Well it's that time to turn our eyes to the upcoming winter
of 2014-2015. There are many things I
look at to try and determine how our
winter will shape up: Sea Surface Temperatures
Anomalies, Eurasia snow cover, sea ice, solar activity, and many other
things. I will touch on some of these
things in this outlook.
Last winter we saw plenty of cold air, with below average
temperatures and above average snowfall across most of the Northeast and Mid
Atlantic.... the Great Lakes saw near record amounts of ice. The phrase "polar vortex" became part of our vernacular.
This is a detailed
discussion that will provide insight into the factors that have lead me
to my thoughts on the upcoming winter. I think it's important for you to read
the details...but I will understand if you just want to move to the bottom and
read the summery, but in doing so you will miss some of the science involved in
my decision.
Many of the factors that led to last winter will again be in
play this winter, but we will have some new factors as well.
The pattern for winter 2013-2014, for the most part stuck
with us during this summer. Which resulted in a cooler than average summer in
2014. The jet stream was more amplified.
The ridging we saw this year that lead to the drought in California, also
allowed cooler air out of Canada to slide down the trough along the East
Coast, that was fairly predominant this
year.
Look at the latest SSTs in the Pacific....
PDO:
I've circled the areas I will be writing about.
I've brought up the idea that we will see a weak El Nino quite a few times over the summer and into the fall. But will this be the case?
SSTs in the Gulf of Alaska and Pacific Northwest are above
normal for this time of year. But this
area of the Pacific had the same conditions for winter 2013-2014.....This will
be an important player in the pattern for winter 2014-2015 as well.
ENSO:
Something new this year will be the warming in the Pacific
equatorial region. Temperatures across
this area of the Pacific are above average ..... with SST profiles showing a
weak to moderate El Nino. Right now the warmest SST anomalies are off
the West Coast of South America..... what we should see happen over the four to
eight weeks is this area of warm water will shift more to the west..... This upcoming
winter should feature a weak central based El Nino.
Both the location and strength of the an El Nino is very
important.....
Above is a CFS V2 image for
January, February, and March 2015 ...this shows most of the warmth is in
the Central Pacific. It supports the idea of a weak central based
El Nino......
Below are two Jamtec (Japanese)
SST model images for Dec, Jan, and
Feb and Mar, April and May...it shows the same basic setup as the CFS V2.
The combination of a centrally based El Nino in the tropical Pacific along with
the warm anomaly in the northern Pacific normally leads to high pressure ridging along the West Coast
of North America.....with troughing over the
East Coast......This kind of pattern greatly increases the likelihood of
arctic and polar air masses making there way into the central and eastern US.
The reason for this is that weather normally moves from west to east in
the northern hemisphere..... storms moving across the Pacific will move north
along the ridge.... then storms and cold air will slide down the trough. This
kind of pattern does favor Clipper systems and cold outbreaks.
NECP NCAR Reanalysis
.... surface air composite
anomalies 1981-2010, you can see the analog years I entered on the bottom of the chart.
This shows that the Mid Atlantic and Northeast saw colder
than average temperatures ....with Maine seeing average to slightly above
average wintertime temperatures. Based on an average of the temperature anomalies of the analog winter years.
Here is an image that show how the jet stream behaves, during winters that see warm SST in the Gulf of Alaska.
The NOAA Extended SST
for 1981-2010......it shows the same pacific SST pattern....warm waters in the Gulf of Alaska and a weak central based El Nino...The same pattern that will be developing for the upcoming
winter......again the analog years are on the bottom of the chart
High Latitude Blocking:
This is important as it acts as another cold air transport for the cold air
in Canada, Greenland, and the even Siberia.
The question being will there be upper level winds to help
move those air masses south into the CONUS?
High latitude blocking is a pressure pattern in the northern latitudes. It
normally sets up blocking near Greenland.
500 mb Geopotential Anomalies:
This is the 500 mb level........departures from average for
the coldest winters .
Looking back at the same cold winters.. Notice the reds and oranges around Greenland.. we see high pressure situated near Greenland ...with the troughing along the East Coast of the US....again the same conditions that look to unfold for this upcoming winter.
AO and the NAO:
AO and the NAO:
When these are negative they support persistent
blocking high pressure over
Quebec, Newfoundland, and
Greenland.
Here is the AO index...
I've circled in blue where the AO index went very negative in early October..... when I looked
back at the coldest and snowiest winters over the last 10 -20 years..... those
winters had a very negative AO in October.
The AO and NAO
indices are likely to spend much of the time this winter in negative territory....This
is normally the case during winters that feature frequent high-latitude blocking patterns
Solar activity:
If you remember your Grade School Science, you will remember
it's the Sun that controls our climate and weather. If
you follow my space weather page you will know the current solar cycle 24 has seen fairly low solar activity, as in a low number of sunspots.......... I believe
this lower than average solar activity will continue to be the case this upcoming
winter.
When I factored in the analog years, they correlate with the years that saw low sunspot cycle activity ..... we again see the same general setup........ a weak El Nino, warm Pacific waters in the Pacific Northwest, and high latitude blocking around Greenland.... the following shows this......
You can see the blocking high pressure over Greenland and the troughing over the East Coast of the US.
Here is a current image of the Sun...you can see there are very few sunspots showing up.
Here is a current image of the Sun...you can see there are very few sunspots showing up.
