Winter 2009-2010: Get Ready
for a Winter of Extremes!
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Alright…what’s it gonna be? Snowy? Cold? Warm? Wet? Dry? We’ll
find out after this long commercial break!
Just kidding 😉 After months of research and preparation I have
finally completed my winter outlook for the nation with specifics
for Western Washington and Oregon. I realize I have readers from
all across the country, so if you would like any specifics for your
area that are not covered in this blog post, feel free to drop me a
comment or e-mail and I’d be happy to provide some insight.
A little disclaimer here: this forecast should not be taken as
gospel. It is quite common for people to take forecasts like this
and expect them to verify word for word. Long range forecasting is
an imperfect science, but I believe there are enough signals out
there that can point to a long range pattern or trend
developing.
Such is the case this winter. We’ve (the
Northwestern region of the U.S.) had a ridiculously
wet fall after an anomalously dry late spring/summer/early fall.
However, storms have been in abundance since May with several
thunderstorms/funnel clouds reported all over the Northwest. This
is highly unusual. Western Washington averages about 2 funnel
clouds/tornadoes a year…we had 2 in just 2 months.
NATIONALLY
Another noticeable quality about the weather lately is the
extreme nature of the weather trends. I expect this same pattern to
continue through Winter 2009-2010. The nation as a whole will
see more snow and ice storms than usual, particularly in the
country’s mid-section. The East and West Coasts, however, will
average about normal storm-wise, though this can be a bit
misleading when just looking at the maps and I’ll explain in just a
moment.
The southern portions of the U.S. will experience more tranquil
weather than the rest of the country, especially in the southeast.
Normally an El Nino winter would equate to cooler and wetter than
normal conditions in the southeast. Not this year. According to my
research, expect drier and milder conditions with mild, but wet
conditions in the south/southwest. Overall, severe
storms will be lacking all across the south.
From coast to coast, the cold and warm air will be distributed
fairly evenly, however the east coast looks to be a bit more prone
to ridging and mild weather, especially in January.
Overall, expect a colder and wetter than normal winter for much
of the nation excepting the far west and east coasts and southern
tier states.
LOCALLY
My forecast for the Northwest from
December-February is calling for extremes in
temperatures and precipitation, with stretches of unusually cold
and wet weather for the first half with unusually dry and mild
weather the 2nd half. When all is said
and done, both ends of the spectrum will be so extreme, it will
even out to “average”, This winter will likely be
warmer and drier than the last 2 winters, however.
Mountain snow fall
will be above normal, averaging anywhere from 120-150% of normal.
Lowland snow fall looks to be above normal as well with a
Seattle/Portland snowfall depth average of
8”.
Despite the moderate El Nino, the Pacific SST’s
(Sea Surface Temperatures) and PDO (Pacific Decadal Oscillation)
are in a negative phase and look to balance between weakly negative
to neutral through the season. That along with an unusually strong
Pacific Jet could very well increase our chances of
receiving greater amounts of snow and rain than in a typical
El Nino year, at least during the first half of winter (Dec and
Jan).
My main analogs are 2006, 1968 and 1965, 2006
being weighted the heaviest. These analogs match closely with our
most recent summer/fall pattern and I believe they will continue
this winter.
DECEMBER: This month looks to
feature less rain than November, but it will still average close to
normal precipitation wise. Temperatures will be fairly chilly,
however. I expect the monthly temperature to average below normal
between 38-39 degrees. The month as a whole will feature a
handful of dry, but chilly, overcast and sunny days, so there will
be plenty of opportunities to get outside! I also see the
strong potential for storminess at the beginning of the month,
but the Jet should relax as the month wears on.
(Temperature Average: 38.5 degrees–1.5 degrees below normal.
Precipitation Average: 5”–0.62” below average) Month Snow Chance:
80%
JANUARY: This will likely be our
most active month. I expect our first real cold outbreak to
occur during this month along with periods of snow.
However, once the cold arrives I see it being a “dry
cold” with most snow occurring during transitional
phases (before/after warm air overrides cold air). I
also expect a fair amount of storminess this month as the
Pacific Jet kicks back up again. Towards the end of the month,
however, El Nino will really ramp up with an impressive amount of
warmth overtaking a good portion of the nation, especially the
Northwest. Temperatures will average near normal with
precipitation above normal. (Temperature Average: 40.0 degrees–0.9
degrees below normal. Precipitation: 6.50”–
1.37” above normal)
Month Snow Chance: 90%
FEBRUARY: Looking for a break
from the rain, cold and snow? This month will be a classic El Nino
month: very mild and dry. I see a lot of record high temperatures
being broken this month. A lot of folks will likely be tricked into
thinking spring is coming early as many will note the lack of
precipitation and cold weather throughout the month. Overall, a
“breather” month for non-active weather fans 😉 (Temperature
Average: 45.5 degrees–2.1 degrees above normal. Precipitation
Average: 1.50”–2.6” below average) Month Snow Chance:
30%
MARCH: The weather will ramp up
again after a “brief” lull. A few early month storms will come
crashing into the Northwest, followed by some anomalous cold and
snow. By mid month, however, we should dry out and warm up, forcing
monthly average temperatures to end up above normal. Precipitation,
however, looks above normal. (Temperature: 47.2 degrees–1 degree
above average. Precipitation: 4.50”–0.75” above normal) Month Snow
Chance: 70%
So there you have it! The pendulum will continue
to swing this winter. We’ll check back in April to see how I
did!
Comments, questions and/or suggestions are always
welcome so feel free!
Have a great evening,
Matthew Leach
Forecasting
Kitsap
E-mail:
forecastingkitsap@live.com
