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Winter Forecasts... 2016-2017

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Snowmageddon 2010

Two storms in 3 days totalling 46 Inches. Remarkable feat on it's own but even more impressive was we were not the true bullseye for either with Baltimore-DC getting 30+ on one, and northern NJ getting 30+ on the other. We did however get plenty from each (28 and 18) to likely give us the two storm total bullseye as far as densely populated regions go.

Around every six or seven years we tend to get a really good winter across the Mid Atlantic and North East. Occasionally anywhere from 20 to 40 years we can get repetitive seasonal hits of big winter weather. It is the exception not the norm. When it comes it is spectacular but for some reason erases our weather memories leading us to anticipate it to repeat every year. It's extremely difficult to do as we saw last winter. This winter will surely be of a more common variety in terms of means and norms but will also have it's own quirks. At the very least a repeat of last winter's horrifically warm and in some cases nearly snowfall void will not be repeated.

Ground Rules

Enough with the long range model runs and doomsday winter forecasts for the I-95

I can get a bit irritable when it comes to the weather or the tasking of opinions. I think a lot of that is a failure to be up front with intentions and a failure to properly label location based commentary. So a couple of ground rules and then off we go. If you're one of the rare socially balanced weather fanatics or are already aware of my approach then feel free to skip this section.

I live in the North East and the majority of my commentary is geared towards North East and Middle Atlantic weather patterns and storm systems. Primary focus is along and east of the Appalachians, the I-95, big cities, and coasts. This is important to keep in mind whether reading this outlook, any successive outlooks, or even my daily twitter commentary. We don't all live in your neighborhood so please keep that in mind if eager to reply to an idea.

We all have our methods and approaches. I am one who is not swayed by opinions on climate, desires on a type of weather, model runs, or outside opinion. I have no claim to fame nor a desire to be famous let alone through "weather promises" or "hero forecasting". We have found while such practices may be highly sought after they surely fail quite often. Simply put, hero forecasting may gain you friends, but we find it rarely works.

Most of the following thoughts were born over the summer I only just now got time to put them into a piece. They're my ideas, I'd like to be right as to not steer anyone wrong, but if they are we'll shift to follow the weather and not seek to support some early outlook. You're unlikely to convince me I'm wrong and any attempts to do so will simply be met with repeating of commentary you're about to read. It's really not that important and I'm still to this day so very unsure why it is to so many folks especially those who just seem keen on forecasting the worst possible winter ever every single year. It makes little sense to do so and is of absolutely no value.

Seasonal outlooks aren't exactly a highly successful endeavor. In fact they can frequently end up trash can material before the central meat of a season takes root. I really have no attachment to any particular outcome of the season itself as I am more invested in tracking individual storm systems and the weather they may bring. I have no concerns over whether this outlook ends up successful or not and whatever the season brings is what we will adjust to and follow. I have no climatological stance that influences how I proceed with daily weather. Simply put I don't have an agenda, I don't scorekeep, I don't do thermal arguments, and I won't be dragged into fights over whether or not it will be cool, warm, stormy, or otherwise. Agenda and a need to be popular has no place in science. It is of no value and I won't be a party to it. I would only like to be correct as to not steer anyone overly wrong. Otherwise I hold no allegiances and I really am not consumed in the outcome of an event versus the thoughts laid out prior to the event. Weather is about adjustment and we'll do our best to do just that. If you do not like what you read below that's fine but I don't understand the aggressive tasking of these outlooks by disagreeable parties. I simply won't reply to many questions about this outlook, as I believe it's self explanatory, and I surely won't respond to any aggressive or inflammatory statements. Nobody is trying to take away your snow. Besides, it's the weather....get over it...and yourselves.

Let's get Started.

A Little Grounding Calendar Helps

Whether it be a storm system of interest, an incoming pattern shift or change, or a seasonal outlook I like to put together a timeline of which to follow. You've probably seen them before and I will utilize this for events along the way this winter.

When it comes to winter there seems to be a couple decent benchmarks to look ahead from. For late fall and the start of winter this tends to be around mid October. For the solid stretch of true winter this appears to occur anywhere from mid December to as late as Christmas to get a handle on things. 

As a way to answer future incoming questions and to clarify some questions already answered on how I believe the Middle Atlantic and North East winter may play out I felt it was worthwhile to do a little winter writeup. I won't be going too in depth and will unlikely have the time to follow up as I did last season. Those 2016 opinion pieces are still available here.

A Quick Stab

I formulated winter's opinions quite some time ago and I still see no reason to change them. Likely wouldn't until we're seeing it all unfold before us anyway. Recently I put the occasionally scattered thought into a quick hit graphic as seen above. I still like it but I think it was time to put a piece together drawing it all together.

You've likely already seen my commentary and the occasional supportive graphics and I truly believe this winter will be quite straightforward as long as you apply one very important word: Variety. I believe we are going to see consistent ups and downs of the temperature pattern on short turnaround wavelengths and this will lead to a high variety of storms and storm tracks at a very low repetition rate.

