Wednesday, February 23, 2011

NOWCAST 4:45 PM: SHOWTIME

Folks...the big threat for central Puget Sound...the one suggested by the model's last night is coming up now.

So far things have gone pretty much on track.... we started with rainshadowing over Seattle and the southern Sound. The as the flow turned more southwesterly the rainshadow shifted northward and the southern Sound had increased snow showers. As the northerly wind picked up a convergence line developed over NW Washington the brought snow to the San Juans to Skagit County...and then the northern Olympic Peninsula (here is a shot from Port Townsend to illustrate.


But now things are shifting to the Puget Sound basin. The northerlies are starting to push southward into the southerlies over Puget Sound (see map):


The radar is showing the impact---moderate echos are now moving toward Everett and down the Sound. (see radar). If the line continues to push southward, the battleground between the two air masses could be fierce and significant snow the result. Temperatures are relatively mild from a day's worth of heating, but melting of precipitation and the ingestion of cool, dry air from the north should help it turn to snow. I think Seattle commuters will be fine....the roads are warm and salted (sound likes a good meal!)...but tonight could get very interesting very fast if this boundary locks over someone. Watch the radar now...if will be very entertaining!

Here is the link to the NWS site:

http://radar.weather.gov/radar.php?rid=ATX&product=N0R&overlay=11101111&loop=yes


5:20 PM---the line has just hit the UW....ice pellets are starting to hit my windows....

38 comments:

  1. So where can we get updated UW model run maps ourselves?

    ReplyDelete
  2. My six year old daughter (who thinks you are in charge of these things) requests that you kindly hurry the snow up. She needs some snow before bedtime, please.

    ReplyDelete
  3. Cliff, will you be NowCasting after dark? Shall we keep tuning in?

    ReplyDelete
  4. "Showtime" Showtime indeed! Love the way you transmit this stuff to us Cliff, we're in such dire need of good science communicators in this troubled era.

    You make it clear, and lots of fun. Please never stop!

    @brian

    ReplyDelete
  5. 5:45 heavy snow coming down in Lake Forest Park.

    ReplyDelete
  6. Dateline, Olympia; 5:45PM
    Temp: 32.5F
    Winds: Calm
    Skies: Mostly clear, but with some significant multiple-layered clouds to the west.
    Snow: Only a trace of all that fell in impressive bursts today. It melted because it was at least 2 deg above freezing, and the sun came out after every squall.

    ReplyDelete
  7. i don't know about nowcast, but you can find the 12z (initiated at 4 A.M. our time) models runs at http://www.atmos.washington.edu/mm5rt/ and click the mm5-nam or wrf-gfs links.

    I am also currently blogging right now at http://charliesweatherforecasts.blogspot.com/. I can't offer the expertise that Cliff (hopefully I'll be calling him Professor Mass in a few years :) ) offers but I can have a fairly good discussion and at least supplement what he is discussing here.

    Cliff, if you don't want me to advertise my blog here, feel free to delete my comment or the link or whatever you want to do. Just trying to provide some additional weather info to our aficionados around here. :)

    ReplyDelete
  8. about 1/2" of accumulation in Crown Hill at 5:30. Mix of corn snow to start, then larger flakes, now tiny flakes. Temperature dropped 8F from about 4 to 5:30

    ReplyDelete
  9. Why oh why does ANYONE listen to the big 3 broadcasting companies?
    During work today all they did was seem to incite hysteria. Buy chains!, buy batteries!, buy candles!, BUY BUY BUY!

    Flurries in Mukilteo today, roads are easily passable as of 6pm.

    Thank Dog for Cliff and his straight-forward and accurate info.

    ReplyDelete
  10. It's a winter wonderland here in Port Townsend, I'm guessing 4-6 inches uptown. Fun!

    ReplyDelete
  11. Its snowing on capital hill in Seattle! Not really sticking yet though... 6:25PM

    ReplyDelete
  12. Yep, now snowing here in downtown Redmond now. Went in to grocery shop and it was a tiny bit coming down. Came out and there was definitely coverage, though not even an inch yet.

    ReplyDelete
  13. I walked into the Woodinville costco to stock up on things at 5:15p with light snow falling and nothing sticking. We finished up and exited the store by 5:45p (it was the slowest I've ever seen a costco!) and there was over an inch of snow and still coming down heavily.

    Wow, talk about instant storm!

    It took some clever route finding to get around all of the stuck 2wd cars on the Woodinville-Duvall road to get home, good luck to the commuters out there.

    ReplyDelete
  14. N Kitsap has stayed snow-shadowed all day. Only a few flurries around sunset.

