Forecast Disaster Possible: Next Weekend

Will it really get to 85 degrees this upcoming weekend?  Is that possible, considering we haven’t even hit 75 yet?  Let me explain.

The very last thing a forecaster in the Pacific Northwest wants to do is predict the warmest and sunniest weekend of the year so far, especially after a cold and wet spring, and have it turn into a cloudy and cool weekend.  This ranks up there even higher than a busted snow forecast since we are all in a delicate emotional state about the 3 month long cold/wet spell.

So I walk in today and see the potential for 80+ degree temps Saturday and 75+ temps Friday and Sunday.  The reason isn’t quite what you would expect.  There is no big huge ridge of high pressure developing over the West Coast.  Instead, another upper-level low (with it’s cool weather and showers) dives south towards us.  That’s nothing new the last few weeks.  However, this time around, models are insisting it’ll stay off the coastline and park itself off the California coast Saturday.  You can see it on the 12z ECMWF, 12z GFS, and 12z GEM (Canadian) models here…all 3 upper-level maps are for 5am Saturday morning.   Click on each for a view you can actually read.  Note they are all extremely similar and all are from the same “initialization” time:

The key is the location of the upper-low.  Note the upper-level winds are then easterly over Washington and Oregon, causing pressures to fall west of the Cascades.  A nice setup for easterly flow and sunshine.  Combine that with 850mb temps up around +15 C and we could easily hit 84-87 degrees here in Portland on Saturday.  It only occurs for one day, but the easterly flow actually starts Friday afternoon and ends early Sunday, so upper 70s would be possible on each “side” of that day.

Here’s the problem…5 days ahead of time we have to assume models are correct with location of the upper-low and the pressure pattern. to get those temperatures.  If the low is a bit closer, right over us, or to our west, forget about real warm weather.  Thus, the high potential for a change in the forecast.  A real pain.  So we decided to keep highs in the 70s on our 7 Day forecast until models are more clear, or at least continue to show the exact same pattern over successive model runs.  Even that is better than we’ve seen so far this season.

In the short term, an active pattern the next two days with southerly or southeasterly flow bringing moisture up over us for showers.  Our RPM model shows a cluster of showers turning up into NW Oregon overnight, leaving us with a very wet start to Tuesday.

On a far happier note:  here are the wedding photos from Brian MacMillan and Sophie Soong.  They both got married Sunday (but to different people…just want to clear that up).  Those are some good looking people!


Chief Meteorologist Mark Nelsen

126 Responses to Forecast Disaster Possible: Next Weekend

  1. W7ENK says:

    New post.

  2. Matt in Eugene says:

    Eugene is getting hit with some very strong winds and rain.

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

    We may need a Severe Thunderstorm Warning in Jefferson County for quarter sized hail. Fairly strong storm just south of Willowdale along US 97 shows a persistent .90 to 1.09″ hail core with a 96-100% chance of severe hail.

    • Rob "Wrath" S.E. Portland says:

      If it holds that is as it enters southeastern Wasco County.

  4. Ben Randall says:

    Radar showing a Rotating tstorm down around Phillomath

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

    3 PM Update

    *Upper Air Analysis
    925Mb: +7c
    850Mb: +2c to +3c
    700Mb: -6c to -7c
    500Mb: -26c

    SBCAPE: 300-500J/kg
    MLCAPE: 200-500 J/kg
    MUCAPE: 300-500J/kg
    LIFTED INDEX: -1 to -3
    MID-LEVEL LAPSE RATES: 7.5 to 8.5C/km
    LOW-LEVEL LAPSE RATES: 6.5 to 7C/km
    BULK SHEAR: 25-30kts
    PWAT VALUES: .70″

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

    Lightning has commenced just south of Eugene. As Derek mentioned conditions are very favorable south of Salem now and this may spread northward.

    • W7ENK says:

      Let’s hops so… WOO HOO!!! 🙂

      Vancouver Island is getting hit pretty hard right now, too… That’s encouraging!

