Comp Day Extra

Slp_63_0000 Slp_72_0000_3 I’m currently using up 3 "comp" days…basically taking 3 days off in exchange for working that snowy Sunday back in late January plus this past weekend.  My daughter had a planned preemptive surgery at Emanuel hospital today, so yesterday and today I didn’t look very closely at maps.  But after running into several people at the hospital that thought it was going to snow in Portland soon, I figured I better take a look.  The last I had checked it appeared that we’d see -7 850mb temps and snow sticking maybe down to around 1,500′ sometime Wednesday-Friday.

So what do I see?  Lots of interesting weather possibilities, which may or may not have an impact on normal folks here in Portland. 

First, the snow:  The forecast 850mb temps haven’t changed from what was shown Sunday for late this week.  At the end of March, to get STICKING snow down to the lowest elevations, you’d need all parameters to come together perfectly.  Steady, heavy precipitation sometime between the hours of 10pm and 8am (nighttime), no mixing south wind, and that cold atmosphere we know is coming.  First off, let’s remember the NAM has not done well this winter and in general doesn’t do as well as the GFS (for sure on low pressure placement!).  It shows a comma-type trough feature moving into the southern/central Valley late tomorrow afternoon, turning winds light through the Valley too.  This is very similar to the sudden 1-3" that fell one night this past winter from Woodburn to Eugene.  The 00z GFS has the trough a bit farther north, keeping the mixing wind going, plus the timing isn’t during the night, so we’ll get 40-45 degree rain in the city tomorrow afternoon.  I doubt we’ll get anything more than a dusting from 1,000-1,500′ between the Coast Range and Cascades the next 24 hours.  Maybe nothing at all below 1,500′.  I bet the west slopes of the Coast Range will see sticking snow down to 1,000′ since the precipitation will be more intense out there.  Thursday should be much more showery with sunbreaks.  This time of year we’ll be in the 45-50 degree range, so the snow level jumps up to at least 2,000-2,500′ in the afternoon, very similar to last Saturday.  Friday is very interesting with a surface low forecast to track towards the N. Oregon Coast, then move inland into S.W. Washington.  If the low is approaching the Coast in the early morning hours (before 8am), the brief offshore flow and steady, heavy precipitation COULD bring snow below 1,500′.  That’s a big IF.  So in general…those of you in the hills around 1,500′ will probably get a few shots of snow the next few days, with a dusting possible to 1,000′ in the late night hours.  Better chance for a dusting below 1,000′ in the Coast Range and Cascade Foothills.  Forget about it in the city…it would have to be a one-time freak occurrence.  It would be as crazy as…having a tornado in January in Vancouver…

A new wrinkle this evening is about possible strong wind:  As I mentioned, the 00z GFS MM-5 brings a surface low (while deepening) up into S.W. Washington Friday morning.  The 10-12 mb OLM-EUG gradient could produce south wind gusts of 30-40 mph.  The 00z NAM goes nutso…deeping the low to 985 mb up around Centralia.  This gives 20-24 mb. in the same area!  That’s major windstorm territory for the KLS-EUG corridor.  BUT…it’s the NAM, so I would discount it for now, but there’s always 12z right?  I’ve included both maps for comparison.  Okay, checking out for now, maybe an update tomorrow evening again…Mark Nelsen

177 Responses to Comp Day Extra

  1. Josh "THE SNOWMAN" from Everett, WA says:

    Good one Mat….are you drinking??? KIO KIO KIO

  2. Mat-ne portland says:

    Twinkle twinkle little Josh
    how he wishes he was posh
    up above the snowline so right
    he probly drinks and smokes weed all night.

  3. Josh "THE SNOWMAN" from Everett, WA says:

    Jingle bell, jingle bell, jingle bell Rob
    Jingle Rob’s blogging, Jingle Rob’s are king
    Blowing and blowing, that gradient way.
    In the Robby way…………..!!!!!!!

  4. Josh "THE SNOWMAN" from Everett, WA says:

    Dashing towards April
    And I think it’s gonna snow
    O’er the blog posts we go
    Laughing and smoking hay….hay, hay , hay
    I think I’ll drink tonight
    Mat is a goober and gay
    Dashing through the day, day , day, day ,day…..Mat’s gay
    Ok, current condtions….34.1….light flurries
    I think it is my turn..ha ha ha ha.

  5. llabrulf says:

    This is a first for me……..frontogenius…get out the thesarus but I get the point.
    not sure if it would count in Scrable………..watching sweetsixteenogenisus?
    DRAWN NORTHWARD WITH THE FRONTOGENESIS TAKING PLACE

  6. Mat-ne portland says:

    I’m at 38.5

  7. mark says:

    Anyone else concerned that we are still in the low 40’s?

