Saturday, February 8, 2014

Nowcast: Light Snow Reaches Seattle

Snow has reached southern/central Seattle and will push northward during the next few hours.

The system is pushing somewhat northward of what the models suggested this morning--yes, this reflects some of the problems of predicting weak Pacific disturbances that I talked about in my previous blog.

Here is the 6 PM radar image..you can see the precipitation shield reaching Seattle.  But remember the radar beams are above the surface and there is a lot of dry air below, which causes serious evaporation.


The other thing to keep in mind is that the snow is light and temperatures have warmed at low levels--well into the mid to upper 30s today.  And with a cloud cover there will not be good nighttime cooling.  Furthermore, the road temperatures are all above freezing, so light snow will melt initially.   Here are the latest surface air temperatures and road surface temperatures from Seattle SnowWatch--you can see what I mean.

Evaporation and melting will bring the temperatures down over the next few hours, but the main roads should be fine for quite a while.  And I know that SDOT is now revving up a response team.  This is NOT going to be another Atlanta.

My favorite short-term forecasting model is NOAA's HRRR...let me show you the accumulating snow it predicts.  Here are totals for the period from 4 PM through 9 PM, 2 AM Sunday, and 7 AM Sunday.  You can click on the images to expand.  You see the drying along the eastern slopes of the Cascades?  That is due to easterly, downslope flow...or "snoweaters" as some call them.  Quite light near the water and in Seattle..perhaps a half-inch by daybreak over north Seattle....a bit more to the south.  More in the Cascades and over southwest Washington.




This minor snow situation will end by 9 AM on Sunday morning.  And then the atmosphere will start warming.  I bet tonight's snow is the last you will see for a long time...




48 comments:

Just AboveNOAA said...

"But no panic is necessary." ...yet you're leaving it open as an option, right?

Rod said...

At 3 PM, I suggested to my wife that it might be prudent to take the front-wheel drive SAAB Turbo to work, rather than the RWD BMW. She agreed. After 35 years of working swing-shift, and graveyard shift, Cliff, I have learned to be wary of snow forecasts. Particularly over-night snow forecasts...

Scott Souchock said...

Thank you Cliff for keeping us the most informed weather users on the planet (at least that I know of!)

Michael Snyder said...

Well we have everything covered here in Normandy Park as of 6:54pm.
Maybe 0.2"
Doesnt look like any real breaks for now in the doppler coverage.

Temp/Dew Point 31/28

jno62 said...

Snow in Shoreline as of 7:30. Sticking to the roads. A "solid dusting" at this point.

Rod said...

The temperature has plummeted from 36 degrees at 1703 to 30 degrees at 1903 here in West Seattle. Just as you have so often explained that it could, Cliff, once the snow starts to fall. The temp has plummeted from 38 degrees to 29 degrees in three hours in Burien, near where my wife works.

Unfortunately, this can cause problems on the roads.

Sometimes I wish that meteorologists would believe their own science when making a local Seattle area forecast.

My wife gets off at midnight...

Thank goodness she will be driving the "bullet-proof" 1992 SAAB home...

Don't worry, Cliff. We will just blame the mayor of Seattle...

Steve Snyder said...

Snowing pretty hard here in woodinville. Everything white. If this keeps up it will be a couple good inches.

Kelly said...

Snowing on Bainbridge Island. With how "off" the forecast was done down in the Portland area could this be something to consider up here?

Helen Welborn said...

I appreciate your work, but what about the romance of weather? Surely you can feel it.

Unknown said...

Incorrect for north ballard.. Snowing hard and sticking to road.. 3/4 inch and counting

windlover said...

We have at least 2 inches and counting here in Eatonville. The roads are a mess! Temp is down to 30 and still falling. Sad that it will all melt tomorrow. But....around the 17th it may get cold again...IF the models don't change their mind!

Steve Snyder said...

