Sloppy Blogging

You may notice in yesterday’s post that I mentioned the latest measurable snowfall at PDX is in early March.  Well, that’s what you call “shooting from the hip” and the information was not correct.  Thanks to Justin-Brush Prairie for pointing that out.  The right answer is one of the graphics sitting on my weather computer that I’ve used lots of times (up above).   Probably like lots of you; I keep a big pile of meteorological numbers in my head that can be spouted off at a moments notice, you know, like at a wild party to impress the women.  Ladies love all that meteorological talk.  Actually I doubt they do, but my wife patiently listens most of the time.  And I’m practically a recluse that hates to leave my little domain in the trees.

That weather info is fine for normal weather conversation, but if you’re a member of the media you need to be extra careful what you say on TV, or in this case on a weather blog.  Jim Little and I used to laugh at another person on TV who seemed to shoot from the hip quite a bit with the weather forecasting.  That was maybe 10 years ago.  Real professional eh?

So apparently the fact in my head was the latest 1″ of snowfall at PDX is March 8th, 1951.  I consider that a “significant” snow for the city.  But the downtown location recorded .3″ on April 9th, 1933.  Airport records only go back to right around 1940.  You do have to watch out for one thing.  In the past hail was sometimes included in the snow accumulation.  I

So could we see snow next week?  A few changes in the last 24 hours.

1.  Arrival of the initial cold front is much delayed (some splitting).  00z models now say it’ll be tough to get anything before Sunday evening, then the cold air is slow to move in behind it.  For example the 12z GFS had a -7 deg. @ 850mb over us Monday morning, but now the 00z only has a -4.  The ECWMF continues to be a bit milder, and it’s been doing better in general.  They BOTH have -6 to -7 deg. temps at 850mb over us by Monday night, but then the precipitation is tapering off.

2. The next system Tuesday PM and Wednesday AM is farther north, or at least the surface pressure pattern quickly goes southerly, so the snow level jumps a bit.

The best chance for seeing snow to the hills would be Monday evening (if there is moisture left).  That’s pretty iffy for now.   It’s all still up in the air, but I wouldn’t get too excited about seeing sticking snow below 1,500′ next Monday/Tuesday.

Saturday still looks like the warmest day so far this late winter/early Spring.  I bumped the high up to 62 degrees at PDX.  Easterly flow (not too strong), totally sunny skies, and 850mb temps support a warm day.  March is the beginning of the Mark Magic Chart season (March-September), and it says a high between 59 and 65 degrees.

I sure notice quite a change next week on the models.  They all have some good westerly flow, frequent low pressure systems and wetter weather in general.  The beginning of a wet El Nino spring?  We’ll see…

Chief Meteorologist Mark Nelsen

70 Responses to Sloppy Blogging

  1. flurball says:

    W7……… we’re on the same page. thanks for your thoughts.

  2. Karl Bonner says:

    What was the air flow (wind direction and air mass trajectory) like during the freak April 2008 snow event? I remember that many spots in western Washington got a mushy inch or so right near sea level, and Eugene got about 1/4 to 1/2″ early on the morning of 4/20. I find it near impossible to believe that an offshore flow in April could possibly pull the snow level down; it seems to me that by then an east wind would almost invariably be a warming force rather than a cooling force.

    Seems to me that the lowest snow levels in March and early April ought to come when the cold air comes straight down the coast from southern Alaska rather than swinging out over the Pacific and coming at us from the west.

  3. Rob "Wrath" S.E. Portland says:

    E-NE wind picking up noticeably now. Gusting over 20mph.

  4. yevpolo1990 says:

    Remember a few years ago (2008?)
    we had same thing and we had like an inch of snow at 500 feet or above, and temps were -5/-6 at 850mb and i believe this was in late february…
    also remember how valley got nothing but mix and occasional snow showers???

    • Rob "Wrath" S.E. Portland says:

      As Justin spoke of earlier this is a maritime air mass. Also the low level flow remains onshore albeit lightly, but that will make it darn hard to get sticking snow below 1,000′. Of course there are exceptions such as if you can managed to get a heavier shower parked right overhead that could drag the snow level lower briefly.

  5. Rob "Wrath" S.E. Portland says:

    It’s nice to see thickness values in ‘bright pink’
    516 is impressive. 850mb -8c. 500mb -39c



    • Matthew says:

      For the second week of March even -8c at 850 mb would be around 43-45f for highs.

    • dabears (Hillsboro-Tanasbourne) says:

      Matthew, you’re not even taking into account the possibility that we wont get any sunbreaks. If we see no sun, it will have a much harder time warming us up to typical March standards. If we get zero sun on Tuesday I can’t see us going higher than 40.

  6. dabears (Hillsboro-Tanasbourne) says:

    The 00z GFS shows PDX not even getting out of the mid-upper 30s on Tuesday. I think that’s going to be the real day to watch.

    • Mark says:

      With the March sun, it’s likely we’d still get into the 40’s. However, at night, temps could be pretty brutal, depending on cloud cover, onshore flow, etc.

    • dabears (Hillsboro-Tanasbourne) says:

      Yeah, but if we can manage to stay cloudy all day, I don’t see us getting above 40.

  7. Mark says:

    Hmm…00Z GFS continues the trend of being pretty cool, seems moderately moist too…

    • Mark says:

      Maybe even a little cooler?

      I definitely like the 00Z GFS; it continues the trend that the 18Z GFS set.

    • dabears (Hillsboro-Tanasbourne) says:

      Sure is a good feeling to see the models get progressively better leading up to an event rather than progressively worse for a change.

  8. marie says:

    Did you hear Mark’s weather update on 750AM around 5:30pm? Classic: “It will be mostly sunny from sun up to sun down.” Good call. If the sun weren’t up, it would be dark.

  9. SalemPhil says:

    Special Weather Statement lol!

    … A change back to more seasonable cool and showery weather on
    the way…

    A cool showery air mass… more typical of normal late winter and
    early Spring weather over northwest Oregon and southwest
    Washington… will make an appearance early next week. A trough of
    low pressure coming down from alaskas Aleutian Islands will bring
    the change in weather.

    A cold front will usher in the cooler weather late Sunday… with
    the coolest air expected Monday. Showers expected Monday will
    bring considerably lower snow levels to the mountains and
    foothills… down to around 1500 feet. Below 1500 feet… the
    showers are expected to bring small hail.

  10. flurball says:

    50.1 here in Clackamas. Clear night it seems it should be so much colder. Change of the seaons but the mind is still suck in winter mode.

  11. Rob "Wrath" S.E. Portland says:

    Breaking news

    My temp after bottoming out at 47.7 is now rising on the heels of a warming NE wind. Oh I’m up to 51.6 now.

  12. dabears (Hillsboro-Tanasbourne) says:

    I would love to know what models the NWS is looking at. A high of 51 on Monday? Low of 38? Really?

  13. flurball says:

    If you use Dec 21st the first day of winter and apply (subtract)approx 70 days on the fall side, this upcoming event would be the equiv of having snow the first week or two of October. How strange and realistic would that be? A scant month after Labor Day? Granted you are going from a elongated heated atmosphere to cold versus the other way around but I’ve always compared it that way. The “seasons” are based on the earths axis position and not…………….I don’t know how to describe it but I hope someone see’s the “false” corrolation that’s hard to ignore. Anyone else think that way?

    • W7ENK says:

      Indeed, I’ve often compared the seasons and particularly the daily sunlight to it’s ‘Solsticial’ opposite, if there is such a thing. For example, I look at the amount of daylight in, say, late August, and transpose that across the Summer Solstice and think to myself, “this is also how light it would be at this hour in early April…”

      And here, I thought I was the only one with crazy thoughts like this! 😆

      • Mark Nelsen says:

        Yeah, the land/ocean/atmosphere definitely lags behind the energy coming in from the sun. Seems like the extremes follow the solstices by about 6 weeks (hottest and coldest average temps). Also, the strong sun but cold upper-level atmosphere in spring really helps convection. Compare that to the very stable Fall setup (chilly valleys, long nights, but warm atmosphere overhead).

    • Karl Bonner says:

      You actually have a very good point to make, despite the fact that you can never ignore “seasonal lag.”

      Actually, when it comes to winter, our normal temperatures bottom out only a couple weeks after the solstice, compared to about 6 or 7 weeks of summer lag. Why the winter lag is so short is something I’ll never understand. You’d think with all the storms and onshore flow during the winter, our coldest average temperatures would come more in the late January/early February time frame, which is exactly what they do in most of western Europe and the British Isles. During November and December (the wettest months here BTW), you’d expect all that rain to pump a bunch of mild air into the Northwest and keep our normal highs up in the 50s rather than dipping into the 40s beginning around Thanksgiving week (here defined as Nov. 22-28).

