NJ Strong 2013-2014 Winter Outlook
Hello! Welcome to this years winter outlook. Long range forecasting has come a long way since "back in the day" when most people would just wake up and look outside their window to see how the weather looks like for that day. Now, most people rely on various social media websites and news stations to get their day-to-day weather. Long range forecasting in particular has gained a lot of attention over the last few years. However, it is not an exact science and with all the moving parts in our atmosphere it is almost impossible to accurately predict the weather a full season in advance.That being said, we could still get a pretty good general idea of how this winter will play out. Yes there will be some assumptions made in this outlook, but I will do my best to provide as much reasoning, facts, and data as possible to make a strong claim and forecast.
Lets get started!
There are five components to this winter outlook that I want to look at closely:
- ENSO (El Nino / Southern Oscillation)
- Stratosphere
- Sunspots
- Northern Hemisphere Snow Cover / Arctic Ice Extent
- Analogs (past years I think match up to current observations)
One thing you all should know before you continue reading...you will see me reference the NAO, AO, PNA, and EPO at times. I will detail what those mean at the end of this outlook in the "wildcards" section, but I will reference them in other sections as well. You should know that a -NAO / -AO / -EPO / and +PNA are most favorable for us if we are looking for colder and snowier than normal conditions in the eastern CONUS.
ENSO
When we try to determine whether the upcoming winter season will be El Nino, La Nina, or La Nada (neutral); it is critical we look at the SST's (sea surface temperatures) of the Equatorial Pacific. The image above are SST's of the entire globe. Red shows above normal water temperatures (warm) while blue indicates below normal (cold) water temps.
Just so we are all on the same page, the ENSO is divided into 4 regions. Here is an image for visualization purposes...
Nino 4, Nino 3.4, Nino 3, and Nino 1+2.
All are important in one way or another, but Nino 3.4 is most important because it has the most influence on the ENSO.
Keep those regions in mind as we now look at SST's in the Equatorial Pacific:
In the central Pacific (Nino 4 and Nino 3.4 regions) the SST's are above normal and still continue to warm. In the eastern Pacific (Nino 3 and 1+2) the SST's are below normal and are still trending cooler.
The best way to classify the ENSO as El Nino, La Nina, or La Nada is by looking at the ONI (Oceanic Nino Index) for Nino region 3.4. It is a 3-month average of SST anomalies for that region.
To classify as El Nino (warm), there must be 5 consecutive months at or above +0.5 degree anomaly.
To classify as La Nina (cool), there must be 5 consecutive months at or below -0.5 degree anomaly.
By looking at the SST anomaly map above of the Equatorial Pacific, we can conclude Nino 4 / 3.4 regions are running above noraml (as of now), and Nino 3 / 1+2 are running below normal. According to CPC, the ONI for Nino region 3.4 for the 3-month mean of August-September-October was -0.3. That falls between -0.5 and +0.5 which indicates LA NADA.
However, the latest ONI value for region 3.4, which is not shown in CPC's graph but rather shown in actual observations is 0.0. So it has warmed pretty nicely through the course of November, and given the SST anomaly charts, evidence shows it should continue to warm through December.
This is the heat content anomaly map for the Equ. Pacific and the orange spike indicates that warming is still taking place for the general area.
Other tools we have access to that we could look at to forecast ENSO are statistical and dynamical models. Note this has not updated since mid-October:
Most seem to fall between the +0.5 and -0.5 range, indicating La Nada for the upcoming winter season.
Here is what the EURO has to say for Nino 3.4 region...
This only updates once a month, but as of October this model was pretty aggressive in taking the plumes at or above +0.5 for Nino region 3.4.
This graphic shows some ensembles getting above +0.5, but the mean (red line) still insists on a La Nada ENSO winter.
One thing to keep in mind is SST's are pretty volatile, meaning they are vulnerable to sudden change which is often why these models do a poor job at forecasting the ENSO. The key is to monitor actual observations such as the heat anomaly chart I posted above and other graphs the Climate Prediction Center makes available to us.
ENSO Forecast
If we look back at the Equatorial Pacific SST's that I posted above, one can argue the current set-up of SST's is similar to those of El Nino Modoki's. I did not notice this until Meteorologist Mike Masco of Baltimore made reference of this on his Facebook page.
The Modoki El Nino is basically strong anomalous warming in the central Equatorial Pacific and strong anomalous cooling in the eastern Equatorial Pacific, and that pretty much aligns itself with the Equatorial Pacific SST map I posted up top.
The top image is the same Equ. Pac. SST anomalous map I posted earlier, and the bottom map is just a general example I found of SST anomalous maps of El Nino Modoki. You can see how both maps look awfully similar. So, we do indeed have a El Nino Modoki going right now, but the question is how long does it last? That is something I do not know the answer to.
