Weather Blog

2010 weather in Seattle: An odyssey in meteorology

2010 weather in Seattle: An odyssey in meteorology
A sledder starts downhill after a push as the Space Needle is seen behind Tuesday, Nov. 23, 2010, in Seattle's Gasworks Park. (AP Photo/Elaine Thompson)

SEATTLE -- 2010 might best be remembered for the winter that was spring-like, and the summer that was fall-like, except for the days when it was Arizona-like, and the Thanksgiving that was Christmas-like and every other holiday (and I mean literally *every* other holiday) where it rained and was very Seattle-like.

The year began with a mild whimper. With El Nino conditions entrenched, January ended up being the warmest on record at 47.0 degrees for an average temperature, besting the previous record of 46.6 degrees in 2006.

About the only excitement for January or February were upper level windstorms that brought hurricane-force winds to the Columbia Gorge and to the Olympic Mountains. On Jan. 10, gusts over 100 mph were reported at Crown Point, threatening to steal the title of "Hurricane Ridge" from its Olympic Mountain counterpart.

But the next day, Hurricane Ridge re-exerted its dominance with a several hour period of 100+ mph gusts, including a gust to 115 mph.

Jan. 10 -- "Hurricane Ridge" has some competition
Jan. 11 -- Hurricane Ridge to Columbia Gorge: Pbbbbbbtt!

On Jan. 18, a more traditional wind storm struck the lowlands with gusts to 50-60 mph, mainly in the north interior with Bellingham reporting a 61 mph gust and Everett a 60 mph gust. Gusts to 49 mph were also reported in the foothills. Damage from falling trees and power lines was estimated at $93,000.

Jan. 18 -- How windy did it get on Jan. 18 storm?

On March 8th, for the first time since mid-December, a few snowflakes were spotted in some spots around the Puget Sound area. Snowflake reports came in from the greater Tacoma area, Bellingham, Oak Harbor, Federal Way, Shoreline and even the U-District, but nothing accumulated.

The following night, temperatures dropped into the 20s to low 30s, causing a few slick roads.

Mar. 8 -- Snowflakes fly, but no need to consult 'snow panic' manual
Mar. 9 -- How cold did it get?

Where's The Snow?

It turns out, that would be it for snow that winter, and Seattle tied with 9 other winters that only managed to record just a Trace of snow observed. In fact, Houston had a snowier winter than Seattle, since they managed to accumulate 1" during a winter storm there.

Mar. 10: Seattle ties record for least-snowiest winter

Attention turned from snow to wind again as spring approached and another windstorm waded through the Northwest on March 16.

Gusts registering 60 mph forced the closure of the Hood Canal Bridge for two hours, as wind-whipped waves blasted across the roadway. Closer to Seattle, a large sailboat sailing in Elliott Bay off West Seattle's Beach Drive ran aground when the winds picked up to 53 mph, requiring assistance from the Coast Guard. Crews eventually freed the boat from the rocks and were towed it back to shore.

Mar. 16 -- Gusty winds cause problems across Western Washington

Proof Headlines Can Jinx Seattle Weather

On March 19, temperatures warmed up as we reached the equinox. Seattle climbed all the way to 67 degrees. A few days later, we reached a record high of 68 on the 24th.

But in retrospect, the headline I chose for the story is dripping with irony in light of what would happen later in the spring. Little did I know...

Mar. 19 -- Seattle skipping spring, going right to summer?

A week later, it was back to the rain and wind more potent storms rolled through. On March 28, winds of up to 58 mph blew in these regions and produced about $2,000 in damages to small structures. Five days later, another storm caused $90,000 in damage

Mar. 28 -- Nature's blockbuster trilogy: Rain, wind and mountain snow
Mar. 28 -- Stormy Stats
Apr. 1 -- No foolin': Mother Nature sends another potent storm
Apr. 1 -- Meteorological Mumbo-Jumbo of Apr. 1 Storm
Apr. 2. -- Wayward April storm hops into Western Washington

Seattle...... Suuuuupppppppeeeerrrrr Con..vergence Zone... (Reference to Headline :) )

On April 21, Seattle was hit by what we called a "Super Convergence Zone" when a batch of rain that moved up from a low in California combined with the colliding winds of a Puget Sound Convergence Zone to add some extra oomph. Seattle received nearly 1" of rain between midnight and sunrise!.

