Saturday, August 30, 2014

Below-Normal Lake Effect Snowfall Expected This Winter

Anomalously low lake effect snowfall is expected this winter.

The image above shows sea surface temperature anomalies across the Great Lakes, averaged out from August 11th to August 26th. In this image, we're able to get a view of SST anomalies across all five of the Great Lakes, something we can use to our advantage as we try to anticipate lake effect snow this winter. Let's go through each lake individually.

Lake Michigan
Lake Michigan is experiencing a generally below-normal summer, directly related to the extremely cold winter in 2013-2014. The middle section of the lake is experiencing anomalies a few degrees below normal, while the northern and southern fringes of the lake are observing generally above normal SST anomalies, though only by a few degrees. Lake effect snowfall for this winter in Lake Michigan is expected to be below normal.

Lake Superior
Lake Superior is seeing a well-below normal summer, again influenced by the very cold winter in 2013-2014. We see temperature anomalies approaching 6.5 degrees below normal in the eastern section of Lake Superior, though the western part is observing generally above normal SST anomalies. Because a strong fall low pressure system could easily eliminate those warm water anomalies, lake effect snow is expected to be below normal.

Lake Huron
Lake Huron is generally following the pattern of Lake Michigan, with the central portion of the basin seeing below normal temperatures. Above normal SST anomalies can be found on the outside fringes of the lake, but lake effect snow should be expected to be below normal this cold season.

Lake Erie
Lake Erie appears to be rather neutral across the board, with little to no noticeable anomalies to speak of in this body of water. As winter approaches and the air masses cool down, the lake should follow suit. Lake effect snowfall should be below normal this winter.

Lake Ontario
Lake Ontario is nearly completely below normal in SST anomalies as of mid August, so we can safely say at this point that lake effect snow should be below normal this winter.


Monday, August 25, 2014

2014-2015 Winter Forecast Update: First Maps & Outlooks Released

This is the latest update to the 2013-2014 Winter Forecast, likely the last one before the release of our Official 2014-2015 Winter Forecast. In this update, we will publish our first maps, to give you a feel of what we've been saying in recent weeks, now in the form of graphics.
This update will be organized into two sections: the Temperature Outlook section and the Precipitation Outlook section, with regional breakdowns for each section.

I. Temperature Outlook: Cold Winter Now Expected

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The temperature outlook for this coming winter can be significantly determined by the global sea surface temperature anomalies we are currently seeing. The image above shows the latest weekly SST anomalies across the globe. We're going to focus in on two major items here.

I. Persistent Warm Pool in Northeast Pacific
We've discussed this a lot this summer, and the enormity of its influence is still a concern for this winter. The large pool of warmer than normal waters is still present in the Northeast Pacific and into the Gulf of Alaska. Last winter, this body of warm waters allowed a very strong ridge of high pressure to form along the West Coast of North America, which then enabled the infamous polar vortex to slide south into Canada, making the winter of 2013-2014 as cold as it ended up being. This winter, it looks like that same warm pool will be back again, which could set up yet another dicey situation for the risk of a cold winter.

II. Warm Waters Offshore Greenland, Canada
Something we didn't see last year, but is now present, is a swath of above normal water temperatures from the area west of Greenland to the waters in northeast Canada. Typically, the presence of these warm waters in this part of the world can enable strong high pressure to form over Greenland, forcing the jet stream in the United States to buckle south and bring cold air flooding into the Central and East US. While this wasn't present last year, it is certainly available this year, and is something we'll need to watch often for an increased risk of a cold winter.

Something else we're using to watch for this winter is the perfect-scoring analog winter of 1958-1959, which we discussed earlier last week.

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The analog of winter of 1958-1959 was quite a cold one, as the image above shows. Temperature anomalies were well below normal across the Northern Plains and Upper Midwest, as well as the Northeast. Below-normal anomalies still extended into the Plains and Mid-Atlantic. From there, warmer than normal conditions were observed across the Western United States, as well as a fraction of the Southeast, in Florida.
The analog year of 1958-1959 matched up with all five of my parameters set forth that help determine the synoptic atmospheric conditions for a long-range outlook. I had success utilizing this method last winter, and current indications are that it could be successful again this winter. Whether or not that happens remains to be seen, but for now, it supports the growing theory that the upcoming winter will be a cold one.

Because this is just an update and not the actual Official 2014-2015 Winter Forecast, we won't go in-depth into my explanations just yet, but some other articles pertaining to my temperature outlook include Sea Ice Records, and the concept of a Modoki El Nino set-up.

That said, here's my first outlook for the upcoming winter.

Subject to potentially drastic change
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My first outlook places the Pacific Northwest in slightly warmer than normal conditions due to the aforementioned warm pool in the Pacific Northeast and Gulf of Alaska, where a sustained ridge may form. The majority of the Rockies and the Southwest may observe around normal conditions, though a bump up to warmer than normal could be in the cards for the 2014-2015 Official Winter Forecast. I expect the majority of the Central and East US to see below normal temperatures for the upcoming winter at this time, with the Gulf Coast around neutral. New England may have to watch for bouts of warmth due to the proximity of warm waters near Greenland, which could spread ridging into the Northeast.

II. Precipitation Outlook Still Cloudy

We're going to start out this section by going back to our analog year of 1958-1959 and seeing what it says.

