30 Hours of Rain; But Mostly Dry Weather Ahead

With just two days to go, January is going to end mild and mainly dry. 

Now as a whole the month was very chilly at the lower elevations due frequent inversions.  Portland will end up with its coldest January since 1993!  But much drier than average; probably just under 3.50″.   The mountains will end up about average, buoyed by the warm weather above the inversion for part of the month.

Take a look at the rainfall totals since midnight:

PLOT_Rain_Autoplot_Valley

Portland saw rain every hour between 5am Monday and 11am today (Tuesday)…about 1.5″ during that time.   Notice the strongly orographic effect to the rainfall.  Lots more rain the past two days eastside metro compared to westside.

Most of the rain lifts to the north the next 2 days as a warm upper level ridge builds in from the Pacific.  Snow levels have already risen above 4,000′ this evening and rise closer to 6,000′ tomorrow as the ridge gets closer.  By Friday, it’s close enough that cloud cover and all rain will be pushed well to the north.  At that time 5000′ temperatures are pushing 50 degrees.  Those warm temps at the higher elevations will continue through early next week. 

Last time this happened we saw very chilly temps in the valleys and lots of fog/frost.  This time it’ll be different for two reasons:

1. We start much warmer with the current mild surface airmass overhead.  Last time we started with a snow level almost at sea level.

2. The sun angle is getting higher and it’s a LITTLE easier to break some of the inversion.   Not a total breakout.  In fact the same atmosphere overhead in late February would push our high temps into the low-mid 60s!  It’s a few weeks too early for that.

Thus, I think we’re going to see our first 50-57 degree mostly sunny days west of the Cascades we’ve seen since early December.  We saw highs in the mid 50s earlier in January, but that was with rain and gusty south wind.

What about the big picture as we head into the first half of February?  I sure don’t see any pattern that would produce low elevation snow, extremely cold temps, or wild and wet storms.  Yes, for the weather geeks this slow winter weather will continue.  Here is a look at the 00z GFS ensemble forecast chart for the next 16 days.  You want to see 850mb temps down to at least -6 or -7 to get snow down in the lowlands.  Notice you don’t see that in the next two weeks:

tseries_850t_000-384_Portland

Chief Meteorologist Mark Nelsen

31 Responses to 30 Hours of Rain; But Mostly Dry Weather Ahead

  1. JJ97222 says:

    It is almost definite now we are setting up for the ahaha move that leads us into thinking that spring has sprung with warmer weather then by late Feb or early March we will get hammered with 2 arctic blasts that come out of no where to put us back in the house again!

  2. WEATHERDAN says:

    A few thoughts about this winter. Late in December I posted that winter was over and was lambasted in this blog site. I have lived here all my life, 59 years. And I know how weather patterns behave. Also global weather patterns seem to be quickly changing for the warmer. Witness the fact that Salem has had a snowy winter only once in the last nine years. All that aside I find as I grow older I really like the milder winters and warmer summers better than I did when I was in my teens. If you really want to see a snowy winter there is still the mountains, or a move to Minnesota. Even Mark Nelsen has pointed out our winters are growing milder and less snowy every decade. I am truly sorry if you feel cheated by the lack of snow, but you must be realistic. Large snowstorms are likely to be much less common in the future. For those of us who like summer heat however I think we are in luck. Heatwaves are probably going to be longer and more intense here than in the past. So as we say goodbye to winter and hello to spring I will enjoy the warmer days and more sunlight. And I really do hope to see a big snowstorm next winter. I just won’t expect it.

  3. Longview - 400 ft says:

    What a grey day: fog hanging around with off and on drizzle and temps in the mid 40’s.

  4. David B. says:

    Fork you, winter of ’12 – ’13!

  5. Garron near Washington Square says:

    Just like October’s epic drought, looks like January will end up not as noteworthy due to the last week balancing act. I wish that the anemometer nearest me wasn’t so south wind protected. There isa bunch of 50 + foot poplar trees about 100 yards from it, so I am sure that the 16 MPH south wind gust had to have been closer to 30 MPH. I don’t suppose the school that it’s located on top of might let me relocate it with out some hub bub. At least when the wind is any other direction, it seems to be accurate.

