The Nitty Gritty Radar Details

January 24, 2012

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

A Quick Poll About Weather Surveillance Radar and Portland TV

January 24, 2012

I haven’t put a poll on here for a long time and figured it’s time for another.  I actually thought of this while driving to work today (distracted driving?). 

Do our viewers know if and which station or stations own their own radar for use in weathercasts?  It’s a sizeable investment (I mean HUGE! investment).

So all I ask is that you just take the poll quickly without putting too much thought into  it.

Punch in your answer without looking it up to see what the answer is please!

Thanks…Mark Nelsen

Heavy Showers Moving In…

January 24, 2012

Just walked into work after a side trip to a large, boxy, orange-ish store with lots of home improvement materials.  Wow…impressive looking radar with a big batch of showers moving through the Coast Range and into the North Valley.  Check out the image from 10 minutes ago: