November 22, 2009

The low is here


10:50 AM update...here is the latest Doppler velocity image. I normally don't show you this. Blue is incoming westerly winds of 36 kts. A convergence zone has formed with heavy rain in the central Sound.



The low pressure system moved in a little south of the last model forecast, but strong winds are now hitting the central and southern WA coast . For example, the above image shows the surge to 45 knots at Tokeland at the north end of Willapa Bay. And Astoria and Westport have done the same.

And here is an official spotter report on the southern coast...85 mph.

0430 AM NON-TSTM WND GST 1 SW OYSTERVILLE 46.54N 124.05W
11/22/2009 M85.00 MPH PACIFIC WA TRAINED SPOTTER

DUAL ANENOMETERS...BOTH READ 84 AND 85 MPH PEAK GUSTS.


You can see the wind transition in the vertical looking at the Westport "atmospheric river" observatory information:You can see the wind switch around 12 UTC (4 AM) to the NW, with winds just above the surface reaching 40-50 kts sustained.


As noted last night, this is NOT a general western WA windstorm. Moderate winds will be limited to the area south of Puget Sound.

The next issue is the Strait of Juan de Fuca. Considering the track of the low the westerly surge will probably be weaker...but it still will happen. But the low has to get past us first. Watch the pressure down the Strait....you want to see the pressure at Quillayute rise significantly against Bellingham. It should all start happening during the next few hours...but again, this won't be one of the major westerly surges that cause major damage. Just a garden variety one. Rain should decrease substantially over the next few hours.

Finally, if anyone is interested KCTS TV is repeating my weather program at 1 PM.

15 comments:

  1. Yeah. Noticed the more southern route before i went to bed. You know know which meso model initialized the best, the TCWB, haha.

    Also, picked up 3+ inches of snow NW yakima (1700ft). Thought I'd wake up to sun and a chinook wind but its still snowing huge flakes. Never seen slop over precip from the mountains make it this far east.

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  2. Central Coast: (Moclips/Pacific Beach)
    WSW 35 mph sustained, gusts to 41mph. Barometer 29.57 and rising. Temp 47F

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  3. My station on Copalis Beach (DW1622) shows the low passing through at 4 AM, 987 mb, wind shifted from E to W. High gust 42 kts at 7:17 and now steady at 27 kts.

    Paul

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  4. Paul (down the road from me 6 miles) - 4am was right on when it switched. Thats the time they predicted too. Just had a gust of 44mph.

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  5. The pressure in Alki is at 991 mb and climbing. It bottomed out around 985 mb three hours ago according to the weather station on the deck.

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  6. My 6 yr old and 39 yr old are going to the MLS Champions match at 1700 - any chance of ultra-light rain? Or are they looking for massive misery at Qwest Field?

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  7. Down here on the south sound (Vaughn Bay, Case Inlet) the winds and surf are combining with the coincidental high tide to rearrange all the logs on the sandspit. Beachcombing later this afternoon will no doubt bring some good finds (floats, dock parts, small boats, etc.)

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    thank you.

    ReplyDelete
  9. Lake Stevens,

    Pressure hit the low point between 3am and 5am as predicted (at 29.0 or 982mb) and has risen back up to 29.4 (or about 996mb).

    Still no wind, actually the wind has been decreasing from about 6mph to about 3mph now, still coming from the east.

    Maybe we'll get part of that westerly surge. They dropped the wind advisory early this morning before it expired...so ironically I bet well get some wind now. :)

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  10. About 5:50 here on the ridge S of Chehalis wind started(?) whistling through bedroom window and woke me up - checked wind gauge, and saw steady at about 21 mph, probably not the highest, forgot to note pressure - back to bed. At about 8 drove south on 603, some limbs on road, mostly smaller debris, but not a lot.

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  11. does anybody know the url/where you can get the images for those wind graphs? I'd really like to have access to them.

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  12. You can get the station location and plots and the raw data from the NWS National Data Buoy Center

    e.g. for the Westport Buoy #1 i.e. WPTP1

    http://www.ndbc.noaa.gov/station_page.php?station=wptw1

    Click on a graph icon to see that parameter ploted as a time series.

    e.g. WPTP1 wind speed 5 day time series plot

    http://www.ndbc.noaa.gov/show_plot.php?station=wptw1&meas=wspd&uom=E&time_diff=-8&time_label=PST

    The current plot is even more dramatic than Cliff's copy .... you can really see the step change in wind speed at 14UTC/06PST and a slow dropoff in speed.

    The "full meal deal" is wind speed/wind gusts/surface pressure for 5 days all on one plot

    http://www.ndbc.noaa.gov/show_plot.php?station=wptw1&meas=wdpr&uom=E&time_diff=-8&time_label=PST

    Change the station ID for other plots e.g. for TOKW1 and ASTO3

    Another useful source of info for offshore wind is QuickSat data (though it's not real time and has coverage gaps because it's a sun-synchronous LEO sat).

    http://www.ndbc.noaa.gov/quikscat.php?station=wptw1

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  13. its days like this am that i wish i still lived in pullman. I would rather have snow and heat that having a window blow out of my home and endangering my children and cats. I have had enough wind for awhile.. having said that I have probably jinxed us all!

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  14. Kevin Purcell said "The "full meal deal" is wind speed/wind gusts/surface pressure for 5 days all on one plot"

    I can see how to get an individual plot, by clicking on the icon at the top of the column. but how do your get multiple values on one plot?

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  15. What is plotted is controlled by the &meas parameter in the URL. In this case &meas=wdpr gives all three datasets but it's not a general feature of the plots

    You'll note that the &meas parameter is at the top of each column. Or here

    http://www.ndbc.noaa.gov/measdes.shtml#stdmet

    And as I have that line bookmarked (or stuck in a HTML page) I forget where I got that one from ... I recall there is another page for the buoy (with a photo of the buoy on it). Searching for it might help.

    Another useful data source is the radial search from a given location that gives a tabular collection of current data from the closest buoys in a given dist(ance) 250nm in this case.

    http://www.ndbc.noaa.gov/radial_search.php?lat1=46.904N&lon1=124.105W&uom=E&dist=250

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