It should be noted none of the graphics below are meant to replace official forecasting, they are not meant to be precisely drawn elements, their intent is a general guide to the general thoughts. If your town is near a line on either side there is no intent to include or exclude with such precision. These are illustrative only.

Temperature Patterns

We've been locked in a fairly consistent pattern since April of 2015 where we spend most of our time above the normal temperatures mixed with the occasional 1-2 day respite. These respites more often than not have served to return us to near normal temperatures before the warmer pattern rebuilds and dominates for another long duration period. I believe we're going to continue this pattern through October if not through November before we begin to see changes.

Long Duration Pattern

After the historical winter of 2014-2015 we kickstarted quite the warm spell beginning in April of 2015. Other than some natural oscillations and variations it's been a very warm stretch of weather. I believe we'll continue this through October and as noted begin to see changes November and December from west to east. 

Shifting our Pattern

I think there's some pretty good signs and agreement that the Upper MidWest and the Great Lakes will likely see a cooler than normal temperature pattern this winter. This probably also includes the northern Ohio Valley region to the Appalachians.

We're already seeing hints of this in recent September seasonal change activity and this will probably become quite frequent this winter. Because of this early activity we will likely first see the Appalachians and points north and west, primarily in western and northern New York state, western PA, and West Virginia start to shift out of this overly warm and persistently rebuilding warmer pattern as November wears on. I think east of the Appalachians, the I-95, coastal plain, big cities and coasts will be waiting until December for the more significant trending down towards a more neutral and typical temperature pattern.

Inhibitors to a Quick and Early Change

We also are well aware of the very warm Arctic Ocean, James and Hudson Bays, Great Lakes, Western Atlantic, and more. We cannot simply make these overly warm and widespread waters disappear and it will take more than a whole winter season of colder weather outbreaks to moderate these temperatures to where they no longer inhibit colder weather patterns.

Mitigating Early Outbreaks

Great Lakes water temps have risen significantly in recent years. When you have a cold weather outbreak crossing these from Canada or the Upper Mid West you're going to see as much as 20 degrees knocked out of those outbreaks. This will greatly reduce the impacts of these cooler weather intrusions east of the Appalachians.

Great Lakes Inhibiting Outbreaks Already

Even now when dealing with a modest colder weather outbreak, of which is merely serving to return us to near normals out east, we can see how the warmer great lakes and atlantic SSTs affect the overall potential impacts. We just cannot translate a cold weather outbreak as it looks prior to crossing the Great Lakes to the North East, Mid Atlantic, and the Coasts. 

How we Change

For now we'll remain warm and then likely follow the climatological curve downwards from above and eventually catch up.

We will see a very warm Autumn that then begins to transition out of this long standing pattern of 18 months and into a more tolerable temperatue pattern. If you like October beach days you're probably going to be happy with this Autumn. If you're eager for an early cool down chances are you're going to be very disappointed.

90 Day Thermal Outlook - January, February, March 2017

Neutral the Big Word but Why

Do not anticipate hot to neutral to cold large pattern shifts that entrench in place for any duration of time. Support high frequency variability that yields a long duration time frame of neutral means versus averages.

This will also create a high variety of storms and storm tracks of which none that are overly back to back repetitive but rather a "throw a dart for the next track" type variety forecasting.

Due to what I believe will be an ample supply of cooler weather outbreaks combined with overly persistent warm SSTs pattern I think we're going to see a lot of ups and downs all winter long. In some ways it may simply oscillate like clockwork. Above normal as warm SSTs and southern high pressure ridges dominate, then an intrusion of colder weather bleeding across the appalachians from the Ohio Valley to the coasts, and then a rebuild of the warmth anew. You can probably rinse and repeat this pattern for most of winter. The combination of short lived warm and cool spells alike will offer a high probability of neutral 90 day mean average temps in relation to accepted norms across the region.

Why Neutral 90 Day Mean

I believe as we trend through December and into January, February and March that the upper level pattern will support repetitive cold weather outbreaks flushing through the BLUE OUTLINE shown above.

I believe in repetitive and aggressive rebounds back warm due to our SST patterns and rebuilding southern ridges pushing these colder intrusions back out of the region to within the RED OUTLINE shown above.

Therefore after numerous backs and forths I think we'll end up with a 90 day neutral mean versus average temperature pattern. This will be misleading due to the continuous high frequency oscillation of the temperature patterns but once you add it all together and divide by 90 days I think we'll end up near normal throughout the region as depicted by the GREY AREA shaded above.

I think you are highly unlikely to find any winter outlook that can be applied to daily or weekly weather because I do believe in such constant variety being on display. This is likely to drive our computer modeling absolutely crazy and I think we're going to be frustrated by the flip flopping of storm track scenarios as models attempt to time disturbances with the consistent flux of warm vs cool rebuilds and intrusions waffling back and forth between the Appalachians and the Coastlines.

