1pm Update

Still looks good for a brief bout of rain/snow mixed or all snow here in the Metro area around sunset or just beyond.  By “brief”, I mean a couple hours or so.  East wind is cranking through the Gorge, gusting to 55mph at 12:11pm in Corbett.  Dewpoints are down in the 20’s or around 30 eastside of town too.  This setup is just maybe 1-2 degrees colder than what we had yesterday morning, but the actual airmass coming out of the Gorge is a few notches colder as well.  I think sticking snow is more likely (at least briefly) near the Gorge.  So I’ll go ahead and predict PDX bottoms out at 35 degrees with evaporational cooling, same at HIO, and 33 at TTD.  Enough to get a dusting in a few more spots, maybe an inch or so at the top of the West Hills. 

Precipitation is moving in a bit more quickly than forecast too.  Looks like it’s just about to Salem. 

If you’re worried about driving, don’t drive after 5pm just to be safe.  But it appears to me any road issues would only be the side roads up on the top of the West Hills and maybe higher Camas, Troutdale, and Gresham areas.  or anywhere else closer to 1,000′.  No matter what happens, it’s mainly gone sometime after 8pm.

I won’t have access to the blog between now and 8pm or so.  Don’t laugh, but I decided that NOW would be the time to finally get the studs put on, and some Christmas shopping too.  So if your comment doesn’t get in…well, you’re out of luck until I get back. 

Chief Meteorologist Mark Nelsen

265 Responses to 1pm Update

  1. Garron near washington square says:

    This TinyURL redirects to:

    57 AM PST MON DEC 20 2010 .SYNOPSIS…SHOWER
    S WILL MOVE ACROSS THE DISTRICT TODAY…PINWH
    EELING AROUND A LARGE LOW PRESSURE SYSTEM OFF
    THE PACIFIC NORTHWEST COAST. A SYSTEM WILL M
    OVE THROUGH WEDNESDAY MORNING GIVING ANOTHER
    CHANCE FOR A RAIN/SNOW MIX TO THE PORTLAND/VA
    NCOUVER AREA. SEASONABLY WET AND COOL WEATHER
    WILL THEN PERSIST INTO THE WEEKEND. &&a
    mp; .SHORT TERM…COMPLEX LARGE AREA OF LOW
    PRESSURE REMAINS PARKED OFFSHORE FROM THE PAC
    IFIC NORTHWEST…ROTATING A SERIES OF SHOWERY
    DISTURBANCES ONSHORE. THE LATEST DISTURBANCE
    HAS DEVELOPED INTO A SFC LOW OFF THE WA COAS
    T…WITH MORE SHOWERS MOVING ONSHORE BEHIND I
    T. WEAK INSTABILITY OVER THE COASTAL WATERS C
    ONTINUES TO PRODUCE SHOWERS WITH SPORADIC LIG
    HTNING STRIKES…THESE SHOWERS HAVE TENDED TO
    BECOME MORE STRATIFORM AS THEY MOVE ONSHORE
    INTO A MORE STABLE AIR MASS. PRECIPITATION WI
    LL BECOME MORE SHOWERY INLAND THIS AFTERNOON.
    ..WITH A REMOTE POSSIBILITY OF A THUNDERSTORM
    OR TWO. BEST CHANCE FOR THUNDERSTORMS WILL R
    EMAIN NEAR THE COAST AND OVER THE COASTAL WAT
    ERS…WHERE WARMER SURFACE TEMPS WILL PROVIDE
    A LITTLE EXTRA BUOYANCY FOR WEAK CONVECTION.
    ALSO 12Z NAM SHOWING 0-1 KM SHEAR VECTOR BOR
    DERING 30 KT ALONG COAST TODAY WITH LOW LEVEL
    LAPSE RATES NEAR 8C PER KM…GIVING SOME POT
    ENTIAL FOR WATER SPOUTS. CURRENT WATER VAPOR
    IMAGERY SHOWING A VORT MAX MOVING THROUGH THE
    WATERS THIS MORNING. REMAINDER OF DISCUSSIO
    N UNCHANGED. A STRONG PUNCH OF JET STREAM ENE
    RGY IS DIVING SOUTHWARD FROM THE GULF OF ALAS
    KA…DEVELOPING A STRONG VORTMAX EVIDENT ON W
    ATER VAPOR IMAGERY NEAR 47N/140W. THIS SYSTEM
    WILL ROTATE AROUND THE LARGER CIRCULATION OV
    ER THE NE PACIFIC…DEVELOPING ANOTHER SFC LO
    W NEAR 40N/130W BY 12Z TUE ACCORDING TO THE 0
    6Z GFS. EXPECT OFFSHORE FLOW TO INCREASE WITH
    THIS SYSTEM DEVELOPING OFFSHORE FROM THE OR/
    CA BORDER LATER TUE/TUE NIGHT…THOUGH SURPRI
    SINGLY THE 06Z NAM ONLY PUSHES 925 MB WINDS U
    P TO 30 KT NEAR THE PORTLAND AREA. SUSPECT TH
    IS IS A LITTLE UNDERDONE…AS THE COLD POOL E
    AST OF THE CASCADES WILL BE GIVEN A GOOD 24-3
    6 HOURS TO BUILD UNDISTURBED. NAM/GFS APPEAR
    TO BE TOO WEAK WITH THE HIGH PRESSURE SYSTEM
    ASSOCIATED WITH THIS COLD POOL TUE/TUE NIGHT.
    ..AND THEREFORE THE OFFSHORE PRESSURE GRADIEN
    TS. EVEN SO…06Z NAM CROSS SECTIONS THROUGH
    THE GORGE SUGGEST THE COLD POOL EAST OF THE C
    ASCADES WILL DEEPEN ENOUGH FOR COLD AIR TO SP
    ILL OVER THE CASCADE CREST NEAR THE GORGE…S
    IMILAR TO LAST FRIDAY. WHILE GRADIENTS WILL N
    OT LIKELY BE AS STRONG AS THEY WERE LAST FRID
    AY…IT SHOULD STILL BE PRETTY BREEZY THROUGH
    THE PORTLAND METRO AREA TUE NIGHT/EARLY WED
    AS THE OFFSHORE LOW AND OCCLUDING FRONT APPRO
    ACH FROM THE SOUTHWEST. STRONGER OFFSHORE FL
    OW WILL HAVE A FEW EFFECTS TUE THROUGH WED…
    FIRST WILL BE EVIDENT TUE AS OFFSHORE FLOW D
    RIES OUT THE LOWER TO MID LEVELS FOR MOST OF
    THE DISTRICT. DECIDED TO TAKE A CHANCE AND PU
    T PARTLY SUNNY SKIES IN THE FORECAST FOR MOST
    OF THE DISTRICT TUE AS IT WILL BE OUR BEST S
    HOT FOR SUNSHINE. OFFSHORE FLOW WILL ALSO LOW
    ER THE WET BULB TEMPERATURES AGAIN AROUND CLA