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

    If instability continues to build we should see something after 3 PM I’d estimate. WV Loop seems to show a vort near Brookings that appears to be pivoting northward.

    • Derek Hodges says:

      Very favorable conditions have developed to our south so with that feature I would say Salem to Eugene and then over to Bend will be the storm formation zone but they could move up here after they form.

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

    1 PM Update

    *Upper Air Analysis
    925Mb: +7c
    850Mb: +2c to +3c
    700Mb: -6c to -7c
    500Mb: -25c to -26c

    SBCAPE: 100-300J/kg
    SBCAP: 0-25 CIN
    MLCAPE: 100 J/kg
    EML: 25-40 CIN
    MUCAPE: 300-500J/kg
    LIFTED INDEX: 0 to -1
    LOW-LEVEL LAPSE RATES: 6.5 to 7C/km
    BULK SHEAR: 10-15kts
    PWAT VALUES: .70″

    • W7ENK says:

      Slightly favorable. I’d like to see that LI a little more into the negative…

      Things are improving! 🙂

    • Rob "Wrath" S.E. Portland says:

      Indeed they are. A good chunk of blue sky appearing here too.

  9. Jesse-Orchards says:

    Looks like nothing but warm, dry weather in sight after the next few days on the 12Z GFS. I’m fine with a few warm days but hopefully the entire month isn’t that way. Not ready for Summer mode yet…

    • Justin (Bellingham) says:

      Not ready for summer mode? Tomorrow is the start of meteorological summer and god knows that our weather doesn’t usually even cooperate for most of that. I think any sane person is going to take whatever nice weather they can get at this point and run with it. We deserve it.

    • Beaverton Chris says:

      Not ready for summer mode? We’ve had a really horrible “spring” so far. I think we need to have above normal temps and no rain for quite awhile to make up for the bad we have had.

    • W7ENK says:

      I whole-heartedly agree, Chris. A two week run in the upper 90s and touching 100 a couple of times would be a perfect recovery from this 55 degrees and raining we’ve seen near constantly since January.

      I think 4 months of constant 4 to 10+ degrees above normal is only fair as a trade off, right?

    • Mark Nelsen says:


      You’re never ready for summer mode. I think your northern European genes like it chilly and stormy. Seriously, I think you’d be happy in Juneau or Iceland.

    • pappoose in scappoose says:

      I’ve enjoyed the cool as well Jesse, but not the rain.

    • Jesse-Orchards says:

      Mark, lol nah, too dark up there. I’m actualy fine with our “normal” Summer weather usually. I would just like to see June filled with lots of sunny, 70-something weather with maybe a few days in the 60s and 80s tossed in, rather than going from 50s to 80s with no inbetween.

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

    Just had my first sun break here. I will post the 1 PM Mesoanalysis shortly.

  11. boringlarry,Lost Creek camp,2600 ft says:

    ……warm,please! after this last week of daze of rain and snow mix, i’m mighty glad i found someones leftovers at the bottom of some cliff nearby! 🙂 ….. seriously, last half of last week didnt see temps out of the mid 40s, hail turned the ground whit on sat., and we are blowing thru propane!…..see ya camping!

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

    As we all know Weather changes often faster than we or the models can predict. You have to constantly monitor Satellite imagery, surface obs, Mesoanalysis, and other things to keep on top of such changes. Well, well, well, it appears Visible Imagery is showing some breaks in the clouds and what appears to be good weakening of the deformation band.
    Notice on this loop how the once thick cloud cover is quickly thinning or eroding? This could mean game on for afternoon t-storms!

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

    Hmmm t-storms today? I would say very slight chance. Visible Imagery Loop
    A thick band of clouds associated with the deformation band won’t move north of the northern Willamette Valley until 2-3 PM? 12z SLE sounding indicates Convective Temp of only 58, Max Temp: 61 and I just don’t feel confident we see enough surface heating for instability to build.