April 21 -- It's a bird. It's a plane. It's a... Super Convergence Zone!

They say April showers bring May flowers, but the petals would have had a tough time staying attached as more windstorms rolled through the region. And then on May 4, it was hail that was the problem as a sudden hail storm snarled traffic on I-405.

May 2 -- 7 weeks to summer…and here comes another storm
May 3 -- Rare May storm knocks out power to thousands
May 3 -- Spring storm brings more wind, rain
May 4 -- Sudden hail storm snarls traffic on I-405 in Mill Creek
May 18 -- 'May'-what? Yet another late windstorm takes aim at Northwest

That last storm would strike on the afternoon of the 19th. But amazingly, if you were out that morning, you'd have never thought a storm was coming. The city went from blazing sunshine to pouring rain within an hour:

May 19 -- From May to November in 2 hours flat

That storm would go on to produce a tornado in Moses Lake:

May 19 -- Moses Lake Tornado

A Loooooooong Wait For Our First 75-degree Day

By late May, we started to notice something -- it hadn't really been all that warm yet despite being less than a month from summer. It turned out we hadn't hit 75 degrees yet.

And the wait would be long. In fact, Anchorage and Iceland hit 75 before we did this year. And it turned out that we wouldn't get there until June 23 -- two weeks later than we had ever been so late to the 75 degree party.

May 25 -- 75 degrees -- rarer than the Loch Ness Monster?
May 28 -- Seattle, now the nation's ice box.
June 11 - 'Juneuary' a more apt name for this month than you might think
June 23 -- So this is what 75 degrees feels like?

In the middle of waiting out the first 75, stormy weather was still pestering us, including a funnel cloud spotted over Monroe on June 4 and a big thunderstorm outbreak on June 9.

June 4 -- Funnel cloud over Monroe
June 4 -- Weather Service: Monroe funnel cloud was not a tornado
June 9 -- Spring storms wreak havoc across Western Washington

On June 15, an incredible rain squall drifted right over Marysville, and one home weather station reported 1.40" of rain in 19 minutes! It's not an official report, but there is some visual evidence of just how wet it was.

June 15 -- The wettest 19 minutes you'll ever see?

It Wasn't That Hot of a Summer, Except When it Was

As we headed into July, that whole "Where's the 75?" was a thing of the past as the season's first heat wave was upon us. Temperatures would soar into the 90s for three days, including a record 95 on June 8.

As we went into August, our second heat wave hit, again sending temperatures over 90 for three days in a row in Seattle. It was the first time Seattle had two separate heat waves with 3 days at 90 or hotter.

The six days over 90 was well above the average of 3 a year, but aside from those very hot days, the rest of summer was fairly benign.

Jul 6 -- As temps rise, heat records in danger of falling
Jul 8 -- Record-high temps bring free outdoor sauna
Jul 9 -- One more hot day, then a gorgeous weekend
Aug 13 -- Break out the flannel swimwear? The 90s are coming back
Aug 15 -- Thermometer reaches lofty heights for second day
Aug 16 -- Another hot day on tap, but cooler weather is in sight
Sept. 30 -- Summer temperature recap

On Sept. 1, a routine cold front moved through dropping about 0.50-0.70" of rain around the Sound and then it was a dry afternoon. Except for one minor detail -- a stubborn and persistent convergence zone set up shop right over Everett, bringing hours of relentless rain.

When it finally fizzled, Rainfall totals exceeded 2" in spots around Everett. It's events like these that help balance Everett's missing rain from when the Olympic Rain Shadow extends east into Snohomish County. It turns out Everett and Seattle have nearly identical annual rainfall averages, but they get their rain in different ways.

Sept. 1 -- Oh, that wascally Convergence Zone!

Rainy Days and Off Days Always Get This Town

Quick interlude: What do you call three days of rain in Seattle? A holiday weekend.

Never was that more true in the summer of 2010, where it poured rain on all four of the major holidays (well, counting SeaFair) Memorial Day? 0.31 inches of rain, a high of 65. Fourth of July? 0.11 inches of rain, a high of 65. Seafair Sunday? 0.19 inches of rain, a high of 66 (heat wave!) And now Labor Day: 0.12, high of 61.

And actually, it turned out that every major holiday in Seattle had rain.