    RK COUNTY AND THE NORTH WILLAMETTE VALLEY…S
    O A RAIN/SNOW MIX IS NOT OUT OF THE QUESTION
    AGAIN LATE TUE NIGHT OR WED MORNING. DETAILS
    REMAIN VERY UNCERTAIN…AND AT THIS POINT MOD
    EL SOUNDINGS SUGGEST ALL RAIN EXCEPT FOR THE
    GORGE AND HOOD RIVER VALLEY. SPEAKING OF THE
    GORGE AND HOOD RIVER VALLEY…EASTERLY FLOW
    WILL CONTINUE TO LOCK COLD AIR INTO THESE ARE
    AS THROUGH MIDWEEK. AS A RESULT PRECIPITATION
    THE NEXT FEW DAYS SHOULD FALL MAINLY AS SNOW
    IN THESE AREAS…ESPECIALLY CASCADE LOCKS EA
    STWARD. THE WINTER WEATHER ADVISORY FOR SNOW
    CURRENTLY IN EFFECT WILL EXPIRE AT 6 AM…THI
    S LOOKS FINE. ANOTHER COUPLE INCHES ARE POSSI
    BLE BY SUNRISE…BUT THEN THE STEADIER PRECIP
    ITATION SHOULD TAPER OFF. MORE ADVISORIES APP
    EAR LIKELY WITH THE WEDNESDAY SYSTEM. WEAGLE
    /WOLFE .LONG TERM…NO CHANGES. PREVIOUS DIS
    CUSSION FOLLOWS…MODELS REMAIN CONSISTENT ON
    BRINGING THE NEXT STRONG FRONTAL SYSTEM INTO
    THE PACIFIC NORTHWEST THROUGH THE EXTENDED P
    ERIOD. THE REMNANTS OF THE PREVIOUS LOW WILL
    SLOWLY DISSIPATE EARLY THU…WHILE THE FIRST
    BATCH OF PRECIPITATION OF THIS APPROACHING LO
    W SWINGS TOWARDS THE COAST. GFS AND ECMWF BOT
    H AGREE ON THE TIMING AND STRENGTH OF THIS SY
    STEM…WITH SEVERAL SHORTWAVES ROTATING INTO
    THE REGION FROM THE PARENT LOW. EXPECT SEASON
    AL TEMPERATURES AND RAINY WEATHER TO PERSIST
    THROUGH THE HOLIDAY WEEKEND…WHILE SNOW LEVE
    LS GENERALLY REMAIN NEAR PASS LEVELS IN THE C
    ASCADES. DIFFERING MODEL SOLUTIONS BEGIN AROU
    ND CHRISTMAS DAY…WHERE MODELS DISAGREE ON T
    HE SYSTEMS TRACK. MOST OF THE ENERGY APPEARS
    TO DIG SOUTH INTO CALIFORNIA AS THE UPPER TRO
    F EVENTUALLY PUSHES OVER THE REGION. A SECOND
    SYSTEM WILL SET UP IN THE GULF OF ALASKA LAT
    E THIS WEEKEND. LR && .AVIATION…E
    XPECT A MIX OF VFR AND MVFR CONDITIONS TODAY
    AS BANDS OF SHOWERS MOVE ACROSS THE AREA. ARE
    AS ALONG THE COAST AND INTO THE COAST RANGE M
    AY SEE A FEW LIGHTNING STRIKES WITH SOME OF T
    HE HEAVIER STORMS. GUSTY EAST WINDS CONTINUE
    THROUGH THE COLUMBIA RIVER GORGE AREA. KPDX
    AND APPROACHES…HEAVY BAND OF SHOWERS NOW MO
    VING THROUGH THE KPDX AREA WILL PERSIST THROU
    GH EARLY AFTERNOON…WITH A MIX OF VFR AND MV
    FR CONDITIONS EXPECTED. AFTER 20Z-22Z EXPECT
    CONTINUED SHOWERS THOUGH NOT AS FREQUENT OR I
    NTENSE…WITH CONDITIONS MAINLY VFR THROUGH T
    HE EVENING. BROWN && .MARINE…A CO
    MPLEX SURFACE LOW WILL ROTATE WELL WEST OF TH
    E COASTAL WATERS INTO MID WEEK. OCCASIONAL IM
    PULSES WILL INCREASE WINDS AT TIMES WITH SMAL
    L CRAFT ADVISORY IN EFFECT MUCH OF THE TIME.
    SEAS 10 TO 13 FT THROUGH MIDWEEK. BROWN &
    ;& .PQR WATCHES/WARNINGS/ADVISORIES… O
    R…NONE. WA…NONE. PZ…GALE WARNING UNTIL
    7 PM PST THIS EVENING FOR COASTAL WATERS FROM
    CAPE SHOALWATER WA TO FLORENCE OR OUT
    TO 60 NM. SMALL CRAFT ADVISORY FOR ROU
    GH COLUMBIA RIVER BAR UNTIL 8 AM PST TU
    ESDAY. && $$ MORE WEATHER INFORMAT
    ION ONLINE AT… http://WEATHER.GOV/PORTLAND
    THIS DISCUSSION IS FOR NORTHWEST OREGON AND
    SOUTHWEST WASHINGTON FROM THE CASCADE CREST T
    O 60 NAUTICAL MILES OFFSHORE. THE AREA IS COM
    MONLY REFERRED TO AS THE FORECAST AREA.