  8. mark says:

    I have 43 here in Beaverton with partly cloudy skies….

  9. jacob BPA says:

    Here is the Pic of the Vessel

  10. Ryan (Walnut Grove) says:

    Its going to have to get a darn sight colder for anything at my place. After a free fall from 50 to 43 degrees in just over an hour (as the sun set) I’ve only dropped 2 degrees since to 41.

  11. jacob BPA says:

    FAB 5 ALERT
    Spring Storm 08
    Look for snow to Develop Early Morning switching over to Rain or a mix Later in the Day
    1-3″ is possible down to the Valley Floor
    Sat may Morning may hold some interest also
    The Fab 5 C130 is Being Deiced as we Speak
    TV will Taking off around 2am
    Steve is Currently Off the Astoria coast on the Research
    Vessel ” I cant Believe its not butter”
    Enjoy the Next 48hrs

  12. Paul(orPbo9) says:

    wow-
    NWS discussion:
    THIS WEEK IS PROBABLY THE LATEST I HAVE SEE THIS
    LOW OF SNOW LEVELS IN THE PAST 18 YEARS.

  13. Paul(orPbo9) says:

    Oh yeah, and if you whack the tree-
    you might want to have an umbrella over your head.
    If the tree is over 15′ tall…um…
    move your car?

  14. Paul(orPbo9) says:

    Wow- A little unsolicited advice-
    *IF YOU HAVE TREES THAT ARE IN BLOOM*
    Gently brush the snow off w/ a push
    broom. If the tree is big, smack it
    really hard w/your foot to give it a jolt. It would only take 1″ of heavy
    wet snow to snap the branches off of
    Plums and Cherry trees that are in
    bloom. Oh yeah, and forget about
    fruit on Pears, Apricots and many
    cherries this year. : (

  15. TheTRIForce says:

    It’s 43.0F and a dark storm front towards the west; clear skies overhead.
    Still the question remains: Who is going to get the showers? Will it be a Portland event where the valley misses out? A Salem event where the moisture goes there and PDX gets shafted? or everyone?
    If my comments are not on the first several ones then I will post my town and elevation.

  16. mark says:

    Wow…Everyone left..

  17. salemphil says:

    Hi all, just got back from Lincoln City/Newport today. Fishing and Crabbing sucked! Had some snow and rain mixed yesterday morning and lots of hail, especially this morning. Some snow on the higher hills also. Looking forward to tomorrow morning!! 🙂 Here is a link to some pics I took at the coast this morning and at the Van Duzer (sp?) Corridor and at Mill Creek Park, just west of Dallas on my way home.
    Enjoy
    http://www.flickr.com/photos/25105316@N04/

  18. mark says:

    New forecast by Mark Nelsen on the weather page…

  19. Steve_Salem says:

    Snow in Salem tonight??? Any thoughts?? I am new to this and trying to learn. I was with you guy’s throught the winter and thought that I would have to wait until next year. Guess I was wrong about that one also. Any help would be appriciated. Thanks