Storm Activity

Storm Tracks and Variety

Given the constant back and forth of temperatures I think we're going to see a lot of storm activity due to the constant interaction of warmer and cooler paterns pushing back and forth and also a high variety of storm systems. I don't feel we'll start out warm then see a dramatic shift in patterns, jet streams, and storm tracks, and then be immersed in a repetitive pattern. I believe instead a constant battle between the overly warm SSTs and the cold weather intrusions will occur with neither winning out for more than a very short term period.

Why High Variety of Storm Tracks

To me this means the timing of each individual disturbance in relation to the current thermal pattern availabile will be different nearly every single time. One day an inland runner, a couple days later a coastal low, a couple days later an Ohio Valley to MidATL redevelopment, then another Ohio Valley low that tracks to the west up through New York to western New England, then a clipper, then another coastal, an inland runner - and truly you can keep this oddball cycle of potluck going most of winter. 

Think there will be very few repetitive strings of similar storm activity and this is because I think we'll see the cold weather outbreaks push over the Appalachians and to the coasts but then rather quickly see the warm SSTs push these back to the Appalachians. No real chance for either the warmer or cooler pattern to set up and dig in. Of course there will always be a moment when you do get a back to back of either rebuilding warm high pressure or of two lows filling the trough and you'll have a week of warmth or week of cooler wx. Yet for the most part I'd shy away from that occurring often and would support a consistent back and forth of temperature patterns and thus a high variety of storm activity.


Wetter than Normal

Every year the snowfall forecasts come out and nearly every year they bust for someone some where. There's plenty good reason for this: You cannot determine the individual storm nor account for the occasional blockbuster event. Without last year's blockbuster blizzard the entire region would have suffered extremely low snowfall totals. Therefore in a season that truly was a very benign winter there was a saving grace for those who use snowfall averages as a measure of a winter's impact. Therefore I think it's utterly useless to bother with such. 

There is overwhelming variety in a season be it the longer duration background wavelengths or the individual storm systems. It's really a crap shoot to call a physical snowfall accumulation number.
It's winter, it's going to get cold, and it's going to snow. It's more up to the individual storm systems than it is the overall seasonal weather patterns themselves. I think it's best to go for a general precipitation guide rather than tinker with the frozen equivalent. 

Potential Busting

Where could this outlook go bust? 

Warm Bust

Perhaps I'm not giving the persistent and widespread warm SSTs in all our important bodies of water enough credit. If it were to bust warmer than thought you'd likely see this occur in the I95 from roughly NYC on southward through DC and then cutting westward across southern Virginia. 

Cold Bust

If it were to bust cold it would likely only do so in an underestimation of potential blocking of which we really haven't seen much of in recent years. If we were to bust on the cold side I think it'd be mostly confined to western PA/NY and northern NY and New England. This would simply be due to giving the SSTs too much credit in the face of the colder weather outbreaks due to come from the west. Repetitive outbreaks, storm activity, and blocking could serve to start turning the SSTs downward from their higher anomalies and this would be less of an inhibitor to allowing colder weather outbreaks to not only come in but to stick around a bit more.

As always, it's the weather, it's going to shift, and when it does we'll observe the changes, re-analyze potential, and form new thoughts.


10th Annual Winter Outlook

Overview of Preset Conditions

The atmospheric/oceanic state in which we find ourselves right now is multifactorial. The super El Nino event last winter aided in inducing a variety of atmospheric tendencies: surged global temperatures such that the ensuing year features an inordinate amount of residual northern hemispheric heat, largely as a function of the excessive latent heat release via prior tropical forcing; the additional, significant injection of westerly atmospheric angular momentum (corresponding to the excessive forcing) precluded the descent of easterly stratospheric winds, thus resetting the QBO into a condition of predominately high westerly shear stress. The enormous latitudinal thermal gradient induced largely by super Nino conditions drove the stratospheric vortex into an insurmountably potent state; however, upon its collapse last spring, the vortex has remained unprecedentedly weak. One may hypothesize that this implicates a repressed vortex status for the ensuing winter, but exogenous indicators suggest otherwise. The ENSO condition is cold-neutral bordering on weak La Nina, which will likely persist for the duration of the winter. SST’s and tropical forcing are reflective of a classic Nina-esque walker cell orientation. It will be important to ascertain the likely modalities and proclivities of high latitude indices, in light of the lesser ENSO forcing (though this isn’t entirely the case). The anticipated behavior of the various global oscillations and their concomitant z500 results will form the basis of this outlook.


Examination of Integral Factors

    • ENSO status is cold-neutral to weak La Nina. The vast majority of model guidance maintains the cold-neutral/weak La Nina regime throughout the winter. Whether the resultant situation is weak Nina or cold-neutral, the z500 and sensible weather outcome disparities would be immaterial.