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During the winter of 1958-1959, the majority of the nation saw quite a dry season. The southern Midwest and Ohio Valley regions were hit by a strong drought-esque episode, which saw precipitation anomalies running more than 5 inches below normal. This episode was observed in the Gulf Coast, Plains, Mid-Atlantic and Northeast, in addition to the aforementioned two regions. Some dryness was observed in the Rockies and along the West Coast, but anomalies are too variable to determine a specific trend. Some above normal precipitation was seen in the northern Ohio Valley, as well as the deep Southeast, but the majority of the nation was dry.

Because some of the other variables are still too uncertain to definitively forecast on, I made this outlook based predominantly off of the analog year of 1958-1959, typical precipitation patterns with ridging in the northeast Pacific, as well as a couple other factors that are expected to play into this winter.

Subject to potentially drastic change.
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As of now, I'm expecting precipitation anomalies to be mainly below normal across the southern Midwest and Ohio Valley into the Mid-Atlantic and parts of the Southeast. Wetter than normal conditions should persist along the Gulf Coast, primarily in Florida, while slightly above normal conditions can be expected in the Southwest. Normal to slightly above normal precipitation anomalies may be observed in the Great Lakes and northern Ohio Valley, while average conditions are currently favored in the Rockies and New England.

These graphics are expected to change, potentially significantly, by the time the 2014-2015 Official Winter Forecast is released. However, this should give you an idea of where my thoughts are right now, even though they certainly are not set in stone.


Sunday, August 24, 2014

Recent Arctic Sea Ice Records Suggest Another Frigid Winter Ahead

This is a follow-up post to the sea ice publication yesterday.

An examination of recent sea ice levels and their corresponding winter temperature anomalies indicates the winter of 2014-2015 may very well be heading down a colder than normal path this season.

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The image above shows observations of sea ice areal coverage from the year of 2007 to the present year. 2014's sea ice coverage is seen in red, with other years defined by the color legend on the bottom-left corner of this graphic. Taking a glance over this image, we find that this year's sea ice coverage is running in the upper percentile of coverage compared to previous years, as the red line is well above the record-setting years of 2007 and 2012. The red line is located very close to the years of 2013 (black line), 2009 (neon green line), and 2010 (yellow-ish green line). To try and see if we can pull any useful data from here for the upcoming winter, I took a look at winter temperature anomalies for years with sea ice coverage similar to this year, in this case the three aforementioned years.

The results are quite ominous.

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The first year we'll examine is the winter of 2009-2010. The sea ice coverage was remarkably similar to what we've experienced thus far in 2014, and is similar to what we're expected to see later on this year. Temperature anomalies during the winter of 2009-2010 were predominantly below-normal across the country. The cold was maximized in the Central Plains and Gulf Coast, while persisting across the Midwest, Plains, Ohio Valley, and Mid-Atlantic. The Upper Midwest, New England, and West Coast regions experienced above normal temperatures this winter. Overall, this winter brought about a significant cold trend to most of the nation, something we may have to watch for if this sea ice similarity stands.

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The following winter, the winter of 2010-2011, also saw a remarkable similarity in sea ice between the year of 2010 and the present year of 2014, even more so than the year of 2009. The winter of 2010-2011 was yet another cold one, with the below-normal temperatures entrenched best in the Northern Plains and Southeast. Below-normal conditions were spread across the Midwest and Central Plains, all the way into the Northeast and Mid-Atlantic. The Southwest observed predominantly above-normal temperature anomalies, as did a portion of the South Plains. Small fractions of the Upper Midwest and New England regions also saw relatively warm winters, though the overall nation was gripped by below-normal temperatures. The trend of below-normal temperatures with similar sea ice coverage is quickly becoming better defined.

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Lastly, the sea ice graph tells us that this past year, the year of 2013, is matching up quite well with sea ice coverage in 2014. So, as rough as it may be to do so, we must re-analyze the winter of 2013-2014. As most of us may remember, this past winter was not a good one, and temperature anomalies reflect this. Anomalies across the country ranged from several degrees above normal, to nearly ten degrees below normal. The core of the cold was placed in the Midwest and Upper Midwest, though below-normal temperatures enveloped a wide swath of the Lower 48. Only the Southwest and Southeast regions saw above-normal temperatures.

While the sample size is rather small, it is no secret now that years with similar ice coverage as the current one saw below-normal to well-below-normal temperatures in the following winter. It'll take a few more months to determine how valid this correlation may be, but this is yet another ominous sign of many that are telling of a cold winter ahead this season.


Saturday, August 23, 2014

Arctic Circle Observations Indicate Immense Cold Air Available

Observations of Arctic temperatures and sea ice indicate quite a plethora of very cold air in the region.

The image above shows a history of sea ice coverage by millions of square miles, recording coverage from present day (black line) to 2005. As the chart shows, we are currently near the upper envelope of sea ice coverage, when compared to the last ten years of sea ice records. The black line even seems to resemble the sea ice coverage from this time in 2013, as the dandelion-yellow line shows. The availability of this sea ice is beneficial to those of us hoping for a cold winter ahead. Such a swath of sea ice enables cold air to sustain itself in near the North Pole for a longer period of time. After all, you can't have a cold winter if there's no cold air up north to begin with.

The chart above shows a record of temperatures in the far north Arctic since January 1st of this year, with benchmark days on the bottom legend. The red line on this graphic depicts observed Arctic temperatures, while the green line indicates average temperatures for a given time of year. The constant blue demarcation is the temperature of 273 degrees Kelvin, the equivalent of 32 degrees Fahrenheit, or 0 degrees Celsius; the freezing temperature. Just eyeballing this chart, we find that temperatures have only risen above average twice this entire summer, with the first occurrence only lasting one or two days. The ongoing above-average anomaly appears a bit stronger, but does not outweigh the general below-normal trend in temperatures for the summer, reflected well in the above normal sea ice anomalies.