  20. Andrew---Ellensburg, Wa and Portrland, Or says:

    Snow Advisory now in effect for western washington, Portland may be next:
    Snow Advisory
    URGENT – WINTER WEATHER MESSAGE
    NATIONAL WEATHER SERVICE SEATTLE WA
    442 PM PDT THU MAR 27 2008
    WAZ001-503>510-514-515-280745-
    /O.NEW.KSEW.SN.Y.0018.080328T1000Z-080328T1900Z/
    SAN JUAN COUNTY-WESTERN WHATCOM COUNTY-SOUTHWEST INTERIOR-
    EAST PUGET SOUND LOWLANDS-WESTERN SKAGIT COUNTY-
    EVERETT AND VICINITY-SEATTLE/BREMERTON AREA-TACOMA AREA-
    ADMIRALTY INLET AREA-EASTERN STRAIT OF JUAN DE FUCA-
    WESTERN STRAIT OF JUAN DE FUCA-
    442 PM PDT THU MAR 27 2008
    …SNOW ADVISORY IN EFFECT FROM 3 AM TO 12 PM PDT FRIDAY..
    THE NATIONAL WEATHER SERVICE IN SEATTLE HAS ISSUED A SNOW
    ADVISORY…WHICH IS IN EFFECT FROM 3 AM TONIGHT TO 12 PM PDT
    FOR THE LOWLANDS OF WESTERN WASHINGTON.
    RAIN AND SNOW SHOWERS WILL CONTINUE ACROSS WESTERN WASHINGTON THIS
    EVENING AHEAD OF A DEVELOPING STORM SYSTEM OFFSHORE. LITTLE OR NO
    SNOW ACCUMULATION IS EXPECTED INITIALLY. HOWEVER…A STRONGER
    SYSTEM BREWING OFFSHORE WILL BEGIN TO IMPACT THE INTERIOR LOWLANDS
    LATER TONIGHT.
    STEADIER SNOW WILL BEGIN FIRST OVER THE STRAIT OF JUAN DE FUCA AND
    SOUTHWEST INTERIOR SHORTLY AFTER MIDNIGHT…THEN SLOWLY SPREAD
    INTO THE CENTRAL PUGET SOUND AREA LATE TONIGHT. SNOW WILL CONTINUE
    THROUGH FRIDAY MORNING…THEN TRANSITION TO RAIN AND SNOW SHOWERS
    BY AFTERNOON. ACCUMULATIONS OVER MOST OF THE AREA WILL RANGE FROM
    TRACE TO 2 INCHES BY DAY BREAK FRIDAY…WITH ANOTHER INCH POSSIBLE
    FRIDAY MORNING. LOCATIONS NEAR THE WATER MAY MIX WITH RAIN AT
    TIMES…LIMITING ACCUMULATIONS TO A TRACE TO ONE INCH.
    FOR THE NORTH INTERIOR…SNOW WILL BE A LITTLE SLOWER TO
    MATERIALIZE. SNOW SHOWERS MAY PRODUCE LOCAL ONCE INCH
    ACCUMULATIONS OVERNIGHT…BUT STEADIER SNOW WILL PROBABLY WAIT
    UNTIL FRIDAY MORNING. SNOW ACCUMULATIONS OF A TRACE TO 2 INCHES
    ARE EXPECTED FRIDAY MORNING…WITH HIGHEST AMOUNTS AWAY FROM THE
    WATER. SNOW WILL DECREASE BY MIDDAY FRIDAY…BECOMING RAIN SHOWERS
    MIXED WITH SNOW THE REST OF THE DAY. AN ADDITIONAL 1 INCH OF SNOW
    IS POSSIBLE DURING THE AFTERNOON.
    BECAUSE THIS SYSTEM STORM IS OCCURRING SO LATE IN THE YEAR…THE
    MAJORITY OF SNOW ACCUMULATION WILL OCCUR ON COLDER SURFACES AND
    GRASSY AREAS. HOWEVER…TEMPERATURES AT THE SURFACE WILL LIKELY
    COOL ENOUGH AROUND THE MORNING COMMUTE SO THAT SNOW MAY STICK TO
    AREA ROADWAYS…ESPECIALLY OVER HILLS AND OUTLYING AREAS.
    A SNOW ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE MAINLY
    TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW COVERED ROADS AND
    LIMITED VISIBILITIES…AND USE CAUTION WHILE DRIVING.

  21. Andrew---Ellensburg, Wa and Portrland, Or says:

    Local mets jumping onboard the snow train for the portland area:
    KGW: 1-3 inches down to 200 feet. All snow between 7am and 10am.
    KATU: Snow level mainly 500 feet 1-2 inches. Dusting and mix possible to valley floor.
    Coast Range Snow Forecast
    * Highway 6 – 3 to 7 inches
    * Highway 26 – 3 to 7 inches
    * Highway 18 – 1 to 3 inches
    * Highway 20 – 1 to 3 inches
    Cascades Snow Forecast
    * Cascade foothills – 5 to 8 inches
    * Cascade mountain passes – 6 to 12 inches
    KPTV: Snow level 500 feet, light accumulations.
    NWS: Trace to 1+ inches
    Weather.com: Rain/snow mix

  22. stevied - let it snow! (North Portland) says:

    Hi all. I’ve been off the blog for quite awhile. Things looking interesting… to say the least! Just watched Zaffino’s forecast on the web… he said 1-3″ in spots tomorrow, all the way to the valley floor. Man, conditions will have to be just right. So weird to be talking about this on March 27th!

  23. jacob BPA says:

    A lot of clearing right now it may get very interesting

  24. jacob BPA says:

    The Threat of low Elevation snow looks to stick around till Sunday

  25. TheTriforce says:

    well so much for the warm part. It’s now 50.4F and overcast with a dark grey cloud over our house moving north.

  26. mark says:

    Alright, thanks Jacob!

  27. TheTriforce: Silverton 360ft says:

    Hi: It’s 51F nice and warm. oh darn there goes Mr.Sun. DP WOW! It’d down to 32F dry,dry,dry.
    Now the question is whether places from Salem eastword to the small towns like ahem Silverton,Mt Angel,Stayton,Mollala could get anything in the form of s-n-o-w?

  28. jacob BPA says:

    Yes Mark it is Possible But Thinking we need to get some clearing Before the snow moves in tonight but yes its possible

  29. mark says:

    Well, this is a nice surprise…I have dropped 3 degrees in the last hour under sunny skies!

