Does A Dry March Mean A Dry Rest of Spring?

I think the short answer is…MAYBE.

As of this evening,  we have seen exactly 1/2 of our average rainfall January-March.  That’s the 3rd driest start to the year here in Portland, and the 3rd driest March too:

 MarkRain_DrySpellFacts

Since I had some free time this evening, I decided to take a closer look at what I had noticed about a week ago.  That lots of dry March years seem to have dry April-June weather too.  So I whipped out the Excel spreadsheet.

I looked at the Airport data that goes back to 1940.  By the way, that’s the official recording site for Portland and one that hasn’t moved for 70+ years.  The downtown location has moved many times, we don’t get real-time data from it, and it was on the roofs of buildings from the 1870s to the late 1920s.  The PDX Airport data is and has been most reliable.  I looked at the data and I see 9 March rainfall totals under 2.00″.  Then I looked at the following April-June rain totals.  This is what I found:

MarkRain_DryMarch_SpringAhead

I could only fit in the last 7 of the 9 years on the graphic.  The other two were 1941, 1942.  Most important is that only 1 out of the 9 springs following were wetter than average (more than .20″ above).  Look how many springs continued to be dry.  I found that real interesting. 

Of course there is no guarantee that we’ve got a drier than average spring ahead (note 1978), but the odds seem to be tilted in that direction.

Short term is definitely quite wet Thursday through early next week.  It’s going to turn chilly again this weekend too.  Get your outdoor projects done by daybreak Thursday if you don’t want to get wet.

Chief Meteorologist Mark Nelsen

52 Responses to Does A Dry March Mean A Dry Rest of Spring?

  1. W7ENK says:

    The trees outside my office are beginning to dance a bit, looks like the winds is picking up. I wonder how strong it will get this evening.

    The rain smells nice and fresh like spring, unlike the cold rains of winter!

  2. runrain says:

    Some nice looking showers starting to pop up out there.

  3. gidrons says:

    ….and in the medium range, the Euro has been showing low snow levels for the following weekend. Maybe Mark will post the geek charts again.

    • archangelmichael2 says:

      Guess it’s time for Dad to wrap up the summer hoses if that comes to pass!

      It’s been so dry we’ve been watering our grass/flowers every few days to keep them from turning ugly.

      Many times last January my parents noticed El Skunko came by and smelt up our yard real bad at night when it was warm.
      We believe he lives in the area and the fog inversion didn’t phase him in the slightest.
      First time ever we have smelled him in the middle of winter!

      They need to find a way to ban skunks in neighborhoods or de smell him so people can breathe at night. They are a major source of pollution, Especially comes summer! LOL

      How about the Anti Smelly Skunk Bill Act of 2013? Or does it need a better title?

    • W7ENK says:

      Hey Kyle! So glad to have you back…

  4. pappoose in scappoose says:

    Beware the DOWNBURSTS!

    NATIONAL WEATHER SERVICE PORTLAND OR
    838 AM PDT THU APR 4 2013

    ADDITIONAL SHOWERS SHOULD THEN BEGIN TO DEVELOP
    THIS AFTERNOON AS THE ATMOSPHERE DESTABILIZES. THUNDERSTORMS WERE LEFT IN THE FORECAST PRIMARILY SOUTH OF SALEM WHERE INSTABILITY
    APPEARS IT WILL BE GREATEST. GIVEN THE WINDS JUST OFF THE SURFACE…LOCALIZED DOWNBURSTS OF 30 TO 45 MPH WILL BE THE PRIMARY THREAT WITH ANY OF THE STRONGER SHOWERS.

  5. chiefWright (Marquam) says:

    Interesting rain pattern on radar this morning. It’s moving upvalley, initiating around Cottage Grove and dissipating around Salem. Would the hills S. of Salem be generating a mild orographic?

    • Punxsutawney (aka HIOPHIL) at work by Sunset High elev ~280 says:

      Not sure,

      Normally I would attribute it to dry outflow coming out of the gorge eating up moisture, but take a look at the observations. That’s definitely not happening. Maybe W7ENK’s dome has expanded.

    • chiefWright (marquam) says:

      I wonder about the radar accuracy between Medford & Portland, especially with light amounts moving in. I’ve noticed that before, where the two stations don’t seem to agree about what’s going on between Roseburg & Eugene. They usually underreport, judging from the ODOT roadcams.

    • Mark Nelsen says:

      Coverage is pretty bad from north of Grant’s Pass to Eugene since the radar beam is so high. It’s even worse out at Newport. That said, I just got up, looked outside and noticed it’s mostly dry. Radar looks much wetter. Although it is actually raining lightly.

    • Punxsutawney (aka HIOPHIL) at work by Sunset High elev ~280 says:

      Medford radar has a bad reputation though I don’t think I am qualified to comment.

      I don’t remember the exact number but KRTX is based at about 1000′ in elevation. My understanding is that the lowest that they can aim the radar beam is 1 or 1.5 degrees above straight horizontal, the Langley coastal radar being the only NWS exception nationally at .5 degrees above horizontal.