Similar to last year, Arctic sea ice is running above normal, while temperatures are running below normal. These two factors are likely to play some role this winter, though to what degree is unknown. What we can gather at this moment, however, is that there is a vast reservoir of cold air available up north; a positive sign for those wishing for a repeat of this past winter.


Tuesday, August 19, 2014

Perfect-Scoring Winter Analog Paints Ominous Picture for Upcoming Season

For the first time, an analog year has matched all five of my parameters for the upcoming winter season, and is now indicating that the upcoming winter could be another rough one.

The analog year that matched all five parameters was the winter of 1958-1959.  The image above shows 500mb height anomalies during the December-January-February period of that winter season. In this graphic, blues and purples depict stormy and cold weather, while yellows and reds indicate warm and quiet weather. The winter of 1958-1959 saw strong ridging/high pressure positioned over the north-central and northwest Pacific regions, with some stormier weather observed near the Gulf of Alaska. This Pacific ridging extended well into the Arctic, helping to dismantle the mid-level polar vortex, sending it to lower latitudes like we saw last winter.
In North America, we observed what appears to be the polar vortex centered in the Canadian Maritimes, spreading its influence across Canada and into the North US. Some slight ridging was recorded in the West US, especially into the Southwest, as well as the Southeast.

Let's push on to the temperature composite for the winter of 1958-1959.

During the winter of 1958-1959, much of the nation was locked into a rather brutal winter, with temperature anomalies in the North US dropping below -6.0 degrees Fahrenheit, anomalies not too far off from what we saw this past winter, in 2013-2014. The core of the cold was placed from the Upper Midwest into the Great Lakes, but below-normal temperatures snaked their way through the entirety of the Central and East US, save for Florida, which saw weak ridging. The West US saw a very warm winter in December-January-February of 1958-1959, again a similar story to what was seen in 2013-2014.

Lastly, let's go ahead and check out precipitation anomalies from this analog.

During the winter of 1958-1959, very dry conditions plagued the Southern Plains, Gulf Coast, and southern Ohio Valley all the way into the Northeast and Mid-Atlantic regions. Precipitation anomalies below -5.0 inches were recorded in Mississippi, Alabama, Louisiana and Oklahoma, just to name a few. The dry conditions extended north into the Midwest and Upper Midwest, but wetter than average conditions prevailed in the upper Ohio Valley, along the eastern Great Lakes. This was also the scene in Florida, and coastal Texas. The Pacific Northwest experienced a rather wet winter in 1958-1959, while some parts of the Southwest dealt with dry conditions.

Let's break this all down.

The winter of 1958-1959 matched five out of five parameters I set forth that indicate what this winter will look like. For instance, it is expected that the winter of 2014-2015 will see a positive PDO, and the winter of 1958-1959 had that as well. Such a comparison happened, successfully, four other times. It's quite rare to find an analog as similar to projected conditions as this one, and we can only hope that the similarities stick as we head into fall.

Analog forecasting gives us a general idea of what the upcoming winter may be like. It's not a set-in-stone picture of what we will experience. While I cannot confirm that we will see a very dry or cold winter, the chances of both are considered to be elevated, if this analog year is to be believed.


Monday, August 18, 2014

Modoki El Nino Gaining Control; Winter Outlook Grows Colder

It appears that a Central-Based, or Modoki El Nino is now gaining control, resulting in the outlook for this winter growing colder.

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The image above, provided by the JAMSTEC agency, shows typical sea surface temperature anomalies during a Modoki El Nino. The presence of this Modoki Nino is clearly shown by the positive anomalies in the central portion of the Pacific, hence the interchangeability between Modoki and Central-Based El Nino. During the Modoki Nino, cooler than normal SST anomalies tend to appear offshore Ecuador, something we'll discuss a little later in this post. Looking towards the north Pacific, predominantly warm SST anomalies are observed, from the Sea of Japan, to the Bering Sea, to the Gulf of Alaska. Warm water anomalies are also recorded near Baja California.
Out in the Atlantic, warmer than normal waters surround Greenland and are placed into western Europe, with cool water providing a separation between that mass of warmth, and the second body of warm water juxtaposed near the Canadian Maritimes. The Indian Ocean also exhibits a slightly negative Indian Ocean Dipole signal (identified by cold water near Somalia and warm water near India) during Modoki El Ninos.

Let's now compare this typical  Modoki set-up with today's SST anomalies.

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Taking a look around the globe, we can identify several points of interest and discussion when comparing the Modoki composite image, and the daily SST anomalies from August 17th. Beginning in the Pacific, we see warm water anomalies off the coast of Ecuador, and cool anomalies in the central Pacific, basically opposite of a Modoki set-up. We'll dive deeper into that a little later in this post. Moving up to the North Pacific, we observe a swath of warmer than normal water temperatures in the Northeast Pacific/Gulf of Alaska, nearly identical to the anomalies seen during a Modoki Nino. The comparison is once again similar when we confirm warmer than normal waters stationed off Baja California, as also seen in the composite image. The Sea of Japan was well above normal earlier this week, as it is during typical Modoki El Nino events, but has since cooled due to the passage of Typhoon Halong over that area.
Transitioning to the Atlantic, additional similarities are found. We can see the warmer than normal waters near Greenland, pushing east into western Europe, as was also found in the Modoki composite image. There isn't much of a cold pool of water just south of Greenland, but warmth is observed near the Canadian Maritimes. The Indian Ocean is also displaying the same negative IOD pattern observed in a typical Modoki El Nino event.