  30. mark says:

    Thanks for da forecast Jacob and thank you FAB 5!
    I was just wondering though….Is a forecast such as 1-3 inches possible in this situation if everything lines up right?

  31. jacob BPA says:

    Fab 5 Alert
    Snow to the Floor temps tonight 31-34
    T-1″ for some
    none for others better acum with elevation

  32. Mat-ne portland says:

    I have a feeling this will be better than the prolonged east wind event of Dec.’03 – Jan. ’04. I think we’ll have more snow and ice than those 2 weeks twofold. Geez, if only that were true.

  33. WHICH* is unlikely. Another typo however is not unlikely.

  34. I guess I just figure with 2 weak lows there won’t be ample moisture, or steady/heavy enough…. But if the moisture is there we do want them both weak, or the southern low to be stronger with is unlikely.

  35. Luvry,
    No offense taken what so ever. This is open for dispute or discussing with anyone. Actually I didn’t base any of this on the previous disappointments we’ve seen numerous times.
    Your reasoning makes good sense as well and I hope I am wrong…. It’s just my opinion given how much models have progressively weakened the low(s), and the 18z NCEP/NOAA forecast map has the northern low about 1010mb and the southern low about 1014mb with neither showing much deepening. Also PDX AFD suggests the northern low may undergo cyclogenesis…. If it’s going north of PDX I believe that would give us far too much southerly gradient even with a second low south….
    Any time the northern low becomes the dominant low in a situation like this I am very wary because as we know just 5-10mph south winds usually spells doom for low elevation snows. We want both lows similar strength such as the 18z NCEP/NOAA forecast map suggest that way we would hopefully endure light to calm winds when the steady precip is falling progressively lowering the snow level.
    – Dr. Rob

  36. Luvry says:

    Yev, the dewpoint is fairly low because the humidity is fairly low…surprisingly enough. That leaves us room for some evaporative cooling…and a fairly low DP
    This is one of the reasons I like the scenario for tomorrow morning, yes humidity will rise during the night time but this is for some reason a fairly dry airmass right now.
    Rob, you’ve been pretty skeptical over the past few snow scenario’s we’ve had. I don’t blame you, I bet it’s because of the dissapointment we’ve gone through this year in the lowlands. You make some very valid points but there also a lot of things in our favor. Possible evap cooling, some sort of easterly drift which will help out a little (can’t hurt us)and there will be at least a drift IMO…overhead airmass is very cold for this time of year! especially at night time, the timing of this system coming in is perfect. The question is whether the moisture will be prolonged for a couple hours…if it is, we see snow. I had a 80% snow shower here at 12:30 at 200 feet! that is insane for this time of year, I wouldn’t underestimate the temp of this airmass. Guess we’ll see but ACTUALLY I have a better feeling about this than any other scenario this year. No offense but I HOPE you are wrong, kudo’s if you are correct.

  37. yevgeniy/beaverton/hillsboro says:

    rob or anyone else..
    what causes the dewp point to be so low
    in portland right it is 47 degrees and a dep point of 30 winds of WSW
    can you answer that?

  38. The more I think about this possible scenario the more I doubt it.
    East wind is not going to do anything to help us this time of year as we are in late March and there is no cold pool or cold air anywhere east of the Cascades. If anything I think east wind might cause too much mixing. You obviously do not want south or west winds either. Perfect scenario is a weak low going just north of us with little or no wind to prohibit mixing and the southern low spinning up a decent amount of moisture over top of us. I still do not see snow regardless because I feel that both surface lows are not going to be strong enough to generate enough moisture for prolonged steady precip rates, to generate its own cold air, or to generate this “gusty” east wind SOME mets are saying will happen. I hope Mother Nature makes a fool of myself.
    – Dr. Rob

  39. Hey Spacetruckin (you posted a snow total around Estacada)…id like to ask you a couple of questions, if you see this!!!…hit me off blog… boringlarry@yahoo.com
    and oh yea…mid winter continues….suns been out, clear up to 41.7, just after a combo hail/snow shower…doesnt look like the sun is going to melt everything today!….

  40. yevgeniy/beaverton/hillsboro says:

    maybe just maybe this is a snowstorm that may shutdown the city, one of those things that arein a la nina page….
    hmmmmmm

  41. SNOWTIME!!!!!!!!!!! says:

    Look at good ol KATU
    Forecast for Friday morning calls for snow down to the valley floor
    Computer models show a wide swath of snow over the Portland/Salem area starting around 5 a.m. The snow would turn to rain by afternoon, except in higher elevations. Travel in the coast range and Cascades will by dicey.

  42. Sarah (E. Gresham) says:

    I haven’t seen a darn thing all day here…I do see some pretty dark clouds to the north though.

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