Here’s what we are thinking for the lower snow levels this weekend:
As mentioned in the previous post, there’s nothing too exciting coming except that most of us will at least see snow in the air sometime between Saturday evening and Sunday night, but it’ll be tough to see much accumulation to the lowest elevations. I mentioned this type of setup 8 days ago during that “winter is cancelled” diatribe during the 10pm newscast. Sure, we can still get these wet snowfalls that don’t last long, but we’re done with actual snowstorms and cold spells (just barely survived that one).
That said, a -7 to -8 degree 850mb temp and 500-1000mb thickness around 520 is good enough for sticking snow to sea level if you get the moisture at the right time of day. And from late Saturday evening through Monday morning, plus again Tuesday, areas up around 1,500′ will score quite a bit.
So the “threat period” for snow in the lowest elevations is late Saturday night through Sunday evening when the moisture runs out. From 9am-5pm Sunday it’ll be too warm in the lowest elevations too due to the February sunshine unless we get some sort of very heavy showers.
Another thought…here’s the 12z 4km WRF-GFS snowfall forecast from 4pm Saturday to 4pm Sunday. When I start seeing “fingers” of snow moving out into the valley hills as I see here, that’s when we get very close to sticking snow in the lowest elevations.
Chief Meteorologist Mark Nelsen


so i heard snow levels here in Washington 800-1000ft im about 700ft so i should climb to the top of trees to see something lol
UPDATED: More and more talk about Valley Floor snow, even a threat through wednesday….
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
228 PM PST FRI FEB 24 2012
.SYNOPSIS…A COLD FRONT WILL SPREAD RAIN…MOUNTAIN SNOW..AND GUSTY
WINDS TO THE REGION TONIGHT. MUCH COLDER AIR WILL SETTLE IN BEHIND
THE FRONT LATE TONIGHT…AND SNOW LEVELS DROP TO NEAR 1000 FEET BY
SATURDAY MORNING. POST-FRONTAL SHOWERS WILL CONTINUE THROUGH
SATURDAY EVENING. THE COLD AIR WILL REMAIN IN PLACE AS A WEAKER
DISTURBANCE MOVES THROUGH SUNDAY…AND LIGHT SNOW ACCUMULATIONS ARE
POSSIBLE DOWN TO THE VALLEY FLOOR. THERE WILL BE A BREAK IN
PRECIPITATION MONDAY BEFORE ANOTHER COLD STORM ARRIVES MONDAY NIGHT
OR TUESDAY.
A VERY COLD AIRMASS WILL REMAIN PARKED OVER THE AREA AS A SECONDARY
SHORTWAVE MOVES THROUGH SUNDAY. SHOWERS WILL BE ENHANCED LATE SUNDAY
MORNING THROUGH AND SUNDAY EVENING WITH THIS DISTURBANCE. SNOW LEVELS
WILL BE ESPECIALLY LOW…WITH POSSIBLY STICKING SNOW IN THE
WILLAMETTE VALLEY. IN AREAS WHERE THE SNOW WILL STICK…SNOW AMOUNTS
WILL BE LOW…LESS THAN AN INCH…WITH BREAKS BETWEEN THE SNOW
SHOWERS.
.LONG TERM…MODELS CONTINUE TO SHOW THE UPPER LEVEL PATTERN AS ONE
OF COOL NORTHWESTERLY FLOW WITH SHORTWAVES MOVING THROUGH THE
PACIFIC AND PROGRESSIVELY CARVING A TROUGH OVER THE WESTERN U.S.
DURING THE BEGINNING OF NEXT WEEK. THE GFS…ECMWF AND GEM ARE IN
GENERAL AGREEMENT WITH THE OVERALL PATTERN AND RELATIVELY CLOSE WITH
TIMING OF INDIVIDUAL SYSTEMS. A SHORTWAVE RIDGE MOVES ACROSS THE
PACIFIC NORTHWEST MONDAY NIGHT…THEN A TROUGH DIGS SOUTH OFF THE
WEST COAST TUESDAY WITH A COLD POOL OF AIR SLIPPING IN OVER THE
NORTHWEST…AGAIN BRINGING SNOW LEVELS NEAR THE SURFACE WED. ONCE
AGAIN IT APPEARS THE COLD AIR ARRIVES WITH SHOWERS AND IS QUICKLY
PUSHED OUT OF THE AREA AGAIN BY A BUILDING UPPER RIDGE. THE GENERAL
SUMMARY OF THE EXTENDED IS A PROGRESSIVE PATTERN WITH COOL SHOWERY
WEATHER BEHIND INCOMING SYSTEMS
We’ve been through this pattern so many times: watching the radar, coast range eating up showers, and hoping that blob passes over your house. Disappointing in January, but I’ll take what I can get in late February. Maybe we’ll be surprised, but 850 temps less than -10 make it seem improbable. I’ll pay more attention to GOLU.