    • Fred482 says:

      Mine had similar problems, moved it 250′ south, bought a remote transmitter, mounted it on a 20′ pole with a clear field all around. Wind speeds are much higher than before. It usually shows 5 – 15 mph higher gusts than Aurora State & SLE stations, the nearest for comparison. Normal winter storm gusts are always 45- 55 when PDX sees 30 – 40. I’m at 500′ near Scotts Mills at the edge of the foothills.

  6. gidrons says:

    The Euro operational shows low snow levels 7 days out. It also hints that the Gulf of Alaska vortex will return around day 10, or lala land in blog terms.

  7. Tyler Mode in Battle Ground says:

    72 hours of rain now…up to 2.55″ since it started raining. This is half of my monthly rainfall in the last 4 days.

  8. Ben T says:

    … Well ok then. Wait, why am I disappointed? This is how most winters go here. That’s what I need to remember.

    • David B. says:

      It’s been a couple years since a good arctic blast, but I remember runs of winters without an arctic blast before. Just based on my memory, it seems as if the western lowlands average slightly less than one such event per year (a slight majority of years have one, some two, some none. Sometimes there’s runs of years with none, just like there can be runs of years with one or more.

  9. fishinpox02 says:

    Not gonna lie, I like seeing the warm weather up on the mountain. Along with being a weather geek, I like to hunt. Less snow over east along The Snake will make my May bear hunt that much better.

    • gidrons says:

      That’s assuming you draw your tag!
      The last two springs east side have seen a lot of snow in the mountains. La Nina is gone but I think we still have a -PDO.

    • fishinpox02 says:

      Tag will be drawn. I have the points, so it’s a guarantee

  10. EY (Oak Grove) says:

    …The wind is blowing pretty heavily here in Oak Grove. Anyone else getting breezy winds around 2 – 3 am?

    • Kassie97222 says:

      Yep the wind chimes have been going here (Milwaukie, down the road from Oak Grove) for a few hours now… There was a 19 WSW gust and it’s currently breezy between 5-8 W.

    • W7ENK says:

      This tired body slept right through it, even with the window open a crack.

  11. Tyler Mode in Battle Ground says:

    Strange how this will go down as my coldest January in my records, yet only a trace of snow.

    Out here in BG I’m up to nearly 5″ of rain for the month.

  12. Here’s a REALLY geeky question. Summer heat waves are often associated with thermal lows moving up from California west of the Cascades, under a strong upper-level ridge. These heat lows can also form during warm spells in the spring and fall. But what about during a false spring? Is there ever any kind of thermal trough over the Willamette Valley during a 60+ day in late February or early March?

    • Garron near Washington Square says:

      Karl,

      I had a similar question maybe a week ago. I was wondering when the effect of thermal low’s begin to warm the atmosphere? We still get thermal low’s swinging up the coast during the winter, but when do the effects actually turn our atmosphere warmer?

  13. bgb41 says:

    1/30/2013 Oregon (All) Temperature Summary

    Warmest:
    High:58 at PROVOLT SEED ORC(1180 ft)
    Low: 46 at BROOKS(187 ft) & PACCTY-2 Pacific(28 ft) & Tillamook Airpor(36 ft)

    Coldest:
    High:26 at POINT PROM II(6607 ft)
    Low: 15 at HOWARD Mt Howard (8150 ft )

    Largest Diurnal Change: 28 degrees
    ILLINOIS VALLEY (56/28 ) (1389 ft )

    Heaviest Rainfall:
    2.83″ at Tillamook Airpor(36ft)

  14. bgb41 says:

    Just a couple of light dustings. Less than half an inch.. But it was fake cold most of the month.

  15. Sifton says:

    Me likey!! Spring is sprunging!!

  16. I still think the Groundhog is going to be partially wrong this year about the shadow leading to a wintry pattern the following 6 weeks. Far more likely is a decent false-spring pattern somewhere between Feb. 10 and month’s end – then MAYBE a late-season “cold snap” the first half of March. (By “cold snap” I mean high temps in the 40-45 range with a chance at one or two of the classic March-style brief “snow events.”)

  17. bgb41 says:

    Oh good, I have 7″ of rain this month so far at Battle Ground Lake

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