Flood Watch Through Wednesday

10pm Sunday…

Most of the FOX12 viewing area over and west of the Cascades is under a Flood Watch (from the NWS) through Wednesday.  It’s pretty straightforward…too much rain is coming in the next 3 days!

I’m at home this evening and not real sure if I’ll make it to work tomorrow.  I can barely talk with some annoying form of a cold & laryngitis.  Hopefully I’ll feel better tomorrow and, more important, sound like a normal human being on-air.

But it doesn’t keep me from posting weather info and charts/maps!

We are in a classic wintertime strong westerly jet stream regime.  We haven’t seen much of this in the past two winters.  But it’s here for another 5 days or so.  Here’s the 250mb jet stream windspeed map for 4pm today:

gfs_jet_250_npac_2

Note the speeds over 200 mph in the central/western Pacific.  It’s pretty much a straight shot from Japan to Oregon the next few days.

So we’ll see one system after another racing eastward with plenty of moisture and areas of low pressure to produce wind tracking along with them.

Between right now and early Wednesday morning, we’re under the influence of a very warm airmass…snow levels jump to 7,000′ or so through daybreak Wednesday.  As a result, keep in mind that all precipitation will fall as rain at ski resorts and mountain passes through that time.

The biggest surge of rain appears to be tonight, tomorrow midday/afternoon, and again Tuesday evening through daybreak Wednesday.  There will be a break for most of us during the day on Tuesday.  That said, models are painting a very wet 72 hour rain total picture for us.

I would estimate we’ll see at least 3-4″ in the “driest” parts of the northern Willamette Valley the next 3 days.

The Oregon and Washington Cascades along with the highest parts of the coast range will receive the brunt of the rain and strong westerly wind runs into the north/south oriented ranges.  Expect 6-14″ on the west slopes of the Cascades and Coast Ranges.  Here are 4 different model forecasts of 3 day rain, this evening’s run of the GFS, ECMWF, & WRF-GFS (UW):

These forecast totals are similar to the big event that started the wet season with a bang back in late October, back then soils were very dry from summer.  This time soils are already wet and there is snow on the ground up above 4,000′ too.  A bunch of that snow is going to melt since a 1 or 2 foot deep snowpack can’t absorb 8″ or more of water dumped on it.  As a result I would expect some river flooding in our area.  Of course if we get too much rain in a real short amount of time that’s when we get the localized urban flooding too.

For the skiers…is it time to panic?  Definitely not.  As mentioned in previous posts, all signs point to a cooldown with COLDER systems after Wednesday.  I have a feeling we will see FEET of snow before we get to Sunday the 13th.  Check out the 3 day total from the WRF-GFS ending Friday morning…maybe 8-12″ on Mt. Hood.

or_snow72.108.0000

Enter a caption

Then 3 days later…2 feet or more additional!

or_snow72.180.0000

The ECMWF model also has a good 2-3 feet of snow on Mt. Hood Thursday through next Tuesday (not shown).  This could set us up nicely for Christmas Break…Ski Season begins AFTER the warm rain this week.

Chief Meteorologist Mark Nelsen

 

55 Responses to Flood Watch Through Wednesday

  1. W7ENK says:

    FLOOD WARNING
    NATIONAL WEATHER SERVICE PORTLAND OR
    1041 AM PST MON DEC 7 2015

    http://inws.wrh.noaa.gov/weather/alertinfo/27248649

  2. Jason Hougak says:

    This will test that expensive BIG PIPE SEWER project the city completed to stop sewage overflow into the river.

    • Pete says:

      The big pipes (Columbia Slough, West Side, East Side) aren’t designed to stop all combined sewer overflows. That would have added enormously to the cost.

      From the Environmental Services bureau today:

      CSO Advisory

      December 7, 2015

      Heavy, sustained rain caused Portland’s combined sewer system to overflow to the Willamette River and the Columbia Slough on Monday, December 7, 2015. The combined sewer overflow (CSO) event began at about 7:50 a.m. on December 7.

      Because of increased bacteria in the water, the public should avoid contact with the river from the Sellwood Bridge to the Columbia River confluence, and with the slough from about N Denver Avenue to the slough’s confluence with the Willamette for 48 hours after the CSO event ends. Updates about the CSO event, including the time the event ends, will be posted on this page.

