Winter Storm Watch for Seattle and all of western WA

[andycottle]

very light sprinkles with a temp of 36 and DP also 36 as of 8:39pm.
Will take a look at the models here in a bit. -- Andy

[TT-SEA]

Thats what I have been telling you guys... all models show warmer and wetter. Its inevitable this time.

[R-Dub]

Albright does mention possible overriding event sat night or sunday. In the mean time, we are in for some very cold overnight lows, coldest of the winter so far.

[andrewr]

TT, do you see it as too warm for snow in the mountains (such as a pineapple express pattern) or just normal?

EDIT: As for the mountains, I mean like Snoqualmie Pass and Stevens.

[TT-SEA]

I would guess good for Stevens and maybe not so good for Snoqualmie.

We need all kinds of precipitation right now. We are way too dry.

[R-Dub]

Looks like I will be seeing a snow shower within a half hr or so looking at radar, also temp has started to fall quickly over the last 20 min.

1/12/05 LK Goodwin WA
8:49:12 PM CURRENT
Cloudy
Temperature (ºF) 34.9
Humidity (%) 66.9
Wind (mph) NW 1.5
Daily Rain (") 0.12
Pressure ("Hg) 30.20
Dew Point: 29.0 ºF
Snow Depth: Trace

[R-Dub]

Don't forget last years overrunning event! All models expected a quick change over to rain, but it didn't happen for almost 12hrs after forecasted allowing much more snow to fall, and also freezing rain.
NWS Portland even says that GFS is usually too quick to scour out cold air. Its not quite over yet!

[andrewr]

There was a lot more cold air though last year. I think I had a high of 22 the day before it happened (Seattle had a high of 27), so that is a big difference.

[AnthonyC]

We'll have minimal cold air in place tomorrow through Saturday morning, but the precip doesn't arrive until Saturday night/Sunday morning. 850 mb heights/temperatures RISE drastically Saturday morning...seems almost unbelievable to go from -12C to 0C within a 12-hour period. We'll have to wait and see...this could be a possible over-running event.

[TT-SEA]

Excellent point Anthony.

The cold air was much more entrenched in the over-running event last year. This is not even close to that situation and still that cold air was scoured out in 12 hours.

Look at yesterday... we woke up to upper teens and low 20's and by evening we had light rain and near 40 degrees.

[AnthonyC]

True TT-SEA. Last year, arctic air was entrenched at all levels of the atmosphere...200mb, 500mb, 850mb, 925mb, etc. This year, that arctic air is alot shallower and weaker. And TT-SEA makes a good point...it was 23 F when I was walking to school on Tuesday morning. By 8pm that night, it was almost 40 F. Hopefully there won't be that much southerly flow ahead of the incoming warm front.

[andycottle]

After a few early morning sprinkles/showers tomorrow...cold high pressure builds in through the 15th and 500MB heights lowering to about 510DM or so. MOS at KPAE(Everett)...nearest station to me...has high 31/low 24 of Friday and high 35/ low 24 on Saturday. So looks like we are in a few down right cold clear nights here in W. Wa. Then on Sunday...a 1000MB low sends a plume of moisture(.25" - .50" of precip) as far north as say... Kelso, and maybe Centraila area, and out to Southern Wa. coast. Places like Olympia, Tacoma, Seattle...will have some cloudy skies. Now as far as snow goes...500MB heights look a tad too warm for when the precip comes into the South sound...as there around 540DM and 850MB temps 0 to 3C. In the long Term...am not seeing any cold weather coming our way.

-- Andy

[TT-SEA]

Andy - what model shows 500mb heights lowering to 510DM??

I see 552DM on Friday (1/14)... about 558DM on Saturday (1/15)... and almost 5640 on Sunday (1/16).

This is true for every model available. GFS... ETA... Canadian... European... NOGAPS... UKMET.

In fact the GFS has 500mb heights of almost 570DM on Sunday (1/16) which would probably put highs in the 50's.

Here is the GFS for Sunday afternoon (500mb heights)...

[andycottle]

Yes I see what you mean, Tim. I was looking GFS 1000 to 500MB/MSL map, but guess I was looking at it just in General. -- Andy

[TT-SEA]

Thats O.K... easy mistake.

All the models looks similar and 500mb heights between 564DM and 570DM on Sunday is quite high for January. That is more typical of May.

[andycottle]

Hey Tim....can ya give the link to the Canadian and European weather models? -- Andy

[TT-SEA]

Sure...

http://weatheroffice.ec.gc.ca/model_forecast/global_e.html


http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!72!North%20America!pop!od!oper!public_plots!2005011300!!/

[R-Dub]

Well I am waking up to a dusting of snow, with the flakes flying at the moment. Looking like the coldest nights of the yr tonight and Fri!

1/13/05 LK Goodwin WA
7:56:47 AM CURRENT
LT Snow
Temperature (ºF) 32.7
Humidity (%) 93.8
Wind (mph) NE 0.0
Daily Rain (") 0.00
Pressure ("Hg) 30.34
Dew Point: 31.1 ºF
Snow Depth: Trace

[R-Dub]

Still snowflakes falling here with partly cloudy skies! The moisture doesn't want to give up.

My latest forecast from NWS

Created: January 13, 2005 09:08:34 PST

Today: Mostly cloudy. Isolated snow showers. Probability of measurable precipitation 20 percent. North wind 7 mph. High 35.

Tonight: Partly cloudy. North wind 8 mph. Low 19.

Friday: Partly cloudy. East wind 8 mph. High 35.

Friday Night: Partly cloudy. East wind 8 mph. Low 17.

Saturday: Partly cloudy. East wind 6 mph. High 37.

Saturday Night: Mostly cloudy. Low 28.

Sunday: Mostly cloudy. Chance of snow. Probability of measurable precipitation 30 percent. High 40.

Sunday Night: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. Low 32.

Monday: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. High 44.

Monday Night: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. Low 34.

Tuesday: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. High 43.

Tuesday Night: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. Low 36.

Wednesday: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. High 43.

Wednesday Night: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. Low 35.

Thursday: Mostly cloudy. Chance of rain. Probability of measurable precipitation 40 percent. High 42.

[PurdueWx80]

Here's another great model site with the Euro, UKMET, Canadian and others...

http://meteocentre.com/models/modelscep_e.html

By the way, after this weekend snow chance, you guys will have to start worrying about major flooding in a week or so with the Pineapple Express setting up...unless of course you live on the east slopes of the Olympics. I have enjoyed your antics in this thread...I hope to end up in the Seattle or Portland area in a few years...LOVE it there. I used to think the weather out west was boring until I did several case studies of Pineapple express flood events for some grad courses in meteorology (October 2003, Feb 96, etc.). Anyway, welcome to S2K...I hope to hear more of your obs, forecasts and antics in the future!