A Very Dry March; Mild Weather Continues

9:45pm Monday…

MarkPromo_FullScreen_Easter5

What a difference one year makes!  Our temps this month are running slightly below average, but rainfall is WAY below normal.  And this weekend was great with excellent weather for getting outdoor projects done; so now my back is tired and I’m “relaxing” at work. 

Last year was our wettest ever March with 7.93″, constant rain and several bouts of wet snow to the lowest elevations.  This year no snow at the lowest elevations and very little even up around 1,500′.  Last year I had 20″ of snow at 1,000′ in March; this year just 1/2″ last Friday morning.  Right now we are at 1.46″ rainfall for the month.  Even if we somehow squeeze out another .50″ in the next 3-4 days (unlikely), that means we’ll be below 2″ for a monthly total.   That’s only happened twice in the past 20 years (2004 & 1994).  This March has been a very nice payback for the really wet March weather we’ve seen the past two years.  It’s especially pleasing that the eastern part of the USA is whining about how “winter won’t let go” as we finally get some nice spring weather for once.

I might be jumping the gun a bit, but a cursory glance at past springs shows that the under 2″ March totals are frequently  followed by a drier than average spring.  Interesting eh?

The next few days involve a real pain for forecasting.  Models are showing weak southwest flow over the Pacific Northwest as a new upper low develops in the Eastern Pacific to our southwest.   So we just have leftover moisture over us that afternoon heating work on.  Most likely we’ll see pop-up showers Wednesday-Thursday afternoons, possibly tomorrow or Friday too.  I’m not really seeing any low lifted index numbers or high CAPE; both would be an indication of nice spring convection.  But we could have some weak “action” those afternoons.  We’ll see what happens each day.

Beyond that, models all agree that the upper-low sits just off or on the California coastline over the weekend with upper-level heights rising off the SW BC coastline.  This is a nice block pattern with offshore surface flow and a warm atmosphere overhead.  The last few days of March we can get some very warm weather out of this.  850mb temps are forecast around +8 to +10 with abundant sunshine and some offshore flow.  That means high temps the warmest we’ve seen so far this spring; right around 70 degrees.  A +10 with perfect offshore wind flow and totally sunny skies has pushed the PDX high as high as 74 degrees in the past in the month of March (according to my chart).

So, it’s a risky forecast, not because of uncertainty, but because it’s a holiday weekend (Easter) and I REALLY don’t want to screw up the forecast.   Nothing’s worse than forecasting a nice weekend on a Monday and then having to back off on that later in the week.

Here are the two ensemble charts from today, the 12z GFS and the 12z ECMWF, click for a better view:

tseries_850t_000-360_Portland tseries_850t_000-384_Portland

Note the unusually high uncertainty beyond Sunday.  Models are all over the place for next week, although splitty flow seems to want to continue.  Split-flow is terrible in winter because it leads to boring weather and weak storms.  But split flow in the spring often means warmer than average weather and sometimes thunderstorm setups.  Example A:  a new wrinkle on the brand new 00z GFS, the upper-low to the south this weekend moves off to the east and ridging stays right over us on days 7-8 (MON-TUE) instead of a cold trough coming in from the north…very nice if you want mild spring weather to continue.

By the way, I’ll have very low tolerance for misbehavior or drama this week on the blog comments.  It’s been real mellow on here; could we keep it that way for a while longer?

Chief Meteorologist Mark Nelsen

57 Responses to A Very Dry March; Mild Weather Continues

  1. pappoose in scappoose says:

    http://www.wrh.noaa.gov/FXC/make_img.php?wfo=pqr&iname=Active_Screen1L&size=1&force=no

    Conditions appear favorable for scattered thunderstorm activity on Wednesday and Thursday. The prime threat time will be during the afternoon and early evening hours. If you are planning outdoor activities during these times, please be prepared to deal with the threat of lightning. Lightning is one of the biggest weather related killers in the U.S. If you hear thunder, seek shelter immediately. The safest locations are in substantial buildings, or hard-topped vehicles.

    • pappoose in scappoose says:

      When I hear thunder, I get outside as fast as I can!
      (don’t try this at home) Hahaah!

    • fishinpox02 says:

      I sure hope it happens, it’s almost storm season in the mid west and I’ll be internet storm chasing. Nice to have a thunderstorm pop up around here for fun.

    • pappoose in scappoose says:

      And it’s easy for us to have fun with it. All we need is a reflection!