Now, all of these similarities are impressive, but what about the El Nino itself in the Pacific? It looks nonexistent- actually opposite, of what the Modoki composite image shows us.

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The animation above shows us water temperature anomalies, the same variable examined earlier in this post, but now analyzed on a depth chart. The legend on the left displays depth in meters along the Equator, while the bottom legend indicates longitude lines. Looking over the animation, we can see that opposite pattern of cool waters in the central Pacific (top-middle of animation) and warm waters in the eastern Pacific (top-right of animation), but what is stirring below is even more interesting. We find a body of cold water pushing to the surface in the eastern Pacific, as well as a swath of positive water temperature anomalies manifesting itself below the surface in the central Pacific. Put two and two together, and the Modoki signal in the Central Pacific is definitely present, just not at the surface yet.

Now that we have shown how the Modoki El Nino is nearly completely present in water temperature anomalies around the globe, let's talk about the effects it may have on the upcoming winter.

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The graphic above displays worldwide temperature anomalies during a Modoki El Nino. As we can see, cold weather is typically observed in much of the Central US during a Modoki El Nino, while warmth prevails in the Western US. Slightly warmer than normal anomalies are also visible along the Eastern Seaboard.
What this tells us is that, at least for now, the risk of another cold winter in the Central US is rising, while a warm winter along the West and into Alaska is also becoming a real possibility. Those in the East may need to watch for a slightly warmer than normal winter.


Sunday, August 17, 2014

Probability of Negative NAO During Upcoming Winter Increasing

The likelihood that we will see high pressure over Greenland this winter, a sign of the negative North Atlantic Oscillation, is on the rise.

The image above shows sea surface temperature anomalies for the day of August 16, 2014. In this image, we can see quite a few areas of interest that we are monitoring for the upcoming winter, but today we'll focus in on Greenland and around the Canadian Maritimes. Looking towards that part of the world, we see a swath of well above normal SST anomalies stretching from the waters south of Greenland towards the Arctic circle. The warm waters also extend to the east, immediately offshore of Greenland.

It is well known that sea surface temperature anomalies can exert a significant influence on the presence of high or low pressure in a given area. For example, areas with warmer than normal waters tend to observe high pressure more often that low pressure, while colder than normal SST anomalies usually result in stormy conditions prevailing over quiet conditions. This was observed well last winter, when the body of positive SST anomalies in the northeast Pacific brought about strong high pressure along the western coast of North America, which permitted the cold weather to penetrate deep into the US.

In Greenland, with the presence of a rather large swath of warmer than normal waters, I wouldn't be surprised to see persistent ridging over this part of the world this winter. If such a scenario does play out, we would enter the negative phase of the North Atlantic Oscillation (NAO), which would allow cold and stormy conditions to prevail over the Central and East US, the latter of which may experience episodes of intense snowstorms, as can happen in negative NAO events.

In the graphic above, we see SST anomalies over four different parts of the Pacific Ocean, centered along the Equator. Nino region 4 is located near the Oceania region, while Nino region 1+2 is centered just offshore Ecuador. By looking at these panels, we can identify a body of warm water on the surface in the west-central Pacific in Nino region 4, as well as the far east Equatorial Pacific in Nino regions 1+2 and region 3.

It is expected that all of these regions may experience additional warming as we progress into Fall, which is when we anticipate the emergence of a Weak El Nino (SST anomalies +0.5 to 1.0 degrees above normal).

Weak El Nino's affect the United States in many ways, but the primary effect is through manipulation of the jet stream. When this happens, the jet stream is forced south along the Eastern Seaboard, allowing cold air to flow deep into the Central and East US. Storm systems are then pushed south as well, and end up following the jet stream along the South US before shooting north as the jet stream is pulled up towards Greenland, where a ridge (Negative NAO) resides. Consequentially, snowstorms pose threats to the Northeast and East Coast, in addition to the cold weather.

The negative NAO and weak El Nino generally tie into each other, as they seem to work in a tandem. If current projections verify for this winter, and the SST anomalies near Greenland persist, the likelihood of a negative NAO throughout the winter significantly rises.


Friday, August 15, 2014

New Climate Model Outlooks Fix Errors; Cool, Snowy Winter Possible

Long range climate model projections of the upcoming winter season, the same ones we discussed a little while back, have been updated. The latest models still retain errors, but two models have come in with drastic improvements.
Bear in mind the typical caveats with long range forecasts still apply.

The image above shows a compilation of multiple long range outlooks, projecting the El Nino-Southern Oscillation phenomenon from the present to next spring. In this chart, we can see the majority of models favoring an immediate commencement to the El Nino expected to form later this year. The issue here, which we elaborated on in the link above, is that these models want to make the El Nino start immediately, something unlikely to happen. Complicating the situation further is the fact that these models want to bring the El Nino to Moderate (+1º to +1.5º above normal) or even Strong (over +1.5º above normal) levels by this winter. Again, this is unlikely to happen. Consequentially, we have been forced to discard these forecasts, as the incorrect SST projections then ruin the remainder of the forecasts.
The new update to these models came in to me today, and I was surprised to find two models that have changed their tune. In the chart above, instead of all models going up and up with the El Nino, the GFDL (turquoise colored line) and GFDL_FLOR (beige line) prefer either an ENSO-Neutral situation, where the El Nino is unable to form, or a weak El Nino, which is what my preference is for this winter. It finally seems as if we have two models that may stand a chance at verifying this winter.

Without further ado, let's review the forecasts from these two models for this winter.