Total fail on this forecast. Snowing hard in woodinville with over an inch. Radar shows no letting up.

tz said...

I'm on a long term visit but subscribed long before I was exiled to Tukwila.

The snow doesn't seem "light" looking outside the window.

At least it isn't "dark snow" which I assume would mean Mt Ranier or similar is having a bad day and I should have evacuated.

I come from Michigan - you know, the place that due to global warming is nearly ice-locked. Superior ice coverage. (How do we get the ice to the arctic? And why no Pacific icebergs and Titanics?). I called a friend today. Coldest winter in memory. And on both issues (I can't unambiguously say "fronts" on a weatherblog) it's going to be cold for a few more weeks.

Yes, there is a "Hell, MI" (Livingston County near Pinckney/Brighton). And it is frozen over.

Oly Girls said...

paulac569
3" and continuing in olympia, but looks like clearing to the south on radar...started to drive to Tacoma at 6:00p but decided to reconsider and returned home.

The Drennans said...

Yep-- definitely over 1/2". 9:50 in Shoreline and we have about 1.25". Light snow looks like it will continue for a few hours. Roads are varied, some busier roads are slushy, but many icy.

Oly Girls said...

3" and counting in Olympia at 9:45pm but looks to be clearing to the south on radar. Started to drive to Tacoma at 6:00 but reconsidered and returned home Looks like the right decision...

Christina Wilsdon said...

Drove home from Lake Forest Park to Cottage Lake...plenty of snow and all of it sticking, sliding on even shallow hills, a few cars in ditches along the way...was a tricky drive even staying on main roads in an AWD Subaru. (And yet some idiot honked at me for driving too slowly for his taste...sheesh!) Safe travels everyone, glad to be home...

Not Gonna Blog said...

Two inches so far in Wallingford, still coming down hard. An inch on main roads, and an inch and a half on side roads. Starting to see some cards with problems on hills.

Dana said...

Roads are pretty bad in downtown Bellevue. We had to park and walk home.

Linnea Emigh said...

About 2" in Shoreline, and still coming down. How certain are we that it will all melt tomorrow?

JetCity Jumbly said...

1.25" now in Broadview, and now it's snowing harder...

JetCity Jumbly said...

1.25" now in Broadview, and now it's snowing harder...

bethday said...

When we went out for a walk almost an hour ago there was about 1" to 1.5", sticking firmly to the roads, and it's still coming down strong here in Crown Hill.

amos said...

#fail
But you forecast weather, so expectations were not high anyways

Yvonne Herbst said...

It is 11PM here in Everett and we have close to 3 inches and it is still coming down quite hard.

James said...

2" and still snowing near Burton on Vashon Island. Roads are pretty treacherous.

Sharon said...

In University Place with at least four inches and snow is still falling.

Not Gonna Blog said...

And 3 inches in Wallingford now, still snowing.

JewelyaZ said...

Bellevue @ 210' ASL with 1.75" of fluffy crunchy snow... and still coming down a bit. 30F here now at 1 am.

Unknown said...

About 2" in Shoreline. Everything is covered and roads are tricky. Seems like it's snowing less. Sooo pretty.

Jóhanna said...

What would normally be a 25-minute drive from Bothell to Seattle took an hour at around 9:30pm... several inches in Mill Creek, roads with any elevation were a mess. Got out our XC skis in Roosevelt and went skiing for an hour around streets and parks... definitely 2-3", if not more.

Rebecca Bush said...

At least a couple of inches here on Capitol Hill.

RLL said...

Hilltops just south of Chehalis. There was about 4 inches of snow when we went to bed at 10, looked about the same in the middle of the night, and finally stepped out onto the deck and measured, 4 inches even. Temperatures staying within a degree or two of 32.

Colleen said...

I wonder if north Whatcom County is the only place in the state of Washington that didn't get so much as a single snowflake out of this weather event. :-/

Targhee said...

