My first
winter update installment was issued well before any of the other outlets. I
also issued my official winter outlet near mid October. This outlook was also
ahead of most of the local and national weather outlets. Some of you have noted
that several weather outlets have updated their winter outlooks to look like
mine. There is nothing new in this post
that wasn't in my three preliminary and my official winter outlook. But I do
try to shed more light on why I think what I do. Here are the links to these previous outlooks
dealing with this winter.
The Euro
Weeklies show more cold than they did...but I think they are still under doing
the amount of cold for the first part of December. I still think a warm up is
coming Midmonth. Again, I think it will not be a blowtorch but surface
temperatures will still be above average.
I see
many are still freaking out about the coming warmth. I'm not sure why, the season is just in its
early stages. We all have to try and keep things in some kind of perspective.
We just had Thanksgiving a little more than a week ago. A Thanksgiving that saw
many long standing record cold temperatures get crushed. We've already had a
few Nor'easters, interior snowstorms, and some lake effect events. If what we've seen is a preview of the coming
winter (and I think it is) winter lovers have no reason for all the angst.
The vast
majority of the cold air in the Northern Hemisphere is and has been sitting
over North America. Canada is almost
completely covered with a snowpack and a
little more than a third of the CONUS has snow on the ground. So far November has brought the Northeast
overall well below average temperatures.
As I've
been saying for over a month, Arctic Sea Ice extent is expanding fast. Here are
a couple of Charts, showing we're seeing more ice than we've seen in a while.
In fact, we're on the cusp of seeing more ice than we've seen in 8 years.
Arctic Sea Ice is also much thicker then we've seen in recent years. So the
idea that the Northern Hemisphere, particularly North America is so cold,
shouldn't be a surprise. The reason for this is the negative looking Atlantic Multidecadal Oscillation (AMO).
Above
Images are from the Nansen Environmental & Remote Sensing Center.
When we
look at global sea surface temperatures (SST) charts; we see the cold signature
of a negative AMO. I will come back to the AMO in a bit, because it is going to
play a big part in the upcoming winter. We also see the El Nino looking very El
Nino Modoki like. There is also the cold east Indian Ocean and the warm blob
south of Alaska. All of these things
effect where the air will rise and where it is falling. When we have sinking air in the eastern Indian
Ocean; the atmospheric wave pattern is such, that we tend to see a trough over
eastern North America. The warm blob in the North Pacific and the Modoki will
work hand in hand to pump that western ridge. Again these are cold signals for
the Eastern CONUS. I will come back to
the Indian Ocean and the Warm Blob a little later.
The
pattern I've been talking about all year, is responsible for all we've been
seeing.
The
Northeast just saw the coldest Thanksgiving in at least a 100 years. This is
just a sample of the cold air that will be available for the pattern to tap
into for this winter. The combination of a negative AMO and a Modoki El Nino
will be a tag team for a lot of cold this winter.
Going
back and looking closer at some of the things above.
The El Nino-Southern
Oscillation (ENSO):
The ENSO
is about the temperature difference in the SST in a specific part of the
equatorial Pacific. If it's warmer than average it's called El Nino; if it's
cooler than average it is called La Nina.
El Nino and La Nina will affect our weather pattern in the East for
months at a time.
The ENSO
is still officially in its neutral phase.
But looking at the SST and subsurface temperatures we can see it is very
close. A El Nino could be declared a little before Christmas, if not then by
the middle of January. This is going to be most likely a weak El Nino; there is
a correlation between weak El Nino and above average coastal storms heading up
the East Coast. If the Cold locked up in
the North can coincide with the these coastal storms, snow lovers will be very
happy. This El Nino, looks to see warmer
than average SST near the Central Pacific instead of farther East and closer to
South America. So a Modoki El Nino is my
call for what is coming. I've had this idea since Spring, and I haven't changed
my mind yet!
We saw
very strong El Nino's in 1982-1983, 1997-1998 and 2015-2016. These El Nino's
kept the cold air locked up in the Arctic and allowed for a flow that had
systems from the Pacific moving straight across the CONUS. This is a pattern
that brings much milder than average conditions to the Northeast and Middle
Atlantic region. These winters also saw well below average snowfall. For the
winter of 2015-2016 Buffalo only received slightly more than 55 inches, which
is almost half of their normal average.
Above images come from the NOAA Earth System Research Laboratory.
Above images are from WeatherBELL Analytics.