 The first model we will review for the temperature outlook is the GFDL_FLOR. The image above shows projected temperatures across the United States for December-January-February 2014-2015. In this graphic, we see that the model keeps the majority of Alaska and western Canada warm, which can be indicative of persistent ridging over the area. Whether that is the case, we don't know, but such a feature would help chances for a cold Central/East US winter. Now looking at the United States, we find the majority of the nation experiencing average temperatures for the winter, with the Plains experiencing slightly below normal anomalies.
This is a rather substantial shift from earlier forecasts of a blowtorch (excessively warm) winter for the nation, which was due to the incorrect SST forecasts. It can be expected that models may project normal anomalies, because these forecasts are being made for months out. However, with this being the first forecast that is not retaining major SST flaws, things are looking up for those wishing for a cold winter.


Turning our attention to the GFDL model, we find a slightly different temperature forecast in store. Much of the Central and Western US is experiencing average to slightly below average temperatures, while the Great Lakes, Southeast and East US in general experiences a warm winter. We see this warmth extend into northeast Canada and towards Greenland, which makes me think that we may need to watch for ridging building off the East Coast if this forecast is correct (which, as we know by now, is not a given).

We now turn our focus on the precipitation outlooks from the two models. The GFDL model, pictured above, shows a wide swath of above-normal precipitation extending from Texas to south-central Canada, bringing the heaviest anomalies to the southern Midwest and western Ohio Valley regions. Wetter than normal conditions are also observed across the Eastern Seaboard, while dry weather prevails into the West Coast.
I'm not willing to say much on this outlook just yet, but since this is the first forecast that doesn't have that dreadful SST flaw, this sort of precipitation pattern may bear watching for this winter. If it did verify, it could spell disaster for California and other drought-affected regions.

Taking a look at the GFDL_FLOR model, we see a somewhat similar outlook as the one portrayed by the GFDL system. In this outlook, the December-January-February period features a very dry West US, remarkably drier than the GFDL model outlook. Slightly above normal precipitation anomalies extend from the Southern Plains and Gulf Coast into the Midwest and Great Lakes. The Central Plains is also included in this wet trend.
Again, though there's not much else to say here, it could bear watching.

Lastly, we'll take a look at the model-projected upper air pattern for the coming winter. The image above shows the Z200 outlook over December-January-February from the GFDL model. We want to maintain focus more on the contour lines than the color shades for this post. Taking a look around North America, we find a ridging signal over the West Coast and into Alaska. As we've discussed extensively, persistent above-normal water temperature anomalies in the Gulf of Alaska may support such a scenario, which could then lead to another chilly winter. Looking downstream, we do see a slight suppression in the contour lines, potentially indicative of some stormy weather. We saw a similar outlook in the months leading up to last winter.
Something else to note is the suppressed contour lines over Japan. This could indicate stormy weather there, and if we apply the Typhoon Rule, it could then affect us here in a substantial way.

Finally, shifting to the Z200 outlook from the GFDL_FLOR guidance system, we still see a cold signal across North America. Eerily similar to outlooks from last year anticipating the winter of 2013-2014, we see strong ridging over the West Coast and into Alaska. This ridge looks to be of similar strength to the one observed last winter, which was the mechanism responsible for the polar vortex scraping the northern US. Once again, we see suppressed contour lines in Japan, again indicative of stormy weather. The most interesting feature, by far, is the depression of contour lines over eastern Canada and into the United States. This is definitely a cold weather signal, dare I say the same signal that eventually brought the polar vortex south. I'm not saying that whole episode will happen again, but if this model is right, cold weather becomes a significant possibility.

All of this looks pretty supportive of a cold and snowy winter, but when it comes down to it, remember that this all rests in the realm of possibility, not certainty. Things do look good from these error-corrected models, but we will have to wait and see if these solutions stick with the updated model forecasts next month.


Thursday, August 14, 2014

Sea of Japan Rapidly Cooling; Winter Implications Possible

The Sea of Japan has experienced rapid cooling in recent days, something that could come into play later on this winter.

The image above, recorded on August 4th, 2014, shows sea surface temperature anomalies across the Pacific Ocean basin, extending from eastern Asia to the west coast of North America, and down to Australia. Though there are many things to be analyzed in this image, we want to focus in on the Sea of Japan, in the top left corner of this image. The Sea of Japan is located between mainland Asia and the island nation of Japan. On August 4th, SST anomalies read well above normal in this area. This was a concerning feature, as above normal water temperatures can induce persistent high pressure to form over the area, an ability well documented this past winter with positive SST anomalies in the northeast Pacific, and consequential high pressure in that same area, which enabled the polar vortex to grace the northern US.
The feature was primarily of concern for winter weather fans, as the persistent high pressure forming over Japan due to the warmer than normal Sea of Japan could continue into the fall and winter, which would then allow for increased risks of warmth in the United States during the coming winter season. The mechanism which may allow for this warm winter would be the highly-touted Typhoon Rule.

In just 10 days, however, the scenario for the coming winter changed drastically.

The image above shows sea surface temperature anomalies, still projected over the same part of the world, but now valid on August 14th, 2014. Gazing around the chart, we find a stunning reversal in water temperatures in the Sea of Japan. Instead of +3.00º to +4.00º-plus anomalies in the Sea of Japan, we now see widespread negative or neutral water temperature anomalies. This rapid cooling also appears to have affected the waters immediately south of the Sea of Japan.
It's quite possible, even likely, that the destruction of these warm water anomalies is due to a strong low pressure system traversing the Sea of Japan. It is quite common for strong cyclones to "mix" the water it passes over, reducing warm water temperature anomalies in the process. It looks like this same process has happened in the Sea of Japan.
If, and I say 'if' because things can very much change in the next several months, these cool water temperatures are to sustain themselves in the Sea of Japan, and warm waters do not return to the area, the chances of a warm winter would likely be reduced. However, we'll need time to monitor this development for another handful of weeks to see exactly what will end up happening.