Airplanes and helicoptes have been buzzing all afternoon here which is very unusual for this area where nothing ever happens.
Airplanes come once in a while like yesterday I saw a guy flying real low over town but that was just a one-time deal.
Wondering why the NAM is always colder?
As I recall:
The NAM was pretty much spot on in November 2010.
The NAM was pretty much spot on in January 2011.
The NAM was pretty much spot on in February 2011.
The NAM was pretty much spot on in January 2012.
It seems that when it comes to cold anomalies, the NAM’s performance has been pretty stellar in the short range. More-so than the GFS or the Euro.
Will the NAM be pretty much spot on in February 2012, make it 5 for 5? We shall see…
How does NAM differ then the GFS?
Also W7ENK will you post a more detailed review of the NAM during those times please?
The NAM was too cold at the surface in January.
As with the similar scenario we had this time last year in Vancouver… If you can get a good shower to roll over your area in the evening you could see a decent accumulation that will stick around overnight and melt off in the morning.
If you get that shower during the day it may be a brief bout of snow and quick melt under 1000′. Alas at this time of year with a strengthening sun you need -10C or colder to get a real snow event in the valleys that can hang around. Otherwise it is brief accumulations at best that melt off quickly.
Just a few pics of some clouds and a corona this morning.
They are the first 3 pics.
http://weathercrazy.smugmug.com/Landscapes/Winter-2011-2012/20963877_fTdBpb
You live next to a pyramid?!? O_O
I wonder if those are high enough to capture sunlight after dark? In the summer, of course… Noctilucent clouds — they have a similar looking structure. Question then becomes, how did they get up there? Typically, they’re blow-off from ultra-high topped thunderstorms, but this time of year? Possibly vapor from entry of some celestial body?? Who knows… It could just be a cloud!
You’re drinking a corona that early in the morning?
One year ago pics from Long Beach:
http://weathercrazy.smugmug.com/Landscapes/BeachSnowFebruary2011/15980154_FCcGxg
Nice to see these low clouds that were over the area rapidly moving north.
http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?vis1km_west_full+6
Sunday lookin pretty chilly Seattle area, couple inches accum on the hilltops eastside look like a good bet
http://www.atmos.washington.edu/mm5rt/data/current_gfs/load.cgi?images_d2/ww_snow24.72.0000.gif
http://www.atmos.washington.edu/mm5rt/data/current_gfs/load.cgi?images_d3/ww_snow24.60.0000.gif
Winter Weather Advisory up for the foothills above 1500′.
Low of 29 this morning.
OK I’m going to start a poll: snow depth, location, elevation.
NE Pdx 0″
Elev. 240′
There I got it out of the way early.
SW Beaverton – 0″snow 0.4″ rain
[Milwaukie] Elev. 155′
We’ll be lucky if we even get any rain this weekend after tonight’s front moves through…
Wake me up when the sunny 70s are an the way.
Longview,Wa Elev. 270 something. 0″- trace.
2/23/2012 Oregon (All) Temperature Summary
Warmest:
High:61 at AGNESS2( 247 ft)
Low: 41 at BROOKINGS(79 ft) & Fremont Bridge W(270 ft) & John Day River B(305 ft) & Rowena(107 ft)
Coldest:
High:19 at HOWARD Mt Howard(8150 ft)
Low: 9 at CRAZYMAN FLAT (6100 ft )
Largest Diurnal Change: 33 degrees
DW9301 Klamath F (54/21 ) (4121 ft )
SELDOM CREEK (50/17) (4875 ft)
BEND WATERSHED (46/13) (5330 ft)
CRAZYMAN FLAT (42/9) (6100 ft)
Heaviest Rainfall:
0.37″ at Aurora State Air(194ft)
So far in accumulations: this is what i see at this point!
sea level-200” snowflakes-1”
300”-500” trace-2”
600”-1000” 1-3”
1000”-1500” 3-6
1500”+ – 6”+
++++++POSSIBLE+++++++add an inch or so if u get an extremely heavy shower
There you go forecasting in 200-foot increments! Mark wouldn’t be too happy if he read this!
