Thoughts On The Upcoming Winter: 2014-15
As the winter of 2014-15 approaches, it’s nearly impossible not to look back at last year’s winter and not recognize the impressive footprint it left in the record books. From winter storms across the Southeast that left a crippling layer of ice across much of the region to incredibly, brutal Arctic outbreaks that blanketed the northern states at what seemed to be a conveyor belt-pace, left a remarkable across the nation.
The question then becomes, what should we expect this winter? A repeat? Could this winter produce a type of cold and snowfall that could rival or even exceed last winter? Or will Mother Nature apply the brakes on the winter ahead?
The driving force behind our weather all year are the waters of the Pacific and Atlantic Ocean. Last winter, an incredibly warm pocket of water in the northeast Pacific Ocean from the Alaskan Gulf down to the coastal Pacific Northwest region of the US was a culprit for the incredibly cold, Arctic blasts we experienced through much of the winter. You might be wondering… how could “warm” water that far to the west be the reason for all the brutally cold air far in the east?
When the waters of the Pacific Ocean along with Alaskan Gulf become very warm, this triggers a ridge to set up across across the western US and a trough to set up over the central and eastern US. Picture a ridge as beautiful mountain sunrise and a trough as a gloomy valley. The reason for such an analogy is that a ridge is associated with fair, sunny weather where a trough is associated with unsettled weather, and during the winter months, this supports colder temperatures. When a piece of the Polar Vortex from extremely high latitudes breaks free, the dip in the jet stream across the central and eastern states caused by the “trough” pattern setup allowed for these pieces of the Polar Vortex to “fall down” so to say and reach this part of the country. Associated with the Polar Vortex is brutally cold, Arctic air over extended periods of time, such as what we experienced last winter.
Before I continue, let me reiterate what the Polar Vortex is, exactly, since major news and media outlets had a field day using this term to no end, not knowing themselves what it “really” is. Many were misinformed, many became panicked and whole mess of a situation ensued and the agenda of the national media was met.
The Polar Vortex is a continuous large upper level cyclone near one or both of the Earth’s poles. It has always existed and will continue to exist becoming stronger during winter months and weaker during summer months. Many times during the course of winter, as mentioned above, a “piece” of the Polar Vortex breaks off and dips south with the jet stream and this is what delivers the cold, Arctic outbreaks and is what occurred much of last winter resulting in brutal cold for extended periods of time. The Polar Vortex is nothing new and not something that can be seen like a tornado and while the Polar Vortex itself is not dangerous, the brutal cold air that comes with the Polar Vortex can be very dangerous.
Looking ahead to the upcoming winter, I have reason to believe that the setup we had over the entirety of last winter will continue into this winter across much of the central and eastern sections of the nation as model data has been suggesting this type of similar setup. A ridge setup from the Alaskan Gulf to the western US would allow for brutally cold air to invade the county once again, especially for much of the central and eastern US where a trough would set up in which the dip in the jet stream would essentially pull the cold air straight down into the states.
Looking at long-range model guidance, note the pockets of above average, warm ocean temperatures through November from the Aleutian Islands over to the Alaskan Gulf and down the US western seaboard. This would all but suggest ridging to set up across the western states and troughing to set up over eastern states. This would deliver a large-scale dip in the jet stream across the central and eastern states which would allow the opportunity for that cold, brutal air to dip down into these regions as we go through the winter months.
Model guidance continues to illustrate these above average, warm ocean temperatures through February suggesting the same ridging in the west, troughing in the central and eastern states is likely to persist through the winter.
When looking at seasonal patterns, there are several oscillation indices that need looked at. In order for the central and eastern states to experience an active winter with cold temperatures, the NAO/AO (North Atlantic Oscillation/Atlantic Oscillation) needs to trend positive while the EPO (Eastern Pacific Oscillation) needs to trend negative.
Looking at these indices via GFS and ECMWF guidance, you’ll notice that the NAO/AO is suggested to trend positive later this month…
The EPO (Eastern Pacific Oscillation) is currently teetering between positive and negative, but I believe that this will begin trending consistently negative late in the month into early November.