Monday, August 11, 2014

Using Summertime Patterns to Predict Upcoming Winter Conditions

The hunt is now on more fiercely than ever: with meteorology growing and advancing at exponential rates in the last few decades to the present day, researchers are working harder than ever to find patterns in the weather to accurately predict long range conditions, months in advance. One aspect of this hunt is being able to predict the upcoming winter using conditions observed in the fall, or even summer. We'll take the time today to discuss methods that may or may not be useful in such long range predictions.

1. Nature Signs
This is a personal favorite of mine, due to the mystery surrounding it. Many weather enthusiasts, and people in general, believe that nature can point us to the intensity (or lack thereof) of the upcoming winter. I've heard mentions of trees producing anomalous fruit in the summer, animals acting in a suspicious manner, and even the color of certain shrubs and plants in the preceding summer/fall. I've even taken it upon myself to monitor roadkill anomalies in the fall, wondering if increased (decreased) animal activity in the fall may indicate a more (less) intense winter ahead, hence the above normal (below normal) roadkill sightings.
The unfortunate truth is that we don't know if these methods work, and likely will never know. The concept is very similar to us as a human race. We monitor certain trees and animals for signs of oddity, but that's like monitoring a certain person for an oddity. It doesn't work, because each person is different than the person next to them. As a race, humanity is quite similar across the board. The same goes with certain species of trees, animals, etc. But we can't observe a few trees and/or animals and make a qualified deduction from it. In order to determine any possible connection between nature anomalies and winter, a large-scale (covering a plethora of states) operation would likely be needed to monitor great masses of the same type of animal/tree, and then attempt to make a reasonable deduction on any winter prediction abilities.

Squirrels are commonly looked to for their ability to predict the upcoming winter, with observers monitoring a squirrel's effort to collect nuts earlier (or later) on in the year.

2. Six-Month Separation
This method involves monitoring conditions in June-July-August to see if conditions six months later (December-January-February) are correlated. The method likely stems from the question of cyclical patterns repeating on a regular, monthly scale; in this case, half a year. One might believe that Arctic 500mb heights in the summer may be related to Arctic 500mb heights that following winter, or the same scenario, except over North America, etc.
The truth behind this method is that it does not work a heavy majority of the time. I did some research last winter, where I compared monthly Arctic Oscillation (AO), North Atlantic Oscillation (NAO), and Pacific-North American (PNA) index values from June-July-August to values for the following December-January-February to determine any correlation. Although I no longer have the exact values with me, I can recall there being little to no correlation between any of the indices' summer and winter values. Looking back, I believe the PNA actually ended up seeing a near-perfect split of 50% of years recording a positive summer PNA and negative winter PNA, and 50% of years recording a positive summer PNA and positive winter PNA, or negative rather than positive for both timeframes. The Arctic Oscillation may have had the "highest" anomaly, with the split coming in at 40%-60% when comparing number of years with positive summer/winter value correlations and negative summer/winter value correlations. To make a long story short, this method is not one worth using.

So far, we've discussed items that either don't work in long range forecasting, or their effectiveness has gone undetermined. Let's now go over some items that do have merit in the long range forecasting field.

3. Sea Surface Temperature Anomalies
Long range forecasters often look to the oceans for their outlooks. Multiple oscillations reside in oceans all around the world, with many of them spreading their impacts on a global scale. Forecasters tend to believe that these long-term oscillations, which may remain in their same state for months or years at a time, can predict winter conditions as far out as summer.
There is definitely some truth to this claim. Persistent SST anomalies in a certain part of the globe can allow forecasters to get a glimpse at the weather for multiple months ahead. Long-term oscillations, like the Pacific Decadal Oscillation (PDO) or Atlantic-Multidecadal Oscillation (AMO), can remain in their same positive or negative phase for years, or even decades, at a time. Some shorter-term oscillations, like the El Nino-Southern Oscillation (ENSO) phenomenon, can still allow for long range outlooks, valid for months in advance.

SST anomalies are often believed to be one of the best & most reliable predictors of long range weather.
4. Soil Moisture & Drought
This theory stems from the concept of feedback loops, which entail that something already in a bad situation gets continually worse, because that something is harming the things trying to improve the situation. In our case, we can apply this to drought. If a drought forms, the soil is anomalously below-normal in soil moisture, making the earth dry. As a result, clouds cannot form, meaning rain cannot fall. This makes the drought worse, and makes for a vicious cycle that continues the drought. Storm systems that move over the drought-affected region cannot produce as much rain as in other regions, because the storm can't draw water from the dry soil. Similarly, areas with above normal soil moisture may see rain continue, as more moisture is available in the soil than is necessary. Thus, the air becomes unusually humid, and any storms that form over this region can produce heavy rainfall, keeping the soil on a wet level.
This method of forecasting is more of a hit-or-miss method. This is because, while the theory of these feedback loops is sound (to an extent), a plethora of external forces, made up of oscillations in the oceans and upper atmosphere, can shift and change to bring rain to drought areas, or deprive precipitation to rain-soaked land. The atmosphere is one big, constantly-changing chess board, if you will, and some pieces happen to be weaker than others. While this drought/soil moisture method of long range forecasting can work, other factors must be taken into account as well.

