Battle Ground Tornado: EF-1

NWS has completed their storm survey and this is what they found:


That matches the intensity of the 2008 tornado in Vancouver.  Also similar to the Longview tornado back in October last year.

So the Aumsville storm from December 2010 remains the strongest in our area since 1972.  It was rated an EF-2

Aumsville Tornado_NWS-Damage_path

A very obvious question comes from our viewers; why aren’t these forecast ahead of time and/or why no warnings in the minutes before?

Two answers

  1. These are relatively weak tornadoes and the circulation is often weak.  I checked today’s radar imagery and I don’t see anything that sticks out.  At least no more shear than we see with our typical cold showers/thundershowers.  There is no big “hook echo” to look for like with the big storms.
  2. Portland’s radar is located at 2,000′.  The radar beam goes up in elevation the farther you get from that location.  As a result we don’t see the lowest 3,000′ or so in the metro area, and nothing under about 10,000′ once you get to Eugene or up around Olympia.  Most of the action is happening closer to the surface so it can’t be seen.

Here’s a look at the ranking of our recent tornadoes:


Chief Meteorologist Mark Nelsen

78 Responses to Battle Ground Tornado: EF-1

  1. I checked out the Weather Underground NexRad weather page and it did indicate a tornado vortex signature in that part of SW Washington on its storm tracks feature around that time. I shrugged it off as noise until I heard about the Battleground tornado. There was another one as well that was listed in the storm tracks but I could not find on the radar map. What I don’t know is how many false positives that system produces, so I can’t say whether people would have benefited from the warning.

  2. 00z GFS looked a bit improved to me, at 500mb especially. The 2nd trough is real close to delivering. I see several opportunities in this run. Definitely colder NW flow. For PDX 00z WRF sounding 7 AM Monday morning is very close to producing snow down to the valley floor, if not 500′. Tuesday morning even colder, but lack of moisture. Thursday chilly east wind develops. Any of these system that dive south of us could continue east wind with a bit of a cold pool already developing over the Columbia Basin with moisture thrown over top of 850s down to -7c. Into la-la land beyond day 10 thickness drops near/under 522 with a threat of a White Christmas, then further into fantasy land he potential is staggering for major snow/ice events for PDX. Strong systems moving in from the southwest. Very strong and deeply suppressed jet. If anything the Cascades could see many, many feet of snow.

  3. The cookie monster says:

    Mark, dont worry about January, I think it’s going to stay active for a little while more. February dies off and then we see our usual wet spring once again. Normal summer and then epic ’16-17 winter. You hears it here first. Hmmmmm, could beeeee.

    How ’bout those euro weeklies to shut us up Mark?

  4. Steven James says:

    I happened to be watching the radar live at the exactly 11:15, only I was lamenting on how it seemed every storm with thunder potential would weave its way around Beaverton …

  5. Jason Hougak says:

    Alright there let’s not start knocking January have faith that it’ll become an epic El Niño winter!
    I have enjoyed working this wet week in the rain and love the snow that’s hitting the mountain.

  6. W7ENK says:

    427 PM PST FRI DEC 11 2015

  7. The much anticipated Bering Sea low #1 is undergoing explosive Cyclogenesis. It is the system I’ve been highlighting in my analysis the past several days. Right now it’s currently located near 40 N, 153 E with a depth around 980mb. The 18z NWS/NCEP Pacific Surface Analysis forecasts this cyclone over the next 24 hours to deepen 35 millibars to roughly 945mb plotted at 49.3 N, 177 E. It then races northeastward towards the far western Aleutians. This drop of 35mb over a 24 hours period is what we call Bombogenesis which is defined as an area of low pressure that drops in surface barometric pressure by 24 or more millibars in a 24-hour period. This storm will more than certainly achieve this. It continues to intensify further through Saturday evening peaking out just north of the Western Aleutians near Shemya as it heads towards the central-northern Bering Sea. 12z runs of the GFS has it bottoming out around 924mb and the ECMWF at 926mb!