    • pappoose in scappoose says:

      You might say about as much chance as having a Stray Albino Donkey wander our way? I’ll take a very slight chance any day. NWS is optimistic.

      822 AM PDT TUE MAY 31 2011


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

    C’mon 12z!!! Continue the trend of very warm to downright Summery weather!!!!!

    • pappoose in scappoose says:

      Right, I don’t want Marks brave forecast to be rewarded with a fail. Hahaah!

    • chiefWright says:

      Best I could tell, Mark was making a forecast of a forecast. Takes this sport to a whole new level.

  15. Andrew Johnson says:

    Up over 4″ of rain now for the month. Over 18″ for the March-May time period.

  16. Boydo3 N. Albany 500' says:

    These warm rains will no doubt aggravate the swollen rivers.

  17. john says:

    hey when should this cold/wet pattern brake and the west coast to warm up for more then 1 or 2 days

    • W7ENK says:

      Late November – just in time for it to be a little too warm for snow… 😦

      Realistically, I’m seriously hoping this pans out next weekend!

  18. Karl Bonner says:

    There’s a bit of rain outside in west The Dalles now, and the airport’s May total is up to 1.80″. Could we break the magic 2-inch barrier by 11:59pm tomorrow night?

    If we get at least 0.14″, we will break the 5-inch barrier for the period March 1 – May 31.

    In a more normal-weather year, while late May and early June usually aren’t consistently hot in the East Gorge, at least the hillsides and soil moisture levels are starting to look like early summer. Not this year: even at The Dalles the south-facing mountain slopes across the river still have patches of pale green, though unless we get substantial rain totals the next 24-36 hours, I bet it will all be gone in about 7 days, especially if the late week and weekend get into the 80s here.

    But all the places that normally have slightly cooler and/or moister soil (including the hills south/southwest of town, Sevenmile Hill, and the Rowena area) still look quite far from summer drought conditions. About a week and a half ago, I took a drive over Sevenmile and almost all the way to Mosier before cutting across to old Hwy. 30. I noticed that the oaks atop Sevenmile were finally leafing out. But I also discovered that at the Rowena Crest plateau, there were still quite a few balsam roots in bloom. Not tons, but quite a few. (Keep in mind that in an especially warm year, balsam roots can begin flowering in the third week of March!)

    UPDATE: We just had another rain shower, and this one was very heavy. It eased up in the last 10-15 minutes but it’s still coming down at a significant clip. I think we now have the 2″ May total in our pocket.

  19. bgb41 says:

    00Z GFS – Looking good

  20. PaulB/Eugene says:

    Looks like the June 3-5 time period will be an interesting one for convection…upper level lows headed to N Cal coast at this time of year is a good setup for thunderstorms. A sub 546dm upper low off NoCal indicates cold air aloft to aid with instability, while S-SE flow should allow low levels to warm up…..exactly two years after the June 4 2009 outbreak with Severe Thunderstorm Watch for NW Oregon

    • Derek Hodges says:

      I agree Paul. I have been watching this and wondering if it might produce some interesting results. I would like to have some exciting weather.

    • PaulB/Eugene says:

      Would not be surprised to see a tornado spin up in the Redding/Red Bluff area with this….

    • Derek Hodges says:

      How do you think we will do? June 2009 redux, i can only hope since I was gone then

    • PaulB/Eugene says:

      Upper low little farther S than two years ago. Could have a deformation band of convection reach into south parts of OR. Still a few days away…

  21. W7ENK says:

    Light sprinkles and distant thunder???


  22. Roman~Snow-Zone says:

    It has been dumping rain here in monmouth for over the past hour.. Finally starting to lighten up.

  23. Dave in South Salem says:

    Loads of heavy rain here but no boomers

  24. Punxsutawney aka HIOPHIL says:

    Go for 80’s Mark!

    Given this spring’s history how could you be wrong? Err…never mind.

