Ice Storm or No Big Deal?

Chilly evening in progress out there with clear spots already in the mid 20’s.  Cold & dry air finally pouring through the Gorge this evening too with dropping dewpoints at Troutdale with a light east wind.  I’m a bit concerned about the low clouds lingering around the metro area at 10pm, but I’m assuming the drier air moving in from the east will evaporate that in the next few hours.  Otherwise low temp forecasts will be in jeopardy.
Now as for tomorrow night’s system…some common themes from 00z mesoscale models.
1.  Precip on all models begins around midnight.
2.  Strong gorge outflow never really develops, probably because the system is approaching from the northwest.  It’s those lows coming up from the southwest that really suck out the cold air and wind.  I wouldn’t be surprised if we dont’ see 8 millibars from DLS-PDX.  In each of our last 3 ice storms that gradient exceeded 12 millibars.
3.  Low pressure tracking by to the north is also very unlike the last 3 ice/snow storms.  This pattern produces a gusty south wind west of the Cascades and kills eastside high pressur quickly too.

This all adds up (in my mind) to a very brief freezing rain event.  I’m amazed how quickly the MM5 and our RPM model warm things up, much faster than they did with the last few storms.  I believe it with this pattern.  Temps tomorrow night may only briefly touch 32 degrees as a result and then quickly jump to 40 by daybreak in most of the metro area.  In fact wind turns westerly in the Gorge (or at least calm) by 10am Thursday!
Snow is unlikely because there is just too much warm air above from what I see, of course a few flakes are possible at first, but that shouldn’t last long.

11pm Extra:   After looking at 00z Canadian, 00z GFS, 00z ECMWF I took the rain out of the 7 Day forecast.  It’ll show up within the hour online…looks like a long term ridge coming up.    But, there may be a silver lining.  Just like last year in early December, chilly air will probably get trapped below the ridge east of the Cascades, especially since there won’t be much chance to melt the snow cover over about half of the Columbia Basin right now.  So I lowered high temps for early next week too…Mark

306 Responses to Ice Storm or No Big Deal?

  1. mback says:

    What about the Low dropping down off of the west coast of Canada? If it drops down and moves inland to our North like late last week, won’t that warm us up with a southerly wind and make us change over to rain?

  2. Ryan (Da Couve) says:

    Wow… The entire GFS model is BORING. Looks like split flow is about to arrive.

  3. Justin says:

    Weather Channel ALSO updating, now saying Rain/Snow late tonight, earlier today they had simply ‘Showers’ no mention of frozen precip. Apparently, if you put any stock into their forecasts, they ‘snow showers’ from 12am to 5am, though their temps look a little screwy.
    Just thought it was interesting that now two sources updating their forecasts to include chance of snow tonight before the changeover.

  4. Jesse says:

    Yeah Rob, check out KPTVs 12Z 850mb ECMWF on Mark’s weather page, has our heights back down to -5 or -6 Friday, reinforcing cold air in the already snow covered columbia basin = cold east wind for us with possible snow still on the ground 🙂

  5. Andrew---Ellensburg, Wa and Portland, Or says:

    New update

  6. snowman says:

    That forcast came from KATU and now Mark sounds like he is agreeing with the warm up!

  7. tyler says:

    Snowman, where on earth did you find that forcast? That is almost guaranteed to be wrong espcially for PDX.

  8. w.w.m. says:

    Paul, I remember that storm from 78 very well. I was in 5th grade and lived in Parkrose. There was a lot of ice and damage from that one. I wish there was a web site to find the trajectory (sp?) of that storm.
    Anyone know of anything like that on the web? I also wanted to see the track for the big storm in 1968.

