Christmas Day Snow, 2012 in Seabeck.
Photo by Don Geidel
Alright, I have put this off long enough! Time to do my yearly
ritual of witchcraft–erm, I mean, long range forecasting.
Let’s make this clear from the beginning: There are many
variables to consider when making a forecast that extends months
into the future; weather forecasters struggle enough to get
tomorrow’s forecast right. Among the most popular ways to determine
long term trends are ocean temperatures, which can play a
significant role in what kinds of land temperatures and
precipitation will be most prominent during a given season.
At the present, the north Pacific Ocean is in a cold phase,
which has correlated to cooler, more active weather for the
West in the past, but isn’t necessarily a determining factor.
In addition, the equatorial Pacific can give us an even clearer
look into general seasonal weather patterns, from the development
of an El Nino event, which leads to warmer and drier conditions for
the Pacific Northwest, or a La Nina pattern, which brings colder
and wetter weather. Unfortunately, neither of those patterns
will be able to help in this year’s forecast because we are
witnessing the rise of what is unofficially known as La Nada.
That’s right: no warm signals and certainly no cold signals. It’s
no wonder meteorologist call this pattern a “wild card”.
Let’s revisit what analogs are and why they might be useful in
constructing a forecast.
Analogs are past years that exhibit some similar weather
activity to the current year, and as a result weather forecasters
try to match up the past with the present to see if there’s
some type of correlation or pattern occurring. More often than not
it’s just a guide, but sometimes history does repeat itself.
Other reliable pieces of data essential for producing a long
range forecast is the ONI, or Oceanic Nino Index to track what El
Nino, La Nina or neutral years in the past match up similarly to
the present day. The records I have go all the way back to
1950. Solar activity can be another major factor to the weather
over the years, but I haven’t weighted that heavily enough in my
forecast mainly because of the lack of data. Lastly, I used the PDO
readings (Pacific Decadal Oscillation) to finalize my findings.
Here are some of the top corresponding years:
2012 (interestingly enough)
If any of you remember the winters of 2012-2013, 1990-1991 or
1978-1979, you will recall that there’s a healthy mix of benign
weather (dry, mild, no snow) and awesome
weather (arctic intrusions, buckets of snow). As it so
happens, that’s probably the best description of what to expect
There are some strong signals indicating December will, once
again, provide us with some of the best opportunities for some
chilly weather, but perhaps not the most ideal for snow. The
reemergence of a pretty healthy ridge will limit the amount of
precipitation we receive, but not for long. After a generally
pleasant beginning to the month, there are signs that the jet
stream will gradually begin to sag south and west, bringing in a
decent shot of cold and moist weather. Could this result in a
repeat of last years white Christmas event? The chances are, of
course, very low, but it looks like we could at least be heading in
the right direction. Temperatures will average a couple degrees
below normal with precipitation right around average, if not a
January, as a whole, looks downright chilly for most of the
country, with very little in the way of temperature fluctuations.
An active jet stream and negative PNA (Pacific/North American
teleconnection pattern) should also increase the mount of
storminess on the West Coast with plenty of mountain snow and
several shots at lowland snow. This doesn’t look like a pattern
conducive to too many “Pineapple Express” systems, however, so
precipitation likely won’t exceed average by much if at all. The
coldest and stormiest periods will be between the 1st and the 15th
with a gradual change for the drier by the end of the month.
February, as has been typical in the Northwest for quite some
time, will be drier than normal, but this time with a twist: It
also looks a bit chillier than normal. This will be primarily due
to cold overnight low temperatures, as most daytime temperatures
should average at or slightly above normal. The most active weather
will be found further east as the PNA shifts to a positive phase
and the North Atlantic Oscillation, or NAO, takes a plunge.
However, it looks like we could run into a few “overrunning” events
along the Hood Canal as we switch to some milder weather towards
the end of the month.
After a chilly start, we’ll likely see fairly tranquil
conditions be the dominant feature through March with below normal
precipitation. In fact, we could see some record high temperatures
towards the end of the month.
So there you have it! A pretty cold and active beginning to
winter with a gradual change to milder and drier weather. We’ll
check back in once spring rolls around to see how I did.
Have a great weekend, and stay warm!
Questions? Comments? Photos? E-mail Matt Leach at: