Tuesday, February 24, 2009

Uncertain Snow in Seattle

Not an easy forecast. A cold front will move through tomorrow...bringing rain showers with its passage. Temperatures will cool behind it, and by later tomorrow evening the air mass will be cold enough for lowland snow, particularly where there is significant precipitation . The problem is that Puget Sound will be at least partially rain shadowed (or snow shadowed in this case). There doesn't seem to be much evidence of a convergence zone developing over the central Sound. Another issue is that there really won't be that much precipitation in the cold NW flow.Clearly, there will be far higher chances of snow showers south of Olympia and over NW Washington.
So to summarize...frontal passage tomorrow with some rain. Show showers later tomorrow evening and Thursday morning, not amounting to much over Puget Sound, but perhaps dropping an inch or two in some locations south of Olympia and north of Everett. Not a big deal, really. But we need to watch the model run tomorrow...if the flow was more westerly, allowing a convergence zone to form over the central Sound, it could be more interesting.

27 comments:

Anonymous said...

How will we monitor any potential snow without a radar? Maybe the old-fashioned way before radar even existed?

andycottle said...

Well if Seattle Radar is`nt back, then can always go to the WeatherUnderGround site..

Anonymous said...

WeatherUnderGround is just a composite of NEXRAD sites... notice the 'down of maintaince' alert text. They down own their own radar. Not helpful information.

You need a website that doesn't just link NEXRAD data from ATX.

Two things you can do are

1. look at the NEXRAD Portland radar until the ATX gets fixed today. It worked yesterday when the flow was S/SSW to get an idea of what was going on to the south of us. With anything coming from the N/NW it won't be a good alternative. Obs. and sat. are a good combo.

2. Find a local media station that has their own radar NOT just linking into ATX NEXRAD data like WeatherUnderground.

Anonymous said...

Correction of my typo above:

'down for maintenance'.

Anonymous said...

Correction of typo 2:

'They don't own their own radar.'

Anonymous said...

If you live north of Everett you could use Environment Canada's radar.

http://www.weatheroffice.gc.ca/radar/index_e.html?id=WUJ

Anonymous said...

So Cliff....The other day you said that later this weekend/early next week that it would just be windy on the Oregon Coast, but not for us. The NWS is still saying it will be breezy to windy...but they are also saying the models are uncertain....have your thoughts on the chance for windy conditions (at least 50 + mph gusts) changed any or do you still think it will mostly just be on the Oregon Coast?

tlcarrut said...

"Show showers later tomorrow evening ..."

I say we show "show showers" the way around us. Don't need another "show shower" here.

"smile"

Anonymous said...

I think Ted Buehner is teaching our Skywarn class tonight or another NWS person. I'll see what they have to say tonight about any snow.

Anonymous said...

Thank you Anon@8:27 for the Environment Canada's radar link.

Anonymous said...

It's about 10:00 AM and we're getting sleety snow flakes mixed with rain up here in Bellingham.

andycottle said...

Somebody on here mentioned about it being breezy or windy this weekend.

It`s possible as the 6zGFS does show a 980-984mb low moving on to the central Oregon coast for Sun and then up through Western WA as a 980mb low. But if you look at the 12zGFS, it`s much further off shore and just shows showers over Western Oregon and Western Wa.

Anonymous said...

King5 Radar

mainstreeter said...

We were supposed to have a high of 46 in Olympia, but so far,at 1pm it's been hovering at 39. The colder air seems to be to the north of here as those stations are struggling to get out of the upper 30's, lower 40's.

Anonymous said...

We have a rain/snow mix in Bellingham right now - all snow in Lynden and Ferndale. The temp at BLI has fallen to 34 and DP is 30.

Anonymous said...

Wow! It's been so long since I've had a nice 30-45 minute walk in that kind of rain and gotten a nice dousing! This is great - finally!

And here in Mill Creek there were occasional very wet snowflakes mixed in when it was at its heaviest. It has pretty much stopped for now, however.

WeatherNerd said...

Cold air has been leaking out of the Fraser Valley the past 1 to 2 hours, causing temps to fall from the high 30s to the low 30s in Whatcom County, resulting in light snow. How far south will it go??

cornbread said...

I just drove from Bellingham to Maple Valley. B'ham had mixed rain and snow, turning to snow just south of town where there was a clearly defined snow line several hundred feet higher on the hills. Snow ended coming down Bow hill. From then on, it was pretty dry most of the rest of the way. Here in MV there is some fairly heavy rain mixed with sleet and 41 degrees.

andycottle said...

Since Seattle radar is still down, we all can use this site for now which shows radar coverage across the western US.
http://radar.weather.gov/Conus/pacnorthwest.php

Anonymous said...

King 5 Has a working Doppler Radar

http://www.king5.com/weather/doppler/indexrad.html?http://www.king5.com/live/weather_images/K5-340mileAnim-640x480.gif&Title=340%20Mile%20Range

It doesn't appear to be the best radar but it will work.

Anonymous said...

Andy, that is simply a mosaic of all NWS radars in the Northwest. Since the ATX (Seattle/Comano Island) radar is down, it's not going to show up on there. The Portland radar does show parts of southern Puget Sound, but even that area is far from the radar there (in other words, the radar is sampling pretty high above the ground).

mainstreeter said...

It might be back later today according to KOMO's weather link.

Anonymous said...

KUIL is now reporting light snow, temp. 35.

sermonti said...

The radar will be down until tomorrow (Thursday) afternoon. See below, message at 2:15 from NWS Seattle.
____
NOUS66 KSEW 252213
FTMATX

MESSAGE DATE: FEB 25 2009 22:15:00

UPDATE: KATX WILL BE DOWN UNTIL AT LEAST THURSDAY AFTERNOON, FEB
26TH FOR REPAIR. THE MECHANICAL FAILURE FOR THE RADAR IS MORE
EXTENSIVE THEN PREVIOUSLY THOUGHT...AND MORE PARTS ARE ON ORDER.

Anonymous said...

Might as well order another radar while they're at it...

mainstreeter said...

and more parts...

Josh said...

Can you post a new updated Snow forecast prediction map cliff?