      Portland’s combined sewer system carries sewage and stormwater runoff in the same pipes. In December 2011, Portland completed a 20-year program of sewer improvements, including constructing big pipes on both sides of the Willamette River. The improvements eliminate 99% of CSOs from the Columbia Slough and 94% from the Willamette River.

      During a major storm event, the big pipes store large quantities of stormwater and sewage while pumping it to the Columbia Boulevard Wastewater Treatment Plant. During very heavy rain storms, some combined sewage can overflow to the Willamette River and Columbia Slough. That is what the system is designed to do and that is the way it operates.

      A combined sewer overflow is about 80% stormwater and 20% sanitary sewage. Before the city completed the CSO control program, combined sewers overflowed to the Willamette an average of 50 times a year. Today, the combined system overflows to the river an average of four times per winter and once every three summers. Today’s overflow to the slough was the first caused by heavy rain since the city completed construction of the Columbia Slough Big Pipe in 2000.

    • W7ENK says:

      That “Big Pipe” project has already proven itself to be a failure, multiple times.

    • umpire says:

      Eric – I worked at BES during the latter years of the Big Pipe project. There is no way pipes large enough to handle 3 plus inches of rain in a day could be built, at least at a cost ratepayers would accept. There are only a handful of overflows a year, which is in the DEQ permit. Given that highway 217 is underwater, this probably qualifies as a hundred year event, though the changes in climate may change those metrics.

  3. schmit44 says:

    WETTEST 24-HOUR PERIOD EVER RECORDED AT PDX DURING THE MONTH OF DECEMBER WITH 2.88″ AND STILL COUNTING

    • Rob - S.E. Portland says:

      WOW!

    • schmit44 says:

      11:00am PNW 24 hour rainfall totals

    • Joshua Downtown PDX says:

      This really puts into perspective how nuts it is when we see other areas get upwards of 10-15″ of rain in a 24 hour period and 2′ or more in a 5 day period. That’s what South Carolina experienced a couple of months ago. Hard to fathom. The all-time US record is 43″ in 24 hours. Worldwide, it is 72″. Can you imagine???!!!

  4. pappoose in scappoose says:

    You called it, Rob!

    IN ADDITION TO THE HEAVY RAIN THERE IS STRONG WIND BEGINNING TO MOVE ONSHORE. GUSTS NEAR 70 MPH HAVE BEEN REPORTED ALONG THE COAST…WITH
    79 MPH REPORTED IN THE PAST HOUR AT ROCKHOUSE RAWS IN THE COAST RANGE. AM SOMEWHAT CONCERNED WITH THE DRY SLOT RACING ONSHORE AS IT
    IS…THIS MAY HELP THE STRONGER WINDS JUST ABOVE THE VALLEY TO MIX DOWN TO THE VALLEY FLOOR. WILL INVESTIGATE FURTHER AND MAKE A
    DECISION SHORTLY ON WHETHER TO UPGRADE THE WIND ADVISORY TO A HIGH WIND WARNING FOR THE WILLAMETTE VALLEY.

    http://www.wrh.noaa.gov/total_forecast/getprod.php?afos=xxxafdpqr&wfo=pqr&font=120&version=0

  5. pappoose in scappoose says:

    “Cars nearly under water in the Pearl District, December 7 2015. (KOIN)”

    • A lake and wetlands once occupied some of the land where the Pearl District now is. That photo looks to be taken near the Fremont Bridge, in precisely that part of the Pearl District. Seems like the heavy rain is temporarily resurrecting the old state of affairs.

    • Dave in South Salem (500') says:

      That Montero is fine. The cars though…

  6. Rob - S.E. Portland says:

    9:00 AM Water Vapor Update

  7. EY (Oak Grove) says:

    We’ve already obliterated the previous rainfall record for today.

    December 7th, 1996 – 0.86″ of rain
    December 7th, 2015 (From 01:53 observation to 08:53 observation) – 1.45″ of rain

    Also, I saw one small stream in my area that is no longer small. It’s already above its banks and is starting to flirt with flooding the yards of surrounding homes.