I'm 95
percent sure we will see a El Nino Modoki this winter. This will promote troughiness over the north
central Pacific. Which will in turn set up a high pressure ridge over the West
Coast. This will split the Pacific flow and the storm track. The ridge will
displace the cold air to the north, and send it south toward the Great Lakes
and East Coast
The Warm Blob:
This
year's blob isn't as warm as the one we had, during the winter of 2014-2015. .
The AMO:
The Atlantic has a definite negative AMO look
to it. I've said it before, and I will
say it now. We're entering into a negative AMO.
Phases of the AMO last 20-40 years. The AMO has a big impact on Arctic
temperatures. This is because the Arctic is exposed to much more of the
Atlantic Ocean, than it is to the Pacific Ocean. Above, I've already talked about how Arctic
Sea Ice is rapidly increasing and that it is thicker than we've seen in recent
years. The reason the Arctic is freezing up faster, is because of the AMO going
into its colder phase. If you think about it; this explains a lot of what is
going on in the Northern Hemisphere.
The warm water off the East
Coast:
Those warmer waters in the Western Atlantic
will mean any storms moving up the East Coast will have a tendency to intensify
very quickly. The stronger the coastal low is, the more cold air it will pull
into the Northeast and Mid Atlantic Region. As the storm gets stronger it will
start to generate its own cold air. This
will help increase the odds and amounts for snow. With the trough looking to predominately set
up over the Great Lakes into the East, we will have a very active storm track
bringing storms to the Middle Atlantic and Northeast. Again more cold air with
increased chances for storms equals a greater chance for a snowy winter.
The Pacific Decadal
Oscillation (PNA):
The PNA
is going to be predominately positive this winter. When we have a PNA that is
positive we tend to see a ridge of high pressure over the West Coast into
Western Canada. The ridge in the West helps build a trough in the East. With the PNA positive it will amplify the
effects of the Warm Blob in the Gulf of Alaska.
The
Indian Ocean:
The
cooler water in the Eastern Indian Ocean is important as we move into Winter
2018-2019. Were we see colder sea
temperatures we tend to see sinking air over that area aloft. The water temperatures in the Indian Ocean
are a part of the MJO. Those cooler waters west of Australia will inhibit
convection (storms). Because of this the SOI will likely stay in the negative
numbers for a big part of winter 2018-2019.
The MJO:
A couple
of weeks ago the Madden-Julian Oscillation (MJO) did briefly go into the warm
phases 5 and 6 before shifting quickly back toward the colder phases. The Euro
and GFS are both showing as the MJO moves into and through the phases 7-1, it
will rotate once again into the warmer phases 3-6. But has it just did the MJO
quickly moves into the NULL and then back into the cool phases for this time of
year. Here is a look at the MJO phase
correlation charts. During November the cold phases are 7-1 are cold here in
the Northeast and Mid Atlantic. Whereas phases 4,5,and 6 are the warm phases.
As we move from December into January the impact from the MJO phase progression
shifts a little. So for January the cold phases are 8,1, and 2. As we move into February and March phase 3
will become a cold phase. If you've read my winter outlooks, then you know I
think the MJO will primarily stay in the cold phases for winter 2018-2019.
The MJO
has been hanging around in phases 7-2 a lot this year. During the hurricane
season this lead to Florence and Michael acting the way they did, and making a
U.S. landfall. As I said earlier the
impact of the particular MJO phase differs depending on the time of year we're
in. This time of year being in those
phases means the Northeast and Mid Atlantic region is cold. In my Facebook and blog post this year, I've
been taking a lot about the idea of a Modoki El Nino.
The MJO
is a wave of tropical activity that propagates (moves) eastward around the
globe. As the waves propagates it strengthens and weakens along the way. This
is where the MJO phase diagrams come in that I show all the time. These allow
us to see what each model thinks will happen with the MJO. The strength of the MJO is signified by how
much amplitude (distance) it is from the center of the diagram. The higher the
amplitude the more the impact is felt.
In the center of the diagram is where the MJO loses a lot of influence
on the pattern. When this happens, the
pattern kind of goes into a holding pattern. The pattern is then determined by
how strong and in what phase the MJO was in before it entered the low/null MJO
center. It's like when you put your song list on repeat. This is a very important concept to
understand. During La Nina the MJO is
very active and highly variable. But
during an El Nino Modoki, the MJO tends to become less active.