      It’s interesting to note that when it comes to snow levels during wet weather, the winter lag is much longer than 2 weeks. It’s not terribly unusual to get snow down to 2,000′ in mid-March, which is about 70 days after the temperature bottoms out in early January. But when was the last time you saw snow that far down in the last week of October, 70 days BEFORE our thermological bottom point? (granted, it CAN happen here, but it’s EXTREMELY rare.) More importantly, 4,000′ snow is about par for the course in March, which isn’t too much higher than the norm in December and January. I don’t have exact stats, but if you went through all the weather records and found the historically average snow level for each calendar date, I suspect the graph wouldn’t slope upward very much in February and early March and would be only slightly higher than January snow levels.


      However, when it comes to dry weather and high pressure, the “Celtic season system” makes at least some sense. In November it probably won’t get very warm under a ridge, in either the absolute sense or the relative sense. Even without the fog inversions, the tendency on a long and clear night is to lose lots of heat while the sun isn’t strong enough to burn off the chill during the day. So there’s likely to be a net loss of heat from one day to the next when radiation – rather than convection – is the main thermal force involved.

      If you’re paying close attention to the weather, you can really observe the effects of the sun angle when radiation is running the show. By the second half of February, a sunny day is likely to experience daytime highs at least slightly above normal, and under good conditions the afternoon highs can get 10-12 degrees on the warm side (low and mid 60s). Later in the spring a strong ridge can push us WAY above average; 20-25 degrees is not out of the question. So a ridge in late winter often brings springlike temperatures while a ridge in late fall usually brings winterlike temperatures.

      The ultimate effect is that during late fall and most of the winter, the warmest weather comes via Pacific storms and subtropical air. During the spring, the warmest days are associated with sunshine and ridging. Hope this makes sense to you, and forgive me from rambling on and on because you probably got more of an answer than you bargained for.

    • Karl Bonner says:

      One more note. When I first moved to Eugene a decade ago I was very mesmerized by the sun angle theory of temperature. I easily concluded that if this were true it should mean that a sunny late February day ought to be quite warm. The result of this is that late February has become my favorite time of year in at least some respects. Every year I look forward to the prospect of a ridge at this time of year so that my suspicions will be confirmed. Unfortunately this specific setup hasn’t happened very often in the past 10 years; we had a “heat wave” at the end of Feb. 2005 but it seems that a “weather gremlin” usually gets in the way and the warm spell doesn’t materialize to the extent that I believe it could. This year the gremlin was a chilly northeast wind. Last year it seemed to be caused by a touch of onshore flow and some passing clouds. In 2008 we did warm up quite nicely but it was somewhat short-lived. In 2007 it only lasted one day, while in 2006 the ridge came just a bit too early in the month for things to get really dramatic (though it was still awesome weather!)

  14. Rob "Wrath" S.E. Portland says:

    How about a new poll?

    Who wants a change to colder/wetter weather?
    Who wants more of the same and this early fake Spring to continue?

    • pappoose in scappoose says:


    • lurkyloo says:

      Well, if it was Jan/Feb I’d go for the snow/cold. But since we’ve all had this early taste of Spring I’m voting for mild (with rain, of course). Give me a good windy, rainy storm and I’m happy. Snow and freezing? Nah. Not now.

    • Eternal Yamcha (SE Milwaukie) says:

      I agree with lurky. If we can see snow out of this, I’ll be happy. Otherwise, get it out ASAP and give us a normal windy/wet storm that’ll bring snow down to pass levels and I’ll be very happy.

      …That or a spat of 60+ sunny days.

  15. Rob "Wrath" S.E. Portland says:

    00z in 2 hours! *Pulls our hair!* 😮

    • Matthew says:

      With that onshore flow, I sure don’t expect anything at the surface. Marchs sun is enough to warm the surface up big time and we would need -10c to get snow to stay during the day,.

      If the 00z Gfs show -7c at 850 with a more offshore flow. MAYBE at nighttime we could get lucky. We will see.

    • Rob "Wrath" S.E. Portland says:

      out* SO pumped up I can’t even type correctly!

    • Rob "Wrath" S.E. Portland says:

      I’m thinking you want calm conditions or perhaps a light N wind. East wind does nothing to help this time of year as there is no cold source/dome over the Columbia Basin.

    • Karl Bonner says:

      Very good point Rob. An east wind helps with snow only if the interior regions are cold. However I am not sure whether or not it has to be below freezing over there for this to work, at least during the day. I bet that if The Dalles were around 40 for highs and 25 for lows, it might actually be enough, provided the incoming moisture doesn’t arrive between noon and early evening when temperatures are near their peak. Also you have the evaporative cooling factor which helps. All this, of course, is contingent on the cold air staying in place as the storm arrives, which requires a strong east wind to back things up. Usually the moisture doesn’t arrive in time to catch the cold air before it dissipates or gets scoured out.

      I’m also curious if it’s possible for incoming precipitation to override a WARM (65+) east wind during the springtime. Common-sense physics and intuition don’t look too supportive of this possibility, but it never hurts to wonder. And if such a scenario were to happen, what would it look like?

      I’d think the best opportunity for this occurrence would be a storm coming up from California while a ridge is entrenched in the Northwest. The north side of a low is prone to have easterly winds, and this might keep the warm dry air in place. And I think the likely outcome is an incredible quantity of virga, far more than under most circumstances.

  16. The 18Z is a snow lovers dream (at least in early March terms)…..Hope the 00z at least follows suit…

    Looks like the active weather continues into late next week…

    Made it to 58.2° today…

  17. cliff gavic says:

    I do remember in the early 1980s, early april (it was the day before easter, our town was having an easter parade) people that were coming down for the parade had measurable snow on their vehicles.

    I believe the snow level then had come down to 1,100 feet that friday eve, into sat morn.

    the snow was in the foothills around estacada, I was volunteering for the chamber of commerce and Ihad to register people for the event.

  18. wendy-silverlake,WA says:

    Figures. I just took off my studs and planted a ton of flowers today.

  19. cliff Gavic says:

    well, as long as we’re going have a brief cold spell the early part of next week, we might as well have the snow level come down to 1,000 feet with about 3 or 4 inches of snow with it.

  20. Jesse-Orchards says:

    The models look cold. I think boydo’s gonna be right about this one!

    Seriously though. The 18Z is the coldest yet, with 850s bottoming out at -9C, and thicknesses at 515dm. That’s straight up arctic air. Moisture is starting to look less limited as well. If they don’t change their tune, I think most will see some snow out of this, if only just a dusting.

    Tueday has the potential to be a really cold day for this late in the seaon. Highs may have trouble hitting 40.

    • Justin (Brush Prairie) says:

      That’s cold air, not arctic air. By nature, we here in the PNW lowlands have to receive our air from the east or northeast i.e. the gradients go completely offshore as high pressure moves in, for it to be considered arctic. We don’t get big clumps of arctic air with westerly flow aloft and tons of upper level moisture.

      What we had last March was arctic air, and the result was relatively unimpressive around Portland. What we’ll be having next week is very cold maritime air, and with it being March the results are sure to be a little more impressive.

    • dabears (Hillsboro-Tanasbourne) says:

      Justin, good to see you actually talking positively. -9C and 515dm is hard to downplay.

    • Justin (Brush Prairie says:

      I’ve seen enough deep troughs here to know the effects are usually kind of interchangeable. We’ll be hard pressed to see anything more than a few minutes of wet slop and I doubt it’ll be memorable.

      Like Mark said though, the temp crash will feel pretty substantial to most people.

    • Jesse-Orchards says:

      It isn’t technically arctic air, but the upper level numbers are close to what you would see in an arctic airmass. That’s what I meant.

      The source airmass has pretty close arctic origins, anyway. You can see the chunk of cold air moving from the Asian continent into Alaska today. It’s moving ESE, making a b-line for us. The speed at which it is traveling is what is going to keep it from moderating much (hopefully).

    • Rob "Wrath" S.E. Portland says:

      If only the Gulf of Alaska and eastern Pacific were frozen over. Oh well…. this isn’t Sweden for crying out loud!

    • Justin (Brush Prairie) says:

      It’s maritime air, dude. You know the drill.

      The moister this airmass is as it arrives, the colder the temps will be. If we stay relatively dry then we’ll easily get into the mid to upper 40’s thanks to the sun angle and onshore component.

      If moisture hangs around, snow levels will be tugged near the surface and highs won’t rise much. We did have a high of 39 in Portland on 3/9/2006 with a similar setup, as we were socked in all day long. That could certainly happen again, just takes loads of precip.

