Stormy Weather Ahead; Winter Meeting Today

8:00am…

It appears that REAL November weather is on the way, with many storms/frontal systems ready to impact the Pacific Northwest in several different ways over the next week (and beyond).   The main issues (threats) will be possible flooding and/or damaging wind.

First, don’t forget the previous posting, the OMSI winter weather meeting starts in just 2.5 hours!  I’ll be manning the rafffle box.

 

Now, on to the weather:

We have a cold front just offshore this morning, with rain showers ahead of it in the mild airmass.  The steady rain with the front will be here in the middle of the day with a break behind the main rain band occurring in the late afternoon and evening.   This first system is pretty weak, it’s just “opening the door”…

From Sunday afternoon through Tuesday morning, a baroclinic zone (boundary between warm and cool air) sets up right over Oregon and Washington, first mainly over Washington, then sliding well down into Oregon Tuesday.  This is an “atmospheric river” event with plenty of moisture to work with; thus a flooding threat depending on where the heaviest rain falls.  

Our 12z RPM (sometimes too wet in the past, but not always) shows the heavy rain:

Several deep areas of low pressure will track along this zone during the period:

Low #1:  This one is somewhat weak, maybe even just an open wave (not a closed area of low pressure).  It is that cluster of clouds/rain behind the main cold front.  It’ll move up along Vancouver Island late this evening and very early Sunday morning.  A decent burst of wind/rain in the middle of tonight with this.

Low#2:  Much stronger/deeper low, maybe 982-988 mb runs right into central Vancouver Island late Sunday evening.  Strong wind at the coast tomorrow evening through the middle of night.

Low#3:  Similar strength and only 8-12 hours behind the first one as it rides along a baroclinic zone (frontal system) sitting just to our north.  Similar location for landfall, maybe a little farther south.

So if you want to go see stormy weather at the Coast, the 24 hour period from Sunday afternoon through Monday afternoon looks best.

Neither of these lows (as of this morning) is enough to give us a big windstorm, but gusts to 70 mph along the coast and 40-45 mph here in the valleys will be the strongest we’ve seen so far this season.

We’ll see about the rain, it’s always tough to know exactly where the heaviest rain will line up.  I remember exactly one year ago we had the heavy rain band sit right over us a little longer than expected the Tuesday before Thanksgiving, giving us some minor flooding.

Finally, snowfall in the Cascades.  Good news and bad news.  The good news is that we could see 10-15″ in the norhtern Oregon Cascades in the next 3 days. 

Most of that will be later today through Sunday morning and then again Monday night and Tuesday morning.  The bad news is that the Mt. Hood ski resorts will be in the warm part of the storm from Sunday evening through Monday afternoon.  Many inches of rain will fall all the way up to 7,000′ during that time.  You can see the difference on the map above; note most of the Washington Cascades on the colder side of the baroclinic zone more of the time equals much higher totals.  Add the new snow and heavy rain together and I’d gamble base totals won’t change between now and midday Tuesday.  Or, pray that the whole zone is 100 miles farther south and feet of snow will dump on Mt. Hood the next few days.

Okay, off to the meeting and on to exciting weather!

By the way, no sign of real cold air for lower elevation snow in the next 7-10 days…in case you were wondering.

Chief Meteorologist Mark Nelsen

 

 

 

50 Responses to Stormy Weather Ahead; Winter Meeting Today

  1. Hmmm,

    12z MM5-NAM offering up a few interesting wrinkles when looking at the finer detail…

  2. Fellow Weather geeks….*Looks around the room*

    12z NAM is about to begin shortly with MM5-NAM running a bit afterwards. We’ll find out today if we just see a blustery to gusty type event with S-SW winds 25-40mph, or a bit more of a decent wind event with 35-45mph+. Models have been quite consistent and last night’s 00z runs were a tad more impressive with WRF showing 40-50kt gusts in the Willamette Valley. Cross Section(or Time-Height) models have routinely shown 40-50kt+ near the surface.