Yeah i know but its for people who r desperate to know what they might see
” means inches, ‘ means feet
Oh just shutup, c’mon now!
Anybody else catch Oregon Field Guide on PBS this evening? Nice segment on the glaciers of the Three Sisters. Using old photos taken over the last 100 years the scientists doing the study were able to document the decline of 40 to 51% of the volume of the glaciers. Matching the climate records (rainfall and temperature) they were able to ascertain that warmer temperatures are the cause of the effect. I climbed the Sisters 34 years ago and remember a rather treacherous terminus at the bottom of Collier Glacier. I wish they would’ve shown that tonite. Guess I’ll have to make another climb and check it out!
Oh Boydo, you’re just an alarmist!!! Pretty soon you’ll have nasty emails sent your way…
I’m kidding of course, about the first sentence.
But yet, I’m a very skeptical alarmist!
Bring on a foot of snow on St. Patrick’s day! I want to shock everyone who says we can’t have big snowstorms after early March!
great video of navy seals dropping into premier of Act of Valor in LA.
amazing.
if video prompts you to open in new window, click on it.
This is a great sign for snow this weekend.
Hey Mark, for Longview at about 270 FT elevation how much would you expect between that time still just a dusting?
Yeah and what about 400′
Sounds like tree climbing time!
Yeah it sure does lol:))
hey about me puyallup,wa at about 700ft
there is suppose to be a what in there lol
A little away from the Portland area again Mark
Up here in Tacoma I put my snowboard back together again after yesterday’s wind took it apart. I have a much sturdier one now with many more nails in it this time. It will take hurricane to take this one apart.
I am at 465 feet here in Tacoma and a decent ways from the water. My thinking is much like yours here. Saturday night into Sunday. We’ll see what I end up with if anything. I am not betting the farm on anything significant.
So if ur at 400-500” that means TRACE to 2 Inches possible???
So it went maybe some snow next weekend, to no snow, to snow this weekend. We will just have to wait and see what happens. I do hope we get a little accumulation at least.
I think it just went from big snow and arctic blast to a dusting on the grass (in the lowest elevations). At least in my forecast thinking. The only reason I didn’t make the exact same graphic yesterday was because the cold & snowy weather party needed to be cancelled first.
I really like a dusting on the grass!
Mark, if no one sees a snowflake…you can always show them the picture i sent. That way they would at least get to see ONE snowflake
44/31 up here today. Currently mostly clear and 34 with a beautiful sunset.
Back in early December I predicted that I would get 10″ of snow during the month of March. I may or may not, but looking at the models it is certainly a possibility.
Hello old man winter you have reached springs voicemail sorry im unable to take your call but you had your time so please stop teasing us lowlanders!!!!!!!
Anyone else in for a shallow snowstorm!
National Weather Service Portland or
206 PM PST Thursday Feb 23 2012
Generally…expect cold
air and snow showers in lower elevations…but no sign of a deep
significant snow storm at this point. Kelson
Beggars can’t be choosers. But I hope they are very wrong. I want to see TV mets out on freeway ramps explaining how they got snookered.
Always great fun to see those folks out there trying to explain how it’s only going to be a minor inconveince!
18z GFS = on and off chances of snow for the west hills and at times below for the entire run. Those are us who are close to 1,000 feet could do quite well.
May not seem like much to you…but I really like to see snow in the air!
You may have to climb your tree in order to make a snowball, though…
I would love to see it too! My little family is house sitting for some friends up on Bull Mtn.. they’re at 750 ft.. I’d like to see some snow!
Well, this makes me feel a little more optimistic now.
Sorry kids, there will be church Sunday morning!
Unless we get a 3″ Vancouver Surprise in 1.5 hours again like last year.
Stop in at the little church by Zigzag on the way to Mt Hood on Sunday morning. Give thanks for the fresh pow that will be falling!
I LIKE SURPRISES!!
It’s all about location, location, location!
1
Not
No.
Hmmm…
Sounds like fun to see snow!