    I notice that the NWS isn’t calling for 80’s yet. No fools there.

  25. Paul D says:

    Please no 80+ weather!! Below 70 is just fine. This afternoon was really nice.

  26. Kyle says:

    Of course the magic 8 ball is right Timmy.

    It WILL snow in Portland tomorrow……… 18 thousand feet! he he he! :p

    You need to be more choosy on your approach.

  27. Kyle says:

    My parents and I once found a road in Central Oregon called Broken Axel Road and we didn’t trust it. 🙂

  28. Kyle says:

    Rob. You come up with the funniest names for towns. I don’t know HOW you do it.


    I wonder if they are near each other.

  29. Muxpux says:

    Spent the 3 day weekend camping up on hood canal, had one brief sprinkle Saturday, then last night about 11-12 it started rainin good. Other than that, couldn’t have asked for better camping weather. Mid 60’s during the day and just enough chill at night to make the fire worthwhile

  30. Cgavic sandy Oregon 1,100 ft says:

    Right now, with the weather that’s going on in the Midwest (f5 tornadoes) and temps (with humidity) up in the 80s, and 90 & 100 degs in the SE and eastern seaboard, I will take our current weather, period.

    Mike bettes is in Nebraska where they’re following severe tz storms…gusts to 70 mph, and lightning flashing so fast …just like the celebrities camera opps. Forget about trying to count in between flashes. Constant flashing.

    We’ve had some widespread light showers today. Right now the skies have cleared out.

    One thing I will say about Oregon summers, at least we can get a lot of low humidity heat, and natural air conditioning.

  31. o.c.paul says:

    For this weekend, my ‘eightball forecaster’ reads, “I Doubt It”. You can take that to the bank!

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

    New heavy shower and possible t-storm just north of Sodaville.

  33. Garron near Washington Square says:

    Thanks for the light at the end of the cold dark tunnel, I just hope it’s sunshine and not a freight train coming through that tunnel!!!

    Just another important date coming that weather greatly affected. D-day, and the weather was horrible, the possible exposing of 3 million troops waiting the go order lay in the balance. A single weather man’s forecast laid the groundwork to one of the most important days in history. Here’s a 2.5 minute breakdown of the event…And a huge congrats to the newlywed couples!!!!!!

  34. PaulB/Eugene says:

    Tstorm in EUG …occ thunder

  35. W7ENK says:

    Thunderstorm in Eugene, moving this way…
    s l o w – l – y . . .

    Apparently it was enough to activate my NOAA Wx Radio.

  36. Ken says:

    I say 60 with showers! Reverse jinx!?

  37. Karl Bonner says:

    Isn’t it funny how a trough and a low over California can set us up for a heat wave?

    One thing I find baffling about next weekend are the warm 850mb heights; where is the warm air coming from?

    • Chuck on Mt Scott says:

      Alaska? 🙂

    • Mark Nelsen says:

      Weak upper level ridging to the north of the low over BC and Alberta

    • W7ENK says:

      Yeah that’s kinda bass-ackwards, don’chya think? Perfect fit with everything going on the past several days up North.

      Kinda like back in February (was it February?) when our chances for “epic cold and snow” were killed by a warm front moving down from the NNW… :facepalm:

    • Jesse-Orchards says:

      Actually a lot of the warm 850mb temps are being drawn up in anti-cyclonic flow from the SE. When the low is the position progged it will work to pull warmer air up from the Rockies/Intermountain West. BC and Alberta don’t really fit into the equation IMO.

      And W7, I don’t remember that. Maybe you’re thinking of January? The arctic outbreak in late Feb went fine from a 500mb standpoint, just not a lot of moisture to work with.

    • bgb41 says:

      Looks like Mark removed your post Jesse. You never learn do ya? lol 🙂

    • Jesse-Orchards says:

      Likely because of some of the language you decided to use in response to it. Kind of ruined what was a lighthearted joke that others thought was funny.