    This is an absolute monster storm and will be incredibly massive on WV/IR Loops. This storm will be a pattern changer and in my opinion it could buckle the large scale pattern more than models are currently seeing right now. That probably wouldn’t be revealed for several more days if so and it would just happen to line up with the time frame the EURO Weeklies is suggesting. Just a thought. Worth also noting this pattern evolution with a very deep, bombing low causing a major pattern change is quite reminiscent of what we saw last year on November 6th and roughly one week later we had a modified arctic blast Gorge east. I’m not saying this is going to happen, I’m saying the potential is there and our past history many times not just last year tells us when we see a major bomb in the Bering/off Kamchatka that it can lead to much colder weather. You can see this read see that here ->

  8. W7ENK says:

    Looks like the center of low pressure is right on top of Hillsboro this hour, heading due East toward Portland.

    Pressure should start rising again soon.

  9. runrain says:

    Lots of heavy rain over the area on I5 in Woodland where that slide blocked the freeway. Hope there is not a reoccurance.

  10. Well, this is a bit interesting. EURO Weeklies paints a legitimate chance of cold/snow during Christmas week. Hmmm, I say. Hmmm.

  11. Jason Hougak says:

    1st winter storm watch issued for the Oregon Cascade winter season!!!

  12. paulbeugene says:

    Friday 12:20pm

    As far as I am concerned, wind advisory not verifying down here in the south valley, gusts into low 30s.

    Nice to see snow on the pass cams, 7″ at Government Camp, 10″ at Santiam pass (on the ground) as of this morning’s ODOT report.

    Rain: should get 1/4 to 1/2 inch of rain tomorrow morning in the valley. As for rain in the afternoon, it is not clear how far north the baroclinic band will hang up before moving S away from the state. NGM has it over the south Willamette Valley whereas the GFS is south of Roseburg with it. It is not clear at this point how much rain we are due for but ultimately it appears a deep trough will dig down from Alaska offshore and progress eastward, with axis of trough over I-5 by Saturday (day 8).

    Mountain snows: hope to get another foot or two at Government camp in the next 7-10 days. Looks to me there will be rising snow levels (up to 6000 feet or above) for a day or two before freezing levels drop with arrival of next trough on Friday evening. This is perfect timing for going skiing the weekend before Christmas. I am confident that Hoodoo and Willamette Pass should be able to open as heavy snows anticipated this weekend. As for Ski Bowl, I don’t see it opening until Dec 20 if not a bit later, unless they get more snow than expected this weekend. If I were ski bowl I would root for the NAM as it has 2 feet of snow falling there by Monday.

    I don’t see any arctic outbreaks occurring on any of the operational model runs (Euro/UKMET/GFS/Canadian/NOGAPS) in next week or two. Doesn’t mean it can’t happen, it’s just unlikely. At least the Cascades are getting a good base of snow established, and the reservoirs are filling up.

  13. MasterNate says:

    What!? No Jason this morning? Oh, wait, heavy mountain powder alert. He must be cruising the slopes this morning.

  14. Lee Wilson says:

    Oh, and I bet we don’t even get snow in the lowlands. .:(

    On the up beat, we didn’t lose power…the Cowlitz PUD, really went to town on prevention. Normally we at least one power outage.

    So not fair, get a generator, and the power never goes out? Grrrrr…

  15. paulbeugene says:

    NAM trending north with heavy rain this weekend, south Willamette valley under the gun for 2″ plus 24h amounts. We can handle it though, as we did not get nearly as much as PDX did

  16. Lee Wilson says:

    We have had 4 or more tornadoes here in the Pacific Northwest region in Washington and in Oregon.

    It seems a pattern is developing.

    I don’t think they are a rare anymore.
    I bet we get 1 next year.

  17. I’m relieved to learn the tornado was a relatively minor event (F-1). Meanwhile, I’m looking forward to this cooling trend that supposed to come soon. Sure hope it gives us at least some near normal temperatures. Presently, my mean temperature for December is 47.9F- that’s way above average, and even almost 1.9F warmer than the first 10 days of November.

  18. Lee Wilson says:

    Are these the new “normal” for us now?
    They do not seem to be to earn of an event anymore.

    • Tornadoes? They are still a fairly rare occurrence in our neck of the woods. Considering we’ve had 4 of note going back almost 8 years I’m going with no.

      It does seem our weather patterns are becoming more extreme (hot/dry) (stormy/wet).

    • W7ENK says:

      Once we break 10 per year, then let’s talk about reestablishing a new “normal” and contemplating the ramifications of dealing with tornadoes all the time. Until then, I think the statistic of 0.5 tornadoes we do get annually is still sufficient enough to call rare.