If these indices trend in these directions, this will be what delivers a similar winter to last season across the central and eastern US and I have a strong feeling they will…
All said, I have a strong feeling this winter could rival last winter. With the type of pattern that seems to reminisce last winter, this will spell every opportunity for cold, Arctic intrusions to pay a visit once again, especially across the central and eastern states. Just how far will the cold dip this year? That all depends on how far the jet stream will dip and pull the cold air down.
Across the nation, snowfall/precipitation will be widely scattered across the central and eastern states, much like the pattern setup that is likely to bring the brunt of the cold air across the same regions. Within these regions, there will be number of “hot beds” of snowfall. I’m using the term “hot bed” to illustrate areas that have the potential to see above to well above average snowfall through the winter season.
Across the upper and central Plains, upper Midwest and much of the Great Lakes, do not be surprised to see spells of brutal cold temperatures, similar to last winter’s episodes, along with average to above average snowfall. Much of the snowfall will be the product of synoptic systems, but the closer you get to the Great Lakes, the more of factor lake-effect snow will play into these snowfall totals, mainly for lakeshore areas. This is where overall seasonal snowfall/precipitation totals become challenging to forecast because lake-effect snow is far from an absolute, constant, rather it is an ever-changing variable. I will explain the science of Lake-Effect Snow in a future article.
Although lake-effect snow will play a factor this season, as it does every winter, there is reason to believe that lake-effect snow may not be a as critical of a factor this winter. The reason for this is that because of the extended spells of cold, Arctic air intrusions last winter, many of the Great Lakes had much of their waters freeze over, especially Lake Erie which saw nearly a complete freeze over. While the lakes are obviously not frozen at this point in the year, the lake temperatures have remained cooler than normal due to last winter’s freeze and will likely hinder any major lake-effect snow events this winter; not to say the Great Lakes will not experience any lake-effect snow at all, just that it will likely be at a much lesser clip than last year.
Across the Mid-Atlantic and New England regions, with moisture from the Atlantic, there is a very good possibility that these regions could be a second “hot bed” for above average snowfall this winter. While cold, Arctic air will likely be a factor across the east as well, the inflow of moisture from the Atlantic could spell for some decent winter storms to develop from the Mid-Atlantic to New England.
Across the southern and southeastern states is where things could become more challenging to make an early call. Looking at last winter’s historic winter storms, in particular, ice storms across the southeast US, you really can’t rule out anything to that magnitude again this winter. Given the anticipated pattern setup, I would not be surprised to see several areas across the south and southeast US receive above average snowfall. In some cases, even areas that rarely get in on the snow action may get a rare taste of snow/ice.
If the southeast wasn’t tricky enough, moving north into the mid-Mississippi, Tennessee and Ohio Valleys, this area could be dealing with everything from above average snowfall to ice to the kitchen sink and then some. This region could turn into a winter “battle zone” seeing a fair share of both snow and ice .
While a majority of the cold and snow will be likely be confined to the central and eastern states, mainly, much of the mountain states will see an average to perhaps slightly above average winter for their respective regions while a majority of the western states are likely to above average temperatures and remain fairly dry. Not a good situation for these drought-stricken regions. If there is a silver lining, it would be that across the southwest, areas could see episodes of steady precipitation.
Florida residents (because everyone says I leave Florida out… you have your own section now…), looking like a winter with average precipitation and average to slightly below average temperatures.
PRELIMINARY WINTER SNOWFALL, PRECIPITATION and TEMPERATURE GRAPHIC…
As you read through these thoughts for the upcoming winter, please understand that these are in fact preliminary thoughts. Nothing here is set in stone, as is the case with all weather, all year round. If there are changes in data, thoughts, etc, you will be the first to know.
I will post a regular flow of winter information as the months draw near as new data becomes available, but for now, this is my thinking. You can follow me using the links below…