Thursday, December 3, 2015

Windstorm is Cancelled!

The latest hourly HRRR forecasts are suggesting that the wind event may be MUCH less than predicted, particularly over Puget Sound.

As shown in my last blog, the 4 AM model runs indicated a strong wind event over our region.

However, the latest HRRR forecast pulls WAY back.  Let me show you.  Here is the pressure and wind forecast for 4 PM for the run starting at 7 AM.  Large pressure gradients with low of 986 hPa.



In contrast, the HRRR forecast starting at noon is much more benign, with weaker pressure gradients.


The latest observations along the coast show that the earlier forecast was profoundly in error.  The low center is not developing as predicted.

We can view the wind gusts forecast by the latest HRRR run.  At 4 PM, only the Puget Sound waters will have gusts of 30-40 mph
An hour later, same thing, with strong winds in the eastern Strait.   Much less on the coast.

A sobering example of the difficulty of getting small scale low developments along the coast.  Northwest Washington will get a good blow, but the Seattle area will only get a breezy interlude, if the latest forecasts are correct.

This kind of failure is unusual, but happens.  Sobering.   I am a bit upset with myself...I didn't spend enough time looking at the ensembles (multiple forecasts) this morning....in retrospect they showed considerable uncertainty with the NWS GFS model (which drives the main local high-res predictions) being an outlier from other solutions.  I won't make that mistake again before writing a blog.

This event is a good case study of why we need to transition to probabilistic weather prediction, with full uncertainly information being transmitted to the public.
.........
And while you are thinking about the winds, don't forget to express your feelings about the proposed termination of KPLU, in the ill-advised sale to UW.  More information here and here.  This sale is marked by secrecy and disinformation by PLU and UW administrators.  KPLU can be saved if listeners tell the UW Board of Regents and the PLU administration to back off.

If any of you are interested in attending a strategy meeting for saving KPLU on Sunday, Dec. 6th at 2 PM, please let me know (you can email me for more information--search on "cliff mass email" to my email address)

14 comments:

Someone said...

Thank you for the update!

Westside guy said...

I know some people will complain, but I don't see a problem with how this forecast has been handled. Even last night's forecast discussion commented on the lack of agreement between models while at the same time posting the high wind warning.

I'd much rather have early notice, and then know I have to keep tabs on the latest information as it develops, than to have you guys hold off saying anything because it's not 100% certain.

Scott K. said...

I'll prepare for a good windstorm then. All of the big ones have not been predicted or are downplayed right before they happen.

A cynic? Maybe. It's just what I've seen for the past 30 years of living here. :)

Unknown said...

Pretty good blow up here on Lummi Island. Pressure at 991 (falling) sustained winds of 36 from SSE. Weather station at Lummi Island Ferry dock http://www.whatcomchief.org/LummiFerry/Current_Vantage_Pro.htm

3pm.

Ferdi Businger said...

It's windy here on Sinclair Island, but nothing out of the ordinary. Since Sunday, when I took my boat out of the water, the winds have been generally lighter than forecast up here. But I'm not complaining. I rather they err on the high side than on the low side, which was a real problem a few years ago. For those of us who have to travel between islands in the winter by private boat this is a big deal.

I'm still cleaning up the county roads from last week's arctic blast.

richard583 said...

Less low pressure, generally, with the main brunt of the colder air mass involved having dived more directly South / Southwest than it had been projected to. ?

Mark said...

... Record high temperature set at Bellingham Airport yesterday...

a record high temperature of 60 degrees was set at Bellingham WA
Airport on Dec 2nd. This breaks the old record of 58 set in 1958.

I recorded a 24 mph wind gust on south Vashon island.

After several windstorms from late August through November causing power outages and post-storm tree clean-up, I'm glad this one did not materialize.

2otaku said...

Most sites are still calling for 60mph gusts possible? I'm not complaining, mind you. The forecast discussion states they will leave it up just in case something develops. What?

Joan said...

Not sure how high the winds were here (6 miles north of Sedro-Woolley), but we lost power for five hours due to downed tree branches. The wind howled through the trees on and off last night and through the day cracking tree limbs and knocking stuff off our porch. So, for us kind of a nice little windstorm.

Dan said...

Westside guy, I couldn't agree more. The original prediction was sober and not sensationalistic. If the low eased up, it eased up. That's not something to beat yourself up over.

Unknown said...

We had a good blow in Bellingham with top gust of 53 mph. It was pretty ferocious as I read of the so-called cancellation...

Mark said...

Near Record Warmth on The Way / December Outlook (But not for Washington state)
By late next week, a subtle pattern shift will lead to the development of a highly amplified, long wave TROF over the western US with a building ridge over the eastern US in in 10-14 days. This should result in sending average Temps from above normal to much above normal in the east and north central US during Week 2 - while Temps fall to well below normal over the west. However with the lack of deep arctic air over Canada, Temps should only drop off to around 2 to 8 degrees below normal over the west, while readings of 8 to 18 degrees above normal appear likely from portions of the upper Midwest eastward into the mid and North Atlantic region by around mid-month.
http://www.wunderground.com/blog/SteveGregory/near-record-warmth-on-the-way---december-outlook--updated

David Beatty said...

I appreciate your candor about the "windstorm that failed". And I continue to appreciate your informative weather blog. Keep at it, man.
David

clive boulton said...

Hopefully cancelled blows over KPLU sale (why would PLU sell off this PNW treasure).