5.0 inches here in North Tacoma, near UPS. Enough for me to ski on last night (after coming home from a business trip to Mexico City). I think the forecasters missed on this one, just like Portland. Fine with me, since I got a rare lowland ski in!

Trevor said...

Don't worry Colleen, you got wind!

MimiTabby said...

such a party pooper! we got 1.5 inches on Beacon Hill, but it was unsuitable for a snow man. very disappointing, but beautiful.

i wish you'd turn off comment moderation, all it does is make your guests crazy and weeds out people with poor typing skills or vision problems.

LewisLucanBooks said...

I'm between Chehalis and Onalaska, up about 600 feet. Lewis County in the Napavine Triangle. 5" on the deck, this morning. Already beginning to melt and drip.

The Wiz said...

Cliff, I really enjoy your blog as do many of my friends and colleagues. I eagerly await the post mortem on this one.

Michael Snyder said...

We had 3.0" officially in Normandy Park.
I saw several cars that slid off of roads, and numerous vehicles were abandoned on Hwy 509.

I think this is a forecast were a simple look at the doppler and the Temp/DP made it rather easy to see a decent snowfall was on its way.

Jackie Long said...

Just as you explain in your wonderful book "The Weather of the Pacific Northwest", calling snowfall accurately here is tricky at best. I look forward to hearing how it was that you missed the call on this one, along with all the other meteorologists around here.

Pete Madsen said...

Couple of inches here in Olalla. The roads were treacherous last night, suspect they're ok now, but haven't been out myself. The snow is still clinging to the trees, and looks beautiful as befitting our only snow event so far this winter.

On an unrelated subject, I was looking at the Seattle area mesowest map, and was again struck by the "outlier" status of the temperature reading at the Bremerton airport station, particularly when I looked at the graph. There has got to be some problem with that...I wonder if there's any way to fix it. The temperature readings there haven't tracked others around it for quite some time now.

MyronsWorld said...

2.6 inches in Capitol Hill. Cliff, we go through this every friggin time there is a snow event. Forget the models and use common sense. You had an extremely cold air mass. Even a weak disturbance was going to ignite it. The dew point spread was closing rapidly in the pm and there were already fairly heavy bands of snow falling less than 100 miles to the south. Even by noon, it was very obvious to me from looking at just the raw data, that we were going to see more than just a half inch.

Michael Snyder said...

Be carefull you guys before beashing Cliff to much, get your own blog and make predictions in advance and lets see how they turn out.

Lots of after-casting here.

I agree forecasters got caught up in the model details when you can throw them out 3 hours prior to an event. Am Anemometer, a barometer, temp, dew point and watching the good old doppler takes front stage at that point.

But post your predictions here first so we can see how you called it BEFORE it happens.

Rod said...

Thick skin is a requirement of being a weatherman/weather woman.

Also a plus: A quick knee to the groin as demonstrated by the Weather Channel's Jim Cantori.

I would hope that Cliff knows that we are all in awe of him.

Colleen said...

Mmm, no, definitely not in awe of Cliff (though I love his book & thoroughly enjoy this blog), but I don't see any "bashing" going on here. It's dialogue. Nothing more, nothing less.

Ron Bodey said...

Wow... inches are really multiplied in comments from neighborhoods in Seattle.

Unknown said...

I also work swing shift, Capitol Hill. When snow started following there at 6pm, I should have left. My car is not bulletproof. They let me leave at 7pm, but I couldn't get ahead of the snow in Redmond. My first 2 months living there and I was not prepared for the slick roads. I got caught on 133rd off Avondale along with about 20 or moe other cars. 2 slid into me, but no real damage.I was in the car when one hit me. Thanks to the kindness of strangers, my car was pushed to safety and I got a ride to a 24 hr QFC where I stayed till 7am. One of the employees drove me home. I have lived here 30 yrs and never been through such an ordeal. The Puget Sound area is never ready for snow.