      Anyway, no need to drag things from the last thread on to the new one, right?

    • bgb41 says:

      Lighthearted huh, so that must be why you’ve been banned or had comments deleted so MANY times then? Like more than ANYONE else on here. There’s a reason why Mark came up with the nickname “Jesse-Hole” the other day. Totally justifiable name for you based the way you treat people on here.
      You just keep hiding behind your little computer little boy 🙂
      Keep trolling people and you’ll get blocked again eventually for sure.

    • Jesse-Orchards says:

      It’s kind of amusing how shaken up you seem over our little computer world. Don’t get yourself all in a huff! 😆

      And now, thanks you you, this string of comments will probably be deleted too. Sigh…

    • bgb41 says:

      Nope, not shaken at all. Just exposing the facts about “Jesse Krause aka the fox12 blog troll”

      Would be really nice if you would grow up and be an adult like everyone else. Its funny how we have 15 year old kids on here acting like adults yet you are like 25 and act like you are in Junior high most of the time. Why do you have to troll people on here and make rude comments? Didn’t Mark ask you to clean up your attitude on here last week? It lasted for a couple of days and then you couldn’t help yourself. I mean it started with Ashley Watson stating her opinion on next winter and you got all upset at her which was wrong. Here you are back to your old self.

    • Mike near Clackamas Town Center says:

      You know Jesse befoe long you might be the only person posting on Mark’s blog 😆

    • Jesse-Orchards says:

      Why don’t you guys stop worrying about meaningless little blog politics and look outside? Gorgeous sunset in progress!

    • bgb41 says:

      Maybe you should go look at the sunset Jesse and ponder why you are such a jerk on the blog. Then when the sun rises tomorrow you can actually contemplate growing up someday and try to become a decent human being.

    • Jesse-Orchards says:

      Dude, you’re what, in you’re mid-40s and your weak little ego can’t even handle an innocent jab at your model output program. I would take a long hard look at myself before judging how much “growing up” others need to do.

      Why are you even wasting an evening making repeated, uninformed posts about me personally. Aren’t you at the age when you should have a family (you know, wife, kids) you’re spending time with or something? Instead you let yourself get all worked up over someone with a snarky sense of humor on a weather blog on the internet. Sad.

    • Jesse-Orchards says:

      Mark, hopefully you can just delete all this crap when you see it.

      Please keep my weather related post intact though! 🙂

    • Mike near Clackamas Town Center says:

      According to the latest model the east wind will come back over the weekend setting up downsloping east winds and this time of year 80’s are a sure bet with the downsloping effect 🙂

    • Jesse-Orchards says:

      Yeah, both Saturday and Sunday look like they could both be 80+ on the 00Z, followed by a sharp cooldown Monday as the low begins to fill in over us.

      Thanks for turning the topic back to weather, btw. Sheesh…

    • bgb41 says:

      Yep Jesse, I have all that.. a good payin job , an education, a nice house on land and a woman. As far as growing up is concerned, looking at my parameters vs yours I am there while you have a long ways to go young boy. Most importantly though, I respect people. Do you realize that 80% of these bloggers are on my facebook group because of your mouth? I would love to see you go 30 days without a rude comment on here anybody. Can you do that?

    • W7ENK says:

      Heh heh heh… this is GOLDEN!

      My turn! :mrgreen:

      Jesse, if you’d just stop slamming people at every opportunity, this blog would actually be the “family friendly environment” Mark intended. You have this propensity for constantly, and I mean CONSTANTLY poking, jabbing, ripping, TROLLING nearly everyone on this blog. The only person you don’t troll (I’ve noticed) is Tyler, perhaps because he’s the only one to successfully put you in your place? He seems to intimidate you for some reason, I don’t really know, but what I DO know is that everyone, including Mark, is sick and tired of your rhetoric. 90% of the time, you bring nothing of value to this blog. You present yourself with an aire of superiority that everyone here sees right through. It’s ridiculous, and it needs to stop. Brian is absolutely correct, you need to stop with the childish behavior, clean up your act, and STOP TROLLING!!!