This index suggests it will continue through the upcoming winter.
Ultimately, my forecast is for a La Nada - ENSO 2013-2014 winter season, but I think by the 2nd half of the meteorological winter, we could see more of a weak El Nino type of pattern evolve over the United States. It depends on how the warming in the crucial Nino regions progresses and how the SOI (Southern Oscillation Index), which forecasts ENSO intensities (weak or strong episodes), progresses.
Sustained below -8 values of the SOI indicate EL Nino, while sustained above +8 values of the SOI classify as La Nina.
The SOI has been fluctuating these last few years, meaning it has been neither consistently positive nor negative, and it looks like it wants to stay that way for now.
When I get to the Analogs portion of this winter outlook, I will show some years that featured El Nino Modoki winters. Like I said though, it is not a given this SST regime continues through the winter months. At this time, I am more confident in stating our winter season will feature La Nada, which often means the ENSO has minimal effect on our weather pattern.
Stratosphere
Our stratosphere is a very powerful phenomena that can have a drastic influence on our winter pattern. It is important we examine it as best as possible, even though it could often be difficult to follow. Often times in the weather world, you hear of something called a Sudden Stratospheric Warming (SSW) event. In laymen's terms, it refers to exactly as it sounds, which is when our stratosphere warms at such rapid levels in a short period of time.
Here is an example of a SSW from last winter, January 2013 to be more specific:
What this translates to is air falling and warming in the North Pole of the stratosphere, while air was rising and cooling over the equator in the stratosphere.
A SSW can either displace, split, or destroy the PV (Polar Vortex) and sometimes tanks our AO (Arctic Oscillation) to a negative phase, which often leads to much colder than normal conditions over the eastern CONUS (Continental U.S.). If you remember last winter, January and early February featured below normal temperatures in the northeast and that came after the SSW event. One thing to keep in mind is there is a 10-day lag until the SSW translates to the surface.
Here is what the arctic PV looks like
We want that Polar Vortex on our side of the pole, which will help usher down colder air into the U.S. A SSW event could help us get it there.
The QBO (Quasi Biennial Oscillation) tracks the wind patterns (easterlies and westerlies) in the tropical stratosphere. It comes in two phases, negative and positive. A -QBO is composed of easterly winds while a +QBO is composed of westerly winds. Our current QBO (shown below) is +11.69 as of October.
When the QBO is in a negative state, meaning easterly winds, there is a higher probability of a SSW occurring during the winter (according to a study done by Holton & Tan in 1980). The orange box is where we currently stand (+QBO). The blue box I circled is the QBO from last October, which was in a very negative phase (-24.51). You can see how it got warmer and warmer as the winter months progressed, and by January (indicated by the blue "J" with my beautiful hand writing), it was at -6.07, which indicated a SSW had occurred and much colder than normal temperatures filtered into the eastern CONUS at that time.
I am not enthused with regards to where our QBO stands right now, or the state of the current stratosphere for that matter. Extremely positive or extremely negative (like last winter) states of the QBO provide the best 500 mb patterns for us during the winter because those phases influence our upper level pattern most. We are working with the westerlies this time (+QBO) in a neutral phase and it will be interesting to see what that does to our pattern (if anything). I'll admit I am not an expert with this stuff but I still find it interesting nonetheless.
Sunspots
In case you did not know, the Sun is pretty big...
Like the Stratosphere, the Sun is another mechanism that has the ability to drive weather patterns across the globe. In fact, scientists say they can make a forecast of how the long range weather will look like just by studying the Sun, ENSO, and Stratosphere.
Sunspots are magnetic storms on the surface of the Sun and sometimes release radiation that comes from the magnetic energy associated with sunspots. Those are known as Solar Flares.
By studying the Solar Cycle and general Solar Activity, we are able to see how this could effect our weather on Earth, in this case, our upcoming winter season.
The image above shows sunspot activity on the Sun at its surface. In the years 2008-2009, the Solar Cycle hit something called a Solar Minimum, which means there was virtually no sunspots on the Sun at that time. It is by no coincidence that those years in parts of the world, including the U.S., featured colder than normal conditions. During times of decreased solar activity, the globe is entering a "cooling" phase; while during times of increases solar activity, the globe is in a "warming" phase.
Where do we stand in regards to the sunspots now? You can see I circled where we were as of November 9th (around 70 Solar Flares). We are obviously out of the Solar Minimum cycle, and according to NASA, we are on our way to a Solar Maximum (they are not 100% confident on this yet, feel free to read the article I hyperlinked). One thing that must be stressed is it takes awhile for the global temperatures to respond to the suns change in Magnetic Field. The best and most simple example I read online is it's like sitting in a bathtub of cold water and turning on the hot water and waiting to feel the difference in the water temperature. Of course we are not dealing with a bathtub here, just with the Earth (no big deal, really) so the lag effect will be much longer.