  2. I wonder if the folks back in the midwest have stopped bitching yet about last year’s warm winter?

  3. runrain says:

    Ahhh, sweet 70’s! Bring it ON!!!

  4. *BoringOregon* says:

    Wow, Kgw is saying 70’s all week I will take that wonder if we will get any thunder storms. I remember a couple of yrs ago working in the garden seeing a huge thunder storm this time of yr ?!?!

  5. bgb41 says:

    PDX weather forecast is gonna bust today. Light rain is moving in off the cascades from the SE right now. Temps only around 50.
    http://radar.weather.gov/radar.php?rid=RTX&product=N0R&overlay=11101111&loop=yes

  6. The 12z now extends 70s through Monday or Tuesday…

    • Marcus says:

      I just saw that!! exciting!!!:) Let’s play ball:)

    • Dave in SW PDX (235') says:

      …which also means tree pollen season could be in full swing by Tuesday, with clouds of pollen billowing from my cedars and firs whenever the wind stirs. Well worth it, though, in exchange for temps in the 70’s. Ah, Spring!

  7. Now, where did I stash those Bermuda shorts……?

  8. Dave in SW PDX (235') says:

    @Mark: Ask and ye shall NOT receive, apparently… smh

    Currently up to 41.6° after an overnight low of 38.4°. Here’s to a warm and sunny Easter weekend!

  9. Brandan (Damascus - 675ft) says:

    Hey what a delightful morning America!

  10. Timmy_Supercell (Klamath Falls @ 4200') says:

    Low of 39 this morning, currently 43. Ground is wet as if it rained off/on.

    Nice gray day!

    Hmm.. not sure whats going on below.

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      Clouds are clearing quicker than they came in.. I wish they would stick around. I didn’t get to see any of the rain!

  11. Hal in Aims says:

    good grief………..

  12. JERAT416 says:

    Mark, how much longer can we have this warm, dry spring before we need to worry about the snowpack?

    • SilentReader says:

      more importantly – This is obviously a continuation of the drought that Mark continues to ignore. come on Mark 70’s in march. surely you now know to warn the public about the long lasting drought conditions that were just “masked” by winter. LOL!!!

    • JERAT416 says:

      I really wouldn’t say “drought” yet, but from being up on the mountain, the snow looks like it’s already on the decline, as in early march was probably the peak of the season. Obviously it goes up and down until later on in the spring. If it doesn’t snow much more up there before summer, I don’t think there will be any skiing/boarding past early June even at TImberline (besides Palmer lift). I can’t imagine we are in an average water year.

  13. bgb41 says:

    3/25/2013 Oregon (All) Temperature Summary

    Warmest:
    High:65 at PROVOLT SEED ORC(1180 ft)
    Low: 46 at NEWPRT Cape Foul(1024 ft)

    Coldest:
    High:31 at HOWARD Mt Howard(8150 ft)
    Low: 16 at ANEROID LAKE #2 (7300 ft )

    Largest Diurnal Change: 38 degrees
    Lorella (62/24 ) (4160 ft )

    Heaviest Rainfall:
    0.55″ at WANDERER’S PEAK(4350ft)

  14. Greg Carstens says:

    To bad the weather is getting better. It would be cool to see more photos of tornadoes over Battle Ground once again.

    It was a balmy 58 degrees for a while in Southeast Tacoma earlier today…Yaaaaaaawn.

    Everything exciting in weather seems to happen over Battle Ground.

  15. W7ENK says:

    Weird weather today, especially up in Battleground! Why is it ALWAYS Battleground???

  16. Greg Carstens says:

    Can someone please give us a complete analysis of this tornado that happened near Battle Ground today. It looks pretty epic to me. I heard someone say it might even be and EF4. Thanks! 🙂

    http://t.co/3FVaw2UGXU

  17. Timmy_Supercell (Klamath Falls @ 4200') says:

    A dry March is going to lead to a very convective Spring. And I know this because… err well, I just know 😀

  18. W7ENK says:

    Warmth… Oh, sweet Springtime warmth!!

  19. bgb41 says:

    **WARM SEASON WEATHER FREQUENCY CONTEST ENTRY FORM***
    http://www.directpaintsaleswa.com/SPRING2013_CONTEST/add.php

    So how well can you predict how many 60,70,80 and 90 degree days we will end up with this year as well as other fields of interest? Fill out this form and I will announce the winner late next fall.

    The 2012 winner of this contest was Keegan Lucas (IceKeeg)

  20. pappoose in scappoose says:

    Who’s on first?

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