Two Potent Storms This Weekend

A very active cold front offshore should move onto the coastline by midnight at the latest, then cross in the Willamette Valley with solid moderate-heavy rainfall.  We’ve seen a ton of lightning off the coastline with the approaching front.  In fact the lightning strikes are all that show up since we have such horrible radar coverage (worst on the US coastline) on the central/southern Oregon coast.  So plenty of flashing the next few hours on the coast and the strong wind gusts should subside right after it passes.  Inland we MIGHT see a flash of lightning, but usually the cooler land kills the most active cells as we move into December.

We get a break tomorrow with just showers and sunbreaks.


Models have come into better agreement (somewhat) tonight regarding the stronger system for tomorrow night.

Several thoughts:

1. Timing has speeded up quite a bit with the surface low or open wave crossing the Cascades well before sunrise.

2. No model develops a strong or deep low.

3. Several have a very weak amorphous blob of low pressure, others have a more defined low.

4. The WRF-GFS and our RPM both have a low tracking from the southern Oregon coast to about Spokane.  Remember strong wind is to the south of the low pressure center, so no model right now shows any threat for strong wind (40+ mph) from Salem northward.  Of course it’s possible  a surface low spins up a bit stronger than what models show (check out February 2002), but there’s no specific reason to believe that.  Hopefully 12z runs tomorrow morning all come together a little more.

It will be very windy with possible damaging wind behind the low in Central Oregon, SE Oregon, and possibly the Columbia Basin & Eastern Gorge early Sunday morning.  High Wind Watches are out for a good portion of that area.

On the positive side, a lot of snow coming up in the Cascades…possible 12-18″ between tonight and Sunday midday on Mt. Hood!

Chief Meteorologist Mark Nelsen


126 Responses to Two Potent Storms This Weekend

  1. 3 hour pressure falls.

    Southern Oregon event…

    • marcus says:

      WOW! Reno NV, winds 190@33G56 and suppose to get stronger through the night! What a storm down south!

  2. Jeff Raetz says:

    Averages\Extremes for the month of November 2012

    Average temperature = 47.5°F
    Average humidity = 89%
    Average dewpoint = 44.4°F
    Average barometer = 29.975 in.
    Average windspeed = 1.8 mph
    Average gustspeed = 3.5 mph
    Average direction = 112° (ESE)
    Rainfall for month = 10.441 in. (Most rain in November on record) (Average is 7.31”)
    Rainfall for year = 52.354 in. (Most rainfall at this time in the year ever)
    Maximum rain per minute = 0.050 in on day 06 at time 19:00
    Maximum temperature = 68.8°F on day 04 at time 14:48
    Minimum temperature = 32.2°F on day 22 at time 03:12
    Maximum humidity = 100% on day 30 at time 07:12
    Minimum humidity = 60% on day 26 at time 02:55
    Maximum dewpoint = 61.7°F on day 04 at time 14:46
    Minimum dewpoint = 30.6°F on day 26 at time 02:55
    Maximum pressure = 30.34 in. on day 22 at time 03:36
    Minimum pressure = 29.41 in. on day 30 at time 04:07
    Maximum windspeed = 16.1 mph from 045°( NE) on day 28 at time 05:01
    Maximum gust speed = 27.6 mph from 045°( NE) on day 28 at time 05:30
    Maximum heat index = 71.8°F on day 04 at time 14:49

    Avg daily max temp :53.3°F
    Avg daily min temp :42.2°F
    Total windrun = 1313.2miles

    Record low wind chill temperature = 29.1 on day 27 at time 05:31
    Record daily rain = 2.98” on day 19
    Record rain in 1 hour = 0.53” on day 19 at time 15:00
    Warmest day (6am to 6pm) = 63.7 on day 04
    Coldest night (6pm to 6am) = 36.3 on day 11
    Coldest day (6am to 6pm) = 41.0 on day 10
    Warmest night (6pm to 6am) = 60.1 on day 05