    Proceed to this site.

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  2. Garron near washington square says:

    TIny url test.

    http://.SHORT TERM…COMPLEX LARGE AREA OF LOW PRESSURE REMA
    INS PARKED OFFSHORE FROM THE PACIFIC NORTHWEST…ROTATING A
    SERIES OF SHOWERY DISTURBANCES ONSHORE. THE LATEST DISTURBAN
    CE HAS DEVELOPED INTO A SFC LOW OFF THE WA COAST…WITH MORE
    SHOWERS MOVING ONSHORE BEHIND IT. WEAK INSTABILITY OVER THE
    COASTAL WATERS CONTINUES TO PRODUCE SHOWERS WITH SPORADIC L
    IGHTNING STRIKES…THESE SHOWERS HAVE TENDED TO BECOME MORE
    STRATIFORM AS THEY MOVE ONSHORE INTO A MORE STABLE AIR MASS.
    PRECIPITATION WILL BECOME MORE SHOWERY INLAND THIS AFTERNOO
    N…WITH A REMOTE POSSIBILITY OF A THUNDERSTORM OR TWO. BEST
    CHANCE FOR THUNDERSTORMS WILL REMAIN NEAR THE COAST AND OVE
    R THE COASTAL WATERS…WHERE WARMER SURFACE TEMPS WILL PROVI
    DE A LITTLE EXTRA BUOYANCY FOR WEAK CONVECTION. ALSO 12Z NAM
    SHOWING 0-1 KM SHEAR VECTOR BORDERING 30 KT ALONG COAST TOD
    AY WITH LOW LEVEL LAPSE RATES NEAR 8C PER KM…GIVING SOME P
    OTENTIAL FOR WATER SPOUTS. CURRENT WATER VAPOR IMAGERY SHOWI
    NG A VORT MAX MOVING THROUGH THE WATERS THIS MORNING. REMAI
    NDER OF DISCUSSION UNCHANGED. A STRONG PUNCH OF JET STREAM E
    NERGY IS DIVING SOUTHWARD FROM THE GULF OF ALASKA…DEVELOPI
    NG A STRONG VORTMAX EVIDENT ON WATER VAPOR IMAGERY NEAR 47N/
    140W. THIS SYSTEM WILL ROTATE AROUND THE LARGER CIRCULATION
    OVER THE NE PACIFIC…DEVELOPING ANOTHER SFC LOW NEAR 40N/13
    0W BY 12Z TUE ACCORDING TO THE 06Z GFS. EXPECT OFFSHORE FLOW
    TO INCREASE WITH THIS SYSTEM DEVELOPING OFFSHORE FROM THE O
    R/CA BORDER LATER TUE/TUE NIGHT…THOUGH SURPRISINGLY THE 06
    Z NAM ONLY PUSHES 925 MB WINDS UP TO 30 KT NEAR THE PORTLAND
    AREA. SUSPECT THIS IS A LITTLE UNDERDONE…AS THE COLD POOL
    EAST OF THE CASCADES WILL BE GIVEN A GOOD 24-36 HOURS TO BU
    ILD UNDISTURBED. NAM/GFS APPEAR TO BE TOO WEAK WITH THE HIGH
    PRESSURE SYSTEM ASSOCIATED WITH THIS COLD POOL TUE/TUE NIGH
    T…AND THEREFORE THE OFFSHORE PRESSURE GRADIENTS. EVEN SO..
    .06Z NAM CROSS SECTIONS THROUGH THE GORGE SUGGEST THE COLD P
    OOL EAST OF THE CASCADES WILL DEEPEN ENOUGH FOR COLD AIR TO
    SPILL OVER THE

  3. bgb41 says:

    12/19/2010 California Rainfall Reports

    Heaviest Rainfall:
    7.49″ at JOHNSONDALE
    7.37″ at TANBARK
    7.32″ at DEVORE
    7.28″ at WOFFORD HEIGHTS
    6.87″ at DINKEY
    6.79″ at LYTLE CREEK

    Most of these are in the Sierra Nevada. 24 hour rainfall totals from today. Wow!

  4. Boydo3 500' North Albany says:

    I don’t see anything in the models that shows a big change from the pattern we have been in for many days. I’m thinking that if the weather is going to be virtually the same day in and day out, it’s time to move to Hawaii. There the weather stays the same but the beaches are warm, the snorkeling is great and the sun comes out almost every day. Mahalo!

  5. bgb41 says:

    00Z GFS @ Troutdale

    Continuing to show colder temps from the 27th onward. Looking quite interesting on the 29th. Remember last year on the 29th was the only snow of the whole winter in PDX.

