Weather Blog

Meteorological Mumbo-Jumbo of Friday's Storm

Meteorological Mumbo-Jumbo of Friday's Storm
In what is indeed looking like a page straight out of November 1st, a strong storm is developing in the Pacific Ocean and heading toward the Pacific Northwest.

High Wind Watches are in effect for all of Western Washington for potential gusts to 65 mph along the coast and north interior, and gusts 45-50 mph in the Puget Sound area.

As usual with wind events, the storm's track and intensity is key in determining who gets the strong winds and how strong they will be.

The strongest winds are typically associated within the area just to the south of the storm center. Thus, a classic windstorm for our area has a storm tracking right over Forks or southern Vancouver Island, and moving east/northeast to about Vancouver, B.C., putting that strong surge over Western Washington.

A stronger storm intensity that moves farther north can have similar effects as a weaker storm that moves in over this classic path. If a storm goes in too far south (say, the southern or central Washington coast), the Seattle area and points north are typically spared the strong winds and it becomes more of an Oregon storm as the surge passes to our south.

So, what about this storm? One forecast model has it fairly potent (central pressure of 976 mb, or 28.82" on the typical home barometer) making landfall around central Vancouver Island, then brings the storm up north of Whistler. That setup is really windy for the coast and Northwest Interior, but marginally damaging windy for Seattle as it appears the storm will be too far north when its surge comes through. In this case, I'd say winds for Seattle would be on par with Sunday night/early Monday -- gusting 35-45 mph.

Our other main model has been pushing the storm center farther south of late with each successive model run -- the latest model showing a 986 mb storm (29.11") making landfall just north of Hoquiam and pushing across Port Angeles through Bellingham. This storm is weaker but closer to home so it could bring similar wind speeds. The caveat here is that with the model trending this storm south, if it keeps up that theme, we could end up with the scenario where it goes *too* far south and this is a non-event for Seattle north, and mostly an Oregon/SW Washington deal.

None of these events spell a major widespread "name that storm" type of event (which is too bad it's not today because an "April Fool's storm" would be kinda neat). To compare, past historical Top-of-the-chart windstorms typically have had central pressures between 955 and 970 millibars. Another trick I've talked about in prior wind storm events is gauging the pressure difference between Portland and Bellingham, which is not a perfect measure of a wind storm as there are plenty of other factors involved, but I like using it for general comparison's sake.

Our big kahuna wind events have had these differences be between 18-22 mb with the record being the 2007 Hanukkah Eve storm that reached 23.2. I'd say a "typical" wind event has this number in the low teens, and models now gauge this storm between 11-13 mb. So noticeable, but not looking catastrophic.

That said, we always have to keep our eye out as anytime you have a storm rapidly developing and forecast to make landfall somewhere between Hoquiam and Central Vancouver Island, it bears watching in case it develops more than the models think it does.

We'll have our eyes glued to the satellite, surface weather charts, and latest forecast models. (This is where not having land out to our west is a big disadvantage. It'd be nice to have more than just a few ship reports and buoys out there to let us know some pressure readings where the storm is developing. If only whales could e-mail!)

Stay tuned!