Still On Track For Drying Halloween Evening

10pm Thursday…

The next 45 or so hours are going to be a real soaker across the region.  Models are in unusually good agreement that we’ll see a strongly “orographic” rain event.  That means the mountains will be favored for the heaviest rain, even more so than normal.  Take a look at our RPM rain forecast and then the UW WRF-GFS accumulated rain forecast:



In general the mountain totals will be around 3-5 times what we see in the lowlands!

By Sunday evening, I expect:

  • 1.50-2.50″ rain in the western valleys of Oregon
  • 2.00-3.50″ from Longview up through Olympia in the valleys
  • 5-10″ in the Cascades and Coast Ranges.  The usual very heavy rainfall areas in the southwest Washington Cascades could see 10-12″.

This shouldn’t produce any significant river flooding since reservoirs are pretty much empty and rivers are very low.  I see Detroit Lake is lower than at any time last winter!  The first few inches will be soaked up by the dry ground too.

There WILL be some local/urban flooding Saturday midday/afternoon as models are showing a very intense band of rain with the cold front.

Check out our RPM midday Saturday:


Whew!  That’s intense…not a good time to be having an outside party.

Then check out the 5pm image:


This is even faster than model runs yesterday.  The WRF-GFS is not quite as fast, showing the rain just leaving the metro area around 5pm.

Either way I think we’re still in good shape in the metro area for Halloween

Behind this system I see a colder airmass with some snow in the mountains.  This isn’t a really cold airmass; at best we get a dusting or 1″ at Gov’t Camp by Monday morning.  But higher up around 5-6,000′ we’ll get a good dumping, the first of the season.  I could see a foot up around 7,000′.  That’ll be it for another 5-7 days though.


Enjoy the weekend, I’ve been working a bunch of weekends this fall so I’m taking tomorrow off.  No blog postings until Monday unless I get real inspired to do it from home.

Chief Meteorologist Mark Nelsen

134 Responses to Still On Track For Drying Halloween Evening

  1. W7ENK says:

    Spotter report, sent to Tyree Wilde at NWS Portland.

    #C568 Spotter Report
    Milwaukie, Oregon

    45° 26′ XX.xx” N
    122° 36′ XX.xx” W

    31 OCT 2015 Saturday
    Peak wind gust SW 22.8 mph
    Observed power outage in Canemah, OR approx. 3:35pm, within 90 seconds after onset of torrential rain/wind assoc w/ FROPA
    (see attached radar screenshot for timing.) Cause unknown.
    Rainfall: 1.93″

    1 NOV 2015 Sunday
    Rainfall: 1.00″
    Observed prolonged localized street flooding, multiple locations.

    2 NOV 2015 Monday (Midnight to 6am)
    Rainfall: 0.28″

    Weekend Storm Total: 3.21″


  2. WEATHERDAN says:

    Very heavy rain on Halloween between 4:00 PM and 6:00 PM. 1.25 inches. Result no tricks or treaters. Worked out fine because I never give out candy anyway. Peace.

  3. schmit44 says:

    11/1/2015 Oregon (All) Temperature Summary

    High:68 at NELSON(2567 ft) & Weatherby Rest A(2390 ft) & ONTARIO(2260 ft) & UNION(2708 ft) & CW2049 Imnaha(1978 ft)
    Low: 56 at UMATILLA RIVER B(586 ft)

    High:30 at Mt Hood Meadows(7300 ft)
    Low: 25 at ALAKES Haines (7979 ft )

    Largest Diurnal Change: 37 degrees
    ABRNAT (64/27 ) (4480 ft )

    Heaviest Rainfall:
    2.90″ at NORTH FORK(3060ft)
    2.20″ at SOUTH FORK BULL(2690ft)
    2.06″ at LOG CREEK(2800ft)
    2.00″ at MCKENZIE(4770ft)
    2.00″ at SMITH RIDGE(3270ft)
    1.95″ at SOUTH FORK(2257ft)
    1.93″ at DW4118 Sandy(1250ft)

  4. W7ENK says:

    0.99″ today.
    1.93″ yesterday.
    2.92″ weekend total.

    I think today turned out wetter than anyone expected. Thankfully it was dry during daylight hours, but the showers last night and again this evening have been really heavy. Impressive to watch the radar.

    • W7ENK says:

      It just quit raining, so I went out and checked one last time before bed and managed to squeeze out one more 0.01″ into the rain gauge, which rounds out today’s total to exactly 1.00″

      That 0.99″ was gonna bug me!!! lol

    • Joshua Downtown PDX says:

      Official PDX total was .19″ yesterday. It was frustrating watching everything go south and north of me most of the day. We might have had slightly more downtown that at the airport, but if so, not by much.

    • W7ENK says:

      Got another 0.28″ overnight.

    • Guess the Dome has temporarily been breached 🙂 .

  5. Tyler Mode in Battle Ground says:

    Be careful jumping to early snow means lots of snow. We had quite a bit more snow in October last year, and we all know how that turned out.