I've
talked about the weak El Nino Modoki and how the MJO has been staying in phases
7-2 a lot this year. Both of these
things tie heavily into how cold it gets this winter. During most of the Modoki El Nino's the MJO
likes to move into the null phase end of December into the first half of
February. This year we have a lot of
warmth in the Pacific, This could keep the MJO more active than a typical
Modoki El Nino. The pattern we've see with the MJO staying habitually in phases 8-3. These are the
colder phases during the heart of winter. But even if the MJO doesn't stay as
active as I think. The when MJO weakens,
the odds greatly favor the notion that we would be in a cold phase when the MJO
decides to go into the null phase. If this happens the winter would go into
that holding pattern, which in this case would mean temperatures for the heart
of winter ending up below to well below average for winter 2018-2019.
Where we stand now as
opposed to what my outlook released in October had to say:
Even
though it has only been a little bit over a month. There have been some big
changes in the SST setup. The equatorial
Pacific looks much more El Nino like.
The warm blob has expanded. and the Atlantic has cooled even more.
These are
all very important. Sea Surface temperatures are what drives the weather
pattern. This is because the oceans
cover 70% of the Earth's surface. The oceans absorb most of the Sun's energy,
and holds 99.9% of the thermal energy available to the overall global system. SST's help us figure out where the predominate
troughs and ridges will setup as we move forward.
The
Changes in Global SST's is very interesting. Right now, November of 2014-2015
is looking very close to the overall look we're seeing right now. For months 2002-2003 was running very close
to the current pattern, but now it appears that 2014-2015 very well could move
into first place, with 2oo2-2003 running right behind it. Both of those winters were brutal here in the
Northeast and Mid Atlantic. This would imply that a warm December into January could be in-store for us. We're seeing
seasonal temperatures right now, but as we saw in both of this analog winters,
we will see the warmth fade as the MJO propagates eastward. 2014-2015 was also when we saw arctic
incursions from the so called Polar Vortex.
The Jet Streams:
When we
transition from Fall to Winter, the northern jet stream becomes stronger. The
increase in wind speed has a major affect on the placement of the polar jet,
which in turn impacts the pattern. When the jet is displaced north in Canada,
the Northeast and Mid Atlantic tend to see warmer temperatures and more
precipitation. But when the polar jet is
weaker, farther south, and more amplified the Northeast and Mid Atlantic tend
to see colder winters.
The
developing El Nino will cause the southern subtropical jet to also be stronger
than normal. The developing pattern is
going to favor an active southern jet. This will have big implications for the
Northeast and Mid Atlantic states.
With the weak El Nino (most likely a Modoki El
Nino) and the warm blob in the North Pacific, there is little doubt that we
will see a persistent ridge in the West Pacific, which will extend over the
Northwest CONUS and into West Canada. This will force Arctic air over Alaska,
the Northwest Territories, and the Arctic southward toward the Northeast and
Mid Atlantic region.
So now what?
As I said
I haven't changed my mind on what I think winter 2018-2019 hold. I've gone into
a lot of detail on weak El Nino's, the Warm Blob, MJO and others that show how
these things are linked to cold and stormy conditions in the East.
Based on the above factors the predominate 2018-2019 winter pattern should look close to this.
We've
seen that the pattern that is in place is capable of delivering extreme
cold. If the arctic outbreak had
occurred in December or January, we most likely would've seen temperatures
20-40 degrees lower than they were on Thanksgiving. The pattern is going to be
very capable of delivering cold and snow this winter. As I said on my Facebook Northeast Weather
Page, I think the odds that many of us have a White Christmas this winter is good.
The
pattern is still reacting to the daily changes to the winter jet stream setup.
so we're seeing daily variations in the overall pattern. But as things settle
in, the pattern should turn the way I've been laying out of months. The
date I posted this was 11/30/2018 after an remarkably cold and snowy November,
we're heading into a very brief warm up for the first weekend of December. But
the cold comes back. Typically weak to moderate El Nino's see at least some warming in December. The 4-10
day of December could see a couple of snowstorms, depending on temperatures. Based on what is going on, I think we will see
some warming around Midmonth But then mid to end of January into March gets wild, with more in the way of cold and becoming very
wintery. We should see persistent dips in the polar jet will lead to a active
storm track. There is a good chance for seeing a split flow in the Jet, with an active southern half, with the northern half bringing cold. This would allow for southern storms and Coastal s. This is why my snowfall map is showing heavy snow across the Virginia's and Carolina's November going into
December for the analog years of 1977,2002, and 2014 looked very similar to
what is going on right now. This winter
will be overall quite cold with above average precipitation snow, mix, and
rain. Also as I've said before there
will be a heightened risk this winter for a moderate to heavy ice storm or two for
parts of the region. Here are the
temperature and snowfall maps I produced back in October. I have made no
changes.
Temperature
Wintertime Precipitation.
