A couple of
weeks ago, I posted on my Facebook weather pages, dealing with my preliminary
outlook and why my outlook is so different from so many others. I received flak
for that post....and I most likely will receive some because of this post. But
that goes with the territory and I'm used to it.
This post
will add to the preliminary outlook, showing more of my thinking and what the
pattern looks like right now, and seems to be heading.
The El Nino
Southern Oscillation (ENSO):
ENSO 4 is
starting to get very warm. The ENSO 1+2 is still cooling. This puts more
credence into my idea of a Modoki El Nino will be in place later this fall and
winter. As I've been saying for a long time, the odds favor a weak El Nino
event. The warmth should start to extend into ENSO 3.4 at some point. But there is a chance El Nino doesn't form, meaning we would see El Nino
neutral conditions. Typically we see a more active southern sub-tropical jet
during a El Nino Modoki than we do during a regular El Nino. The added lift the
Modoki adds to the jet pattern, does increase the odds somewhat for East Coast
storms.
I've said
repeatedly there are different flavors of El Nino's and no two are exactly
alike. I've also said, there are big differences between a normal El Nino and
an El Nino Modoki. But on average this is how they work out.
Other
Teleconnections:
The Quasi-Biennial
Oscillation (QBO):
January to
July the QBO was strongly negative (east based). If this continues into winter it's a good indication for a colder than average December - February.
When the QBO
is easterly, the northern jet is typically weaker; This increases the odds of
sudden stratospheric warming (SSW)events to occur. When we have a SSW event the
polar Jet often weakens (this jet is often called the polar vortex); this leads
to the likelihood of cold polar air to break off and spiral southward into the
Midwest and Northeast. An easterly QBO increases the odds for more frequent
negative Arctic Oscillation (AO) outbreaks which further increases the odds for
a colder than average December through February. There is a strong correlation between a
weak/neutral ENSO and an east based QBO to colder winters here in the Northeast
and Middle Atlantic.
A negative factor for cold this upcoming winter will be the fact that we look to have an east based QBO with an El Nino. El Nino's tend to negate the influence from the QBO. But this being a Modoki El Nino it will help offset that impact somewhat.
A negative factor for cold this upcoming winter will be the fact that we look to have an east based QBO with an El Nino. El Nino's tend to negate the influence from the QBO. But this being a Modoki El Nino it will help offset that impact somewhat.
Here is an
image that shows how we fair during a normal and Modoki El Nino event. I also
show how east based QBO of various strengths impact the region.
Arctic
Oscillation (AO):
The AO
measures the differences in atmospheric pressure between the Arctic and
mid-latitudes. As all oscillations it has a positive and a negative phase. In
the positive phase arctic air on average stays locked up to the north. Whereas
the negative phase on average sees a greater likelihood of more cold arctic
outbreaks. In this regard it would work with the Modoki El Nino and QBO helping
to up the odds for a colder winter.
Pacific warm
spot:
We have that
blob of warm SST south of Alaska. This is a good sign that we will see upper
level ridging develop in western Canada. This would also up the odds for colder
air in Siberia and northern Canada to flow downstream along the trough that
extends eastward. How far eastward is
one of my biggest question marks right now. One other thing about Modoki El
Nino's is they also help punch that upper level ridge pattern over the West
Coast.
Sunspots:
It's been
awhile since I've talked about solar activity and its impact on global weather. But as I've said before, the sun and solar
activity do play a big role in terrestrial weather and climate. There is
correlation between low solar activity and upper latitude blocking near
Greenland and Iceland. Given that we're
heading into the minimum those odds do
increase. The last time we were in a
solar minimum phase was 2007 to 2009.
The winter of 2009-2010 also had a somewhat moderate El Nino. That
winter saw a lot of cold and snow in the Mid Atlantic Region.
Great Lakes:
Lake Erie
and Lake Ontario are very warm. Lake Surface temperatures are in the 70's. This
will play a role in the upcoming winter as well, especially during the first
half of winter as cold air moves over those warm lake waters.
Atlantic Mult-decadial
Oscillation (AMO):
I've been
talking a lot about the AMO. I do believe the pattern in the North Atlantic is
showing a change occurring in the AMO. This cool ring in the northern Atlantic
is further evidence for a cooler winter for the East Coast along with Europe. The increasing snowpack over Greenland and
those cold SST in the far northern Atlantic are a sign that the AMO is
switching from a positive AMO to a negative AMO. If this is indeed the case; we
could be on the cusp for many colder winters in the years ahead.
As a side
note the winter of 2002-2003 is one of my analog years. Right now, the pattern
is closely matching up with that winter. If this continues it could mean a bit of warmth during December. But 1977-1978 was another analog, that stayed cold from November to March....so we will see.
Remember
this isn't a real outlook/forecast. This is only where my thoughts are right
now and some of the things I'm looking at and considering as we move along. it
is all subject to change as things evolve and the pattern adjust. But I think October will see a big turn toward cooler weather, with perhaps many of us seeing our first snows of the season.
I will stop
here; but I will in all probability release one more post dealing with more signals
on where we are heading and how I think that will work out, before I release my 2nd
winter outlook for the winter of 2018-2019. I still plan on releasing my final
winter outlook end of October or the first part of November.
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