The National Weather Service issued a “High Wind Watch” advisory Thursday afternoon (April 1), and unlike some of our earlier stories, this one’s no joke – expect wind speeds between 35 and 55 MPH beginning around 10am Friday, April 2nd.

This means that there could be downed trees, power outages, road hazards, and of course, messy hair aplenty.

It also means snow and high winds in the mountains, along with treacherous pass conditions, so be careful if you’re traveling anywhere for Easter weekend.

Here’s the language the weatherfolk are using:

…High wind watch remains in effect for the greater Puget Sound region…east Puget Sound lowlands…and the lower Chehalis valley from Friday morning through Friday afternoon…

A high wind watch remains in effect from Friday morning through friday afternoon. * very strong…possibly damaging…south winds may develop along and behind a cold front on Friday…over portions of interior Western Washington.

There is still some uncertainty as to the exact track and depth of the associated surface low moving near or just north of washington. At this time…the most likely scenario would generate south winds of 25 to 35 mph with gusts up to 55 mph.

However…if the surface low deepens more than expected…wind speeds could reach close to high wind criteria. Therefore the high wind watch remains in effect until details are more certain. * the very strong winds could result in some power outages across portions of western washington friday afternoon and evening due to power lines being damaged by tree limbs. Some of the regions trees have begun to leaf out already…which could add to the potential for wind damage to occur. Rain soaked ground could allow trees to easily topple or become uprooted.

Precautionary/preparedness actions… A high wind watch means conditions are favorable for damaging winds. High winds can topple trees…down power lines…and damage some structures.

• Confidence is high that strong winds and heavy snow will affect the mountains.
• Confidence is high that damaging winds will affect the Washington Coast and North Interior
• Confidence is only moderate that damaging winds will affect the Central Puget Sound area

A strong spring storm system will develop offshore and rapidly move through Western Washington Friday

• Strong and damaging winds are expected, especially along the coast and in the northern interior of Western Washington
• Trees have begun to leaf out, so there is a greater likelihood of downed limbs and trees
• Heavy mountain snow of 1 to 3 feet is expected in the Cascades and Olympics above 3000 feet.
• Increased avalanche hazards in the Cascades and Olympics
• Heavy rainfall at lower elevations of the Southern Olympics will cause rises on the Skokomish river, though flooding is not expected at this time. Other rivers will not flood.

Bulk of Puget Sound area and Southwest Interior: S to SW 35 (with) Gusts of 55 mph beginning 10 AM PDT

For the latest updates, check out the National Weather Service’s Seattle-area website here.

We’re pretty sure that the last time a tsunami hit the northwest coast of the U.S. was in 1964, shortly after a major earthquake struck Alaska; far as we know, it damaged some places on the Oregon coast, including Cannon Beach.

Saturday morning (Feb. 27th), imagine our surprise when we saw an “Advisory” posted in our Weather Widget in the right sidebar. Clicking on it revealed that yes, a “Tsunami Advisory” had been issued for the northern and central Washington coast after a huge, 8.8 quake hit Chile´.

We don’t think this is cause for panic in the Puget Sound region, but we wanted to share this info because, well, who knows – maybe a small, tsunami-based wave will hit the shorelines near Des Moines late this afternoon? Maybe not?

The advisory warns that, if indeed a tsunami wave makes it up the coast, takes a right turn through the Strait of Juan de Fuca, makes another right and heads down through the upper islands of Puget Sound…when (and if) it hits Pier 48 in Seattle it’s predicted to be .13 feet high, which, according to our rudimentary math skills, equals a measly 1.56 inches high.

According to this NOAA website, the predicted time for this wave to strike Seattle is 1641 PST – for us non-military types, that’s 4:41pm Saturday afternoon.

If you happen to have a video camera and a lot of free time this afternoon, why not hang out near Des Moines’ waterfront around 4:30-5pm and see if you can videotape a 1.56 inch wave barreling down from the north? We’d love to post it – please email us if you do!

And if you know anyone who lives on the coast, or in Hawaii, please make sure they’re aware of this advisory, as it could be very serious in those areas.

According to the National Weather Service:

Persons in tsunami advisory areas should move out of the water… off the beach and out of harbors and marinas.

Tsunami advisories mean that a tsunami capable of producing strong currents or waves dangerous to persons in or very near water is imminent or expected. Significant widespread inundation is not expected for areas in an advisory. Tsunamis are a series of waves potentially dangerous several hours after initial arrival time. Estimated times of initial wave arrival for selected sites in the advisory are provided below.

Here’s the “Tsunami Advisory” language as posted at 9:18am:

Tsunami Advisory

Statement as of 9:18 AM PST on February 27, 2010

… A tsunami advisory remains in effect for the northern and central Washington coast…

A tsunami advisory remains in effect for the northern and central Washington coast.

There is no Tsunami Watch or warning in effect for the Washington coast. Repeat… there is no Tsunami Watch or warning in effect.

A powerful 8.8 magnitude earthquake occurred at 1034 PM PDT Friday near the central coast of chile. It has generated a tsunami wave… which is now spreading out across the Pacific Ocean.

The first tsunami waves are expected to reach the Washington coast between 250 PM and 310 PM PST this afternoon. The following are the
estimated arrival times of the first waves.

• Seaside or… … ..246 PM PST
• Westport WA… … .257 PM PST
• Neah Bay WA… … .307 PM PST

The largest tsunami waves are expected two hours after the first arrival.

The waves are not expected to be large enough to cause coastal flooding along the Washington coast. However… some coastal areas could experience dangerous currents and surges in harbors and bays. Forecast tsunami wave amplitudes follow.