  • The oceanic-atmospheric coupling has been relatively weak thus far. SOI daily values have been near neutral or even negative at times – in concert with a strongly heightened angular momentum state – the resultant regime has more closely projected on the climatological El Nino z500 pattern rather than La Nina (at least in the Pacific). The extended Pacific jet is a consequence, with a flood of warm, maritime air into Canada. This regime will experience significant alterations over the coming weeks. The atmospheric coupling response will manifest more robustly as Indonesian/Maritime tropical forcing and rapidly decreasing angular momentum (that is, a removal of atmospheric momentum from the energy budget), will eventually cause the Pacific jet to retract. The more classic low-mid latitude Aleutian ridging and concomitant troughing in the eastern Gulf of Alaska and Western US will develop by late November. The momentum will decrease to such an extent that lower than normal geopotential heights will dominate the northeast Pacific. Inter-seasonal low frequency tropical forcing should congregate in the W Pacific/Indonesian region thus winter – principally within the “domain space” of MJO phases 4-5-6. Large scale subsidence should dominate the dateline and Western Indian Ocean regions, with potentially a secondary, less potent upper divergence area near northern South America. So far this autumn, the dateline eastward in the Pacific – both tropically and sub-tropically – has been largely devoid of 200hpa negative velocity potential, while the inverse has been true to the west of the dateline. All of the aforementioned has implications insofar as Rossby wave driving and mid latitude responses.

  • Tropospheric boundary layer conditions thus autumn have been suggestive of a highly perturbed vortex and would – in a vacuum – portend a weak winter stratospheric (and consequently tropospheric) vortex. Both snow cover extent and advance has been quite impressive when juxtaposed with the majority of seasons over the previous 30 years. The resultant Siberian high development and concomitant Taymyr geopotential height anomalies have been robust; namely, higher than normal geopotential heights have generally persisted in that region. The development of certain tropospheric patterns is crucial as often times they will project strongly onto climatological wave 1 and wave 2. The significance of this is that a tropospheric pattern which constructively interferes with vertical wave driving will converge and perturb the vortex.

  • As noted prior, the westerly shear stress has persisted in the stratosphere. The westerly QBO strengthened (became more positive over the past couple months. The ensuing winter state will be strongly positive, becoming more moderate late, and likely reversing into the negative state (finally) by spring 2017. Solar conditions have been variable but largely depressed. 10.7cm solar flux values are very low; generally under 800. This will continue or decrease during the winter. Solar minimum with respect to cycle 25 will occur between 2018-2020. Geomagnetic activity (proxy: AP index) min-max cycles are typically lagging that of flux and sunspot numbers. Geomagnetic parameters suggested a decline this summer, but it has been rather active again this autumn.


  • Precursor sea surface temperatures in the Atlantic Ocean were analyzed for specific trends/anomalies which could be relevant insofar as NAO modality trends.

  • Research has demonstrated that there might be a tendency for the development of poleward Aleutian mid-level ridges under a cold ENSO/+QBO regime. The correlation is a strong one. However, I have noted disparities in the recent autumn/current pattern, in terms of atmospheric behavior and forcing which do not project onto the +QBO/-ENSO z500 result. This casts doubt on the notion for a persistent poleward ridge in the Pacific.

  • The PDO has been in a predominately positive phase, though declining over recent weeks. The Gulf of Alaska has cooled dramatically due to the extended jet and low geopotential height anomalies. However, the forcing emanating from this region is immaterial, and provides positive feedback at maximum in terms of the ensuing pattern. A more interesting propensity has been the latitudinal sea surface temperature gradient with very warm waters running horizontally across the sub-tropical Pacific and cold waters immediately to the north. This will add momentum to the Pacific jet and aid in precluding, at least in a protracted fashion, significant poleward blockiness. However, the westerly shear stress via the QBO and its connection to forcing modulation may result in a period of such poleward blockiness.

  • The AMO has been mostly positive with the western Atlantic warmer than normal. The feedback generated from this will be insignificant compared to the Pacific, but it could aid in intensifying extra-tropical cyclones near the East Coast. Additional available energy increases the likelihood for a reversal in the predominate precipitation pattern from dry to wet across portions of the Northeastern US.

  • The sum of methodologies has included analysis of exogenous indicators such as solar, geomagnetic trends/behavior, stratospheric winds, and internal variability of the PDO, AMO, ENSO, tropical forcing, NAO, AO, EPO, PNA (including a relationship I’ve examined which – retrospectively – correctly predicted the NAO modality in 86% of seasons since 1950); prior years have been juxtaposed with the present/recent pattern in attempt to ascertain an extrapolation of this year’s regime. The totality of indicators yields the following prognostication.

Indicator Outlook for DJF mean:

PDO: Near neutral to slightly positive

AMO: Positive

EPO: Positive average; transient periods of negative

NAO: Positive (potentially strongly at times); one month of negative is possible

AO: Near-neutral; favoring early winter for the negative periods, becoming more positive

ENSO: Cold neutral to weak La Nina

PNA: Near neutral; periods of both positive and negative

AAM: Predominately negative/easterly

QBO: Strongly becoming moderately positive/westerly

Anticipated Progression:

In examination of prior years, there were innumerable disparities which made it exceedingly difficult to select analog years. However, the totality of indicators studied yielded the following for closest years:

Primary analog: 1973-74

Secondary analog: 1975-76

Tertiary analog: 1999-2000

There were some notable similarities to 2011-12 as well, though insufficient to utilize it as a higher echelon analog. One will note that all three of the analog years were actually moderate to strong La Nina’s, which differs from the current ENSO state. However, there were numerous other (arguably more important in my view) strongly similar variables. I anticipate a suppressed AAM state, a strengthening polar vortex, La Nina-esque walker and Hadley cell behavior, tropical forcing, which more closely reflects the –QBO/-ENSO years rather than the +QBO/-ENSO years.