  9. Andrew---Ellensburg, Wa and Portland, Or says:

    …WINTER STORM WARNING IN EFFECT FROM 10 PM THIS EVENING TO
    10 AM PST THURSDAY FOR THE GREATER PORTLAND METRO AREA…THE GREATER
    VANCOUVER AREA…THE WESTERN COLUMBIA RIVER GORGE AND THE NORTHERN
    OREGON CASCADES..
    THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A WINTER
    STORM WARNING…WHICH IS IN EFFECT FROM 10 PM THIS EVENING TO 10
    AM PST THURSDAY. THE WINTER STORM WATCH IS NO LONGER IN EFFECT.
    A PACIFIC SYSTEM WILL PUSH MOISTURE INTO THE NORTHERN WILLAMETTE
    VALLEY…CLARK COUNTY IN SOUTHWEST WASHINGTON…THE WESTERN COLUMBIA
    RIVER GORGE AND THE NORTH OREGON CASCADES STARTING LATER TONIGHT
    AND CONTINUING INTO THURSDAY MORNING. THIS PRECIPITATION WILL
    OVERRUN THE COLD AIR IN PLACE AND PRODUCE AREAS OF FREEZING RAIN
    WHICH WILL MIX WITH SNOW IN THE CASCADES AND WESTERN COLUMBIA
    RIVER GORGE NEAR HOOD RIVER. THE PRECIPITATION WILL BE GREAT
    ENOUGH TO PRODUCE ICING OF ROADS AND SURFACES THROUGHOUT THE
    FREEZING RAIN AREAS. SOME TREES OR BRANCHES ALONG WITH POWER
    LINES MAY COME DOWN.
    IN THE COLUMBIA RIVER GORGE SIGNIFICANT FREEZING RAIN IS EXPECTED
    WITH THE POTENTIAL OF DAMAGE IN THE FORM OF DOWNED TREES AND POWER
    LINES…THE FREEZING RAIN WILL BE COMBINED WITH FROM 1 TO 3 INCHES
    OF SNOW IN THE HOOD RIVER AREA.
    OVER THE NORTH OREGON CASCADES 4 TO 8 INCHES OF NEW SNOW WILL
    COMBINE WITH AREAS OF FREEZING RAIN IN THE PASSES AND THE HOOD
    RIVER VALLEY. SIGNIFICANT ICING IS EXPECTED WITH POTENTIAL OF
    DOWNED TREES AND POWER LINES.
    A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW..
    SLEET…AND ICE ARE EXPECTED OR OCCURRING. THIS WILL MAKE TRAVEL
    VERY HAZARDOUS OR IMPOSSIBLE.