Sept. 6 -- Seattle makes do with yet another soggy holiday.

A few weeks later, a Seattle-esque rainy and 60 was probably preferable to the Atlanta-like mugginess on Sept. 27, when the average dew point was 63 in Seattle, reaching a peak of 66 degrees during the day. That made it the most humid September day ever.

Sept. 27 -- Monday was Seattle's most humid Sept. day ever

Stormy Season Begins Right On Cue

October brought its usual quota of wind storms -- one that brought a 43.3 foot wave 300 miles off shore and 30-foot waves to the coast as a very deep low pressure system on par with strong hurricane (28.47" of mercury, or 964 milibars) swirled out off Vancouver Island.

Oct. 22 - Storm brings rain, wind, and really, really big waves.

Oct. 24 -- Blustery day to kick off the fall stormy season

Oct. 25 -- High surf pounds coast; heavy snow falls in mountains

The storm also produced what might qualify as the weakest tornado ever, as it hit just outside of Toledo. Damage was limited to some tree branches and some deck plastic. Official damage was estimated at $1,000 but sounds like that was pretty generous.

Oct. 27: Weak tornado touches down near Toledo

Feeling Hot, Hot, Hot! Then, Ice, Ice Baby!

November brought quite a dichotomy to the city, starting out quite warm. In fact, on November 3, Seattle tied its hottest day ever with a 74 degree reading -- some thick irony considering how difficult it was to get to 74 in May and June.

After the "heat wave" was over, it was time for another windstorm that seemed to form out of nowhere and blast through the Puget Sound area on Nov. 15. Wind speeds themselves weren't that impressive -- mainly 40-50 mph, but with the wet soils combining with it being the first true storm of the year, it took out a lot of the weak growth from the summer. Over 200,000 people lost power and it would go down as the worst windstorm by damage since 2006 and 14th worst sine 1984.

Another wind event came two days later on the 17th.

Nov. 3 -- Seattle ties for hottest November day in city's history
Nov. 15 -- Now this is November -- windstorm batters region
Nov. 15 -- Wind storm stats
Nov. 17 -- Another day, another windstorm in Western Washington
Nov. 17 -- By damage, Monday's windstorm was worst since '06

Then the weather got downright wild with a snowstorm in Bellingham on the 19th -- the "canary in the coal mine" to the arctic blast the rest of Western Washington would get a few days later. Winds gusted to 60 mph in Bellingham and the San Juans. Winds also gusted in the Puget Sound area a few days later -- mainly Kitsap Peninsula -- and another 80,000 went into the dark just before the Thanksgiving holiday.

Nov. 19 -- Bellingham blanketed in region's first snow storm
Nov. 20 -- Winds pick up as W. Wash. awaits Act II of weather drama

Anyone Still Commuting Home From Nov. 22?

Then, the region's first major snow event since December 2008 struck on Nov. 22, just days before Thanksgiving. Most places ended up with 1-3" but parts of the Olympic Peninsula got nearly a foot of snow.

But for Seattle, it made for a nightmare commute. The snow began falling in the early afternoon and by evening, the entire region was coated in snow. But as the snow stopped, the temperatures quickly plummeted into the 20s, turning roads into sheets of ice and bringing the city to its knees.

As articulated buses and semi trucks jackknifed on the slippery roads, portions of I-5 and SR-520 became hours-long parking lots. Stories of being stuck on the road for 8-10 hours were not uncommon. Perhaps the worst was on the southbound lanes of I-5 near MLK Jr. Way, where a jackknifed bus and several spinouts shut down the freeway well into the pre-dawn hours.

In the wake of the snow, temperatures continued their plummet to where lows were in the single digits and teens and highs didn't make it out of the 20s. It was so cold that Seattle ended up being several degrees colder than Barrow, Alaska.

Seattle's low of 14 on Nov. 23rd made the 60 degree spread between the 74 degree high on Nov. 3 the largest temperature spread ever within one month.

Nov. 21 -- Snow pays a visit to a few places; more on the way?
Nov. 22 -- Snow, wind, ice make for hours-long commutes
Nov. 23 -- How did we end up colder than Barrow, Alaska?
Nov. 23 -- Out of the snowfall, into the ice box

On Dec. 8 an intense squall line of thunderstorms pushed through the region, bringing winds of 50 mph and snarling the commute -- and of course, making for a spectacular light show.