December should begin with a neutral to negative tropospheric and stratospheric AO due to the exceptional tropo-stratospheric perturbation. The Pacific will largely be unfavorable with a positive EPO and low geopotential heights amplifying in the Rockies/W US, indicative of a –AAM regime. The NAO could potentially trend negative for a time, combatting the poor Pacific, enabling some troughiness to develop in the C/E US. Many of the analog years featured one month of colder than normal temperatures with more conducive z500 regime. 1975-76 featured a very cold January, and 1973-74 a colder than normal February, and 1999-2000 a colder than normal January. However, there are a number of adjustments that should be performed. There is significantly greater global/hemispheric warmth compared to the 1970s analogs due to the post super Nino conditions. Secondly, the state of the stratospheric vortex is very weak right now, and projected to remain that way through November. There’s a high correlation between November and December outcomes. Thus, I think December is the month most likely to feature high latitude blocking. However, it must be sufficiently significant, especially in the NAO domain to mute +EPO induced Western troughiness. The Southeast ridge will be attempting to burgeon northward. Thus, even early winter, I am conflicted, but given signaling and analogs, December should be near normal temperature wise in the Northeast corridor, with possibly slightly above or slightly below temps. Given the precursor factors and analogs, I expect the precipitation pattern to become increasingly wet across the northern tier and Northeast. I don’t believe it will be sufficient to reverse the drought in the Northeast, but a normal or wetter than normal winter is likely with a warm W Atlantic an active Pacific stream.

January will become increasingly warm with a rapidly intensifying vortex. In the Pacific, the continuance of a low-latitude Aleutian ridge with low heights across Alaska/NE Pacific and NW US should persist. However, periods of poleward Aleutian ridging are possible, occasionally suppressing the Eastern ridge and providing wintry threats. The vast majority of the time, the Atlantic should be unfavorable. Transient blocks are not out of the question. January should be warmer than normal for most of the South and East, with colder weather confined to the Rockies and northern tier.

February should look like a classic Nina-esque regime at z500 and likely in the low levels. An active jet with numerous snow threats across the Mid-west and northern New England should dominate. A continued unfavorable Atlantic and increasingly unfavorable Arctic, coupled with an indeterminate NPAC state could yield occasionally mild to record warm temperatures in the Eastern US. Snowfall will be highly dependent upon transient blocks and baroclinic zone suppression via poleward NPAC ridging. Overall, the month looks warmer than January. Cold weather dominates the N Plains.

In sum, this winter will be colder than last year (not surprising given the record warmth), but warmer than normal across the South and most of the East. Colder than normal departures will be found across the NW US/Rockies and into the Mid-west. The most likely period for a severely cold outbreak, including the East is between December 20th-January 15th. If a coupling can occur between high latitude blocking and poleward Pacific ridging, the wintertime source region of cold can expand southeastward. All three analogs featured a period of colder than normal weather in the East. For the most part, the East Coast will be battling milder weather. Precip should be normal to above from the Mid-Atlantic northward, and snowfall normal to below from the Mid-Atlantic southward. There should be more frequent light-mod snows across the North with fewer large events. Bigger events are possible in the Lakes/Interior Northeast with intensifying inland lows.


Outlook Temperatures:

For the Local New York City Region:

Dec-Jan-Feb Temperature Departure Outlook: +1 to +2; Warmer than normal

[Expected evolution is near normal December, warmer than normal January, and warmer than normal February].

Dec-Jan-Feb Precipitation Departure Outlook: Near normal (possibly above to the north)

Nov-Mar Snowfall Departure Outlook: Near normal to the north of NYC and below normal from NYC southward

Snowfall guesses for various CONUS locations:

Burlington, VT: 90-100”

Boston: 40-45”

New York City: 21-26”

Philadelphia: 13-18”

Baltimore: 10-15”

Washington DC: 9-14”

Richmond, VA: 5-10”

Raleigh, NC: 0-5”

Atlanta, GA: <2”

Houston, TX: <1”

Chicago, IL: 45-50”

Denver, CO: 60-65”

Seattle, WA: 5-10”








Primary analog z500:









Judah Cohen winter outlook: Cold for Eastern U.S., snowy in Washington

The Eastern United States should brace itself for a cold and potentially stormy winter, pioneering seasonal forecaster Judah Cohen says.

Cohen, who works at Atmospheric and Environmental Research, has become well-known in the weather prediction community for his unconventional winter forecast methodology. Whereas many winter outlooks, such as the one produced by the National Weather Service, heavily rely on temperatures in the tropical Pacific Ocean, Cohen’s outlook is most influenced by the behavior of snow cover in Eurasia during October.