      What this means is that by the time the beam reaches the area between Salem and Eugene it has risen some due to the angle, but also because the earth is curving away at the same time. I’m guessing that the echoes we were seeing were not making it to the ground down there either, except at higher elevations, and closer to the radar the base reflectivity was still dry. Even when echoes showed up over me here, it took a while before the precip made it to the ground.

    • W7ENK says:

      Medford radar is at 7,500 feet on Mt. Ashland.

      There’s just a LOT of terrain around there, not to mention the fact that it’s up so high anyway it doesn’t “see” at the lowest levels of the atmosphere.

  6. bgb41 says:

    4/3/2013 Oregon (All) Temperature Summary

    Warmest:
    High:76 at LAKE OWHEE AND O(2400 ft) & Rye Valley(I-84(2230 ft)
    Low: 54 at Rye Valley(I-84(2230 ft)

    Coldest:
    High:43 at Lake(6184 ft) & Mount Hood Meado(6601 ft)
    Low: 23 at CHRISTMAS VALLEY (4360 ft )

    Largest Diurnal Change: 45 degrees
    Horse Ridge (US (69/24 ) (4160 ft )

  7. pappoose in scappoose says:

    I can clearly see your point, Larry! Hahaah!

  8. o.c.paul says:

    LOL Larry. Serious, LOL

  9. o.c.paul says:

    In this case, stock brokers are just like mets. ‘Past performance is no guarantee of future results’.

  10. MasterNate says:

    I think I see a pattern here. Going for average rainfall from now till the 4th of July.

    • JJ97222 says:

      No way with this trend we will be on the dry side just imagine the possibilities of being outside enjoying the beautiful sunshine till October in Portland ]{}}#%^*+= it was just a dream it will most likely rain like he.. Till the 4th

  11. I’m cautiously an optometrist.

  12. W7ENK says:

    Heh. Okay. 😛

  13. Mark Nelsen says:

    Yeah, yeah…that’s enough I think

  14. ashley watson says:

    does anybody have snowfall data for sandy, oregon for the past 5-10 years???????

  15. Dave in South Salem (500') says:

    NWS flip flopped. Maybe they can blame their computer. They called for clouds Tuesday and 60’s with sun Wednesday and 70’s. The opposite happened but hey, it could be worse.

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

    This could be another 2004… which could mean, some interesting possibilities for Stray Albino Donkeys in the Willamette Valley this Spring and Summer!!

  17. W7ENK says:

    70+ today? It’ll be close, but I’m pulling for it! 🙂

  18. JohnD says:

    I, personally wish that downtonw weather data WAS
    typically included in historical statistical studies
    and find is disappointing and frustrating that it is
    not. The 1940 airport start date to me is also
    skewed by the fact that the “official” airport
    recording site has also moved several time (I am
    pretty sure) over the ensuing years–albeit in the
    same “general” vicinity. It seems to me that ANY data
    is “good” data when if comes to dipping back into
    historical times when weather records in the West
    were in their infancy. I am envious of Salem and
    other stations that have managed to sustain the
    continuity.

    • Mark Nelsen says:

      Sometimes I’ll mention downtown too, for example with late or early season snowfall events you want to know if something is possible. In that case you want to check all the records. Precipitation definitely shouldn’t be mixed between the two since it’s known that Swan Island and Downtown are both slightly wetter (on average) than the Aiport location.

  19. pappoose in scappoose says:

    NATIONAL WEATHER SERVICE PORTLAND OR
    838 AM PDT WED APR 3 2013

    WILL NEED TO WATCH THE UPCOMING MODEL RUNS CLOSELY. THE 00Z ECMWF INDICATES THAT A BORDERLINE HIGH WIND EVENT IS POSSIBLE THU AFTERNOON…BUT AT THIS POINT THIS SOLUTION IS VERY MUCH AN OUTLIER.

  20. And to add to this, or not, in this case, the steadier rain for Thursday now looks like a few bands of rain vs. a steady all day rain.

    • W7ENK says:

      That wouldn’t offend me one bit! Portland is still a bit ahead for the water year because of the wet fall we had, so let’s reinforce the dome for once and shunt all the rainfall to someplace like… Redmond? They need a good shower over there.

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      More like down here! Even the rainfall on the 1st did almost no help.

  21. bgb41 says:

    4/2/2013 Oregon (All) Temperature Summary

    Warmest:
    High:76 at BULLY CREEK RESE(2500 ft)
    Low: 55 at John Day River B(305 ft)

    Coldest:
    High:41 at Rim(7050 ft)
    Low: 24 at Horse Ridge (US (4160 ft )

    Largest Diurnal Change: 41 degrees
    PRINEVILLE 4NW (68/27 ) (2840 ft )
    Horse Ridge (US (65/24) (4160 ft)

    Heaviest Rainfall:
    0.16″ at Medford, Rogue V(1329ft)
    0.13″ at Astoria Regional(10ft)

  22. Aleta- West Gresham says:

    So what might the pass be like, say late afternoon Sunday?

  23. After the past 3 years, we deserve a dry spring for once.

  24. bgb41 says:

    That’s excellent news. I love dry weather 🙂

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