The Nitty Gritty Radar Details

The results of the evening poll (below) were sure interesting:  we’ve never had such a large turnout for a poll, especially since it was open for only 6 hours.  Over 400 responses!

34% think KGW has their own radar
25% guessed that more than one station owns a radar
19% all stations use NWS radar only
15% say we here at KPTV have our own radar
1-3% think KATU or KOIN have their own radar

Another way to read that is 1/3 of you think KGW has their own radar, and 2/3rds do not or are not aware of that.

The truth?

-KGW is the only station that owns a radar system.  They installed their own radar somewhere between 1997-1999 on Livingston Mountain north of Camas.  They are the only station that’s ever purchased a unilateral radar system here in the Portland television market.  As far as I’m aware, it still works, although many times I’ve watched and it’s just the NWS radar (your tax dollars at work!).  Not sure if it’s failing or is just expensive/difficult to maintain.  You can tell if it’s just the NWS radar because the “circle” of higher echoes will be up around Dixie Mtn. (the NWS radar site) near Scappoose, not north of Camas.  Interesting that it’s labelled as their own radar even at those times.  BUT, before I find the “speck” in that eye, let me pull the “log out of our own”…the other 3 stations stretch the truth a little too.

-Beginning around 2005, weather graphics vendors starting ingesting Nexrad Level II info from the NWS radars.  That’s all the volumetric data produced as a steady stream that all 4 tv stations in Portland use.  So we all have the ability to plot data as soon as it leaves the radar.  It is slightly delayed compared to having your own radar; I’ve been told 20 seconds to 2 minutes after it leaves the radar site it shows up on our displays.  On the other hand, the NWS radars are significantly more powerful than privately owned  radars.  Our graphics software adds the sweep line and the final product is what you see on television.  Local stations all call that “Live” radar.  And of course you can argue about what is “live” and what is not.  That’s what I mean by “stretching the truth”.

So in the end, in the year 2012, all the television radar displays look just about the same.  That might account for the confusion in the survey above.  It would not be worth it nowadays for a Portland TV station to buy their own radar, partly due to our lack of severe summer weather (thunderstorms) and partly for the reasons outlined above.

There are some nifty little tricks in the software that we can all use to differentiate the look: 

1. We have the ability to color the intensity levels any way we like.  We choose a green-yellow-red scheme here.  I remember we colored it blue in the early 2000s on FOX49; a poor choice of mine, I admit it.  I think we go to yellow around 35dbz.

2. We can display the volumetric data (showing the height of the various echoes, also called 3D).  This one looks a little messy to me (my opinion only of course) and I think it’s really only useful for big summer thunderstorms.  So we choose not to ise that much here.

3. We can apply a “mask” for winter weather precipitation types and color that any way we want.  This is based on elevation, short term model info, and surface observations.  This is the green-white coloring or maybe green, white, pink coloring (pink for freezing rain) you see on FOX12.  Remember that as of early 2012, this “winter radar” view is only an estimate, NOT the radar itself telling us what is rain and what is snow.  The new polarimetric data is not flowing out to local tv stations yet.

Chief Meteorologist Mark Nelsen

32 Responses to The Nitty Gritty Radar Details

  1. Ian says:

    I didn’t participate in the poll since I never watch Portland TV and I’m more familiar with Seattle broadcasting. It appears that KING and KCPQ have their own radars in Washington – or used to, at least.

  2. Kyle says:

    Despite the calendar saying *winter* we are having a super sized fall and it’s pretty impressive.

    I am not looking forwards to it when the pattern flips no matter what time of the year it happens since I am not feeling good.

  3. Brad says:

    KPTV have their own radar…LOL. They can’t even get the temp. sensors on their towers to update faster than once an hour…. 😉

    • Brad says:

      Yeah, I’m pretty sure the DEQ owns the sensors, but still….

    • Mark Nelsen says:

      Yep, we have no control over those sensors. BUT, our engineer has proposed getting a wind sensor back up there again. That would be real nice to get speed and direction at 1,800′ don’t you think?

  4. gidrons says:

    Nice write up on the AMS meeting in today’s Oregonian, page 1.

  5. wwm says:

    hmmm… interesting stuff. I always thought only KGW had the ability to do the 3D, especially since they are always telling the viewers they are the only ones in town with 3D Dopplar.

