Winter Storm Watch: Major Ice Storm Possible Central/East Metro/Gorge

Noon Monday…

The Portland NWS has issued a Winter Storm Watch for many areas west of the Cascades for Tuesday.  A WATCH means conditions are set up for a certain event to occur.  These will likely be converted to Freezing Rain Advisories and Ice Storm Warnings (depending on ice accretion expected) this afternoon.

A few thoughts:

  1. A major and possibly crippling ice storm is POSSIBLE in the central/east metro area similar to the 1996 event starting tomorrow and continuing through sometime Wednesday AM/midday
  2. The Columbia River Gorge (all of it) is LIKELY to see a major/crippling ice storm tomorrow through Wednesday.  This on top of heavy snow/ice already could lead to roof collapses in that area.  Get roofs cleaned off today if you have the ability to do so.
  3. Most of the rest of the metro area will LIKELY see at least some freezing rain Tuesday before temps creep above freezing, not a big ice storm but enough to cancel schools and turn roads icy for a good chunk of the day.

HIGHLIGHTS

  • The low-level airmass doesn’t change at all through Tuesday AM as frigid air keeps pouring out of the Gorge.  We remain below freezing in most of the Portland area.
  • Rain arrives sometime between 7am-11am Tuesday, freezing on contact in almost all areas in the western valleys of Oregon/SW Washington
  • Roads in most of the metro area (that aren’t already icy) will turn icy within 15 minutes of the rain arrival
  • Light freezing rain continues through the afternoon as temperatures rise to near/above freezing south and west metro.
  • Temps remain in the 20s East Portland to around the Gorge entrance…solidly frozen all day there.
  • Heavy rain arrives around sunset and it pours all night long into Wednesday AM as a brief “pineapple express” parks itself overhead
  • West and south metro should be slightly above freezing during this time, thus avoiding a big ice storm.
  • DURING THIS PERIOD, EAST PORTLAND OUT TO THE GORGE LIKELY REMAINS BELOW FREEZING
  • If models are correct, 1-2″ ice could form on all exposed surfaces, doing tremendous damage to trees/powerlines that we haven’t seen in 20 years.
  • Any precipitation through Wednesday midday/afternoon should be freezing rain in the Gorge.  1-2″+ is likely out there.

COMMUTERS/SCHOOL

  • I’d say both should be skipped tomorrow
  • Check right away in the morning when you get up to see how temperatures are doing and where the precipitation is of course.  Maybe I’ll be totally wrong this time and we’ll get lucky!

The main reason for the forecast change in the past 24 hours isn’t just the usual “oh, the cold air is sticking around longer than expected”, it’s because models have backed off on bringing lower pressures to our north.  Surface low pressure centers are expected to stay much farther offshore now.  This only gives us weak southerly flow up the valley and not until Tuesday night for central/south valley.  Since we have the low-level cold air in place and it is VERY cold, that means a longer period of time spent below freezing central/east metro.  The preferred ECM

 

WF model shows the progression pretty well, 4am Tuesday wind…strong easterly gradient and we’re in the deep freeze

ecm_tuesam

Then 4pm Tuesday…still 7 millibars easterly gradient (cold east wind still sending cold air into metro area).  Only a very light southerly flow up central/south valley.  We’re still frozen most of metro area at this point.

ecm_tuespm

Wednesday 10am, southerly wind has taken over south of metro…easterly STILL going central/east metro.  This would keep central/east metro frozen through midday Wednesday!

ecm_wedmidday

And the really bad news.  Check out how much rain has fallen during that period, a solid inch to two inches glaze ice over the below-freezing areas.  There is no loss of precip in this case from the dry Gorge wind as we’ve seen in snowstorms because that dry air is very thin, in the lowest 1,500′ of the atmosphere:

ecm_precip_wed_midday

That’s a major ice storm that we haven’t seen in many years central/east metro and the Gorge.  The WRF-GFS model’s rain forecast is similar, showing 1-2″ rain in the metro area by Wednesday afternoon.

wrf_precip_wed_pm

Wednesday evening a cold front passes overhead and we change to a showery pattern.  Then temperatures even in the Gorge will gradually rise above freezing and in the metro area too.

Is there anything you can do to prepare?