    Daily rain totals
    00.33 in. on day 1
    00.17 in. on day 2
    00.19 in. on day 3
    00.01 in. on day 4
    00.14 in. on day 5
    00.26 in. on day 6
    00.01 in. on day 8
    00.54 in. on day 11
    00.51 in. on day 12
    00.03 in. on day 13
    00.01 in. on day 14
    00.01 in. on day 15
    00.84 in. on day 17
    00.48 in. on day 18
    02.98 in. on day 19
    00.73 in. on day 20
    00.46 in. on day 21
    00.01 in. on day 22
    01.41 in. on day 23
    00.25 in. on day 24
    00.06 in. on day 28
    00.30 in. on day 29
    00.70 in. on day 30

    *Records since October 2008*

  3. Just checked buoys off the Oregon and northern California coast. It is obvious a southern wave is developing as greatest pressure falls are now occurring Coos Bay south. That doesn’t seem to bode well for anyone wanting a wind event in PDX.

  4. EY (Oak Grove) says:

    Okay, I think I’ve found the general area of the storm, but I can’t pinpoint exactly where it is…

    Rob? This is you.

    • Could have sworn it is at 42 N, 131.5 W, but another wave to the south is supposed to develop according to the 00z MM5-NAM and it didn’t even initialize a low pressure center/wave at all, which clearly appear there is one near Buoy 46002.

  5. flurball says:

    HA! Sorry EY. Great minds………….

  6. flurball says:

    Quoted from Mark……… Just went to Costco after making the forecast but before promo shoot at 6pm. That should give you a general idea of my priorities this evening and how worried I am about a big wind

    Batteries? Wood Pellets? Candles? Gallon of Ketchup?:)

  7. Jesse-Stevenson says:

    In Lincoln City at the moment. Any guesses on winds here? I think we will be south of the low so they could get pretty crazy.

  8. Tuesday the day everyone should be looking at for a strong wind event.

  9. Update….

    Last 2 frames on WV Loop now show some slight northerly component rather than due eastward movement with the low.
    What does it mean!? I have no idea !!!!

    • pappoose in scappoose says:

      Ya, doesn’t really matter at this stage of the game, who’s right or wrong about this or that.
      Time for the GOLU model!
      Let’s have some fun, I’m gonna go ahead and put a WATCH on the developing low! Hahaah!

    • No strong winds tonight. 1. Mark not posted the first clue to NO STRONG WINDS TONIGHT. 2. No strong winds tonight 3. Enjoy another rainy night.

  10. More info…..

    As of 3:50 PM
    (Buoys update every :20 after the hour. Next update will be at 5:20 PM for the 4:50 PM readings if that makes sense)

    Anyhow, now seeing greatest pressure falls slipping northward off Newport. You know the drill, low pressure tends to follow the greatest pressure falls.

  11. It is now very obvious we may have quite a bit deeper low on our hands tonight than any of the 12z/00z models indicated.

    As of 2:50 PM
    Station 46002 – 275NM West of Coos Bay, OR
    Atmospheric Pressure: 29.39 in (995mb)
    Pressure Tendency (PTDY): -0.11 in ( Falling Rapidly )

    As my previous analysis indicated the low is 995mb or deeper which is well ahead of 12z initialization or 18z for that matter.
    Scanning all Buoys along the Oregon Coast I am beginning to see similar pressure falls now spreading north up the Coast rather than only being confined to off the southern Oregon or northern California coast.

    WV Loop shows the low is mainly moving due east.
    Not yet seeing any northward progress nor am I seeing any southern wave development either.

  12. W7ENK says:

    The lack of chatter on here all day doesn’t bode well if you want a wind event/storm in PDX or northern Willamette Valley. This thing was over before it even got started, done and done.

    My original analysis from two days ago still holds:

    This thing stays well to the South of PDX and the Willamette Valley. The Low will likely come ashore somewhere between Coos Bay and Brookings, pass between Roseburg and Grants Pass, cross the Cascades to the North of Crater Lake, and work its way across the High Desert well to the East of Bend. Areas South of the Low’s center get high winds. We don’t.

    • runtmc says:

      Yippee! One of your self-congratulatory posts. I’ll choose “lack of chatter” if this is the alternative.

    • True, Erik, except that was with a weaker low than has already developed, right? … I believe…

    • flurball says:

      An “I told you so” post already?

    • W7ENK says:

      That’s not an “I told you so”, I’m just standing my ground, sticking with my original thinking, and stating that it’s unchanged. Not once have I ever said I told you so.