When snow advances quickly across the Eurasian continent during October and covers a large area, Cohen says, it heavily favors a cold winter in the Eastern United States.

I emailed Cohen to ask him about the behavior of the snow cover this fall and what exactly it means for winter. His answers are below, lightly edited for length:

Talk to us about how Eurasian snow cover behaved this fall.

This year the advance of October snow cover in Eurasia (south of 60 degrees north latitude) was the fastest on record going back to 1998.

The snow coverage (for all of Eurasia) was fourth highest on record.

What do you think the snow cover behavior predicts for the winter?

I would say that the predictors that we follow are strongly indicating a colder-than-normal winter.

Our U.S. forecast is posted below (and also available on the National Science Foundation website):

Any sense as to where the harshest winter conditions compared with normal will focus?

First, let me say I think the most impressive cold will be across Eurasia. But here in the U.S., extensive Eurasian snow cover favors colder than normal temperatures in the Eastern U.S. more than it does in the Western U.S.

Based on the recent evolution of the polar vortex, however, I do think that initially the most severe winter weather could be across the Western U.S. Also, La Niña has me thinking that the worst of the winter weather will be focused farther north (in a relative sense). Therefore, I expect the worst of the winter will be across the northeastern quadrant of the U.S.

Siberia has been extremely cold in recent weeks while the North Pole has been at record-warm levels. What do you think this signifies?

Most of the climate community believes that the cold in Siberia or elsewhere around the Northern Hemisphere continents is not attributable to a warm Arctic. I strongly disagree and believe that the two are dynamically linked. I also believe a warm Arctic favors a weak polar vortex. When the polar vortex is weak, cold air usually spills out of the Arctic to lower latitudes.

In the fall, the weak polar vortex results in more severe weather (snow and cold) across Siberia that expands to other regions during the winter, usually first to East Asia but later to Europe or the Eastern U.S.

You’ve noted on Twitter there are signs that the polar vortex might split. When might that happen, and what would that mean for weather in the U.S., and when?

Any disruption to the polar vortex usually precedes an increase in severe winter weather but, in my mind, when the polar vortex splits, this is the single greatest atmospheric phenomena that promotes blockbuster snowstorms in the subsequent weeks.

Recent model runs are no longer predicting a significant polar-vortex split but rather a weaker one in the near term. Regardless of what occurs in the near term, my thinking remains that there will be at least one more significant weakening of the polar vortex this winter and possibly a polar-vortex split.

How much snow do you predict for the D.C. area this winter?

I ran our model and it predicts 23 inches for this winter. [Normal snowfall in Washington is about 15 inches.] Snowfall forecasts are extremely difficult, and I provide the forecast in the spirit of trying to push the envelope and for fun. With that said, I was very pleased with last winter’s forecast. [Cohen predicted 28 inches and the actual total was 22.2 inches]

How confident are you in your outlook?

Every winter has its own unique challenges.

The forecast for a cold winter depends on correctly predicting a significant weakening of the polar vortex typically in midwinter (January).

The polar vortex is currently weak, but I do believe that the success of our forecast may depend on a subsequent polar-vortex weakening later this winter. For status updates, follow my blog and Twitter account.

Your winter outlooks are a bit controversial. For example, a forecaster at the National Weather Service said, “Some of Cohen’s mechanisms seem a little bit challenged” and that your methods aren’t “actionable.” What is your response to this criticism?

For the past seven winters, if you used a simple prediction of a cold winter when October Eurasian snow cover was above normal and a warm winter when October Eurasian snow cover was below normal, the forecast was correct six of those winters. The only winter that was wrong was last winter with the record strong El Niño. That is an impressive track record for climate prediction. But I am happy for the community to be skeptical of our ideas and create a void that I am willing to fill.

Some people have pointed out your forecast for last winter didn’t work out that well and that it shows your method doesn’t take enough factors into account. How do you respond to such criticism?

No forecasting system will be perfect but I would argue that we take into account more factors than other long-range forecasters, including the National Weather Service.

First, we do include El Niño and La Niña (ENSO) in our model. The source of our error last winter wasn’t simply because snow cover. Part of the cooling our model predicted in the Southeast and Mid-Atlantic, which turned out to be wrong, was reflecting the record strong El Niño.

Second, the models used in seasonal forecasts predict ubiquitous and incessant above-normal temperatures. There is no variability in those model forecasts. Our forecasts show much greater regional and interannual variability.


Utilizing commonly used parameters for long-range forecasting, but largely staying away from the various atmospheric and oceanic indices frequented by weather vendors, an outlook for the winter season of 2016 - 2017 was compiled, with illustrations. While the DJF time frame is given special and obvious consideration, a review of the bordering "shoulder" months of November and March are also included in this prediction.


The greatest part of this discussion involves use of suitable analog years that displayed obvious similarities to conditions seen during summer and autumn of 2016. Some, like the trends seen on satellite images are meant to either adjust or re-enforce the prediction. But most are tied to quantifiable (and easily recognizable) factors such as ENSO/ONI character; overall SST anomaly outlay; and temperature and 500MB height array. Once the years are obtained, a simple arithmetic mean is derived for a feature. In the case of surface temperature anomalies, a smoothed graphic is presented.