  • Get plenty of gas for your generator if you have one of those and live in the ice storm area
  • Watch for falling trees/limbs Tuesday night and Wednesday AM.  I don’t expect significant icing until after dark Tuesday when the heavier rain arrives

Chief Meteorologist Mark Nelsen

 

 

 

 

83 Responses to Winter Storm Watch: Major Ice Storm Possible Central/East Metro/Gorge

  1. Ken Hoover says:

    I live in Camas and in the little temp window in the bottom right of the newscast, the temp for Camas is always wrong. It seems to be 10 degrees warmer than it actually is. What is that about ?

  2. boydo3 N Albany says:

    When you see this site show southerly winds, you’ll know that relief is soon to come..
    http://www.wrh.noaa.gov/mesowest/timeseries.php?wfo=pqr&sid=KCVO&num=48&raw=0&banner=off

  3. Deer Is. at 750' says:

    I’m trusting Mark on this one. All my crews are staying home tomorrow. Clean up can commence on Wednesday.

  4. Buckaroo says:

    Well it sure has been one heck of a winter for the record books and for that matter in my recollection of winters past. Looking forward to a good old rain. I think I’ll go and stand in it ’till I’m soakin’ wet!

  5. Scooter says:

    Isn’t life grand?

  6. W7ENK says:

    Yeah, I don’t really get it. Everyone (professional mets) seem to be downplaying this whole ZR thing for everywhere to the West of I-205, but the temperature in my neighborhood hasn’t been above freezing for a week now. I’ve still got 6 inches of snow on the ground, and it’s down to 26 right now. Locations in the Gorge are al down into the teens, or even single digits at this hour, and all that air is pushing down into PDX metro as I type this. We all know what happens, cold air being dense and getting trapped at the valley floor, it doesn’t scour out all that easily. Plus, Milwaukie/Clackamas, we’re in direct line with the Gorge outflow, which tends to bottle up in Happy Valley, then squeezes through the gap between Scott and Mt. Talbert (Sunnyside Road) and blasts straight down into this area. Hell, Dave Saleski’s breakdown for tomorrow barely even mentioned the possibility of ZR West of 205 or South of Foster Road.

    I dunno, this Winter has made me a believer again, I don’t think this ZR threat is anything to pooh-pooh…

    Then again, there’s this Dome…

    • Jake-(Gresham near Nadaka Nature Park) says:

      I’m of this opinion with you Eric. I’ve snapchatted friends and younger cousins who work at UPS and refereed them to this blog. I’ve also called a few family members that I know don’t really watch the news. Not taking any chances with already compacted snow on the roads.

    • JF says:

      The dome lost its power last Tuesday!

    • JJ78259 says:

      Dude your correct in your thinking 1979 the rain came in and it poured it was 30 to 31 degrees it did not warm up. The east wind kept blowing. Inch of ice, all of our trees came down. Cold air was trapped. History will repeat.

  7. Lee Wilson says:

    I dedicate this post to W7NENK

    avalanche Watch
    WAZ019-520-521-042-568-569-182000-

    BULLETIN-IMMEDIATE BROADCAST REQUESTED
    BACKCOUNTRY AVALANCHE WATCH
    NORTHWEST AVALANCHE CENTER SEATTLE WASHINGTON
    RELAYED BY NATIONAL WEATHER SERVICE SEATTLE WASHINGTON
    200 PM PST MON JAN 16 2017

    THE NORTHWEST AVALANCHE CENTER HAS EXTENDED AN AVALANCHE WATCH…

    TIMING…
    TUESDAY NIGHT THROUGH 10 AM WEDNESDAY JANUARY 18TH.

    LOCATION…THE EAST SLOPES AND CENTRAL AND SOUTHERN WEST
    SLOPES WASHINGTON CASCADES.

    AVALANCHE DANGER…THE TIMING OF INCREASED AVALANCHE DANGER HAS
    SLOWED AND IS NOW EXPECTED TO BECOME HIGH IN THESE AREAS WITH VERY
    DANGEROUS AVALANCHE CONDITIONS DEVELOPING LATE TUESDAY OR TUESDAY
    NIGHT. TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED TUESDAY
    AFTERNOON THROUGH WEDNESDAY AS NATURAL AND HUMAN TRIGGERED
    AVALANCHES SHOULD BECOME VERY LIKELY. CHECK THE FORECAST FOR MORE
    DETAILS.

    REASON…INCREASING HEAVY RAIN AND SNOW BEGINNING LATE TUESDAY OR
    TUESDAY NIGHT WILL ADD SUFFICIENT LOAD TO THE SNOWPACK TO CAUSE
    NATURAL AVALANCHES. WET SNOW AVALANCHES BECOMING LIKELY IN AREAS AND
    ELEVATIONS THAT CHANGE TO RAIN. ALSO…STRONG SOUTHWEST WINDS WILL
    BUILD NEW AND UNSTABLE WIND SLAB ON LEE SLOPES AT HIGHER ELEVATIONS
    THROUGH WEDNESDAY.