    • Pete says:

      I’ve always wondered if the 12:53 am observation should also be counted. In any case, serious rain. I wonder if the December single-day record of 2.17 (Dec. 27, 1942) might be in jeopardy.

    • EY (Oak Grove) says:

      I’d say that it is in Jeopardy now. I know the rain is going to start getting lighter, but there’s still a good hose aimed at us. With only .72″ (or less) left to go and still about 15 hours? It’s looking possible.

    • Pete says:

      0.48 more in the hour ended 9:53 a.m. Wow.

  8. Jason Hougak says:

    I’m headed up to Rhododendron on a job now. I’m going to stop at Sandy River bridge on Lolo Pass and take some pictures. I’ll post up later. The NWS in Portland should be posting a Flood Warning. There are creeks already over flowing banks and crossing roads. I’m hoping I’ll be able to get home up Eagle Creek drainage later today.
    Timberline did pickup 8″ last night which is melting away😕
    Mark can you get the NW Avalance Center to get the gauge working on the mile. They have had ALL freaking summer!!!

    • Dave in South Salem (500') says:

      This may be the week the drought monitor upgrades the mountains and foothills from severe drought to moderate drought. We’ll see.

  9. paulbeugene says:

    Beware of the triple point

  10. Jason Hougak says:

    Help, need an ark ASAP!!!! Flooding around our shop, water flowing down roads. This is a major event and just the beginning.
    Residents on Lolo Pass on Mt.Hood need to take action right away!

  11. Lee Wilson says:

    Multiple accidents happening on I-5 In Southwest washing Near Castle Rock area.

    Bus Driver said Radio traffic has been “buzzing with accident after accident” People really need to slow it down.

    I have noted flood watch for the Kelso Area.
    there is one area between Kelso and a Marijuana shop that can flood. will be keeping an eye on that.

    in a flood situation the city of Kelso has a large steel beam they can place to prevent traffic from taking West Side Highway.

    Only once have I ever seen it used. and that was a very long time ago.

    • muxpux (Longview) says:

      Huh? What shop are you talking about? I’m in Kelso, and I believe all the weed shops are in Longview. There’s the one out at Nevada and West Side. My parents live up on Sandy Bend, and in 96 west side flooded that section and was closed. Is that the “steel beam” your talking about? Im more worried about the section of west side by hazel dell rd, where it has slid a few times. That poor section is gonna fall away some day.

  12. Rob - S.E. Portland says:

    Great post, Mark, thanks and feel better.

    All eyes to the west. A Strong storm riding a 150-160kt jet is developing near 45.3 N, 135 W due west of roughly Seaside-Astoria and is screaming eastward. 4km Loop shows a nice dry slot and darkening along with increasing circulation. 250mb chart shows that jet pushing into the northern Oregon/southwest Washington Coast. Good strengthening/Cyclogenesis seems possible. Wind Storm possibly coming? Wind Advisory looks like a good call to me right now. Not the most classic track for a wind storm, but we’ve seen several on this west-east track in our past. We need to keep an eye on this and pressure falls, 3hr Pressure trends later this morning offshore.

    • Rob - S.E. Portland says:

      Click the image in case the current WV isn’t appearing.

    • Rob - S.E. Portland says:

      12z MM5-NAM doesn’t develop or strengthen this low even 1mb from now through 1-2 PM(landfall) keeping it around 998mb and that just simply looks incorrect no way this low isn’t deepening(perhaps rapidly) as we speak….

      Just checking Buoy Station 46005 tells us the low is likely under 1000mb already…. I have high confidence that it is. So now it supposedly stops intensification/cyclogenesis? Unlikely.

    • Rob - S.E. Portland says:

      3hr Pressure trends shows strong intensification occurring. Hmmm. Models are not handling this well

    • runrain says:

      I noticed Newport had a .06 drop in pressure in 20 minutes. Obviously, things have to line up just right to get a strong wind event here, but it is important each time the potentiality arises that attention is heightened. Just ask Jack Capell!

      Pearl Harbor Day today – 74 years. Thank you to our veterans once again. If you want to get a taste of what it would have been like without their courage, watch that miniseries The Man in the High Castle. Wow.

    • Lee Wilson says:

      Holy crap, this is bad…

    • Lee Wilson says:

      We are at 2962 and dropping, our system is basically at ground level as I can not erect a pole with in city limits.