  21. cliff gavic says:

    well, as long as this short period of cold weather is going to come down to the portland area, the snow level hopefully will come down to 1,000 feet with at least 2 inches.

  22. stevied (North Portland) says:

    If 18z text output verifies, I would be highly surprised if we didn’t see solid flakes in PDX or even a light dusting at times on the floor:

    Note the -8c, 516 thicknesses, plus some moisture around Monday morning. Tuesday morning even a bit chillier with some slightly lighter moisture around. Wow… then next Friday an easterly component with heavier moisture and -3/-4c. Very interesting with maybe a little surprise for some in store if THIS were to verify.

  23. Nodnarb (Damascus 800 ft) says:

    Hey guys, anyone take a look at the new 7 day posted? First time I’ve seen flakes in it in months!

  24. pappoose in scappoose says:

    Say Mark, someone needs to change the F.A.Q’s in the blog where it states, “In Washington, the all-time record high temperature is -48 degrees…”

  25. yevpolo1990 says:

    Ummm this run is shivering!

  26. dabears (Hillsboro-Tanasbourne) says:

    The 18z is probably the coldest run yet. Hard not to get excited about thicknesses around 516.

  27. k5mitch says:

    Well with all of this exciting weather the wifey and I are going to pull the RV up to cascade locks for the weekend…(NO KIDS CATS OR DOGS)

  28. Rob "Wrath" S.E. Portland says:

    PDX/TTD-DLS is hovering around 1mb offshore flow and you’re telling me there isn’t abundant excitement on the blog? Wow. What are things coming to.

    57.0F rising. Filtered sunshine. Hummingbirds are hummin’ away.

  29. W7ENK says:

    … And an eerie silence settles over the blog…

    The suspense is killing me!

  30. SilentReader says:


    thanks for not saying “first”.

  31. stevied (North Portland) says:

    Hmmmm… IF enough moisture Monday morning, may see some flakes around based on the 12z GFS just out.

  32. Canasian711 says:

    El Nino ski season begins Monday.

  33. pgiorgio says:

    I don’t bother saying much to my wife about the weather unless its really snowy or severe. It’s obvious that most women find it boring and geeky. She has to suffer when my geekness becomes overwhelming and I have to tell everyone about the impressive weather.

  34. Karl Bonner says:

    What interests me most about next week’s weather is the question of whether or not it will be cold enough to slow early spring plant activity to a crawl. Everything is currently way ahead of schedule – the plants are probably about where they “should” be in the last week of March. However, some plants seem to have been affected more than others, suggesting that the chronological order of this spring’s blooms and leafouts could be somewhat different from a normal year.

    But the fact that many plants think it’s almost April means that they will be expecting more April-like conditions in the coming week or two. The further along in the spring cycle we get, the more heat is needed to progress one more step. Because of this, it might not take too much cold weather to put things into near-suspended animation.

    If we weren’t ahead of schedule, highs in the low 50s might be plenty to keep the ball rolling since the earlier phases of spring are less heat-demanding. This whole phenomenon with phenology should mean that it’s quite difficult to keep everything ahead of schedule throughout the spring. In order for bulbs, flowering trees, and leaves to all experience bloom dates similar to northern California, we’d need California-like temperatures to persist for a very long time. This means about 5 degrees above average every single month from January through at least April. And while we can sometimes get a single month to come out that far on the warm side, it’s madness to think we could maintain that lead for months on end – if that were to happen and persist for almost half the year, and the other half of the year was not unusually cold, we might end up with a calendar year where temperatures average out to 56 or 57 degrees!

    • ChuckyD81 says:

      There were a ton of Grass Widows (wildflowers) out in bloom between Hood River and The Dalles yesterday.

      I know nothing of such things, but the friend I was with said they were about 2 weeks ahead of schedule. Some on the Washington side near Catherine Creek were already going to seed!

  35. flurball says:

    OK. Mark’s forecast 10-15 degrees warmer than the GFS everyone’s looking at. Comments?

  36. Paul D says:

    Mark: I can see you in the middle of a room full of partiers and you start spouting weather facts by the bucketload. The room comes to a complete standstill and everyone is mezmerized by your weather geekness.

    Then you woke up 🙂

  37. Rob "Wrath" S.E. Portland says:

    Mark, thanks for the update.

    Good night all.

  38. W7ENK says:

    I guess we’ll just have to wait and see what happens…

  39. Jerry says:


  40. Sandi (Wilsonville) says:

    Thanks Mark!

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