      I guess we’ll just have to see how this thing plays out tonight/tomorrow.

    • If this storm is such an imminent threat than how come Mark has remained off the grid today?

    • I’d love to hear what Mark has to say, imminent threat or not.. I’m still unsure if it tracks far enough north to do much PDX-SLE, but SLE-EUG is another story. The pressure falls shifting north is a good indicator though as well as the low quite a bit stronger already outside of 130 W than any model showed.

    • Josh in Sherwood says:

      The bigger storms happen when Mark stays off the grid….

    • W7ENK says:

      The latest PQR AFD keeps the low track and strongest winds way to the South of Portland as well.

      No dice.

    • Did you read Seattle NWS AFD?

    • When tomorrow is over we’ll see how things turned out for the area.

    • Ron says:

      Mark mentioned that with Stephanie gone for two weeks he has to do all the evening broadcasts and wouldn’t be available much.

      • Mark Nelsen says:

        Two weeks? 3 months! She’ll be back in two weeks though. Just went to Costco after making the forecast but before promo shoot at 6pm. That should give you a general idea of my priorities this evening and how worried I am about a big wind event. I’ll blog a little later.

    • If Mark is working today then we’ll get a better idea of what’s coming on the news tonight.

    • W7ENK says:

      Rob, I did read the Seattle AFD, and I have absolutely no idea why they would even bother mentioning this low when, even if it did produce damaging winds PDX-SLE, it would have exactly zero impact on their forecast area to begin with.

    • flurball says:

      Erik, not questioning your forecast, just thought posting your previous mention of it was a little chest thumping on something that has such a low degree of happening in the first place. Sorry if i took it wrong.

    • Brad says:

      Seattle AFD > Portland AFD

    • We’ll just have to see what happens..

    • EY (Oak Grove) says:

      Curse you Mark and your cryptic messages. I don’t get what a COSTCO is. CO ST CO? Colorado State, Colorado? We need code breakers!

      In all honesty, it is kinda vague. People go to Costco to stock up on supplies… So it could be a nasty storm potential. But considering he isn’t pouring over the data and staying around the computers could indicate he’s not worried.

      No one burst my bubble.

    • W7ENK says:

      @runtmc, please explain to me how anyone could possibly congratulate themself over something that hasn’t not happened yet?

  13. Seattle NWS AFD excerpt gives a little better idea as to what may develop.


    This sounds like PDX will see gusty-strong winds and if it deepens more than models show, High Winds? Don’t rule it out because in my previous 153 analysis it is clear the low stronger right now and developing quicker than 00z/12z runs showed.

  14. 3:00 PM Water Vapor imagery enhanced with low center placement

    Looking quite healthy now.

  15. Bit of an update..

    Looking at WV Loop
    Low is currently near 41.8 N, 134 W moving east perhaps east northeast last few frames. Buoys observations show sharper pressure falls beginning with a few moving into the Rapid stage off the southern Oregon Coast signaling stronger deepening or cyclogenesis may be underway.

    Station 46002 – 275NM West of Coos Bay, OR
    Atmospheric Pressure (PRES): 29.43 in
    Pressure Tendency (PTDY): -0.11 in ( Falling Rapidly )
    Based on this observation and distance from the low to it I estimate the low is 993-995mb at this time.

    Greatest pressure falls are found along the southern Oregon coast and northern California coast which if that trend were to continue doesn’t bode well if you want a wind event/storm in PDX or northern Willamette Valley with the best changes SLE-EUG. However, if the storm deepens at this point all the way past 130 W and towards landfall it is plausible for it to curve northward moving the wind threat areas further north. We need to keep an eye on how things develop the next 6-8 hours.

  16. EY (Oak Grove) says:

    Wind’s suddenly whipped up here in Oak Grove. Tall trees blowing around.

  17. For those that don’t have Facebook here’s the November contest results.

  18. Based on WV Loop and Buoy reports it appears our developing low fairly recently crossed Station 46006 600NM West of Eureka, CA at roughly 998-999mb. As noted by the pressure leveling off and now rising at this station we can determine the low has indeed moved east of this location. The low is near 135 W as is probably 995-996mb by now as it is deepening. Pressure falls are now occurring the Oregon Coast with greatest found along the central and southern sections. As of right now I don’t see this tracking far enough north to give PDX-SLE a wind event/storm. Watching WV loop and buoy observations will be key over the next 6-8 hours to get an idea how much cyclogenesis may be occurring as well as where the low is tracking.

