Slicing Up Local Radar

Josh Stein is an alert “06880” reader, and frequent commenter.

He is not, he emphasizes, a weather expert. But after years trying to track storms — without finding local radar imagery — he writes:

If you look at the radar from station OKX (Upton, New York) on any radar website or app during a storm, you will see that a slice covering our area is missing. Here is an example from the most recent storm:

Westport is smack in the middle of the radar “slice.”

On a Reddit thread, someone asked about the slice. Someone else replied: “Google reveals a water tower and smoke stack to the NW of the radar dome which could be the cause.”

If you look at the radar tower on Google satellite images, you will see it. You can follow the angle to see a water tower structure nearby, blocking it.

There are also smokestacks somewhere in between. But my guess is the water tower is the issue.

Composite radar pieces together radar from multiple stations (e.g. Boston, Philadelphia, Binghamton, Albany and New York City, aka OKX). That is why you likely do not see the slice if you are watching the news or looking at a composite map (but I have seen the slice on TV many times).

However, composite view may not be the best source of data. For example, on Sunday night when there was rotation indicated while the storm was coming towards us (but still in Westchester), I could see the potential cell on the OKX radar but not on the composite view.

If I looked at any of those other radar stations (Boston, Philly, Binghamton, Albany) I could not see anything useful — most likely because Westport is out or range, or right on the outskirts of what they can reach. Meteorologists may have different tools at their disposal.

Perhaps another “06880” reader is more of an expert. Perhaps it’s not a big deal for Westport, because a storm approaching can still be seen while over, say, Stamford, Darien or Norwalk. Maybe it’s a bigger deal for warning Fairfield and Bridgeport?

But missing a piece of the puzzle may also hamper historical reviews when there is a possible tornado.

Again, I’m no expert. Still, I think this is worth exploring.

19 responses to “Slicing Up Local Radar

  1. My guess, the WLNY tower, shown on the sectional as 821 feet.

    Someone could do the math on how wide the arc is at some further distance, and then how wide it would be at the tower.

  2. I think you should consult legendary weather expert, Richard Berler, Staples class of 1973. Known as “Heatwave,” he just celebrated his 40th anniversary as the weatherman on KGNS TV in Laredo TX, after 4 years at KDAL in Duluth, MN (where I watched him do his report right at the station.) His Twitter handle is@HeatwaveKGNS.

  3. Larry Perlstein

    Didn’t Storm Tracker 4 adequately cover the area? It appears to be accurate when I’m looking a storm positions.

    • It could cover the area but they are not an official weather radar listed on any database that I see. I don’t think you can access NBC’s data and track down to low-level like you can with OKX. Hence, if there is a storm coming at us and one wants to keep an eye on extreme weather/cells/possible rotation, I dont think you can.

  4. I’ve noticed the same slice on the app I usually use (NBC CT) and have often wondered what the cause was. If anyone finds the answer, please post it here.

    • The answer is posted above. Please read what Dan posted that I discovered. A tower is right in front of the radar basically. You can see it on Google satellite view.

  5. I forgot to mention – has anyone noticed that those of us in southwestern CT are “weather orphans”. Most of the New York TV stations avoid mentioning Connecticut weather conditions, even Ch. 2 where Lonnie Quinn (who lives in Westport) rarely mentions anything further east than Greenwich. The Connecticut stations ignore anything west of New Haven leaving those of us in Fairfield and western New Haven county out in the cold . In fairness, the one exception I have found is Lee Goldberg at ch. 7 and, of course, Ch. 12 on our Tinkertoy cable system.

  6. Wendy Crowther

    I’ve always noticed this slice too and have wondered why it was always there. Josh, thanks for putting the question out there. If anyone gets a definitive answer, please post it. I’m so curious.

  7. I found an email address for WSR-88D boffins in Northern Indiana and emailed them this question, and they have kindly forwarded it on to Upton. If I hear I’ll post something.

    The WLNY tower is roughly 5.9 miles on that bearing. The slice looks to be about the distance from Newburg to New Windsor at a distance of around 95 miles, which gives me something on the order of an arc of 500 feet at the tower.

    These 88Ds radiate at 750,000 watts with a maximum vertical arc of 22.5 degrees, and since they are sensitive enough to track raindrops they also track bugs and have a lot of ground clutter. So software filters the responses received to clean up the signal. I’ll be curious to find out if the slice is actually a software artifact of the filter.

    If you google the Upton 88D you can find a paper written by the staff in 1988 after using the doppler for a while, showing plots from then. The slice is there from the beginning.

  8. Richard Berler

    Meteorologist Ryan Hanrahan at NBC CT would be quite knowledgeable about this topic. He is very well versed in radar meteorology. On Twitter, he can be found at @ryanhanrahan

  9. Try WFSB CT out of Hartford which has been very good above covering the entire state & has live pinpoint Doppler. Their website is quite good.

  10. Leslie Petersen

    Hi. So interesting, this “slice”. I totally get what you are saying. I too am frequently trying to guess what’s about to happen within it.

  11. Hi everyone,

    Ryan Hanrahan from NBC Connecticut here. Richard Berler pointed me in the direction of this thread. The big “slice” from the National Weather Service radar is from a large water tower on the campus of Brookhaven National Laboratory on Long Island just northwest of the radome. This effectively blocks low level radar data over Westport and Wilton. There is a smaller and less noticeable blockage over Norwalk from a smoke stack. This certainly can hamper weather warnings in the area but it’s small enough that it’s generally not too detrimental to warning operations. I hope this helps.


  12. Ernie Lorimer

    I did get a response from the boffins at Upton, and it isn’t the TV tower. At the water tower the beam would be about 50 feet wide. They write:

    Ernie, what you’re seeing is what is sometimes referred to as “beam blockage”, or the radar shadow you mention. The doppler radar pulse is being blocked by a nearby tower that’s about 307 degrees (west-northwest) of the radar location here in Upton, NY. Nothing can therefore be “seen” by the radar down-beam. Hope this explains things.