Satellite-Derived Teleconnections
Inline image 17


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Himawari-8 imagery reveals that the Madden-Julian Oscillation remains over the Indian Ocean and the Maritime Continent. Therefore, computer model and analog-derived forecasts for a warm West vs. chilly East alignment may be somewhat premature. Typically, such an atmospheric response will occur only when the MJO is in Phases 6 through 8, that is in approach to the International Dateline. Such a position would enable typhoon injection and Kelvin wave pulsation into the polar westerlies, thus forcing greater amplification (blocking signatures) into the jet stream in the key -EPO, +PNA, -AO and (later) -NAO locations.

Another argument against a cold start to November is the strong, semizonal flow across the northern Pacific Ocean. Unencumbered by any blocking mechanism, the storms embedded in the wind field appear destined to move largely without digging/deepening along the U.S./Canada border through the next three weeks. There is concern, however, that the percolating moisture axis along the Equator may feed future storms, increasing precipitation threats and perhaps enabling intensification of a southern branch jet stream from Texas and Dixie on along the Eastern Seaboard.

Note the immense storm affecting eastern Canada, which may be an early symptom of cyclonic systems that travel up the East Coast with a deep moisture connection out of the Caribbean and Sargasso Seas.

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Best Match: 2012

The expansion of the snow cover over Siberia and northern Canada after October 19 is not without precedent. Still, the rapidity of growth is reminiscent of previous years where the snow filed led to easier generation of Arctic air in the regions about the North Pole. So far, the best analog to this autumn is 2012.

Global SST Anomaly Array
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Best Match: 2014
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Best Match: 2013 (September 1 - October 15)

Again, I use a two-stage projection here to eliminate bias toward one particular season, and also to prevent over-reliance on the ENSO sectors or other oscillations. Remember that the Madden-Julian Oscillation is NOT a viable forecast parameter for seasonal outlooks, as that measure is subject to rapid and unforeseen change.

The summer SST anomaly array across the world had its closest analogy to 2014. Note the relation to the 2013 global oceanic thermal character, sometimes cited as a catalyst for the fairly severe winter that year in the Midwest and Northeast.

ENSO State And Projection

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Margin-call analogs are 1959, 1983, 1995 (x2)

While there has been considerable waffling among vendors and official (NOAA) sources concerning the strength (or even the existence of) an incipient La Nina episode, the numerical models and current observations lead me to believe that a fairly standard -ENSO signal is taking shape over the central and eastern Pacific Ocean. It is entirely possible that a more neutral signal may appear in sector 3.4 with the coming of spring. But for the DJFM period, a "weak' La Nina designation seems a good bet, especially when employing the three main prediction equation sets. I used 1959, 1983 and 1995 (twice) as comparison tests showing a summer going from a positive to negative transition in sea surface temperatures over the central portions of the equatorial Pacific Basin.

Preceding Summer Temperatures In The U.S.
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Best Match: 2012

As it turns out, the June - August period of 2016 was the sixth hottest in recorded U.S. history. When September is added to the profile, the JJAS time frame was second only to 1936 for intensity of heat. I used 2012 as the analog, if only because the night temperatures in the 2016 summer were so hot and moisture/precipitation amounts were higher than the Depression-era inferno.

Preceding Summer Precipitation In The U.S.
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Best Match: 1961

It is interesting that despite the widespread, awful display of heat, precipitation in much of the U.S. was in many cases well above normal. Exceptions were noted in California, Appalachia and the urban Northeast. A very close match to the summer wetness outlines was 1961.

500MB Configuration(Seasonal And Nearer Term)
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Best Match: 2006  (June 1 - August 31, 2016)
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Best Match: 2005  (September 1 - 15, 2016)

I have seen a pattern developing where the summer and fall upper air pattern resembled those of the past decade, albeit with more intensity and durability to the heat ridge complex of the Great Smokies/Bermuda type. There was even frequent linkage with the Sonoran subtropical high, making for an unprecedented display of hot air that sometimes encompassed the entire nation. 2006 (summer) and 2005 (first half of autumn) are used in the analog assembly for the winter forecast.

Tropical Cyclone Season Comparison Test

Best Matches: 1990, 2000, 2008, 2013

Using ratios of 13-17 named storms in the Atlantic Ocean and 16-20 tropical cyclones over the eastern equatorial Pacific Ocean, four years since 1990 meet the criteria. Of the designated seasons, 2008-2009 and 2013-2014 presented fairly cold and snowy winters.

Sunspot Pattern
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Best Match: 1928

A valuable factor in determining the propensity for atmospheric cooling in seasonal and yearly cases is the sunspot cycle. The general rule is that the lower the count of solar eruptions, the colder the surface temperatures should be on Earth. While we are in a suppressed maximum, there are no recent matches for count and position on the graph of sunspot numbers. You have to go back to 1928 for a similar solar character. So that year is included as an analog for this discussion.