  19. masterblast says:

    Mark must be sleeping in today?

  20. paulbeugene says:

    I think that low will track across Woodburn-PDX….and if the southern wave does not develop into anything then 30-40 G 60 for Salem south to Albany/Eugene looks possible.

    My guess is that the southern low will become evident on the satellite imagery in the next 6-8 hours if it is going to be a player…so will have to wait a while before getting any more excited.

    • alohabb says:

      With that being said, how does PDX fair with your current projected path?

    • Yeah, good post I agree….I’m scanning WV/IR loops looking for any southern development…. I see Seattle NWS AFD
      siding with the MM5-NAM northern low/track suggesting stronger wind over southern CWA.

    • W7ENK says:

      @alohabb, if the low tracks to the South of Portland, even if by only a handful of miles, we get winds NW 10-15 max.

  21. paulbeugene says:

    It looks to me that the dominant low will be the one clearly shown by the baroclinic leaf at 42N, 133W. The southern low does not really show up at all on WV…only slight darkening seen down there.

  22. Good jet support fueling tonight’s low seen punching well inland upwards of 120-140kts.

  23. 12z Analysis
    MM5-NAM – 925mb/SLP model
    10:00 PM Saturday
    2 waves of low pressure developing. One is near 45.4 N, 127.7 W and the other is much further south to the southwest of Brookings.

    1:00 AM Sunday

    Move ahead 3 hours and now these waves have deepened closing off into surface lows. 991mb moves over Medford and a northern low 989mb west of Astoria.

    4:00 AM – 7:00 AM
    The southern low ejects quickly off into northeast Oregon, but the northern low slightly intensifies now at roughly 986mb over the Olympic Peninsula.

    PDX-EUG peaks around -4 to maybe -5mb, not enough for strong winds, but gusty yes. The southern low is not a good thing if you want a wind event/storm in the Willamette Valley. It negates the pressure different the northern low has generated as you ideally want 1 solitary low moving by to the north with higher pressure moving in behind the low “chasing it” as it passes with pressure rises occurring quickly. MM5-NAM shows this would not be the case.

    WRF-GFS – 925mb/SLP model
    10:00 PM Saturday

    Here we see the southern wave lifting further north compared to the MM5-NAM moving onshore near Cape Blanco closed low 991mb. You also see there is northern wave or closed low. This model would have less of an impact throughout western Oregon except for extreme southern Oregon and eastern Oregon. I am not buying the WRF suggesting a weaker scenario with a low well to the south. I’ll tell you why next….

    Now, look at WV Loop
    There is our system for Sunday beginning to develop near 41.8 N, 138 W. Looking healthy, but no, not impressive as of yet. There is a strong jet stream punching into it as noted by sharp dry slot. Don’t see a lot of cold air feeding into the low, so that might keep it from rapid cyclogenesis. Judging by what I am seeing I would lean more towards a northern low developing moving onshore somewhere near the Washington Coast and perhaps deeper than 987mb as well. Unsure about the southerly wave being a factor, but it could.

    All eyes today will be on WV Loop more so than any model as I think we have a surprise unfolding late tonight. We’ll see…

  24. paulbeugene says:

    Looking at satellite imagery…can see the next wave developing…looks to me at about 135W, 41-42N. I think this will turn into something noteworthy.

  25. 12z gfs lookin good for cold, snow at this location @ 174 hr, colder thru 240. Hopefully ensembles and euro will be on on on board.

  26. Compared to many previous runs of the GFS, the 6z was a heck of a lot better in terms of 500mb progression, in fact it is downright close to being a gem. It’s quite similar to ECMWF in that aspect.

  27. *BoringOregon* says:

    Wow, got some very windy conditions about 35 to 45 mph wind gust. I can hear pops all over, thanking maybe tree stuff breaking off the trees ect. Hope we don’t lose power !!

  28. karlbonner1982 says:

    Hey….I’ll gladly take an East Gorge damaging windstorm! If the Gorge gets damaging wind will it be more westerly or southerly?