Dec. 8 -- Thunderstorms drench morning commute
Dec. 8 --- Scenes from thunderstorms

Aloha, Oy!

A few weeks off the region's first snow storm in two years, the region's first Pineapple Express rain storm hit on Dec. 12.

Rainfall of 6 to 11 inches in the mountains and 1 to 4 inches in the lowlands occurred. Flooding was widespread with record flooding on two forks of the Stillaguamish River and five rivers exceeded major flood category including the Snohomish, Snoqualmie and Skokomish Rivers.

A total of 17 main stem rivers exceeded flood stage. The heavy rain amounts also resulted in a number of smaller streams to rise over their banks as well as urban flooding of a number of roadways. Over 50 landslides were reported -- some closing state and local highways as well as the main north-south rail line.

Dec. 12 -- Rescues, evacuations as drenching rains target W. Wash.
Dec. 13 -- Flooded rivers cresting, but problems remain
Dec. 15 -- Stormy tidbits from flooding storm

There's An East Wind A'Blowin...Rather Strong We Might Add

Wind became the major issue again on Dec. 17 when a strong east-wind event struck the Cascade foothills. About 112,000 lost power as winds gusted to 60-73 mph.

Dec. 17 -- Strong winds down trees, power lines in foothills

There was no White Christmas this year, but the year did finish off on a chilly note as a Convergence Zone dropped anywhere from 1-5" of snow around the North Sound areas, while the foothills and South Sound were dusted with an inch or two of snow as well.

And as a parting shot of the system, the South Sound was covered in a strange Styrofoam-like snow pellet known as graupel.

Dec. 29 -- Snow pummels North Sound today
Dec. 29 -- Hail, lightning, freezing temps give Sound second punch.

December would end up with 8.69" of rain -- the 7th wettest on record. But believe it or not, Seattle wasn't the wettest large city on the West Coast. That "honor" went to Los Angeles, which recorded an amazing 8.83" of rain at LAX.

Dec. 31 -- Seattle in December: Drier than Los Angeles

In Summary

Seattle ended up the year quite wet, finishing with 46.99" in the rain gauge -- nearly 10" above the normal 37.07". That's thanks to the 4th wettest September and 7th wettest December on record. Eight daily rainfall records were set, with those eight days accounting for 18% of the year's rainfall.

As for temperatures, when combining the mild start to the year, the cool spring and November, and average December, temperatures in Western Washington were about one degree above normal for the year. Most of the record temperatures set during the year were high temperature records with very few record lows set.

2010 Year End Statistics For Seattle

  • Annual Rain: 46.99". (Average: 37.07")
  • Number of days with measurable rain: 190 (average: 154).
  • Number of sunny days (0-30% cloud cover): 40 (average: 58)
  • Number of partly cloudy days (30-70% cover): 164 (average: 81)
  • Number of overcast days (>70% cloud cover): 161 (average: 226)
  • Number of days 80 degrees or hotter: 21 (Average: 25)
  • Number of days at 85 or hotter: 11 (Average: 10)
  • Number of days at 90 or hotter: 6 (average: 3)
  • Number of days at 95 or hotter: 3 (Average: one every other year)

Seattle Monthly Rain +/- Normal Avg. Temp +/- Normal
January 6.17 +1.04 47.0 +6.1
February 3.52 -0.66 46.8 +3.5
March 3.76 +0.01 47.0 +0.8
April 3.49 +0.90 49.5 -0.7
May 2.83 +1.05 53.2 -2.6
June 2.49 +1.00 58.3 -2.4
July 0.31 -0.48 64.5 -0.8
August 0.64 -0.38 65.4 -0.2
September 4.80 +3.17 60.9 -0.2
October 5.24 +2.05 53.3 +0.6
November 5.05 -0.85 43.2 -2.0
December 8.69 +3.07 43.2 +2.5
Annual 46.99" +9.92 52.7 +0.9

Record Highs for Seattle:
Jan. 13: 56 (Tied)
Mar 24: 68
July 7: 90
July 8: 95
July 9: 93
Aug 14: 95
Aug 15: 96
Nov 3: 74

Record Lows:
Mar. 9: 28 (Tied)
July 13: 50 (Tied)
Nov. 24: 14

Have a happy and safe 2011!