We've only reviewed a few of many long range patterns known in the world of weather, but hopefully this gives you an understanding of some aspects of long range forecasting. While some methods don't tend to work well, others have experienced a decent amount of success. The hunt for a long range predictor with considerable accuracy will continue into the foreseeable future.


Thursday, August 7, 2014

Long Range Models Likely Incorrect in Winter Outlooks

After extensive analysis of multiple long range climate models, it looks like the consensus is for a moderate to strong El Nino on all guidance members, something that is not expected to occur, and thus rendering their forecasts incorrect.

The image above shows sea surface temperature anomaly forecasts from eight different long range models, all valid for the month of August 2014. These forecasts were made in July 2014, meaning this is only the first month forecast. Even though it's only one month out, we still see incredible inconsistencies. Starting along the top row, the CFSv2 model has warmer than normal SST anomalies persisting to the north and south of the Equator, with neutral anomalies along the Equator itself. This is a reasonable scenario, and we will examine this model further later on in this post. The CMC1 model allows a moderate to strong El Nino to develop, projecting SST anomalies of 1º to 2º C above normal (dark red) to form. Closer analysis indicates anomalies of over 2º C are actually present, seen in the dark brown. Checking out the CMC2 model, a relative of the CMC1, we still see moderate to strong El Nino conditions present per the SST anomalies, something highly unlikely to happen in the next ~25 days. Lastly, analyzing the GFDL_FLOR model, we once again find well above normal anomalies present along nearly the entire Equatorial Pacific region, from Ecuador to Australia. Aside from the well above normal anomalies, full-basin coverage of the El Nino is not anticipated, further degrading this model's credibility. Out of the four top-row models, only the CFSv2 model seems somewhat reasonable right now, and even that assertion is debatable.

Moving on to the bottom row, we come upon the GFDL model, a close relative of the GFDL_FLOR model. As such, the GFDL model continues the above normal sea surface temperature anomaly trend, though not as intense as many of the top-row guidance. This makes me think the GFDL may be on to something worth watching, and this will be discussed later on in the post. The NCAR model initiates a likely-Strong El Nino in the next couple weeks, something that will not be happening. The NCAR_CCSM4 model follows up with a nearly-identical scenario, so we can toss that solution as well. Lastly, the NASA model shows a moderate El Nino in place for the month of August. Because it's not such an extreme solution, we'll go over it further down the road.

After analyzing these models, we have found three of the eight models - CFSv2, GFDL, and NASA - to have somewhat reasonable scenarios. That means only ~38% of these forecasts have a chance to verify. Think about that- over half of these models can't even get the forecast right in the first month. It's pitiful, to some degree, but that's why we have scientists working to improve them.

Let's now analyze a sea surface temperature anomaly forecast for 3 months out, rather than 1 month out, to see how well our three aforementioned models are doing.

Let's now analyze the CFSv2 model in the top-left corner. In the forecast month of October, the CFSv2 has a Central Pacific-based moderate El Nino, possibly nearing Strong El Nino-strength. Unfortunately, considering conditions seem favorable more for a weak El Nino (MAYBE up to a moderate El Nino), we'll have to toss this forecast model.

Analyzing our second chosen climate model, the GFDL, brings about mixed results. On one hand, we see the forecast for a likely-moderate strength El Nino, something not too far from the realm of possibility. However, the El Nino is based in the west-central Pacific, something not showing up on other forecast models. For that reason, it may be wise to toss this forecast model as well.

Our last model of hope, the NASA model, shows unfortunate circumstances for October 2014. The model induces a moderate to strong El Nino across nearly the entire Pacific basin, something highly unlikely to happen. We can discount this forecast, too. Even lightly auditing the first-month forecast models can't save our chosen three models from the poor forecast ability just three months out.

Why do I think this is important? Many long range guidance models are calling for a warm United States winter, possibly accompanied by a cool South Plains at times. However, when you look at the SST forecast, it becomes apparent that the forecast cannot be trusted, due to a very slim chance of the SST anomaly outlook actually verifying. Thus, don't take the predominantly warm forecasts as they are unless verifying the SST outlook; the same goes for predominantly cold winter outlooks, as their SST forecasts must be verified as well.


Tuesday, August 5, 2014

Weak El Nino Preparing to Surface; Atmosphere Not Responding

The warm water anomalies in the central Pacific look to be pushing towards the surface, possibly inducing the expected weak El Nino for this fall and winter.

Refresh the page if animation stops looping
The animation above shows water temperature anomalies along the Equator, on a depth-longitude graph. We can see the extremely above-normal waters pushing into the surface earlier this summer, a byproduct of the Kelvin Wave that traversed the Pacific during this past spring. After the warm waters dissipated, we saw a swath of below-normal water temperatures take over. This put us back to the same neutral-ENSO / Cool-Neutral ENSO situation we've been in for the past couple of years. Fast-forward to the present, and we see a new situation developing.

Warm water anomalies have been steadily building underwater around the Central Pacific region, between about 100 to 200 meters below the surface. These waters have been organizing themselves in recent days and weeks, and the eastern-most portion of these positive anomalies has begun shifting towards the surface, and towards the east. It is currently expected that these warm waters will push east and eat away at the below-normal water temperatures. If the warmth can sustain itself and hit the surface, this should be our weak El Nino, possibly more towards a moderate El Nino at best.