      Either the rain gauge is malfunctioning or we have been dumped up on .
      it is reading 1.16 already and showing a steady rain fall of .49 inches an hour. and the total monthly amount so far is showing.23.69 inches?
      is that for real?

    • Anonymous says:

      Are you saying this system is possibly going to bomb?

    • Lee Wilson says:

      Ok, being a little less dramatic but adding a tad bit of drama, are you stating that this system has a potential to be a bombogenisis?

    • pappoose in scappoose says:

      Potential “POWDER KEG” you might say, Lee.

      NATIONAL WEATHER SERVICE PORTLAND OR
      858 PM PST SUN DEC 6 2015

      THESE SYSTEMS HAVE PLENTY OF
      BAROCLINICITY AVAILABLE TO THEM…WHICH COMBINED WITH THE POWERFUL JET IS CREATING A POWDER KEG OF POTENTIAL FOR CYCLOGENESIS THE NEXT
      FEW DAYS OFFSHORE. ALL THESE FEATURES WILL ALSO MAKE FORECASTING ANYTHING BEYOND 24-36 HOURS VERY CHALLENGING WHILE THIS PATTERN IS IN
      PLACE…AS SMALL ERRORS IN INITIALIZATION CAN LEAD TO VERY LARGE ERRORS IN A SHORT PERIOD OF TIME.

  13. W7ENK says:

    Upgraded.

    FLOOD ADVISORY
    NATIONAL WEATHER SERVICE PORTLAND OR
    618 AM PST MON DEC 7 2015

    http://inws.wrh.noaa.gov/weather/alertinfo/27245449

  14. Wet.windy and warm(my 3W’s) pretty well sums it up around my area.. I sure hope that cooling trend comes as predicted. Wolf Read tells me he’s already seeing swelling buds on the Whitcomb cherry trees in his neighbourhood here in Vancouver BC..

  15. Brian says:

    Mark, go get you some ginger root. Cut off a little piece, chew on it some and spit it out or swallow. Spicy! Drink some water to flush it. I had some kind of garbage a few weeks back and that really helped with the cough.

  16. schmit44 says:

    12/6/2015 Oregon (All) Temperature Summary

    Warmest:
    High:63 at DW9612 Umapine( 797 ft)
    Low: 53 at Bullards Bridge(23 ft) & Gold Beach (US 1(60 ft) & BROOKINGS(79 ft) & EW1135 Yachats1(32 ft)

    Coldest:
    High:28 at Mt Hood Meadows(6540 ft)
    Low: 23 at Rim (7050 ft ) & HOWARD Mt Howard (8150 ft )

    Largest Diurnal Change: 23 degrees
    Arlington (57/34 ) (449 ft )
    MALHEUR RIVER BE (54/31) (3305 ft)

    Heaviest Rainfall:
    2.76″ at HEBOWX Mt. Hebo(3160ft)
    2.44″ at CEDAR(2220ft)
    2.30″ at SOUTH FORK(2257ft)
    2.24″ at TIDEWATER(2035ft)
    2.06″ at HORSE CREEK(3402ft)
    1.87″ at RYE MOUNTAIN(2000ft)
    1.86″ at TILLAMOOK(11ft)
    1.75″ at CANNIBAL MOUNTAI(1939ft)

  17. Benjamin (West Salem) says:

    I hope you feel better. It’s going to be a wet week for sure, nice that there should be a lot of snow falling after the warm rains come as opposed to before.

  18. Lee Wilson says:

    Hope you do get well soon.

  19. Lee Wilson says:

    You could signed, if you know how ,or you could use PECS.
    Or you could use your devices text to speech.

    But then, it might be better not to share it.
    And it it is as bad as you say it is going to get, maybe we all should just stay home, because there won’t be any roads to drive on.

    Oh what is with the snow on the page? Or rain drops?
    Is the super computer weeping?

    • sds says:

      It is winter and we dream of snow–so a little snow flake here or there keeps us in the mood.

    • Lee Wilson says:

      I like it. 🙂 but I am thankful this is not a snow event..as much as I like snow , this would paralyze us. I think?

      hmm on the plus side..it would have given us all a break 🙂 ok, I wish this was a snow event.

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