Forecasts for the Sunspot Cycle does show it heading toward a Solar Maximum, as NASA expects. I do not believe this will have much of an effect on THIS years winters, but it could in the ones to come.
Northern Hemisphere Snow Cover / Arctic Ice Extent
The Stratosphere and Sunspot Cycle are factors that are studied at the Macro level when it comes to forming a winter outlook. The Micro level involves looking more closely at the H5 pattern and what drives it. The NH snow cover and Arctic Ice Extent could help us do that.
As of November 16th, Arctic sea ice is at 9,524,937 km^2. 2013 was on pace of having a much better Arctic Sea Ice Extent compares to recent years, however, a close examination of the graph above shows it heading back down to below average levels. Despite the recent melting, NSIDC says Arctic Sea Ice is "notably higher" this year than last, due to the colder than normal summer. We are still far from the long-term average (1981-2010), but it is an improvement.
Northern Hemisphere snow cover is also important to look at in an attempt to gauge what our H5 pattern will look like this winter.
Above is a tabular chart of snow cover for different regions in the world. I outlined October 2012 and 2013. This year is off to a better start in regards to our snow cover compared to last. This is important because the cold air that comes with the dips in our jet streams this winter (troughs) will not drastically moderate as they move into the U.S. from Canada. During years of above normal snow cover in the Northern Hemisphere, our Arctic Oscillation in the winter has a higher probability of being on the negative side of the phase.
Analogs
Before I highlight my analogs, I want to give some background on the teleconnections that DIRECTLY influence our pattern and are most important to us for the winter. These are short term indices that cannot (in my opinion) be predicted ahead of time (2+ months out), but you could make assumptions and draw conclusions based on other pieces of information available to us.
NAO (North Atlantic Oscillation Index) - defined as the height anomalies that extend into Greenland, also known as "blocking."
AO (Arctic Oscillation Index) - defined as the degree into which Arctic air penetrates into the mid-latitudes of our atmosphere.
PNA (Pacific / North American Index) - defined as the height anomalies over the western U.S. or eastern Pacific Ocean.
EPO (Eastern Pacific Oscillation Index) - defined as the heights anomalies over Alaska, western Canada, and the Arctic.
Like I stated in the beginning of this outlook, -NAO/-AO/-EPO/+PNA is where we want these signals to be if we are looking for colder/stormier than normal conditions in the eastern CONUS. They DO NOT all have to be favorable in order to get that type of weather pattern, but it surely helps.
Here are the analogs (past years I think this winter could mimic) I chose for the 2013-2014 winter season. The first thing I should say is we are in a +AO/-EPO/-PDO regime right now. These three signals have not wavered much since the end of summer and through the fall.
The PDO is likely to remain in a negative state given the below normal SST anomalies in the northeast Pacific Ocean. This correlates well to a -PNA H5 pattern and that is most likely what we will see through this winter as well.
The difference here is though the EPO has a good chance of being in a negative regime as we go through this winter. There seems to be constant ridging taking place near Alaska, the Aleutian Islands, and sometimes into the Arctic. This could be a good mechanism in providing a terminal for cold air to filter into the eastern CONUS.
Lastly, the AO. The AO is a tough forecast for the upcoming winter. It is at an extremely positive state right now (2nd highest all-time for this time of year).
+4.3 to be exact (as of November 14th).
I do think it will trend negative as we progress through the winter months, but it could take a SSW event to drastically change its propagation, which is why the analogs I chose show 3 different types of AO winters (neutral, negative, and positive). Keep in mind even with a poor Pacific pattern last year (-PNA/+EPO), we still managed to get a blizzard in February thanks to the -NAO/-AO couplet. If the pattern on one side of the county is poor, but favorable on the other end, it could still provide us with a chance to see a storm. When both are in sync, conditions are RIPE for a snowstorm.
Putting all those analogs together, we come out with a temperature anomaly map that looks like this:
Not much in the way of above normal temps. anywhere in the U.S., but the western U.S. is in a deep freeze with noticeable below average temp. departures from normal. 1990-1991 is on there because the AO in December of 1990 was at +1.30 and it slowly trended cooler. By the time we got to February, we were at a -AO. The only issue is it featured a +EPO pattern and I do not think we will be seeing much of a +EPO this winter.
The issue with this analogs map though is it shows too much of a -PNA/+EPO type of pattern and I do not think that will be the case this winter. I do like where our EPO is right now, and feel the -EPO could persist through most of the winter (obviously there will be times of relaxation when it goes positive for a period of time).