    • Andrew Johnson says:

      I wasn’t living in Silverton last year, but my dad said he got a couple inches on the 29th. On December 29, 2003 we got about 4.5″. So historicially its a good day 🙂

  6. Snowing, 34F at my home in bellevue. Click on my link to see the webcam if you feel snow deprived.

  7. RobWaltemate says:

    1) big grain of salt here, but…
    2) are we not setting up for another H on the East side and then a deep 500 mb trough at the same time with a lot of cold air at the surface out over the ocean later this week? I don’t want to jinx us by using the “S” word for next weekend. At the least it doesn’t look like it is going to be “warm.”

  8. Snow-Zone/Monmouth-Elv200' says:

    Around 2:30 this afternoon when the precip started I had a rain/snow mix for a good while.

  9. Andrew Johnson says:

    Some of these are interesting. Andrews has a foot on the ground and 53 mph wind gusts…NICE!

    Local Storm Report

    12/19/2010 0900 PM

    Burns, Harney County.

    Snow e6.0 inch, reported by law enforcement.

    5-6 inches total snowfall since last night.

    12/19/2010 0733 PM

    1 miles NNE of Andrews, Harney County.

    Heavy snow m8.0 inch, reported by trained spotter.

    8 inches of new snow since 930 am MST… areas north of
    Andrews had up to 12 inches of new snow.

    12/19/2010 0733 PM

    1 miles NNE of Andrews, Harney County.

    Non-thunderstorm wind gust e53.00 mph, reported by trained spotter.

    Peak gust to 53 mph. Spotter also reported blowing snow
    and power outages in the area.

    12/19/2010 0148 PM

    Frenchglen, Harney County.

    Snow u0.0 inch, reported by dept of highways.

    Snow covers Oregon 205 at Frenchglen elevation 4189 ft
    msl per webcam.

    12/19/2010 0145 PM

    1 miles NNE of Andrews, Harney County.

    Snow m3.0 inch, reported by trained spotter.

    4200 feet very wet snow bending branches on trees. Still
    32f at 145 MST.

    12/19/2010 0955 am

    Burns, Harney County.

    Snow m3.0 inch, reported by trained spotter.

    Snow overnight. About a foot on the ground.

  10. Andrew Johnson says:

    HEAVY SNOW AT PENDLETON! Cover that basin!

    • Derek Hodges says:

      Entire basin and gorge should be snowcovered by now. Even spotty snow in the metro area now! So with east winds returning I bet the next few days stay chilly.

  11. RobWaltemate says:

    What are yalls thoughts on the 72hr Nam
    http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?mm5d1_e_slp+//72/3
    Sure looks like a lot of cold air out over the mid Pacific. Any chance that the low off the coast is going to go ANYWERE?

  12. David Mall205 says:

    Was at my parents house on yacolt mt rd, about a half inch give or take, they are at 1300ft. once i droped off the mnt it was gone until i got to mall205 and east.

  13. Jesse-Orchards says:

    00Z GFS is looking more promising for a pattern change after Christmas.

  14. Derek Hodges says:

    Today was nice for what we had. Still some slush on the roads in a few places and most of what fell on the cars or grass or other similar surfaces is still there. Just two days ago models had shown the basin moderating right now when its still pretty cold. They are trying to do the same thing again but I see nothing to mix it out. So, cold winds should return as we wait for the next system. Looks warmer when the next one comes in aloft though. So…we will wait.

  15. For those that watch that extended outlook on the Meteostar.. Just an FYI beyond day 7-10 that thing flips more then President Obama. I think every run today was different. It has shown a snow storm, next run rain, next run a snow storm, next run crazy amounts of rain and now back to snow again, well for TTD anyway. So that thing is not reliable even beyond day 7, just FYI.

    • BGB41 says:

      Pilot,

      I post it for that very reason. Not to mention that I programmed the meteostar website in vb.net. Many of us like to model ride on here and most of us know how unreliable the GFS is in the lower resolution period beyond day 8.

  16. Cherie in Vernonia says:

    Not that we will be able to see it but….has anyone mentioned the lunar eclipse on Dec 21st. Nest time there is a lunar eclipse on the first day of Winter is in 84 yrs. Bet most of us will miss that one!

  17. Jerry says:

    Mark, with Judy Garland…..

    http://www.imdb.com/media/rm4100691968/nm0000023

    Sorry, too good not to share, IMHO.

  18. PDX Weather Nut says:

    Had a very small amount of snow here tonight — it was nice while it lasted … back to the usual cold rain now

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