this in hopes of getting to express my thoughts about the upcoming winter season. Hope you enjoyed it and remember to prepare yourselves if you are in one of the areas that I expect to see lots of wintry action. Stock up on the non-perishable food, batteries, a generator (if you have the money to spend), water, etc. You know the drill. Don't overdo it if you're shoveling and take frequent breaks. We've had enough folks getting a heart attack from doing too much shoveling all day. Take care everyone.