Overall Thought's
I feel this winter could turn out to be stormier as a whole for the U.S. Note: "stormier" does NOT mean "snowier." Some things not mentioned in this outlook such as the MJO (Madden Julian Oscillation) and STJ (Sub-Tropical Jet Stream) could play a VERY critical role in determining whether this above normal precip. type of winter comes to fruition in the eastern CONUS or not. Those two indices, along with the positive trends in SST's in Nino region 3.4, are making me feel confident about a stormier than normal winter for the eastern U.S. which could produce potent storms as two jet streams (north and south branches) come together for a phase.
I do not like doing month-to-month breakdowns (predicting temp and precip. departures from normal) since I think those are very volatile forecasts and it is difficult to pinpoint exact H5 setups months ahead of time. Therefore, I did a National Outlook with my thought's on each region.
National Outlook
(most confident for eastern U.S.)
Region 1 - Avg. Temps / Above Avg. Precip.
This is the area I feel the polar and sub-tropical jet streams could come together to produce large storm systems. Where they phase (off the coast or inland) will determine precipitation types (snow, rain, ice) for certain areas. This is why predicting snowfall amounts is a crap shoot, because 1 power house storm that brings 1 to 2 feet of snow could already bring you to an average or above average season. I definitely think there will be at least 3-4 storms this year that could be considered "major" and possibly 1 "historic" depending on how the STJ cooperates (not necessarily meaning snowstorms by the way). Daily temperatures will act as a roller coaster ride, meaning some days consisting of much below normal temps. and others as much above normal. In the end, everything should work out to an average winter, but I would favor the above normal temperatures to win out at the end.
Region 2 - Below Avg. Temps. / Above Avg. Precip. (except Maine)
I actually think this could be a very snowy winter for this part of the country. Usually it is not a question of needing the cold air (since it is already there), it's just you need the storms to track there. The pattern should support storms to cut west of the Apps this winter, which is why I think a well above normal snowfall is in order for this region. The worst of the cold, getting down to arctic-like and very dangerous levels, will come IF (note the "IF") the AO gets to neutral or negative this winter. I'm not quite sold on that just yet.
Region 3 - Below Avg. Temps. / Below Avg. Precip.
A very west-based -NAO could allow storms to track and stall over this part of the region, but I do not see it happening this winter. I think there will be periods of extremely cold temperatures, but there will not be much in the way of large storms systems. However, there probably will be numerous small-type storm events as short wave energies ride along the polar jet stream. Will be interesting to see if one cuts-off or not.
Region 4 - Above Avg. Temps. / Above Avg. Precip.
This is probably the area I am least confident in of all the regions. This fall we have seen some strong storms effect this part of the country, and that could be due to the sub-tropical jet feeding off the Gulf of Mexico. This has the potential to continue through the winter months, but I do not see much in the way of frozen precipitation (sorry Dallas) falling since too much warm air will be available.
Region 5 - Above Avg. Temps. / Above Avg. Precip.
I was deciding between warm / wet or warm / dry for this area. Do not get me wrong, I do think there will be periods of cold shots that work there way in behind the storms system that will cut west of here. But overall, since I see storms cutting west of this region, I think heights will be raised enough where the winter will end in an above normal state. The difference with this area and I-95 is storms do not have the opportunity to dynamically cool the atmosphere which would change precip. from rain to snow since the coldest air is to the north and west.
Region 6 - Avg. Temps. / Avg. Precip.
I have been seeing a lot of forecasts for a warm western U.S., but we have to remember we are still in a -PDO cycle and that usually leads to -PNA regimes, which promote trough's instead of ridges. I think there will be periods of cold and warm shots all winter long, with occasional storminess as well. Pretty much an average winter.
Just like month-to-month breakdowns, I also do not believe in trying to predict accumulating snowfall for specific areas since so many variables are involved; BUT I will go ahead and just put out a few random cities with my "gut" feeling of how much they could see:
NY, NY: 26-31 inches of snow
Nassau County, NY: 28-33 inches of snow
Suffolk County, NY: 27-32 inches of snow
Newark, NJ: 27-32 inches of snow
Sparta, NJ: 35-40 inches of snow
Philadelphia, PA: 18-23 inches of snow
Baltimore, MD: 15-20 inches of snow
I hope everyone enjoyed reading my 2013-2014 winter outlook. At the end of the season, I will "grade" the outlook and look at what I need to improve on and study more in order to make a more accurate outlook for the following winter.
Remember to please register to my weather forum at www.njstrongweatherforum.com to join along in the daily discussions that become especially important before large storm events.
Thanks for reading,
Francesco Paparatto
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