    PRECAUTIONARY/PREPAREDNESS ACTIONS…
    PLEASE VISIT http://WWW.NWAC.US FOR FURTHER INFORMATION.

    ADDITIONAL INFORMATION… THIS WATCH DOES NOT APPLY TO SKI AREAS
    WHERE AVALANCHE MITIGATION MEASURES ARE PERFORMED.

    TRANSMITTED AT THE REQUEST OF NORTHWEST AVALANCHE CENTER IN SEATTLE,
    WASHINGTON.

    $$

    Flood Watch
    ORZ001-003-005-006-WAZ020>022-039-040-171800-
    /O.CON.KPQR.FA.A.0001.170117T1800Z-170119T1200Z/
    /00000.0.RS.000000T0000Z.000000T0000Z.000000T0000Z.OO/
    NORTH OREGON COAST-COAST RANGE OF NORTHWEST OREGON-LOWER COLUMBIA-
    GREATER PORTLAND METRO AREA-WILLAPA HILLS-SOUTH WASHINGTON COAST-
    I-5 CORRIDOR IN COWLITZ COUNTY-GREATER VANCOUVER AREA-
    SOUTH WASHINGTON CASCADE FOOTHILLS-
    INCLUDING THE CITIES OF…ASTORIA…CANNON BEACH…TILLAMOOK…
    NETARTS…PACIFIC CITY…VERNONIA…JEWELL…SUNSET SUMMIT…
    LEES CAMP…TRASK…ST. HELENS…CLATSKANIE…HILLSBORO…
    PORTLAND…WILSONVILLE…OREGON CITY…GRESHAM…TROUTDALE…
    WILLAPA…FRANCES…ELK MOUNTAIN…RYDERWOOD…RAYMOND…
    LONG BEACH…OCEAN PARK…NASELLE…CATHLAMET…
    CAPE DISAPPOINTMENT…LONGVIEW…KELSO…CASTLE ROCK…
    VANCOUVER…BATTLE GROUND…RIDGEFIELD…WASHOUGAL…YACOLT…
    AMBOY…TOUTLE…ARIEL…LAKE MERWIN…YALE LAKE…COUGAR
    328 PM PST MON JAN 16 2017

    …FLOOD WATCH REMAINS IN EFFECT FOR THE NORTH OREGON COAST AND COAST
    RANGE…PORTLAND/VANCOUVER METRO AREA…AND SOUTHWEST WASHINGTON
    FROM THE WILLAPA HILLS TO THE SOUTH WASHINGTON CASCADE FOOTHILLS FROM
    TUESDAY MORNING THROUGH LATE WEDNESDAY NIGHT…

    THE FLOOD WATCH CONTINUES FOR

    PORTIONS OF NORTHWEST OREGON AND SOUTHWEST WASHINGTON…
    INCLUDING THE FOLLOWING AREAS…IN NORTHWEST OREGON…COAST
    RANGE OF NORTHWEST OREGON…GREATER PORTLAND METRO AREA…
    LOWER COLUMBIA AND NORTH OREGON COAST. IN SOUTHWEST
    WASHINGTON…GREATER VANCOUVER AREA…I-5 CORRIDOR IN COWLITZ
    COUNTY…SOUTH WASHINGTON CASCADE FOOTHILLS…SOUTH WASHINGTON
    COAST AND WILLAPA HILLS.
    FROM TUESDAY MORNING THROUGH LATE WEDNESDAY NIGHT.
    FREEZING LEVELS WILL RISE TO 8000 FEET TONIGHT WHICH WILL ALLOW
    SNOWMELT TO BEGIN IN ELEVATIONS ABOVE LOW LEVEL INVERSIONS WHERE
    COLDER AIR IS TRAPPED. HEAVY RAIN WILL BEGIN TUESDAY AND CAUSE
    RISES ON RIVERS AND CREEKS DRAINING THE COAST RANGE…SOUTH
    WASHINGTON CASCADES…AND WILLAPA HILLS. THE HEAVY RAIN WILL
    LIKELY CAUSE URBAN FLOODING IN THE PORTLAND/VANCOUVER METRO
    AREAS AS THE RAIN WILL HELP MELT THE EXISTING SNOWPACK. BLOCKED
    STORM DRAINS MAY ALSO CONTRIBUTE TO PONDING OF WATER ON STREETS.
    RAINFALL AMOUNTS THROUGH THURSDAY…
    PORTLAND/VANCOUVER METRO AREA…1 TO 2 INCHES
    NORTH COAST RANGE/WILLAPA HILLS…3 TO 6 INCHES
    SOUTH WASHINGTON CASCADES FOOTHILLS…3 TO 6 INCHES

    PRECAUTIONARY/PREPAREDNESS ACTIONS…

    A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON
    CURRENT FORECASTS.

    YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE
    FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
    PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.

    LANDSLIDES AND DEBRIS FLOWS ARE POSSIBLE DURING THIS FLOOD EVENT.
    PEOPLE…STRUCTURES AND ROADS LOCATED BELOW STEEP SLOPES…IN
    CANYONS AND NEAR THE MOUTHS OF CANYONS MAY BE AT SERIOUS RISK
    FROM RAPIDLY MOVING LANDSLIDES.

    &&

    $$

    Freezing Rain Advisory
    WAZ040-171330-
    /O.UPG.KPQR.WS.A.0002.170117T1200Z-170117T2200Z/
    /O.NEW.KPQR.ZR.Y.0003.170117T1200Z-170118T0200Z/
    SOUTH WASHINGTON CASCADE FOOTHILLS-
    INCLUDING THE CITIES OF…TOUTLE…LAKE MERWIN…COUGAR
    313 PM PST MON JAN 16 2017

    …FREEZING RAIN ADVISORY IN EFFECT FROM 4 AM TO 6 PM PST TUESDAY
    BELOW 1500 FEET FOR THE SOUTH WASHINGTON CASCADE FOOTHILLS…

    THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A FREEZING
    RAIN ADVISORY BELOW 1500 FEET…WHICH IS IN EFFECT FROM 4 AM TO
    6 PM PST TUESDAY.

    TIMING…SUBFREEZING AIR TRAPPED IN THE CASCADE VALLEYS WILL
    LIKELY CAUSE FREEZING RAIN. VALLEY TEMPERATURES ARE EXPECTED TO
    CLIMB ABOVE FREEZING AROUND MIDDAY TUESDAY…ENDING THE FREEZING
    RAIN THREAT TUESDAY AFTERNOON.
    ICE ACCUMULATION…VALLEY ICE ACCUMULATION AROUND ONE TO TWO
    TENTHS OF AN INCH IS POSSIBLE. RIDGETOP TEMPERATURES WILL BE
    SIGNIFICANTLY WARMER…SO NO SIGNIFICANT ICING IS EXPECTED IN
    THE HIGHER TERRAIN.
    IMPACTS…SEVERAL DAYS OF VERY COLD TEMPERATURES WILL MAKE
    GROUND SURFACES RECEPTIVE TO ICE ACCUMULATION. IT MAY TAKE A
    COUPLE HOURS OF TEMPERATURES ABOVE FREEZING TO COMPLETELY END
    THE FREEZING RAIN THREAT AT ANY GIVEN LOCATION. ICE ACCUMULATION
    ON TREES AND POWER LINES MAY RESULT IN DOWNED BRANCHES AND
    LINES…WHICH WOULD BRING THE THREAT OF POWER OUTAGES TUESDAY.

    PRECAUTIONARY/PREPAREDNESS ACTIONS…

    A FREEZING RAIN ADVISORY MEANS THAT PERIODS OF FREEZING RAIN OR
    FREEZING DRIZZLE WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
    SLIPPERY ROADS. SLOW DOWN AND USE CAUTION WHILE DRIVING.

    &&

    $$

    Freezing Rain Advisory
    WAZ022-171330-
    /O.NEW.KPQR.ZR.Y.0003.170117T1000Z-170117T2200Z/
    I-5 CORRIDOR IN COWLITZ COUNTY-
    INCLUDING THE CITIES OF…LONGVIEW…KELSO
    313 PM PST MON JAN 16 2017

    …FREEZING RAIN ADVISORY IN EFFECT FROM 2 AM TO 2 PM PST TUESDAY
    BELOW 1000 FEET FOR THE INTERSTATE 5 CORRIDOR IN COWLITZ COUNTY…

    THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A FREEZING
    RAIN ADVISORY BELOW 1000 FEET…WHICH IS IN EFFECT FROM 2 AM TO
    2 PM PST TUESDAY.