Snow pack:
There is quite a bit of snow in Canada...right now it at near
record amounts for this time of year. North America snow cover extent actually reached record highs
at the end of September in records dating back all the way to 1967 . I got this data from the Rutgers snow lab.
Also snow cover is advancing across Eurasia; it's also running above average for this time of
year.
Here are a few images that show snow cover across Eurasia and North America.
All of this supports the idea of a deep cold air pack setting up across northern Canada and the Polar regions, along
with the idea of high latitude blocking. The buildup of snow in North America and Eurasia would help keep the temperatures cold in the arctic region...... It would also increase the odds of a cross polar connection, increasing the likelihood of Polar and Siberian air moving south into North America.
The Great Lakes and lake effect snow:
In spite of ice being on the Great Lakes into June this year, that won't have an effect on this season, currently the lake temperatures on Erie and Ontario are just slightly below average for this time of year..
This year is shaping up to be average for those who live in the snow belts ,
leeward of both Erie and Ontario.
Coastal /Nor'easters:
A weak central based El Nino allows above
average moisture to infuse the southern
branch of the jet stream, with extra moisture, we could see large coastal
storms moving up the East Coast.
The high latitude blocking over the Canadian Maritimes and
Greenland often allows the coastal storms to track along the coast....with
upstream blocking the storms have a tendency to slow down.
The waters of the Atlantic are still quite warm for this time
of year. The warmer than average water temps, will continue into Winter
2014-2015.
Nor'easters are fueled from the cold arctic air
from the north, and the moist air from
the Gulf of Mexico and Atlantic ocean off the east coast. When this happens the
storm undergoes rapid strengthening (bombing); this causes the storm to pull in
even colder air from the northwest side of the storm....resulting in the snow amounts that often stack up.
Colder air and warmer Atlantic SST along the East Coast, increases the odds for stronger coastal storms.
Colder air and warmer Atlantic SST along the East Coast, increases the odds for stronger coastal storms.
Before I conclude, I want to remind you, this winter outlook is based on averages of
the analog years I listed above. A
winter outlook is not a forecast; it's a broad overview of what I expect to
unfold this year..... an outlook can't tell when individual storms are going to move through,
nor how big those storms will be. It can't foretell the air and surface
temperatures each individual storm is going to encounter. There is no way I can tell how much snow will
be on the ground at any given time, nor the amount of snow that will fall from
a storm. The reason I give them is to
give you an idea what the winter will look like based the factors I've looked
at......basically a winter outlook is just a highly educated guess.
Conclusion:
Temperature:
Temperature:
I looked at past winters going back over 60 years. The winters I listed above matched up fairly well to the conditions I expect to unfold for winter 2015-2015. A positive PDO with warm sea surface temperatures in the waters of the Pacific Northwest up into the Gulf of Alaska. Featured a weak to moderate El Nino, and had high latitude blocking around Greenland.
The analog winters of 1958, 1964, 1966, 1970, 1977, 1978, 1979, 1984, 1986, 1994, 1996, 2003, 2010, and 2014....were some of the coldest winters in the last 60 years.
So based on this, I think winter 2014-2015 will be colder than average in the Northeast and Mid Atlantic. If fact, it could be a very cold winter. The exception will be northeast New England Mainly central and northern Maine. This area of the Northeast will see average to slightly above average temperatures. December into January could be above average to average; but for the end of January and especially for February it could be much colder than average.
Wintertime precipitation:
As for lake effect
snow....this year is shaping up to be average for those who live in the snow belts ,
leeward of both Erie and Ontario. I
expect to snowfall across the Tug Hill and other areas affected by lake
snow from Lake Ontario will see average
snowfall for the upcoming
winter. The same should be the case for
those areas impacted by Lake Erie in western New York and northwest
Pennsylvania. Lake snow is dependent on
wind direction, some areas might see higher than average amounts, but on
average the snow amounts region wide should be fairly typical .
With high pressure ridging out West and troughing in the
East, it's a pattern that will allow Clippers to move out of Canada. These should increase the odds for above
average snowfall .
We've already seen three fall
nor'easters this year. The reason for this is the weak El Nino taking affect in the Pacific. There is a very good likelihood this will be a weak
El Nino during
winter 2014-2015 , making the nor'easter
king. Based
on the likelihood this will be a very weak El Nino winter, we
most likely will see quite a few coastal storms during winter 2014-2015. The likelihood of at least one major coastal
impacting the major cities along the I-95 is fairly high.
Based on this, I feel seasonal totals across central and
eastern New York, much of New England, and the Mid Atlantic will see seasonal
snowfall that is above average...... ending up 25-45% above average. Of course
the track the coastal storms end up taking will decide who sees what. So again some
areas will see less snow than others, but on average region wide what I've outlined should be the case. When I looked back at the analog years, one thing I noticed was southern and eastern New England seeing more snow than average . So it is quite possible that southern and eastern New England could be very well, in fact it could be a near to record breaking season.
As for far northern New York, northern Vermont, New
Hampshire, into western and northern Maine average to slightly above
average snowfall looks more likely. so
average to perhaps 15% above seasonal averages.
I didn't have time to look up the seasonal averages for all
the cities in the Northeast or Mid Atlantic states. ... If You want, I will add
those either to this outlook or post them
in another post with a link back to this one. As always I welcome your questions.