    The issue is does the wave of low pressure for Monday develop as shown, does it struggle to do so, or does it undergo Cyclogenesis too soon thus curving it further away and reducing the threat for a good Wind Event. In a situation like this with fast moving pieces of energy moving along a Baroclinic zone all of these options are still on the table. As of right now I am still going with a forecast of 35-45mph+ with a Wind Advisory likely. Barring any unforeseen mixing I don’t think we’ll ratchet up to a High Wind Warning, BUT the winds aloft are very strong and available if they can be tapped.

    We’ll find out in about 1-2 hours.

    • EY (Oak Grove) says:

      First post in… Forever, essentially.

      As a bit of a wind nut, the NWS’ AFD gave me something to drool over:

      THE SECOND AND STRONGER WIND EVENT WILL COME MONDAY. NAM HAS BEEN
      VERY CONSISTENT IN PROVIDING 85-95 KT WINDS AT THE 850 MB LEVEL AND
      80 KT WINDS AT 950 MB…JUST 1200-1500 FT ABOVE SEA LEVEL. WITH WINDS
      ALOFT THIS STRONG…WILL NOT BE SURPRISED IF SOME OF OUR WINDIER
      HEADLAND LOCATIONS SEE TRIPLE-DIGIT WIND GUSTS FROM THIS SYSTEM.

      I realize that we absolutely won’t see these gusts in the Valley, but it’s still incredible for them to even mention 100mph+ gusts for any part of the coast.

      It’s not a sure thing, more-or-less the “worst case scenario” we’re talking about to be honest. But man, that’d be awesome to see considering the lack of any really good wind events in the region since 2006/2007.

    • Hey, EY, yeah I haven’t seen you since, … can’t remember. Yeah that big 100 number is always staggering to me. I completely agree I am down for a December 2006 type event, or at least many gusts 45-50mph…. Just something exciting!

    • EY (Oak Grove) says:

      Gimme a decent south wind event and a few days of good, strong east winds and I’ll call this winter a success.

      Snow and arctic blasts will be icing on the cake…

  3. Benjamin (West Salem) says:

    It looks like no one has said anything about the possible arctic intrusion shown on the EURO on days 10 and 11. At least it looks good to my eyes :)

  4. bgb41 says:

    11/17/2012 Oregon (All) Temperature Summary

    Warmest:
    High:61 at EAST BIRCH CREEK(1617 ft)
    Low: 46 at Gold Beach(16 ft) & Florence Municip(52 ft) & Tillamook Airpor(36 ft) & & Port Orford(0 ft) & PACCTY-2 Pacific(28 ft) & BROOKINGS(79 ft)

    Coldest:
    High:31 at ANTELOPE(6460 ft)
    Low: 20 at Timberline Lodge (7001 ft ) & Mount Hood Meado (6601 ft ) & Rim (7050 ft )

    Largest Diurnal Change: 28 degrees
    MADRAS (58/30 ) (2441 ft )

    Heaviest Rainfall:
    3.13″ at RED MOUND(1753ft)
    2.20″ at QUAIL PRAIRIE LO(3183ft)
    2.03″ at BROOKINGS(79ft)
    1.92″ at Astoria Regional(10ft)

  5. paulbeugene says:

    mm5 GFS has an astounding 5 inches plus of rain for Eugene in 12 hour period Monday night into Tuesday morning. I find that hard to believe.

  6. W7ENK says:

    Lots of thunder and lightning being reported along the Northern Oregon Coast…

    I see why: http://i50.tinypic.com/2wfqyr6.jpg

  7. 7:45 AM Update
    00z MM5-NAM Analysis

    00z MM-NAM 925mb/SLP model

    http://www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d2_e_slp+//72/3

    Wind Gust model

    http://www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d2_e_wgsfc+//72/3

    The timing of these features are as follows
    (For the Willamette Valley)
    *Sunday 2:00 PM – 6:00 PM
    983mb surface low into Northern Vancouver Island. Also, a modest 996mb wave moves onshore near Ocean Shores
    – Winds 25-30kt gusts
    *Monday 12:00 AM – 2:00 PM
    990mb surface low moves onshore just south of Forks.
    – Winds 35-50kt gusts. Gradients aligned just a tad better.
    *Tuesday 11:00 AM – 4:00 PM
    984mb surface low into northern Vancouver Island
    – Winds 25-30kt gusts
    Kind of interesting to see timing differing now and an additional low for Tuesday.