      You think you’re so much smarter than everyone else, but intelligence is not just a measure of knowledge. It’s also a measure of conduct, how you interact with and treat the people around you. You might be knowledgeable about the weather, but your interpersonal skills are seriously lacking. I’m willing to bet you don’t have a lot of friends, do you Jesse? If you treat people in real life anything like you do online, you’re probably a really lonely little human being.

      Attacking Brian’s character, his status in life, wife, kids, etc…? What’s about moving out of Mommy’s apartment, Jesse? Maybe you’re socially incapable of living on your own? I’m not going to judge, it’s not my place. Perhaps you should examine this idea and adopt it into your own life??? Maybe you shouldn’t judge, it’s not your place, either.

      I hope Mark doesn’t delete this. I hope he leaves it up so everyone will see this exchange, and maybe, just maybe you’ll find yourself embarrassed by the way you conduct yourself, which might spark a change? Not likely. There’s about as much chance of that happening as there is of us hitting 100 degrees before the end of the week…

      There, did you see that? I just made this weather related! 😆

    • Jesse-Orchards says:

      God this is all hilarious. You guys need lives!! 😆

      W7’s dissertation on me is just the cherry on top. I don’t think I spend a tenth of the time fretting about you guys as you do me.

      Anyway, I can’t waste anymore time on here. Work beckons in the morning. Night! Thanks for the laughs though! 😀

    • W7ENK says:

      And with that, he signs off for the night…


      Classic hit-and-run style trolling. He’ll be back in a couple days, don’t you worry! 😉

      Nighty-night, Jess. Make sure Mommy tucks you in extra tight tonight after that horrible beating you got from all those nasty-wasty bully boys here on the weather blog… 😆

      Sleep tight, sweetheart.

    • bgb41 says:

      I have a better life than you will ever experience Jesse. Obviously yours is miserable or you wouldn’t act the way you do. Go ahead and continue to assume that your superior to everyone buddy. Keep the dream alive!!

    • Rob "Wrath" S.E. Portland says:

      Really? ….

      I do have to say for once it is great not to be involved or have my name mentioned by either party. Ahhh yes a drama free policy is the best way to live. Meanwhile I’ll either ignore or enjoy the entertainment between this ongoing feud. I do think Mark would have to have a level of tolerance for things such as this and there has to come a point where Mark just says to himself enough is enough.

      My stance on this? This may be the internet, but attacking anyone, being rude, provoking, nitpicking, etc. why? I don’t get it and never will, especially from an Adult. It isn’t becoming of an Adult period whether that’s merely on the net or real life. So, why do it and for 4-5 years now? Look at the end result thus far. It does nothing but draw negative attention. To push others buttons, why? It’s time for it to stop, it is long overdue. Step up.

    • pappoose in scappoose says:

      You have a better chance of getting struck by lightning than you do of stopping this ridiculous bickering Rob. I certainly agree it’s a sad thing to see such bright people degrade themselves this way.

  38. bgb41 says:

    NCEP 6-10 day outlook yesterday showed this scenario and I commented on it. The hard to predict cut-off lows in late spring/early summer are like rolling the dice 5 days out. I think most of us would settle for 3 days in the 70’s again like what we had a few weeks ago. Looks like model riding this week.

  39. Sandi (Wilsonville) says:

    Never mind. That’s what happens when I try to read and post when my teenagers are talking to me (about nothing important)… next Friday is the last day of school. The *following* friday is the outdoor graduation ceremony. 😛 So much for multi-tasking.

  40. Sandi (Wilsonville) says:

    Outdoor graduation ceremony next Friday evening… so here’s hoping for the nice and warm weather!!

  41. ryanintd says:

    so is the flooding going to get even worse with this possible “warm spell.”

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