      Oklahoma is probably laughing right now…

  19. muxpux (Longview) says:

    Not often I recall seeing a low spinning up the coast only to loop counter clockwise and come back at us, lol.

  20. 00z ECMWF day 4-6 a bit more like the GFS. After day 7-8 it turns unfavorable. Day 9-10 is much different and very improved. Not too bad with ridge/height anomaly along 160 W.

    • Jack Frost says:

      I am a very long time lurker on this blog and never comment. Just wanted to say that I’m glad to see you back Rob with your insightful and down to earth analysis. I suspect you can probably bank on a white Christmas this year given that I will be in the Philippines – bloody typical!

      Cheers all.

    • pappoose in scappoose says:

      Cheers, Jack!

  21. schmit44 says:

    12/10/2015 Oregon (All) Temperature Summary

    High:60 at BANDON( 79 ft)
    Low: 48 at EW3638 Yachats(33 ft)

    High:26 at Mt Hood Meadows(7300 ft)
    Low: 20 at Mt Hood Meadows (7300 ft )

    Largest Diurnal Change: 24 degrees
    Hermiston Munici (57/33 ) (636 ft )

    Heaviest Rainfall:
    2.37″ at ILLINOIS VALLEY(1389ft)
    2.36″ at QUAIL PRAIRIE LO(3183ft)
    2.25″ at EW7191 Selma(1394ft)
    2.23″ at CW8876 Williams(1640ft)
    2.20″ at TOKETEE AIRSTRIP(3240ft)
    2.16″ at TIDEWATER(2035ft)
    2.07″ at Sexton Summit(3842ft)
    2.00″ at EW4806 Grants Pa(942ft)
    1.91″ at BALD KNOB(3630ft)
    1.91″ at MERLIN SEED ORCH(1144ft)

  22. High Desert Mat says:

    I think its pretty sweet that we have an ensemble member that goes to -20C 850’s right at Xmas. If only…..

  23. 00z GFS – Much better looking ridge, very amplified, further west, nice tilt and configuration. Anomaly looks much better than previous runs too. Through day 10 500mb pattern a bit better, 850s only slightly colder. So close to being SNOWY, just need the trough to dig deeper. This is the best run in a long time really. Ridge/pattern is a bit too progressive still, but there is no mistaking that this is a step in the right direction. Thicknesses under 522 with 850s -7c close to snow down to valley floor. Hopefully no S-W winds, or if so very light.. Not bad. It could be an outlier, but this isn’t an impossible solution either. Even if the trough were to dig deeper and we had a modified blast, it would probably be brief, at least deeper cold air. The low-levels would be cold much longer duration. This run just offers cold NW onshore flow. It’ll be snowy up at 1000′ for sure. It’s not an impossible solution though.

  24. W7ENK says:


    Here we go again…

    839 PM PST THU DEC 10 2015

  25. paulbeugene says:

    Certainly looks like El Niño wants to dress up as La Niña for the holidays

  26. Hard to believe that the NWS never put up a winter weather advisory today for central Cascades. Santiam pass received at least 8″ today.
    And still coming down.

  27. Thanks, Mark good post

    We had 30kts low-level shear and 0-1km Helicity 200-250m2/s2 in place, the lower atmosphere was primed for the possibility. What a crazy active weather pattern this has been.

  28. Wendy-Silverlake, WA says:

    1.5 inches so far today and the radar is not letting up this direction. In fact it turns more red and orange each time I pull it up.

  29. Sapo says:

    third! lol

    18z gfs was pathetic compared to yesterday’s 18z…but who knows

    • W7ENK says:

      It’s the 18z…

    • JohnD says:

      …and I got timed out for that!…
      Gut check time is already ensuing. At least our valley “’40’s and rain and copious mountain snow” theme is sure to prevail for a while (unlike last year!) So amid the progressive pattern, an anomalous low elevation “event” still could miraculously occur. We’ll see. Seemingly gone are the days in weather history when city snow wasn’t a matter of “if” but “WHEN”!

  30. W7ENK says:

    Mark, you said you’d be live on Facebook to answer questions at 7:05, but you never showed!!

    I cried. 😥

  31. Jerry says:


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