• Long Beach WA… ..0.46 ft
• Westport… … … .0.78 ft
• Moclips… … … ..1.27 ft
• Neah Bay… … … .0.65 ft
• Port Angeles… … 0.33 ft
• Bellingham… … ..0.46 ft
• Everett… … … ..0.13 ft
• Seattle-pier 48… 0.13 ft

The minimum wave height for a tsunami advisory on the Washington coast is 6 inches or 15 centimeters.

The initial wave will not be the largest. Coastal residents are advised to stay out of the water… off the beach… and away from harbors and marinas. Wave heights and currents are amplified by irregular shoreline and are difficult to predict. The tsunami may not be visible among the common ocean surf… yet tide gages will likely report some fluctuations.

Mariners in water deeper than 600 feet should not be affected by a tsunami.

Repeat… no Tsunami Watch or warning is in effect for the northern and central Washington coast.

And just ‘cuz we found it and we love science, here’s a pretty cool simulation video of what might happen if a tsunami hit Elliott Bay:

[youtube]http://www.youtube.com/watch?v=n2AGlhuCQ-A[/youtube]

The National Weather Service issued an unusual Advisory Monday (Jan. 18th) – this one for a “minor tidal overflow” that will be in effect for Puget Sound Tuesday morning and possibly again Wednesday morning.

According to the report, “very high astronomical tides combined with lower than normal atmospheric pressures” as well as high winds may cause some flooding.

So, if you live near the shoreline and your street/yard/area has a tendency to flood, you might want to put out some sandbags just in case.

Here’s the actual advisory:

… Coastal Flood Advisory for minor tidal overflow is in effect for Puget Sound and the north interior from 5 am to 11 am PST Tuesday…

The National Weather Service in Seattle has issued a coastal Flood Advisory for minor tidal overflow from Puget Sound to the north interior… which is in effect from 5 am to 11 am PST Tuesday.

Minor tidal overflow may occur along some of the shorelines and nearby low-lying areas around Puget Sound and the north interior Tuesday morning… around the time of high tide. Minor tidal overflow is caused by very high astronomical tides combined with lower than normal atmospheric pressures. The Table below shows time of high tide for areas around Puget Sound… along with the normal tide table value and the expected total tide.

Time of tide table expected expected location high tide value anomaly total tide

• Seattle 7:30 am 12.2 ft 1.6 ft 13.8 ft
• Port Townsend 7:06 am 9.1 ft 1.8 ft 10.9 ft
• Bellingham 8:12 am 9.6 ft 1.9 ft 11.5 ft

Minor tidal overflow problems usually begin at 13.5 feet around Seattle and 11.5 feet around Bellingham… and the current forecasts for those areas just meet or exceed those levels. In addition… the atmospheric pressure could be a little lower than forecast… and local winds may cause water to pile up along shorelines more than expected… possibly higher than the expected total tide values. Southeast winds 20 to 30 knots are forecast over the northern inland waters Tuesday morning as another deep low pressure system moves northward offshore. Winds over the waters of Puget Sound are expected to be south 10 to 20 knots Tuesday morning.

Another very high astronomical tide will occur Wednesday morning. The forecast tides for Wednesday morning are slightly lower than for Tuesday… but computer model forecasts indicate the anomaly will still be large enough so that minor tidal overflow problems remain a possibility.

Precautionary/preparedness actions…

Minor tidal over flow can cause local flooding along shorelines and nearby low-lying areas.

The National Weather Service issued a “Special Weather Statement” Tuesday, Nov. 3rd at 4:57pm, warning of “very strong” winds and rain hitting the area Thursday (Nov. 5th) with gusts possibly as high as 50mph.

Here’s the warning in all its glory:

Statement as of 4:57 PM PST on November 03, 2009

… Windy conditions for the mountains… coast… and northern interior Thursday…

A strong Pacific frontal system will impact western Washington on Thursday. Breezy southeasterly winds on Wednesday night will become south-southwest on Thursday for the north interior and coast increasing to 20 to 30 mph with gust as high as 50 mph.

Winds just above the surface will be very strong on Thursday. Ridgetop winds for the Olympics and lower south facing slopes will range from 45 to 65 mph with higher gusts possible. Ridgetop winds along the southern slopes of the Cascades will also be windy… with sustained winds up to 50 mph possible. The strong winds will also be accompanied by heavy rains… combining for dangerous conditions in the mountains.

So…considered yourself warned – hold on to your hats and batten down your boats Des Moinesians!

It snowed last night, continues in some areas, and as of 6:32am Thursday Feb. 26th here are the latest weather-related school and travel updates:

• HIGHLINE SCHOOL DISTRICT: 2 HOURS LATE

Updated: 5:42 a.m. February 26, 2009

Highline Public Schools will operate two hours late today. Emergency bus transportation is in effect.

*There will be no breakfast, no morning classes for preschool, kindergarten, ECEAP, or PSSC. Afternoon classes for these programs will be on time.

*Schools will dismiss at regular times.

Snow and power failures can cause disruptions for schools and families. During these difficult times, HIghline Public Schools will do all it can to communicate vital information to parents and students.

Our top priority is student safety!

Here’s the latest from the National Weather Service:

Statement as of 4:35 AM PST on February 26, 2009

… Additional snowfall of an inch or two and freezing temperatures will warrant caution this morning…

Hazardous driving conditions will be the rule across western Washington this morning due to snow that has already fallen… possible accumulations of another inch or two… and freezing temperatures.

Scattered snow showers will continue this morning as the upper level low pressure system over the area moves eastward. Local
additional accumulations of an inch or two are possible. In addition temperatures have fallen below freezing across most of western Washington this morning… so roads and sidewalks will be icy even if they are free of snow.

These conditions will be relatively short lived. Temperatures will climb above freezing by noon today with highs around 40… and most of the area will have partly sunny skies.

For all you commuters out there, here are some live feeds from area webcams: