A Wet Week Ahead

I don't know how many of you look at these maps, but sometimes they are quite useful.  This is the GFS 12z Ensemble Spaghetti Chart for hour 168...next Friday.  It shows the 558 dm 500mb height line for each of the ensemble members.  Basically the model is run many times (something like 20?) after the initial conditions are changed slightly or "perturbed".  We often get an idea of how confident models are of future weather patterns by seeing how well the different "versions" line up.  What I notice today is a heck of an agreement for westerly flow continuing through all of next week.  That's unusual for 7 days out in time.  Usually the different ensemble members are really diverging after 4-5 days.  Notice how the lines are clustered very tightly in the Eastern Pacific and into California/Oregon.  So what does it mean?  It's going to be wet and cool for Oregon's Spring break.  You can find the spaghetti charts on my model page here.  As always, you can click on the picture here for a larger view too.

I'm posting early today because I'm procrastinating doing the weather graphics for a few minutes...a rare moment of inspiration.

Enjoy the bright and warm sunshine tomorrow.  It still looks like 60 degrees or so in the afternoon.  Cold front moving in Sunday brings the opening round of the next rainy period.  I'm working this weekend for Stephanie too, so if I get REALLY inspired, I might post again...Mark Nelsen

Comments

[Professor Mback (TTD)]

Hmmmm, I am not an actual professor it should read. However, I am a former spelling and typing champion.

[Professor Mback (TTD)]

Well, this about sums it all up. I think we are all going to die soon based on this:

http://www.kptv.com/weather/15708160/detail.html#

Nice knowing you all!!!!

Professor Mback

Disclaimer: I am not an actually professor. In no way is this intended to poke fun at Dr. Rob and all he has done for this blog...

[Sandi (Wilsonville)]

I'm sorry to hear about your loss, Mat.

[Andrew---Ellensburg, Wa and Portrland, Or]

Report of snow coming down below the 1000 foot level in the NW Oregon Coast range.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Hmmmm then we take a look at the same model 0z NAM but the windcast.
http://img03.picoodle.com/img/img03/4/3/26/f_FridayMarchm_621cc12.png

Appears to show an OLM-EUG of -22 to -23
OLM-PDX itself is -11 to -12

[Sandi (Wilsonville)]

Just returned to Wilsonville from Tigard. Heavy rain coming down.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Friday, March 28th - 5:00 PM
00z NAM
http://img27.picoodle.com/img/img27/4/3/25/f_FridayMarchm_7debeaa.png

OLM-EUG -18 to -20mb. Interesting.
What I notice about this low is that it is a loner storm. No real surface lows ahead of it to create large scale low pressure which wouldn't allow for much of a pressure gradient to develop. Well we will just have to see if future runs pick up on anything.

- Dr. Rob

[Steve Pierce (Vancouver, WA.)]

WINDSTORM FRIDAY???

This certainly caught my attention. I count 20mb's from Eug to Oly. That would be good for almost 60mph, maybe a bit more if the NAM has anything to say about this. Great cross valley line up of the isobars as well. GFS has same path, yet weaker low. Only 15mb gradient from same to locations. 500mb trough looks to be in good position for something to spin up.

See enclosed.

http://www.atmos.washington.edu/mm5rt/data/current_nam/load.cgi?images_d2/slp.72.0000.gif
and
http://www.atmos.washington.edu/mm5rt/data/current_nam/load.cgi?images_d2/500t.66.0000.gif
and
http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?mm5d2_e_wssfc+//72/3

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Camas Momma,
Don't apologize for not posting weather information. The simple fact is for nearly every family a pet becomes a family member. Myself I am partial to Cats as well. I know how difficult it is....
Hang in there Mat.

- Dr. Rob
(Seriously when I type "Dr." I don't feel worthy to do so) lol

[Camas~Mom]

Mat - I'm sorry to hear about your cat. We had to put our 20 yr old kitty to sleep in early January. It sucked, but she too was suffering (mostly just a worn out body). May I recommend getting a very small (best age is 7 weeks) kitten - they'll be in season very soon. We were able to find 2, they're 4 months old now and such a joy. It really has made our loss much easier to take. But you have to find them really small so you can mold them into the kind of kitty you enjoy (in my case, ones that can handle young girls).

Sorry, I don't have anything weather related compared to that. Our pets are such a part of our lives....

[Mat-ne portland]

Thanks Larry. Its harder than I thought. She got put down about 5:15 tonight and now I'm getting drunk. Sometimes I feel better when I drink. Nice to see snow coming low over the next couple of days. It'll sure be cool to see it in the air if thats what we get though.

[Tyler Mode in NW Vancouver (Hazel Dell)]

Posted my pictures of the rainbow and cloud structure on my myspace. www.myspace.com/nove4dammit

[Andrew---Ellensburg, Wa and Portrland, Or]

Snow Advisory

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE PORTLAND OR
233 PM PDT TUE MAR 25 2008

...SNOW LIKELY TONIGHT THROUGH EARLY THU IN THE CASCADES FOOTHILLS
AND COAST RANGE..

.AN UNSEASONABLY COOL WEATHER PATTERN WILL AFFECT THE REGION
DURING THE NEXT SEVERAL DAYS. A WEATHER FRONT WILL MOVE OVER THE
AREA TONIGHT AND BRING RAIN AND LOW LEVEL SNOW TO MUCH OF THE
AREA. SNOW LEVELS WILL BEGIN ABOVE 2000 FEET...BUT WILL LOWER
OVERNIGHT TO AROUND 1000 FT. THE SNOW LEVELS COULD DIP EVEN A BIT
LOWER WEDNESDAY NIGHT. SNOW WILL TAPER OFF THU...BUT ANOTHER COLD
WEATHER SYSTEM WILL ARRIVE ON FRIDAY...POSSIBLY WITH MORE LOW
LEVEL SNOW.

ORZ003-004-WAZ020-261230-
/O.NEW.KPQR.SN.Y.0021.080326T0700Z-080327T1200Z/
COAST RANGE OF NORTHWEST OREGON-
CENTRAL COAST RANGE OF WESTERN OREGON-WILLAPA HILLS-
INCLUDING THE CITIES OF...VERNONIA...JEWELL...TRASK..
GRANDE RONDE...TIDEWATER...SWISSHOME...FRANCES...RYDERWOOD
233 PM PDT TUE MAR 25 2008

...SNOW ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 5 AM PDT
THURSDAY FOR THE COAST RANGE OF CENTRAL AND NORTHWEST OREGON AND
THE WILLAPA HILLS OF SOUTHWEST WASHINGTON..

THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A SNOW
ADVISORY FOR THE COAST RANGE OF CENTRAL AND NORTHWEST OREGON AND
THE WILLAPA HILLS OF SOUTHWEST WASHINGTON...WHICH IS IN EFFECT FROM
MIDNIGHT TONIGHT TO 5 AM PDT THURSDAY.

SNOW SHOWERS WILL BEGIN LATER THIS EVENING AND INCREASE IN
INTENSITY OVERNIGHT. SNOW LEVELS WILL LOWER TO 1000 FT BY EARLY
WED AND MAY DIP TO NEAR 500 FT LATE WED NIGHT. SNOW ACCUMULATIONS OF 2
TO 4 INCHES ARE POSSIBLE BY MORNING. AN ADDITIONAL 1 TO 4 INCHES OF NEW
SNOW IS POSSIBLE ON WED. SNOW SHOWERS WILL CONTINUE AT TIMES WED
THROUGH WED NIGHT BEFORE TAPERING OFF THU MORNING.

A SNOW ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE PRIMARILY
TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW COVERED ROADS AND
LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.

[TheTriforce Silverton OR 360ft]

Thanks Pressure Gradient for the response. So it sounds like the convective air mass isn't even here yet?

Wow! Rod is forcasting a mix to the valley floor? That is so unlike him. Usually: he is conservative till the last minute. I am at wow 49.8 now and dropping steady! Overcast, DP 32. Looks like we might have some fast temp drops due to the lower dewpoints tonight?

[Tyler Mode in NW Vancouver (Hazel Dell)]

Great rainbow out there and now a good view of an impressive storm structure.

[B1900 Pilot -- Bethany, OR (400')]

Rod Hill calling for a mix to the valley floor for tomorrow. Anyone else care to make a forecast?

My Prediction: Mix in the air above 700' (over Sylvan Pass) sticking above 1000'. No accumulations on the valley floor.

[Tyler in Vancouver]

KM Mountain is about 700' in elevation. Looks like a shower is about to move through here.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

[Radar Loop]
http://www.wunderground.com/radar/radblast.asp?zoommode=zoom&num=6&delay=15&rbscale=0.24413478260869564&scale=0.367&noclutter=0&ID=RTX&type=N0R&lat=45.51471710&lon=-122.50512695&label=Portland,%20OR&showstorms=0&map.x=464&map.y=265&centerx=402&centery=210&lightning=0&showlabels=1&rainsnow=0
Batch of showers approaching PDX. Some areas showing a little bit of intensification.
[IR Loop Enhanced]
http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?ir4km_enhanced+12
Looks like one area of showers moving onshore now. The next area with the accompanying shortwave is approaching 129 W and even farther offshore a vast area of cold air cumulus is present. Looks like there is fairly good dynamics/lift with the cold air mass as well.

- Dr. Rob

[Luvry]

Wind is definetely picking up out this way in Tanasbourne...pretty raw out there right now, moderate shower rolling through.

[Luvry]

Tough to tell Tyler...what's that elevation anyways?

[Tyler Mode in NW Vancouver (Hazel Dell)]

Snow flakes at KM Mountain?
http://wsdot.wa.gov/traffic/swcam.aspx?cam=1251

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Hey guess what, that was me.

Temp: 51.8
Dewpoint: 30
Wind: S @ 5.8

The leading edge of the colder air mass has now arrived.
Looking at SPC parameters...
http://www.spc.noaa.gov/exper/mesoanalysis/frames.php?sector=7
SB CAPE of 250J/kg has developed along the Washington Coast and sections inland as well.
MU CAPE of 100J/kg has developed along NW Oregon and all of western Washington.
LI still remains unfavorable
Mid-level lapse rates of 7c/km are nosing into NW Oregon and 7.5c/km across western Washington.
Low-level lapse rates of 8 to 8.5c/km across western Oregon and 7.5 to 8c/km across western Washington.
IF we can manage sun breaks as we had today tomorrow the atmosphere should destabilize sometime after noon. If we do not achieve sun breaks we likely will have a hard time reaching the convective temperature which convective initiation occurs. It's a toss up really.
I will be monitoring the parameters tomorrow and update them likely too.

- Dr. Rob

[Boring Larry in Cherryville el.918]

sorry to hear, Mat.....think good thoughts...

...got to spend a couple hours in the sun in Colton area, it was nice about 52 for a little while...long enough to kick some horseshoe b***...and now possible snow by morning....gotta snatch those spring moments when you can!
...raining and 42.5 up here currently...

[Mat-ne portland]

Thanks guys. I appreciate it.

[Luvry]

haha, of course Mat, guess it is a little late :)
Sorry to hear about the cats. I know when I lost mine about 2 years ago, it was tough, was with the family for 15 years. My condolensces bro.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Exiting* our area....
I need an 'edit' button

Temp: 47.1
Dewpoint: 32
Wind: Calm

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Mat,
Sorry to hear that.
We lost both of our cats to the same thing back in 1997 within a 2 month period right after the big December 1996 ice storm.

[Mat-ne portland]

Luvry, this early? I thought it was late. Besides, I'm putting my cat to sleep today. She has lymphoma and is suffering now. I felt the need for a few drinks. I'm really going to miss her.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Lol

Well scratch that idea of capping day time temps very much. The clouds are not increasing quickly enough with quite a few sun breaks evident. I'm up to 44.8 now. A transitory ridge of high pressure is over top of us and is slowly existing our area, maybe too slowly.

[Luvry]

Mat, drinking this early?

[Mat-ne portland]

C mom, youprobably won't have any snow this go round. Maybe only us lowlanders will. hehe

[Camas~Mom]

I had to turn the heat up this morning for my girls who were huddled in their beds freezing - poor things! I'll hook up the station this afternoon so I can get a good reading tonight of the temperature.

Looks like it's gonna get exciting over the next couple of days for us up here! I hope you guys get the Big March Snow 2008 (I really do)! Only bummer is that means I'll get more, and I'm all done with snow for this year. ;)

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Heat,
What I was referring to was if we can cap day time high temps today and when the colder air arrives late tonight-tomorrow that gives us even a better chance of snow below 1,000'
The convection shouldn't develop until Wednesday.

[TheTriforce]

Here are my soundings without sound. It touched 32! WOOO HOOOOOO!!!!! First time since that mini artic event in Jan. :) DP is not recording so I think my weather statoin doesen't record dew below 32F. oh well. Pressure Gradient: We don't want cloud cover because that will limit convective activity which brings us "exciting weather." plus chances for lower then forcasted snow levels too.

I told you guys we would get blasted in the spring.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

Good morning everyone.

8:30 AM and just now cracked freezing. Fairly impressive.
If clouds increase enough to limit the day time heating I might not reach 45. Tomorrow-Thursday night looks interesting.