    ReplyDelete
  15. This nowcasting could take off: even the NWS is doing it :)

    http://forecast.weather.gov/showsigwx.php?warnzone=WAZ508&warncounty=WAC033&firewxzone=WAZ654&local_place1=Downtown+Seattle+WA&product1=Short+Term+Forecast

    EVERETT AND VICINITY-SEATTLE/BREMERTON AREA-
    432 PM PST WED FEB 23 2011

    .NOW...
    HEAVY SNOW SHOWERS ASSOCIATED WITH THE LEADING EDGE OF ARCTIC AIR WILL DROP SOUTH THROUGH NORTHERN KING AND WESTERN SNOHOMISH COUNTIES DURING THE EVENING COMMUTE. THESE SHOWERS ARE CAPABLE OF PRODUCING LOCALLY HEAVY SNOWFALL AMOUNTS IN A SHORT TIME...AS HAS BEEN REPORTED BY WEATHER SPOTTERS IN PORT TOWNSEND AND AROUND WHIDBEY ISLAND.

    ReplyDelete
  16. You are so awesome, Cliff. Thank you!

    We have about an inch at Carkeek Park now (6:50pm). Lovely. light and fluffy.

    ReplyDelete
  17. Checked out our blog, Charlie. Very impressive for a high school senior. You have obviously educated yourself a great deal about weather. I imagine Cliff would be happy to have you as a student someday.

    Well, we finally got some action in Redmond but no much more than inch of graupel/snow mix.

    ReplyDelete
  18. Snowmaggedon in Skagit County. Haven't seen this much on the ground since December 2008. Time for sledding!

    ReplyDelete
  19. We just broke 12" of snow in this second wave up here in Mount Vernon. This was measured on our deck that was cleared off from the 8" this morning. So, we've had 20" of snow in the last 14 hours, but we lost about 4-6" to melt in the late afternoon. There's a good 14" in our grass right now...

    ReplyDelete
  20. I like this site for radar. The NWS site is hard to read.

    http://www.wunderground.com/radar/radblast.asp?num=6&delay=15&scale=1.00&noclutter=0&ID=ATX&type=N0R&lat=0&lon=0&label=you&showstorms=0&showlabels=1&rainsnow=0&MR=1

    ReplyDelete
  21. Not showtime here in Kirkland at this point. Wet slushy, 1/2" tops. LWSD should be cancelling tomorrow's classes any time now.

    ReplyDelete
  22. a light dusting in capitol hill. nothing serious yet.

    ReplyDelete
  23. When it started snowing here in Shoreline this afternoon, I called my husband at work to give him an update on the weather. While I was in the middle of talking about ice pellets my 5 year old came up to me and asked "Who are you talking to Mama? Is it Cliff Mass?" :)

    ReplyDelete
  24. ESE of North Bend 700' - Just a dusting. Stopped snowing again. Probably got about 8" total, 1" today with the off and on snow. My kids have been waiting all day for the supposed 6"-12" we were supposed to get just today and tonight. I guess the night's not over......

    Just want to say thanks Cliff. We love coming on here no matter what happens!

    ReplyDelete
  25. Cliff, you need to relocate to Darrington. We've received over 40 inches of snowfall in the past two days, with 28 inches of accumulation - and it's still dumping. Yee ha!

    ReplyDelete
  26. This was a bust. Further north. Ball game over. Winter Weather Advisory now replaces Winter Storm Warning. Bedtime.

    ReplyDelete
  27. Getting home tonight was a nightmare, especially because of worrying more about other stupid drivers. Yeah someone slammed me in the back.

    ReplyDelete
  28. Since the first go around with will we or won't we get snow you have been spot on. Thank you for all you have been blogging and making it easily obtainable for the masses. Every chance I get I keep telling people about the blog and to read it if they want the real news.

    I'm a high school coach that is outside a lot and having real knowledge of what to expect is immeasurable. Thank you again Cliff.

    ReplyDelete
  29. This one hurt! Yeah, I'll never learn my lesson. I get sucked in everytime. Could have been so beautiful...50 degrees please!

    ReplyDelete
  30. Just flurries and 31 degrees here in West Seattle/Alki. No stickage.

    ReplyDelete
  31. Dateline, Olympia; 8:30PM
    Temp: 32.4F (ONE lousy degree lower than my last report 3 hours ago!)
    Winds: Calm
    Precip: Light, lightweight frothy white stuff: Put it in your mouth and it's sublime . . .er, no ... it sublimes.

    ReplyDelete
  32. Finally get some real snowflakes here in the Mt. Baker foothills. Amazing how little snow we've received compared to our neighbors in Skagit County.

    ReplyDelete
  33. 3/4 of an inch and large flakes sticking on the roadway in Normandy Park West of SeaTac .5 miles from the Sound.

    Mike

    ReplyDelete
  34. Southeast Bellevue (just SW of Factoria) up to 2" now and still coming down. LOVE it! The street in front of our house is somewhat slushy, but with tracks where cars have gone by...

    ReplyDelete
  35. Wow! Just checked NWS and now they are calling for 7-11" here ESE of North Bend! Tomorrow morning real WILL be interesting!

    ReplyDelete