    Cross section
    *PDX – http://www.atmos.washington.edu/mm5rt/data/current_nam/images_d2/kpdx.th.gif
    45-55kts near the surface
    *SLE – 45-55kts near surface
    *UAO – http://www.atmos.washington.edu/mm5rt/data/current_nam/images_d2/kuao.th.gif
    *50-55kts near surface
    *EUG – 40-50kts near surface
    **NAM has ramped things up a bit again. My forecast is unchanged. Gusts 35-45mph+. If we did see mixing we could possibly see gusts 50-60mph+

  8. pappoose in scappoose says:

    Some Stray Albino Donkeys wandering about. Look!

    Can see a line of showers headed in here:

    http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?ir4km_enhanced+12

  9. W7ENK says:

    Great meeting today, as always! It was nice to see some familiar faces today, both friends from the blog, and local TV/professional mets.

    I’ve already been working on editing the video, my plan it to have it all online Monday.

  10. Thomyee says:

    Has anyone seen La La land? It appears that the Newfoundland High is back, and if it settles over there, we could be in for a later December Arctic outbreak. Not sure if it will be all snow, cold, or large hail that drifts into large chunks of ice, but keep your eyes on the CAPE. If that rises, and the 880mb temps get to zero, we are all in for it. As for wind next week, I just do not see it; the high pressure is just too low and the low pressure is just too high to create large, small, or medium sized winds.

    • W7ENK says:

      Hahaha!!! This guy’s a riot! :lol:

    • Josh in Sherwood says:

      Good troll. Pays attention to whats being said. Only issue with this AWESOME troll post is that he said, 880mp temps….. That’s all you need to know. He is entertaining to say the least.

  11. paulbeugene says:

    SEA WSO should stop watching football and pay attention to rain that is coming their way…their hydro discussion this morning does not seem to reflect what they may be facing later this week.

    .HYDROLOGY…PRECIPITATION THROUGH SUNDAY WILL NOT BE HEAVY ENOUGH
    TO WARRANT ANY REAL RIVER FLOODING CONCERNS…EVEN FOR THE UNIQUELY
    AND EXCEPTIONALLY FLOOD-PRONE SKOKOMISH RIVER.

    TWO SYSTEMS WILL MOVE THROUGH DURING THE LATE SUNDAY THROUGH MONDAY
    NIGHT PERIOD…AND THEY WILL BRING MORE SIGNIFICANT PRECIPITATION.
    OUR QPF HAS A MEAN AREAL PRECIPITATION OF 4.3 INCHES OVER THE
    SKOKOMISH BASIN DURING THAT 36-HOUR PERIOD. THAT WILL PROBABLY DRIVE
    THE SKOKOMISH OVER FLOOD STAGE. ADDITIONAL FLOODING IS POSSIBLE ON
    THE SKOKOMISH LATER IN THE WEEK…ESPECIALLY WITH ANOTHER FRONT
    AROUND TUESDAY NIGHT OR WEDNESDAY.

    WITH REGARD TO THE OTHER WESTERN WASHINGTON RIVERS…THE MOST LIKELY
    OUTCOME IS THAT NO OTHER RIVERS IN OUR FORECAST AREA WILL FLOOD
    DURING THE NEXT WEEK.

    THIS IS NOT THE CLASSIC FLOOD-PRODUCING WEATHER PATTERN FOR WESTERN
    WASHINGTON. THE SNOW LEVEL WILL ONLY RISE TO AROUND 5500 FT…AND
    THERE IS NO INDICATION THAT THE FLOW WILL TAP INTO DEEP SUBTROPICAL
    MOISTURE. HOWEVER WE SHOULD NOT ABSOLUTELY RULE OUT MINOR FLOODING
    ON A COUPLE OF THE MOST FLOOD-PRONE RIVERS. IF NOTHING ELSE…IT IS
    WORTH KEEPING IN MIND THAT HISTORICALLY THE FREQUENCY OF RIVER
    FLOODING IN WESTERN WASHINGTON REACHES ITS PEAK DURING THE WEEK OF
    THANKSGIVING.