November 2016
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WEATHERAmerica Prediction For Temperature Anomaly

It is interesting that recent global model output is hinting at a change to a warm West vs. colder Central/East skew in the first week of November. Frankly I suspect those schemes may be jumping the gun, even though there is decent support among the analog set for the new month to turn colder to the right of the Rocky Mountains. For now, I will hold to the idea that any deeper polar or Arctic intrusions will hold off until after mid-month. Note the very warm signal over the West and tendency for dryness in most of the country, two factors which lend support to a lower heating-demand scenario nationwide.

December 2016
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WEATHERAmerica Prediction For Temperature Anomaly

While the middle of the nation may have some intrusions of cold air to deal with, the still somewhat relaxed upper air pattern will allow for mild values to dominate both the western and eastern thirds of the U.S. One major concern after December 15: signs of a pattern buckle with a major snow/ice/rain event affecting the gap between the Mississippi River and Appalachian Mountains. Lake effect snowfall may be an issue across parts of the Midwest by the week of Christmas and New Year's Eve.

January 2017
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WEATHERAmerica Prediction For Temperature Anomaly

While a rather strong Hudson Bay vortex is taking shape, much of January may in fact be dominated by what appears to be a Bermuda High. Cold air will slowly take root over an area from the Continental Divide into the Great Lakes and Mississippi Valley. But the Eastern Seaboard, for most of the first month of the new year, misses out on cold intrusions. At some point in the second half of the month, there will be the threat for a broad storm moving through Texas and the Dixie states up along the western rim of the Appalachian Mountains. This feature may start the trend of lowering temperatures along the fabled Interstate 95 corridor. And yes, ridging and downslope flow keep California and the West Coast mild and dry.

February 2017
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WEATHERAmerica Prediction For Temperature Anomaly

While the first week or so of February may still show containment of very cold air over the Great Lakes and Mississippi Valley, the presence of so much blocking (-EPO/-AO/-NAO) looks to force south and east displacement of a deep 500MB low into the Urban Northeast by and after Valentine's Day. A winter storm may impact sections of the Old South into the Mid-Atlantic states, while lake-related snows expand as far south and east as the Appalachian Mountains. In the West, the net effect of so much ridging creates drought concerns as well as lowered heating demand.

March 2017
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WEATHERAmerica Prediction For Temperature Anomaly

An impressive -EPO/-AO/-NAO blocking array appears to cave in to a more semizonal flow at 500MB in the second half of the month. Still, it would appear that early March will feature a genuine breakthrough of Arctic air following a large coastal storm. That major precipitation event may bring an unusually heavy amount of snow and ice from lower Appalachia into the Northeast. Before ridging erodes, California and the West continue with unseasonably warm temperatures and drought.

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One gets the very real impression that the European subcontinent will be facing a "warm start, cold finish" course in the DJFM period. Analog sets point to a very strong -NAO signal that, in time, will buckle and depress the jet stream with a colder, stormier February and March. The Balkan Peninsula and Anatolia may largely escape the worst of the cold, while northern Europe and Russia suffer greatly beginning in the last week of January.

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The build-up of snow cover in Siberia during recent weeks may be symptomatic of a very cold winter in Russia overall. Drainage of the Arctic values into the Orient (especially Manchuria into the Japanese Archipelago) may occur with a frequent offshore storm track. Impacts on agriculture could be severe in India and Southeast Asia.

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Analog Set Used:

1928-29; 1959-60; 1961-62; 1983-84; 1990-91; 1995-96 (x2); 2000-01; 2005-06; 2006-07; 2008-09; 2012-13 (x2); 2013-14 (x2); 2014-15


I would term the 2016-2017 winter as moderately cold, with the harshest temperature effects from the northern/central Great Plains through the Great Lakes and Midwest. The West looks warm and dry, with volatility in temperature and precipitation the key words for the Dixie and Eastern Seaboard states.

The look of the DJFM outlook is fairly close to the outcome of the 2007-08 and 2008-09 winters. There may be a tendency for a breakthrough cold event in February into March over the eastern half of the nation.

Storm threats may be quiet profound over the Southeast, Appalachia, and the Atlantic Coastal Plain.

Drought issues may increase in the California markets, with some hope for precipitation in a breakdown of the general pattern at some point in March.



If an Appalachian Mountain storm track locks in during January, the East Coast states may continue to dodge the threat of cold for the remainder of winter into spring.

Should the analog-based forecast verify, the Great Lakes and Midwest cities could see multiple cases of snow/ice followed by repeated cold intrusions in January well into March.

Any injection of a typhoon, or energy from an eastward shift of the Madden-Julian Oscillation, might result in a far more severe January/early February for cold and storm threats into the Deep South and Eastern Seaboard.

Prepared by Meteorologist LARRY COSGROVE on 
Monday, October 31, 2016 at 7:00 P.M. CT

The previous statements are my opinions only, and should not be construed as definitive fact. Links provided on this newsletter are not affiliated with WEATHERAmerica and the publisher is not responsible for content posted or associated with those sites.

Copyright 2016 by Larry Cosgrove
All rights reserved.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.

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