  10. Justin says:

    Also, mentioned here in the AFD
    FXUS66 KPQR 292207
    AFDPQR
    AREA FORECAST DISCUSSION
    NATIONAL WEATHER SERVICE PORTLAND OR
    230 PM PST WED NOV 29 2006
    .SYNOPSIS…HIGH PRESSURE OVER IDAHO GIVING OFFSHORE FLOW TO AREA
    SHIFTS SOUTH TONIGHT AS PACIFIC FRONT APPROACHES NORTH COAST. FRONT
    WILL MOVE THROUGH NORTH COAST EARLY THURSDAY AND THROUGH AREA
    THURSDAY MORNING. WEST NORTHWEST ONSHORE FLOW OVER AREA THURSDAY
    NIGHT AND EARLY FRIDAY TURNS NORTHERLY FRIDAY AFTERNOON AS HIGH
    PRESSURE BUILDS NORTH INTO WASHINGTON. UPPER RIDGE BRINGS DRIER
    WEATHER TO AREA FOR THE WEEKEND. ANOTHER PACIFIC FRONTAL SYSTEM WILL
    FLATTEN THE UPPER LEVEL RIDGE SOME EARLY NEXT WEEK.
    &&
    .SHORT TERM…WARM FRONT MOVING ACROSS AREA WITH ACTIVE PORTION
    MAINLY N OF AREA. WILL MENTION A FEW FLURRIES IN ZONES FOR THIS
    AFTERNOON AND EVE. MAIN PRECIPITATION MAKER COLD FRONT. LOW LEVEL AMS
    STILL COLD NEAR COL RIVER INTO SW WA. REST OF AREA MODERATING ABOVE
    FREEZING AND LIKELY TO STAY THERE WITH A FEW PATCHES OF BELOW
    FREEZING CENTRAL VALLEY TONIGHT. WILL BE UPGRADING WATCH TO
    WARNING/ADVYS FOR MAIN THREAT AREA NORTHERN CASCADES/SW WA/ N WILL
    VALLEY. BY 12Z FRONT NEAR KKLS BY 12Z MOVES THROUGH AREA THU MORNING
    WITH LINGERING RAIN THU AFTERNOON SOUTHERN MOUNTAINS. W TO NW ONSHORE
    FLOW BEHIND FRONT TH AFTERNOON CLEARS OUT LOW LEVEL COLD AMS WITH
    MILDER MARINE AIR. ALL LOW ELEVATION ABOVE FREEZING THU AFTERNOON.
    HIGH PRES OFF COAST THU NIGHT WITH ENOUGH CYCLONIC ONSHORE FLOW TO
    KEEP SHOWER THREAT FOR AREA ESPECIALLY NORTH PART. SHOWER THREAT
    CONTINUES INTO FRI MORNING FOR N PART BEFORE HIGH BUILDS INTO WA
    TURNING FLOW MORE NORTHERLY. HIGH PRES SHIFTS INLAND FRI NIGHT GIVING
    LIGHT OFFSHORE FLOW. SKIES CLEAR BUT AREAS OF FOG LIKELY TO FORM.
    OFFSHORE FLOW STRONGER SAT GIVES LOTS OF SUNNY AREA. HOWEVER INLAND
    VALLEYS WHERE FLOW IS WEAK WILL HAVE DIFFICULTY CLEARING. KOSOVITZ
    .LONG TERM…ECMWF AND GFS SIMILAR IN THE LONG RANGE BUILDING A
    RIDGE OVER THE NORTHEAST PACIFIC AND DRYING OUT THE AREA. ENSEMBLES
    BEGIN TO BREAK DOWN ON DAY 4. NEVERTHELESS THE AREA IS IN A RIDGING
    PATTERN. A DISTURBANCE IS EXPECTED TO PASS THROUGH ON MONDAY NIGHT
    WITH LITTLE PRECIP. PACIFIC NORTHWEST KEEPS NORTHWESTERLY FLOW OVER
    THE AREA REGARDLESS OF THE ENSEMBLE MEMBER YOU PICK – SO KEPT
    GENERAL IDEA OF MOSTLY DRY. PRECIPITATION MORE LIKELY OVER THE
    NORTHERN PART OF THE CWA AS WEATHER SYSTEMS RIDE ACROSS THE RIDGE.
    INCREASED POPS TO A CHANCE FOR MONDAY.

  11. Rob *Southeast Portland* says:

    Jesse, we have reinforcing cold air now that’s moving in Friday/Saturday? Is this air mainly moving in eastern Washington/Columbia Basin?

  12. Justin says:

    NWS just did a big upgrade for me, now says flurries tonight early with freezing rain
    ”A few flurries early…then rain developing with areas of freezing rain after midnight. Lows 30 to 35 with temperatures rising away from The Gorge after midnight. Southeast wind 10 to 20 mph except east wind 15 to 25 mph near The Gorge decreasing after midnight.”
    This after saying ‘freezing rain in areas, mainly near the gorge’, so definitely a more bullish update.

  13. Keith says:

    Just thought I would let you all know that it is now a WINTER STORM WARNING IN EFFECT FROM 10 PM THIS EVENING TO 10 AM PST THURSDAY. So now a Winter Storm Warning and not a watch 🙂

  14. Jesse says:

    Also back down to 33 out here with a lowering dewpoing of 24 and increasing ESE winds. High here was 34.3, cold day, as expected.