    So from what I understand you saying is while KGW does have their own radar, you guys can still use NWS radar and make it 3D or give it the 3D look?

    Seems like they (the other station) are telling a “half truth” to me

  6. pappoose in scappoose says:

    Hahaah! Beware of the Napavine Triangle. Or how about BURIAL BY SAND!!!

    • Cue Rod Serling….”an ordinary place in an ordinary time…but just around the corner you might find yourself in the Napavine Triangle…a place like no other…except the Twilight Zone…”

  7. philinforestgrove says:

    Debris on lawns and streets this morning in old town FG and on Pacific U campus from the wind last night. Mesowest observation points screwy here. NK7NKE is only station that records accurately. Other 2 must be inside barns or behind buildings as they recorded little or no wind last night.

    • Jane - Forest Grove says:

      It was really blowing last night. Was it just here? It didn’t really cause any discussion anywhere.

    • philinforestgrove says:

      Saw a large branch down on Birch street and plenty of litter and branches on the Pacific U campus as I drove by this morning.
      Must have been the “FOREST GROVE EFFECT”.

    • Kyle says:

      We are basically having a *super sized* *fall* which never really went away except for the brief shot of low snow levels in late November and I think last week or is it now 2 weeks ago?

      Mother nature said: “Super size me!” like back in the days Mc Donalds had super size fries and drinks.

      When this supersized pattern finally breaks apart we are going to get our *dues* but the question is not a matter of *if* the current upper air pattern folds but *when* it folds and I am NOT looking forwards to when that happens.

      10-4! Over and out.

    • Jane - Forest Grove says:

      Boy, I guess it was the ‘Effect’ Was hardly mentioned last night on the news. Maybe it’s because Mark gave us too much attention last week for the snow. Nursery down the road looked like a bomb went off, with all the plants laying down.

      What were the peak winds, 50? Thank goodness it wasn’t raining.

  8. chiefWright (Marquam) says:

    What’s polarmetric data, and why is NWS apparantly hoarding it?

  9. Sifton says:

    Here is something I’ve noticed; 46.1 (which is KGWs radar channel on over the air TV) always seem to be somewhat behind & not as detailed to there website radar display online. I always wondered if it’s the same radar tower feed why the slight variations in echo return readings??

    • The center of 46.1’s radar sweep is Camas — so this would not be the NWS radar site.

    • Mark Nelsen says:

      I’ve never noticed the extra radar feed on TV. You are correct though, if it’s centered north of Camas it’s their own radar.

    • Sifton says:

      Late night, I meant ‘their’. Also I learned after I posted that the dedicated radar channel is not carried on the Comcast cable system, & yes Jethro it’s KGWs tower the center being Livingston Mtn. North of Camas & directly due East of my home a few miles. My thought in question though was why the detail was so much finer on the web than on the channel if it’s the same tower.

  10. Tinmy-scappoose says:

    Good info mark! However, I believe the results are skewed because I’m sure people thought this was a “loaded” poll based on who was asking it. That would explain why the “kptv” option got the percentage it did, since your station does not let on that you have your own. Where as Koin often indicates “NEXRAD” leading viewers to believe it is special in some way

  11. bgb41 says:

    1/24/2012 Oregon (All) Temperature Summary

    High:62 at Highway 42 at Co( 448 ft)
    Low: 47 at BROOKINGS(79 ft) & Port Orford (US(90 ft)

    High:26 at WOLF CREEK(5699 ft) & HARL BUTTE(6071 ft)
    Low: 2 at CRANE PRAIRIE (5500 ft )

    Largest Diurnal Change: 34 degrees
    CW3808 Enterpris (53/19 ) (3927 ft )

    Heaviest Rainfall:
    4.62″ at RED MOUND(1753ft)
    3.72″ at LOG CREEK(2800ft)
    3.61″ at DW0237 Lees Camp(699ft)

  12. Danny in Troutdale says:

    Mark, Im heading to I-84 with my camera. Make sure the Speedo covers everything. Will post on blog 🙂

  13. philinforestgrove says:


  14. Longview - 400 ft says:

    Sorry I missed the pole!!! Thanks Mark!

    • Longview - 400 ft says:

      I knew KGW was the only TV station that had their own radar system because you told us at some point this last year.

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