Tuesday, November 3, 2009

Big Storm




Sometimes I look at the computer forecasts and just have to say WOW!.  Take a gander at the sea level pressure forecast over the NE Pacific on Thursday--an amazingly intense low center dropping below 950 mb.  And the SUSTAINED winds SW of the low center are roughly 55 kts  (other plot)--certainly with hurricane force gusts.   Look how close the isobars are (and how strong the corresponding winds are) for a vast area of the Pacific.  Just plain impressive.  They don't call these storms hurricanes because they aren't tropical, but they pack a bigger punch.  Huge size and big winds.   And very, very dangerous to be near them on the water.



And can you imagine the waves?  Well, you won't have to imagine anything..they will hit our coast.  Wave development requires strong winds, large ocean area to work on (fetch), and time.  This storm has it all!  The NWS runs the Wavewatch3 wave model, which is driven by the output from the atmospheric model forecasts.  I have included some sample forecasts.  Huge waves develop--reaching roughly 40 feet--and these waves propagate as swell towards our coastline.  It will get pretty amazing along the Washington coast this weekend...I am sure the NWS will be providing marine warnings of 20-30 foot waves.

You won't have to watch Deadliest Catch on TV or watch a DVD of the Perfect Storm to see big storm waves...Westport or Ocean Shores will do just fine.





26 comments:

Must read blogs said...

so what does that translate for those of us inland.

veo_ said...

Woah, I have a timeshare in Ocean Shores. Should I rush there to weather watch or stay away for fear of flooding?

Leif said...

Thank you for the heads up, Cliff.
This is indeed an impressive situation developing...

Must read blogs said...

the NWS has all sorts of warnings up for the area including the passes, just in time for my husband's cross country team to go to pasco for state. If i have my way they will go through the gorge.

Bryan E. said...

sounds exciting. where on the coast would you recommend going to get the best view of the show?

Euphoria Gibbons said...

but are we sure? is this more drama from the post-tropical transition or whatever?
I like weather for the same reason I like backgammon better than chess. Playing that random variable right requires a different kind of ju-ju.

Brian said...

Pretty dang gusty here, east of Redmond. I'm assuming it's the east wind that's suppose to warm us up today.

I like this kind of wind. Dry wind. ;)

Kevin Purcell said...

What does it mean for us inland? A fair bit of rain and a bit of wind. This will not be a big windstorm ashore. That's not what Cliff intended to communicate.

Take a look at this 36km WRF 10m wind speed loop to get the plot above in context. You can see the spectacular winds move around the south side of the low and peter out before they get to the coast.

So this will be a big wave generator as Cllff blogs but this is not going to be a big storm ashore.

I think the reason these sort of storms don't get the attention of a hurricane is that most of us never see them because those spectacular winds don't make it ashore. When they do then we notice them.

That said, I wouldn't like to be out in the Gulf of Alaska in the next couple of days though ... yikes.

Cliff Mass Weather Blog said...

Exactly--no big windstorm here..the action is way offshore. It will get breezy here..no major wind event.

Gator said...

Here's an animated image of the big swell coming our way.

http://www.lajollasurf.org/images/pacanimne.gif

Jay said...

Lots of east wind blowing in North Bend today and along I-90 towards Snoqualmie Pass. I've noticed that the east wind tends to flow along the bottom of the upper Snoqualmie valley like a river. At the Mason Lake trailhead and on slopes higher up along the Ira Spring Trail, it was amazingly calm and warm.

Something to keep in mind when you arrive at a trailhead along I-90 and that nasty strong east wind is blowing. Often you can hike out of it.

mb in Port Angeles said...

Lovely animation, Gator. Thanks.

dfseattle said...

An insteresting little treatise on waves and swells may be found at

http://www.stormsurf.com/page2/tutorials/wavebasics.shtml

New Moon Birth said...

So this is the reason that babies are popping out of women all over town! This big low is causing all those full term mamas to go in to labor! All the birth professionals in town are getting calls like crazy! Thanks Cliff!

Must read blogs said...

the nws in spokane is calling for gusty winds. is that because when you get to the pullman and spokane the air is lifting since they are higher in elevation thatn chehalis?

dayn_1 said...

Cool blog, very educational, though I jumped the gun after reading the 1st post and told several people there was a big wind storm coming in.

At least now I can explain the true facts and eat crow with some degree of dignity....Dohhhhh!

I'm glad I didnt get a razor clamming license for this weekend, those razors will be hunkered down hard, though I would love to go out and watch those waves come in at Greyland.

Scott K said...

I noticed the NWS pulled all of the weather warnings (at least for my area of Lake Stevens) down last night (or didn't renew them).

Is there a change in the system coming today to warrant that move? We had something like a severe weather warning or something along those lines posted up Almost all day yesterday, but it was gone in the evening.

Rob said...

Cliff, Non storm related question. I have been wondering about this for awhile why does the weather.com 10 day forecast usually has snow predicted when their low tempature does not support it? I have been wondering about this for awhile.

Raillynn said...

Thanks for the animated gif, Gator. I am curious, just like Scott K, has the forecast changed?

Eleri Hamilton said...

The Deadliest Catch guys are out on the Bering Sea right now. Please keep them in your thoughts.

natchrl8r said...

So, Cliff, is this an extratropical cyclone? From what I could see of the satellite images it almost appears there is an eye up near the Queen Charlottes. I'd be very interested to hear a discussion on these big cold storms.

smokejumper said...

Hey Cliff,

Front looks on track. I'm sure you'll blog about this later, but what's the post front weather looking like? Very impressive cellular cold air cumulus behind the front. Cool IR satellite pic of those clouds starting to form right off the Siberia coast moving due west. Also, CAPE values (don't know what that is) on GFS are quite high but do know it correlates to thunderstorm potential. Just wanted to know your thoughts on that. Ttyl

Scott K said...

Another wave related question. Will the waves along the coast be worth checking out tomorrow (Friday) or will it have died down by then? I'm thinking of driving along hwy 101 through oregon.

CC said...

Dr Mass
This is somewhat off the subject, but could you give a little info on the precip predictions of the UW probabilistic model? I live a little east of Stevens Pass and the precip predictions of the model are consistently way under what we actually get, i.e., the measured precip is always near or above the 90% confidence limit (“as much as”). For example for last Friday night/Saturday (oct 31) storm the expected value (‘likely amount”) was .25”, “as much as” was 1.44”, and we got 1.45”. For last week’s (2 day) storm the “likely amount” was .52”, “as much as” was 3.35”, and actual precip was 3.93” (including 13” of snow). This pattern was also true last year. My specific questions are: 1)is the model only valid for the lowlands or does it take into consideration mountain conditions? The expected values always seem ridiculously low re the forecasts and forecast discussions of the NWS; 2) why is the variability so high, the 90% confidence limit is typically about 7 times the expected value. This is almost meaningless for those of us for whom predicted precip amounts are critical, e.g. “expected amount of snow is 5 in., but there is a 10% chance you will get 40 in.” At least for the mountains, the NWS regional and point forcasts give a much better indication of how much precip we are going to get than the UW probabilistic model. Your thoughts?

doubletrouble said...

Hello from the other coast-

That IS a beast of a storm. I do hope it's not as unpleasant as our notorious big one- the pic of the the Andrea Gail does not bring fond memories.

Luck & safe harbor to the Deadliest Catch...

zmb said...

Right around midnight/early morning, it started blowing hard complete with hail going against the windows. Certainly wakes you up.