  15. snowman says:

    This is one of the local forcasts anyone agree
    PORTLAND, Ore. – The threat of freezing rain in the Willamette Valley is diminishing, but the Columbia River Gorge may get hit hard Thursday morning.
    cloud cover may keep temperatures in the valley high enough that we will not see freezing rain.
    However, cold east winds will most likely create problems for the Columbia River Gorge and areas east of town, like Troutdale and possibly the Gresham area.

  16. Tyler in Vancouver says:

    I love it how it’s right on the edge of snow/freezing rain/rain.
    I remember back in 1996, it was an easy call. It was in the mid 30s at Government Camp, 22 down here in Vancouver. Ya, made the call for freezing rain. It seems so odd when you walk outside, it is 22 degrees and raining.
    Remember that the west hills also stop the east wind so it builds up colder air on the east slopes of them. This can give the east slopes of the west hills a better chance of snow. And remember, the higher up you are in a freezing rain event, the first you will be to warm up. I remember a freezing rain event where I barely had any ice, but downtown Vancouver, 300 feet lower, had ice on everything.
    34.0 here, DP 24.
    Tyler

  17. tracy says:

    soooooo, anything for sherwood tonight? or are we going to be left outta this one?! hope we get a little something.

  18. Andrew---Ellensburg, Wa and Portland, Or says:

    Anyone know why i have been getting a very light snow shower for the last 6 hours, so light that only a trace has accumulated. Yet, it does not show up on the radar? Could this be from snow blowing off the cascades and drifting down here or is the radar screwy?

  19. Jesse says:

    I am REALLY starting to see a lot of indicators that make me think this will start out as snow or maybe even be mostly snow. Here is a very important observation for everyone who wants snow: at Welches, Oregon on the way to Mount Hood at 1,500 feet it is still 30 degrees, that means the mid-levels haven’t warmed much at all which is crucial to whether we see snow, freezing rain, or nothing. Another thing I was thinking about is that with this storm the freezing level is only supposed to go up to 4,000 at the highest before colder air moves in again Friday/Saturday. now usually when we get a storm that scowers out the cold air it has a good tropical connection with freezing levels 6,000-7,000 ft, so this storm, coming from the NW and all, will not be able to properly scour out all the arcic air over the region right now, especially with reinforcing cold 850mb heights moving down again Friday/Saturday as I mentioned. I am beginning to think we may see some snow and sleet and the cold front may pass over and dry air move in again before we ever even have a chance to mix out and change over to rain. Thoughts?

  20. Rob *Southeast Portland* says:

    I mentioned this earlier, but.. Is there ANY chance no matter how remote that areas near the Gorge never get scoured out completely? IMO I see to much high pressure remaining west of the Rockies, and very strong I might add.
    Also, I just don’t see a good southerly flow developing with this system and it’s weak.
    They won’t be scoured out in the Columbia Basin/north central-eastern Washington for sure.
    Well just wondering.

  21. Justin says:

    *coming from the NW in the Pacific was what I meant to say*

  22. Tony says:

    In my opinion, the mets are underestimating the power of the gorge again! We will start off as snow and IMO get a good couple of inches here on the valley floor down to Salem. It will change over to sleet and freezing rain by morning, I don’t think we chnage over to rain until afternoon tmr.

  23. Justin says:

    Droppin, I feel the incoming trajectory from the NW could pull in a stronger easterly flow AT FIRST, before the south winds start to encorach up the valley. So I don’t think it would be too weird for there to be a short while when Salem was 45 or so and PDX was near 30, definitely think its possible in the pred dawn hours. Hopefully this is a NW Pacific version of December 18, 2005.
    BTW, the cold water, GOA trajectory will help a bit IMO with limiting tne 850mb temps from skyrocketing, so the air could stay down to or below freezing for longer than expected there and who knows, higher snow amounts could be possible. Not looking ‘likely’, but we’ll see.

  24. Snowman says:

    I guess we get to play the waiting game! will it or wont it anyone have any good guesses the weather people don tseem to think it will.