    TIMING…LIGHT FREEZING RAIN IS EXPECTED TO DEVELOP TUESDAY
    MORNING AND END BY TUESDAY AFTERNOON.
    TEMPERATURES…ARE EXPECTED TO SLOWLY CLIMB ABOVE FREEZING
    AROUND TUESDAY AFTERNOON…ENDING THE FREEZING RAIN.
    ICE ACCUMULATION…AROUND A TENTH OF AN INCH.
    IMPACTS…SEVERAL DAYS OF VERY COLD TEMPERATURES WILL MAKE
    GROUND SURFACES LIKE ROADS AND SIDEWALKS VERY RECEPTIVE TO ICE
    ACCUMULATION. IT MAY TAKE A COUPLE HOURS OF TEMPERATURES ABOVE
    FREEZING TO COMPLETELY END THE FREEZING RAIN THREAT AT ANY GIVEN
    LOCATION.

    PRECAUTIONARY/PREPAREDNESS ACTIONS…

    A FREEZING RAIN ADVISORY MEANS THAT PERIODS OF FREEZING RAIN OR
    FREEZING DRIZZLE WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
    SLIPPERY ROADS. SLOW DOWN AND USE CAUTION WHILE DRIVING.

    &&

    $$
    Ice Storm Warning
    WAZ019-171330-
    /O.UPG.KPQR.WS.A.0002.170117T1400Z-170119T0200Z/
    /O.NEW.KPQR.IS.W.0002.170117T1400Z-170119T0200Z/
    SOUTH WASHINGTON CASCADES-
    313 PM PST MON JAN 16 2017

    …ICE STORM WARNING IN EFFECT FROM 6 AM TUESDAY TO 6 PM PST
    WEDNESDAY BELOW 3000 FEET FOR THE SOUTH WASHINGTON CASCADES…

    THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED AN ICE STORM
    WARNING BELOW 3000 FEET…WHICH IS IN EFFECT FROM 6 AM TUESDAY TO
    6 PM PST WEDNESDAY.

    TIMING…LIGHT FREEZING RAIN IS EXPECTED TO DEVELOP TUESDAY
    MORNING WILL THEN INCREASE IN THE AFTERNOON. FREEZING RAIN WILL
    BECOME HEAVY AT TIMES TUESDAY NIGHT AND WEDNESDAY. TEMPERATURES
    WILL SLOWLY CLIMB TUESDAY NIGHT BUT MANY LOCATIONS MAY NOT
    CLIMB ABOVE FREEZING UNTIL WEDNESDAY AFTERNOON OR EVENING.
    PRECIPITATION WILL TAPER TO SHOWERS WEDNESDAY NIGHT.
    ICE ACCUMULATION…ICE ACCUMULATIONS OF ONE INCH TO ONE AND A
    HALF INCHES EXPECTED TO BE FAIRLY WIDESPREAD.
    IMPACTS…HEAVY ICE ACCUMULATION WILL LIKELY BRING DOWN SOME
    LARGE BRANCHES AND POWER LINES. POWER OUTAGES MAY LAST MULTIPLE
    DAYS DEPENDING ON HOW WIDESPREAD THESE IMPACTS ARE. THIS EVENT
    WILL ONLY ADD TO THE EXISTING HEAVY SNOW AND ICE LOADING ON
    ROOFTOPS…WHICH MAY CAUSE SOME ROOFTOPS TO FAIL.

    PRECAUTIONARY/PREPAREDNESS ACTIONS…

    AN ICE STORM WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
    EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF ICE ACCUMULATIONS
    WILL MAKE TRAVEL DANGEROUS OR IMPOSSIBLE. TRAVEL IS STRONGLY
    DISCOURAGED. COMMERCE WILL LIKELY BE SEVERELY IMPACTED. IF YOU
    MUST TRAVEL…KEEP AN EXTRA FLASHLIGHT…FOOD…AND WATER IN YOUR
    VEHICLE IN CASE OF AN EMERGENCY. ICE ACCUMULATIONS AND WINDS WILL
    LIKELY LEAD TO SNAPPED POWER LINES AND FALLING TREE BRANCHES THAT
    ADD TO THE DANGER.

    &&

    $$

  8. Lee Wilson says:

    Were at 31.

    apologies for posting freeze flood freeze.
    I guess i was a bit a head of time.
    W7ENK, I was right after all . I was just a head of myself.

    Remind me never to post what I see in a dream online on the way.for Tuesday morning.
    W7ENK intellicast still has flood alerts up. as well as avalanche,and ice storm

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