  29. JJ97222 says:

    I was in Memphis all week nothing but sunshine cool with frost in Morning but still the sun is so nice to see and now rain on top of rain. It will not stop……Tennessee weather was nice.

  30. LurkinginFG says:

    Wow… very windy with a torrential downpour right now. Since midnight I’ve got. 2 inches in the bucket. Yeah, real close to 1″ per hour rates. It has now calmed down since typing this. Enjoy the cell snowedin and others

  31. bgb41 says:

    11/30/2012 Oregon (All) Temperature Summary

    High:64 at DW9526 King City( 160 ft) & NATRON(518 ft) & DW9370 Portland(98 ft)
    Low: 54 at CW4650 Pendleton(1152 ft) & North Bend Munic(16 ft) & BROOKINGS(79 ft)

    High:30 at Timberline Lodge(7001 ft) & Mount Hood Meado(6601 ft)
    Low: 26 at ANTELOPE (6460 ft )

    Largest Diurnal Change: 31 degrees
    Lexington Airpor (63/32 ) (1624 ft )

    Heaviest Rainfall:
    2.87″ at TIDEWATER(2035ft)
    2.30″ at SADDLE MOUNTAIN(3250ft)
    2.29″ at QUAIL PRAIRIE LO(3183ft)
    2.23″ at RYE MOUNTAIN(2000ft)

  32. W7ENK says:

    Okie dokie, here you go Brian et al. As promised, the daily breakdown of my November monthly rainfall.

    11/1 – 0.44″
    11/2 – 0.11″
    11/3 – 0.23″
    11/4 – 0
    11/5 – 0.14″
    11/6 – 0.14″
    11/7 – 0.02″
    11/8 – 0
    11/9 – T
    11/10 – 0
    11/11 – 0.34″
    11/12 – 0.40″
    11/13 – 0.03″
    11/14 – 0.05″
    11/15 – 0
    11/16 – T
    11/17 – 0.80″
    11/18 – 0.42″
    11/19 – 2.68″
    11/20 – 0.83″
    11/21 – 0.56″
    11/22 – 0.02″
    11/23 – 1.50″
    11/24 – 0.20″
    11/25 – 0
    11/26 – 0
    11/27 – 0
    11/28 – 0.05″
    11/29 – 0.30″
    11/30 – 0.77″

    Total – 10.03″

  33. AdamInAumsville says:

    Getting some pretty strong winds here right now.

  34. W7ENK says:

    I believe I just heard a tremendous roar of thunder off toward my SW. Stepped outside but just missed it. What’s really odd, it’s raining moderately, yet I can clearly see the moon through only a thick haze!

    There’s some strange stuff going on tonight!

    • AdamInAumsville says:

      I thought I heard thunder earlier too. No flashes though?

    • W7ENK says:

      I’m inside with all the shades pulled. Had there been a flash, I probably wouldn’t have seen it, esp considering the windows here in the living room are North facing.

      Maybe, who knows??

      Pouring again!

  35. 00z ECMWF
    If you don’t like this, then there is something wrong with you!

  36. W7ENK says:

    I think that first front is already here… About a half an hour ago, I was over at a friends’ place and the wind came up so suddenly we thought their awning was going to rip off the back of the house! Then the rain, absolutely coming down in sheets! Lots of standing water, running water, ponding all over the place on my drive home. Even now, it’s still pouring.

    • W7ENK says:

      My phone is doing some weird shiz… I posted this (above comment) here in this post, but when the page reloaded it actually posted in the previous post. So I copied and pasted here, and it denied my comment with an error, but when I manually reloaded the page, here it was!

      Whisky Tango Foxtrot?!?

  37. lurkyloo says:

    Pouring big-time here near Rocky Butte. Really big-time.

  38. Sandi (Wilsonville) says:

    A very blustery, wet night out!

  39. 1st power outages of the night assuming wind related given the numerous reports of gusty-strong winds 35-40+mph in Washington County.

  40. 93rd…. Maybe the winds tonight will be a bigger story….

    • Mark Nelsen says:

      Nice little surge of wind about 15 minutes ago here in Beaverton, a gust to 32 mph. You can just barely see the line on radar as it snakes across the metro area.

  41. EY (Oak Grove) says:


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