  25. Tyler in Vancouver says:

    I keep looking forward to the weekend and next week. I’m a big hiker, so I like some nice weather in the winter to get a hike or two in. It’s looking very nice for that as we get an inversion. It’s sort of weird, hiking up in elevation but it gets warmer.
    This looks like it could be the first long spell of east winds for the gorge, probably 4-6 days.
    Tyler

  26. Andrew---Ellensburg, Wa and Portland, Or says:

    Man, i would like to see a day our of the teens here. The cold was fun at first, but now it is getting kind of annoying. Hard to walk to class when the daytime temp never gets out of the teens. Anyways, i am thinking also of this cold air over here has got to be a good thing for portland in the long run or even here tonight if those gorge winds get going.
    As a side note, i don’t think i have ever seen the NWS be so wrong with forcasting temps for ellensburg. The keep putting us at highs in the mid to upper 20’s, but we have not been above 18 in the last 3 days, usually hovering around 13-15 degrees.

  27. Paul says:

    An encouraging story from Jan, 1978. Only about 32 around 10pm and they were calling for a brief freezing rain event with a strong storm and then all rain. Started raining around midnight (hard) and kept going all night. I went to bed thinking it would turn to all rain shortly. Was awoken about 4am by the blue flashes from transformers and power lines arcing. Looked outside. It was still just 32 degrees and all that rain froze. A good inch of ice. This was in Lake Oswego. Found a wounded seagull with a broken wing from the ice walking around and took it inside. Later in the morning drove west and noted the ice ended almost in a perfect line just west of Kruse Way and Carmen Drive. Never iced at all in Tigard, but all points west were coated in thick ice and most power was out. Anyway, the point is there is still hope even with just marginal freezing temps. They often underestimate how long it takes to get the cold air mixed out.

  28. Derek-West Gresham says:

    Yep Tyler, folks from Salem north will need to watch this. This will of course quickly moderate there but this event IMO indeed is worth the WSW.

  29. Tyler in Vancouver says:

    Above freezing on the Olympic coast now, 33 at Quillayute.
    Tyler

  30. Derek-West Gresham says:

    Some current temps.
    My surface – 325ft – 32 degrees
    Marks House – 1000ft – 26 degrees
    Zigzag – 2500?ft – 30 degrees
    Government Camp – 20 degrees
    Looks like a pretty cold airmass all the way up right now. Now I don’t want to sound arrogant or anything but as I thought, the cold air indeed stayed in place. So I definately am on bored for snow at first, then sleet and ZR. I don’t know if we see some “big warm up” but it doesn’t look all that likely. If we do get above freezing tomorrow, certianly no 45 at my place.

  31. Ryan (Da Couve) says:

    I am at 36 degrees over my house as of 2:00pm. No idea if it was going up or down when I left. 😦

  32. tyler says:

    what is the farthest south everyone is thinking for any chance of frozen precip even if its just for an hour. My guess is salem might even see something for a short while. What do you guys think.

  33. Tyler in Vancouver says:

    Josh…I was referring to a calm night, cloudy conditions mean a warmer night than one with clear skies, which is why we didn’t drop very much last night.
    34.0, DP 23.
    Ty

  34. Kristan says:

    Boy it sure is dark and cloudy here in Tigard…

  35. Rob *Southeast Portland* says:

    Justin, with the placement of both of those strong high pressure areas moving E and lower pressure approaching from the W, wouldn’t that really increase the Gorge winds within the next 4-6 hours?

  36. Ryan (Da Couve) says:

    Million dollar question is what are the temps at the layers between 500′ and 3000′? If those middle layers are warm we will scour quick. If it is 32 at the surface and progessively cooler all the way up above 5000′ then I would have to imagine that it will take a little while to scour out the cold air.
    Also, it isn’t like this is a warm storm. It’s coming from the northern pacific where ocean waters are likely in the low 50’s upper 40’s.

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