[Sean (Lebanon, Indiana)]

Also, I'm glad to see that Spotter Training courses are being held by the Portland NWS. Hopefully all you weather geeks make plans to attend a training session. Talk about a weather geekfest! :)

[Sean (Lebanon, Indiana)]

Wow, that's pretty chilly there. Looking at the records for the next few days, which are in the upper 20s at the airport. Could be getting close to setting some record lows.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

28.2

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

28.6

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

28.9 crystal clear skies. It looks like a Winter night to me.

[Steve Pierce (Vancouver, WA.)]

** WEATHER GEEK ALERT **

Ok, I may have been hibernating for the past 2 months weather wise, but I have been awaken promptly by what I saw on tonight's MM5. The 0Z GFS and NAM both have very interesting soundings for this week at PDX and other locations in the Pac NW. At PDX, constant 850mb temps of -7 to almost -9, thicknesses of 514-519dm and ample moisture (albeit showers). It seems like each run just looks better and better. In fact, the NAM and GFS both give accumulating snow to PDX overnight Wednesday night into Thursday. I would be shocked if this actually happened, but I have to say it really looks like some March daily temp records could be in jeopardy. The GFS decoded even shows KVUO dropping into the teens next weekend in a cold, clear northerly flow after the trough this week with perhaps some snow around on the ground. BURRRRR!!!!

Dare I say this looks like the best shot for lowland snow all winter,,, now that it is spring? STAY TUNED FOR SURE!

SP

[TV Weather Producer]

Quick Met 101 lesson: Graupel

What is it ? AMS Glossary says:

Graupel—Heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except for the size convention that hail must have a diameter greater than 5 mm.
Sometimes distinguished by shape into conical, hexagonal, and lump (irregular) graupel.

Weather.com says:
A form of frozen precipitation consisting of snowflakes or ice crystals and supercooled water droplets frozen together.

So just a quick heads up on what it really is. Graupel starts off as a snow flake. It passes thru supercooled water and forms ice crystals on its core and you end up with a slushball basically. You can't have snow and graupel at the same time. Its either snow or graupel. IT CAN'T BE BOTH !!!!!!

I think its really easy to get them mixed up in these parts. I recall a private met telling me that 9 times out of 10 that it is snow during fall-winter-spring. We are more likely to see graupel with convective events like the storms that roll off the Cascades and stronger storms that form in the valley during the summer. I think all we see this week is snow.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

33.6

Be back later.

[GradientKeeper~AtmosphericWrath -Far S.E Portland-]

My updated thoughts are as follows....

Valley floor - Snow/graupel mix at times is possible
500' to 750' - Wet snow at times is possible
750' to 1000' - Wet snow and accumulating snow at times is possible
The best chance for ANY type of frozen precip is going to occur if you can manage to get right under a heavy shower as the moisture will likely be of a convective nature and lowering of the snow level will rely heavily on precipitation rates to progressively drag down the freezing level as the precipitation is falling.
I find it very difficult to imagine any "real" snow below 500' as this is late March now. Also do not forget these systems are traveling 500+ miles across a 40-50f Ocean.

- Dr. Rob

[pdxops1]

Pdxops1 here, where did my name go.

Runrain, please don't make me stay in Arizona, I'll survive for a week, but don't even get me started on that horrid state. Just a trip to the inlaws combined with some hockey, some baseball and the NCAA tournament. Good times!!!!

Seriously though, I will be bummed if you guys do get some snow while I'm gone. But have to say, I will be laughing at my co-workers if things do go to heck at work because of the weather :))))))

[Tyler Mode in NW Vancouver (Hazel Dell)]

Pictures from the last few days up in Longview...

http://www.flickr.com/photos/9203111@N06/

[Jesse-Orchards]

**Correction**

Portland had a late snowfall April 1st, 1936

The latest ever was actually April 22nd, 1961.

Not sure where I got April 26th, lol.

[Jesse-Orchards]

Mat, this is about the closest we get to arctic air in late-March.

A "true" arctic airmass (highs below 32, lows below 20) has NEVER invaded NW Oregon/SW Washington after March 15th. The airmass coming in over the next couple days is about as cold as it gets for this time of year.

That said, snow to the lowest elevations is still certainly possible this late in the season, and this setup will be no exception.

Portland and Vancouver have seen accumulating snow as late as April 26th, 1936.

[Mat-ne portland]

What we need is a true bonified arctic front to sag south for Portland to see any sticking snow this time of year. I think a few of us will see snow in the air (perhaps in the morning hours) and then cold showers and possibly hail. 1500 feet and above might see sticking snow overnight briefly before it melts as I just don't see temps going much below 32 with cloud cover. Or, maybe it'll snow over my house and nowhere else. haha. Still wanting a positive FAB 5 update after the meeting. Thanks Fab