In order to actually see an El Nino develop, however, we'll need to see the atmosphere respond, which isn't happening just yet. Shown above are two panels; one shows the mean surface wind currents across the Equatorial Pacific, while the bottom one displays anomalous wind currents. In order for the atmosphere to indicate an El Nino is present, we would have to see winds going from west to east, as part of the reversed Walker Circulation, which is displayed below in the form of the regular circulation.

Switch wind direction  and warm/cool anomalies' places to observe reversed (El Nino) Walker Circulation.
In the Walker Circulation, surface winds go east-to-west, where the air rises due to convection near Australia. Upper-level winds then push west-to-east, before sinking near the South America coastline, completing the circulation. This is commonly seen in a La Nina event. The El Nino reverses the Walker Circulation, where surface winds push west-to-east, allowing convection to develop along the coast of South America. Upper level winds are carried westward, before sinking near Australia.

If we look back at the surface wind current image above, we can see the winds along the Equator pushing predominantly to the west, indicating that the atmosphere is not favorable for an El Nino. We have yet to see if this will change in coming months, and if it may allow for an El Nino to actually establish itself.


Monday, August 4, 2014


After some thinking and analyzation of where the blog is at now, I've decided to go ahead and enlist advertising for The Weather Centre. These adverts will be placed on the sidebar of the blog only, so as not to disrupt the environment of the blog.

I decided to enlist advertising to benefit the blog, and all of you. If I am lucky enough to collect any substantial revenue from these ads, I hope to invest in products to improve the blog's experience. Such investments may include paid model subscriptions, enhanced radar software, and other ventures.

These ads are not meant to be a big source of revenue for me- that's not my intention, at all. These ads are only meant to better the blog as a whole.

Unfortunately, I cannot control the majority of ads that appear on the blog, so I apologize in advance if any are not related to the website, may be controversial, or are just "odd", for lack of a better term.

If you have any concerns or suggestions on these ads, please don't hesitate to voice them, since, at least from my point of view, this may be a rather controversial move.


Sunday, August 3, 2014

Arctic Sea Ice, Temperatures Indicative of Winter Ahead

Latest observations of Arctic sea ice anomalies, as well as temperature anomalies, may hint at what's to come this winter.

The above graph shows past records of Arctic sea ice over time, categorized by color, with the key on the bottom left. This year's sea ice observations are shown in the thick black line, while 2013's sea ice observations can be viewed by the orange-colored line. Glancing around this chart, it's quite evident that sea ice anomalies in comparison to recent history are above normal this year. Showing itself more recently, these above-normal sea ice anomalies appear to be eclipsing the observations of 2006, which appears to be the highest areal sea ice coverage minimum in the last ten or so years. This recent slowdown of declining ice coverage indicates the presence of cold air over the Arctic Circle, something that stays in that area year-round. What's more important this time, however, is that the cold air is allowing less ice to melt, which in response provides more cold air, and so on and so forth.

The next chart we will analyze is a graph of observed temperatures in the Arctic Circle. The red line on this graph shows observed temperatures, in units of Kelvin. The green line indicates the average temperature for a given date, and the solid blue line depicts the freezing temperature. Arctic temperatures have remained almost completely below average since this spring, a rather remarkable feat. Temperatures currently are above freezing, as is to be expected for the summer season, but observed temperatures remains below the average temperatures. As we discussed earlier, the presence of cold air and slowing of sea ice melt are likely playing into these below normal temperatures in the Arctic.

To break it all down, these developments tell me the chances of a cold winter ahead are being raised. If we were to see low sea ice levels and warm Arctic temperatures, I'd probably root for a warm winter ahead. However, seeing substantial sea ice presence in the northern Hemisphere, as well as consistently below-normal Arctic temperatures, I believe that these factors could play into the risk of another cold winter ahead.


Friday, August 1, 2014

Mid-August Unseasonable Cold Blast Appearing Likely

Yet another blast of unseasonably cold air can be expected, this time around the middle of August.

Tropical Tidbits
The first graphic we will examine shows the GFS model's forecast of 500mb height anomalies over the western Pacific. Blues indicates stormy and cold weather, while reds show warm and quiet weather. This forecast graphic, valid on August 9th, shows a typhoon moving north into the southern portion of Japan. We can identify this typhoon feature by the tight collection of isobar contours, as well as the concentrated nature of the below-normal height anomalies. This typhoon is expected to be weakening as it makes its move north into Japan.

Tropical Tidbits
This next graphic shows the same GFS forecast of 500mb height anomalies, now valid on the evening of August 9th, whereas the first graphic showed the forecast for the morning of August 9th. In this picture, we can still see our typhoon feature, now pulling itself northeast through the main part of Japan. The isobars are no longer as concentrated, and this can be contributed to both weakening of the typhoon, as well as the lower resolution forecasts this GFS model makes after forecast hour 192 (you'll notice that this graphic shows the forecast for hour 204).

Why is all of this significant? The general premise that I've discussed numerous times on this blog, particularly in the wintertime, is that the weather in East Asia can affect our weather here. To clarify, for example, high pressure over Japan would mean high pressure over the US 6-10 days later. Similarly, low pressure over Japan could indicate stormy weather in the US 6-10 days later, and so forth. We can use this rule to our advantage here. We see a strong typhoon hitting southern Japan on August 9th, and tracking through the middle of the country before shooting east into the open Pacific. By using this correlation technique, we can identify that cold weather and a general stormy pattern may be anticipated 6-10 days after this August 9th impact. Do the math, and we can expect an unseasonable cold weather event around the August 15-19 timeframe.

Details still need to be refined, as this is a long range forecast, but the chances are good that cold weather may be expected in the middle of August.