  12. Yikes Anyone check out late thursday friday time frame rain totels.? If it comes true yes i know it”s far out but we will have some major flooding 20-25 inches of rain in passes and a good 10 inches in the low lands.

  13. Reblogged this on thesurvivalplaceblog and commented:
    Add your thoughts here… (optional)

  14. Reb says:

    Thank for clearing up that last bit, because yes…. I was wondering. Lol hopefully soon.

  15. pappoose in scappoose says:

    Hahaah! Gusts of 80mph or higher will make travel very difficult!

    Greater Portland Metro Area
    Special Statement
    Statement as of 5:14 AM PST on November 17, 2012

    A second even stronger front will move in on Monday. This front
    has the potential to bring damaging winds along the coast…
    including the coastal communities. At this time… gusts to 70 mph
    appear possible in the coastal communities… with gusts to 80 mph or higher on the beaches and headlands. It would not be surprising to see hurricane force wind gusts with this storm… particularly
    along the beaches and exposed headlands… where gusts to 80 mph or higher are possible. This will make travel very difficult along
    Highway 101 and other coastal highways. Confidence on the strength of this front is moderate to high.
    There will also be very strong winds in the Coast Range… especially in the higher exposed elevations where similar gusts to those expected on The Headlands may occur. Lower Coast Range elevations may see gusts to 60 mph.
    For the Willamette Valley and interior locations… Monday will
    also be windy. At this time… sustained winds up to 30 mph with
    gusts to 45 mph are expected… though local higher gusts are a
    possibility if the storm track changes.

  16. 9:58 AM Update
    12z WRF Analysis

    12z WRF 925mb/SLP model

    http://www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d2_slp+//84/3

    Several waves to impact the region tonight through Monday night

    Wind Gust model

    http://www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d3_wgsfc+///3

    The timing of these features are as follows
    (For the Willamette Valley)
    *Saturday 6:00 PM – 11:00 PM Saturday
    Weak 1000mb wave into Forks/Olympic Peninsula
    – Winds 25-35kt gusts
    *Sunday 2:00 PM – 1:00 AM Monday
    994mb wave/weak surface low into Forks/Olympic Peninsula
    – Winds 35-50kt gusts
    *Monday 4:00 AM – 1:00 PM
    994mb wave/weak surface low into Forks/Olympic Peninsula
    – Winds 35-45kt gusts
    Interesting to note all 3 of these features whether it is a wave or weak surface low are generally tracking over the same location. Also, the long duration from Sunday 2:00 PM – Monday 1:00 PM nearly 24 hours of gusty winds.

    Cross section
    *PDX – http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d3/kpdx.th.gif
    40-50kts very near the surface
    *SLE – 40-50kts just a few hundred feet off the surface

    A bit weaker for the southern Willamette Valley
    *UAO – 40-50kts just a few hundred feet off the surface
    *EUG – 35-40kts just a few hundred feet off the surface

    In addition I find it hard to believe that the wave Monday is shown to barely develop. The NAM and now GEM especially are much stronger with it.

    Check out today’s 12z GEM(Canadian)
    978mb into southern Vancouver Island!

    Something to keep an eye on!

  17. Danny in Troutdale says:

    FIRST!!! oh wait… :(

  18. PaulO says:

    6z GFS extracted shows cool spell in lala land I wonder if this will become a trend?

  19. paulbeugene says:

    12z GFS farther north with heaviest precip……Chehalis will need to watch out

    • Kyle says:

      Figures! They always seem to get bulls eye. I assume due to the geography being more *open* to the beach. Just like in the summer they always get socked in with marine layer when we are not.

      Storms always travel the path of least resistance.

  20. Thanks for the update, Mark.

    Really thinking 40-45mph is a lock and may be a bit conservative based on cross sections. We’ll see. Would like to see the WRF bring the wave Monday a bit further south for a better trajectory.

    Then a much deeper low moves up towards Queen Charlottes in 10-14days buckles the pattern with a ridge developing around 160 W. That’s the hopes(or wishcast) anyhow…

  21. W7ENK says:

    I’ll be headed on my way there in just a few minutes, I’ll be the guy in the back running the camera! :)

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