Snow to Sea Level?

Hah, got your attention!  It’s a slow sunny afternoon (but very nice) in Oregon, so I figured we’d look forward to winter; at least the stormy/snowy/cold part, not the constant rain.
As discussed in GREAT detail in the previous post’s comments, weather maps suddenly changed over the weekend.  We have a strong upper level ridge right over Oregon this afternoon.  500mb heights are near 590 dm, which is classic summertime sunshine and little/no marine layer along the coastline.
But over the next 60 hours, the ridge suddenly retrogresses, leaving it out near 145-150W longitude by Thursday morning.  That opens the back door wide for several strong disturbances to drop south out of the Yukon and Northwest Territories of Canada, carving out quite a strong trough of low pressure directly overhead.  Sound familiar?  We would be approaching snow/cold freak-out stage if it was anywhere between November 15th-March 5th or so.  The constant live coverage would be ready to start at a moments notice. 
But it’s not winter, so no snow to sea level and no WINTER BLAST coverage.  Instead a sudden downturn to Octobery weather for at least a few days.  No change tomorrow, except for a strong marine push by evening.  Wednesday is the transition day with strong westerly flow developing above and marine air at least 5000′ thick overhead.  Then Thursday we get a cool & unstable airmass overhead for scattered showers.  This pattern is not really conducive to a prolonged period of steady rain, unless the low sits right overhead and we get a cluster of showers together (that could happen).  Still cool/showery Friday, then maybe a break before a 2nd system comes through later Sunday or Monday.  That one is similar to what we’d see in winter when a warming/wetter system approaches from the west and wipes out the cold air.  Long range maps all over the place but the ECMWF and 12/18z GFS seem to point us back to warmer weather again, but below 80 degrees.
How low will the snow go?  Looks like 850mb temps drop to around 2 deg. Thursday-Friday AM.  500-1000mb thicknesses don’t drop below 545 dm. (5,000′ snow in winter).  So I doubt it’ll stick below 4,500′.  But Mt. Hood will sure be white once skies clear, maybe on Saturday?
The big picture says…enjoy the warm sun on Tuesday!  Mark

48 Responses to Snow to Sea Level?

  1. luvrydog says:

    Derek, I’m kinda worried about the rain shadow effect we could expierence. It looks good for us to get some decent showers/ possible thunderstorms on Friday but with the low directly to our North wednesday, thursday I think the flow being almost directly westerly(since it is not moisture laden) will be affected by the coast range and then the cascades and hold out the moisture for the first couple days. Friday definetely looks good for some showers, possibly some brief steady rain. I’m thinkin tomorrow, 70, mainly dry, Thursday, dry again but a bit cooler, around 65, then friday, I think frequent showers, some tstorms a slight possibility and cooler yet, about 62ish. At that point I think we may get a few showers saturday but start to climb out of the low and see some highs around town get back to about 70 with some morning showers and afternoon clearing.

  2. Derek Hodges says:

    The blog in the nice format http://stormteam12.typepad.com/
    Radar/Satellite Types
    http://www.wunderground.com/radar/radblast.asp?num=6&delay=15&scale=1.00&noclutter=0&ID=RTX&type=N0R&lat=45.51471710&lon=-122.50512695&label=Portland%2C+OR&showstorms=31
    http://www.weather.com/outlook/homeandgarden/pets/map/USOR0148?from=36hour_map
    http://sat.wrh.noaa.gov/satellite/loopsat.php?wfo=mfr&area=west&type=vis&size=1
    This is the water vapor
    http://sat.wrh.noaa.gov/satellite/loopsat.php?wfo=pqr&area=nw&type=wv&size=4
    Lightning, not the very best but good for free πŸ™‚
    http://www.weather.com/maps/activity/golf/uslightningstrikes_large.html?from=mapofweek
    Severe Weather Data
    http://www.spc.noaa.gov/exper/mesoanalysis/
    Northwest Oregon Temps
    http://www.wrh.noaa.gov/mesowest/frame.php?map=portland
    GFS (I am putting troutdale but you could list other code names by it for other cities. KPDX is Portland, and I believe KRDM might be Bend but…?)
    http://wxweb.meteostar.com/sample/sample.shtml?text=KTTD
    ECMWF
    http://www.cascadeaccess.com/~mnelsen/Models/ecmwf850wsi.html
    Marks Page (Tons of links as well as those two I just put up)
    http://www.cascadeaccess.com/~mnelsen/markswxlinks.html
    3 Day severe storm outlook
    http://www.spc.noaa.gov/products/outlook/day3otlk.html
    My websight πŸ™‚ Hey I had to do it haha
    http://weathergeeks.spaces.live.com/
    Portland Area Records and past temperatures. Can be changed to other cities from websight easily. It may have to be updated monthly since its favorited on Setember and will be next month too.
    http://www.wunderground.com/history/airport/KPDX/2006/9/13/MonthlyHistory.html
    Incredible database for temp/precip in any recording station in the country.
    http://climate.usurf.usu.edu/products/data.php
    Here is a good anomalies page to watch for el nino/la nina, as well as PDO
    http://www.osdpd.noaa.gov/PSB/EPS/SST/climo.html
    You can check out past nino events on this page and their strength as well as current
    http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
    I will finish this later all right lol

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