  6. Jason Hougak says:

    Sure there can be similarities in El Nino’s but they can’t be exactly alike. After a dull 14-15 winter I’m hoping for some weather excitement and drought busting rain and mtn snow.
    Washington’s Stevens Pass getting good snow accumulation. Timberline is getting snow but 39 and rain in Govy.

  7. MasterNate says:

    This is good news for possibly a good start to building snow pack and a good ski season. They mentioned that this winter is starting out similar to 1982. Also an El Nino year apparently.

  8. Jason Hougak says:

    I for one don’t like moving the time back one hour. I’d rather have an hour in the dark going to work and having some light when I got home. It totally sucks getting dark at 5. We should vote to end this time change.

  9. schmit44 says:

    October 2015 at PDX ended up the warmest of all time averaging 60.08°
    Last year October 2014 was the previous record at 60.06°

  10. Jason Hougak says:

    What a great Halloween, we walked through downtown Estacada through the pouring rain and hit all the shops giving candy to the gooles and goblins. It was great to see all the umbrellas again. Then we enjoyed a harvest barn party in our small community. The night was perfect for a spooky Halloween night.
    33F at T-Line with snow starting to accumulate. Discounted season passes available til Nov. 8th.

  11. David B. says:

    .55″ in the past 24 hours, .89″ in the 24 hours previous, 1.44″ total for this event. Freezing level is now down to 5,000 feet going by decoded aircraft observations this morning.

  12. W7ENK says:

    0.68″ from midnight to ~7:30am.
    1.25″ from ~3:30pm to midnight.

    1.95″ storm total.

    Without looking at any other locations, I’d say rainfall estimates were pretty much spot on.

    This closes out October with 4.51″ total rainfall at my location.

  13. High Desert Mat says:

    Well, this sure was a good sight for sore eyes. It rained everywhere with a nice amount, not to mention prolonged on and off rain with the ground soaking it up along with trees, shrubs, bushes, lawns etc. etc. What amazes me is that we’ve been so dry and all the models have been overachieving as of late with ridiculous rain totals and now we finally have gotten a really good fall storm. At least it has over here in Redmond. Winds all day yesterday and today blowing 20-30 sustained, and has been raining here since 830pm. Kind of strange, hasn’t rained this much at one time since last April. Welcome change for the fish, rivers, reservoirs, and certainly the people of drought stricken areas. Only .21 in the bucket but I feel its more. Night all

  14. schmit44 says:

    10/31/2015 Oregon (All) Temperature Summary

    High:78 at DW6803 Ashland(1890 ft)
    Low: 60 at EW0059 Myrtle Po(174 ft) & SWAIN(366 ft)

    High:38 at Mt Hood Meadows(7300 ft)
    Low: 30 at Mt Hood Meadows (7300 ft )

    Largest Diurnal Change: 32 degrees
    DW6803 Ashland (78/46 ) (1890 ft )

    Heaviest Rainfall:
    5.70″ at NORTH FORK(3060ft)
    5.33″ at HEBOWX Mt. Hebo(3160ft)
    5.01″ at CEDAR(2220ft)
    4.25″ at YELLOWSTONE MTN.(3080ft)
    3.76″ at LOG CREEK(2800ft)
    3.51″ at EW6414 Mill City(1007ft)

  15. Paul D says:

    I was in Beaverton near Murray & Hwy 26 at 7pm watching it rain quite steady and telling my daughter we wouldn’t be trick or treating when we got home. We drove to Hillsboro where it wasn’t raining, and as we were walking around the neighborhood, I saw stars up in the sky! So I’d say Mark didn’t totally blow it on his forecast!

  16. Garron (1/3 of a mile from Hillsboro airport) says:

    I’m having an issue with mesowest reporting stations not updating. Is it my internet connection, or are they just having issues?

  17. W7ENK says:

    Well, let’s compare…

    Forecast for 11am

    Reality at 7:30pm

    8-1/2 hours late on a critical forecast day.
    I’d call that a bust.

    • Tom (NE Portland) says:

      Huge bust. Only had about 20 minutes of dry time and now it’s pouring again.

    • pappoose in scappoose says:

      Splitting hairs. Get real.

    • () says:

      Nobody’s as perfect as you guys.

    • Mark Nelsen says:

      Erik, that was a two day old model run! Later runs slowed it down, while I wasn’t working (no work Friday or today). This morning it looked like it would be raining until around 6pm. 2 hours late obviously a screwup, but no need to make it worse than it was

    • Mark Nelsen says:

      I just checked this morning’s WRF-GFS, it was much closer to reality: 5pm-6pm total shows rain across a good chunk of the metro area. I’ll definitely do a posting on this Erik because you bring up a good point about trying to nail something to the hour

    • W7ENK says:

      Hey Mark, I’m just giving you a hard time. Really, I understand it’s not an exact science… hence The Dome!! lol

    • Runtmc says:

      W7 knows all. He’s stetching his naysaying, I-told-you-so, believe-it-when-I-see-it muscles in preparation for the winter. I’m eagerly anticipating his first condescending, after-the-fact forecast of the winter. He brings arm chair quarterbacking to a whole new level. I love it. It’s the first sign of winter.

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