Bizzare weather forecast - New Zealand

66i weather forecast. One for the reasons for purchasing an inReach was the ability to access the weather forecast. I had tramped (New Zealand term for hiking) with a friend previously where access to the forecast via their inReach was useful. But on October 9^th it threw a curved ball. At 3 pm we called up then weather and the readings were

3pm 10deg c

5pm 10deg c

7pm - 17deg c (yes minus)

9pm -17

11pm -16

1am -1

3 am + 8 (back in the positive side)

5am +8

We were at about 825 metres, there was some rain (not heavy) and the wind was significant but in reality we felt the temp never got down lower than 1deg. We were at Rocks Hut in the Richmond ranges in the Nelson Region of the South Island, New Zealand. For anyone who knows NZ we are subject to quick changes in weather but this forecast was bizzare.

We would love to know how this could have happened as I will now view forecast temps with skepticism.

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0 Jordan249 over 2 years ago

@9642996

It's possible that when you asked for weather, there was a problem with the U.S. Department of Defense GPS system and your location data was unreliable. It thought you were somewhere else. Or there was some kind of unknown interference. It's not common, but can rarely (occasionally) happen. I've been using GPS since 1996 and never had it happen though. The link below shows a problem in Dallas, TX USA a few days ago so it does happen. The interference lasted of a couple of days.

https://arstechnica.com/information-technology/2022/10/cause-is-unknown-for-mysterious-gps-outage-that-rerouted-texas-air-traffic/

Also, recently BAE Systems has been delivering the new M-Code receivers to militaries around the world including USA and Germany as well as others. Based on the level of testing in USA, (intentional jamming tests at US military bases), I suspect there has been a lot of testing around the world. It's not impossible that the New Zealand government (or Australian Govt) is testing the "jam proofness" of new M-Code receivers and a mistake was made where you might have been briefly or temporarily jammed. Obviously there is a war going on in Europe, and many countries (allies to US) are scrambling to test the new BAE Systems M-Code receivers. The only way they can truly test the new receivers is by attempting to jam the US DoD GPS. This is usually done in a controlled manner, of course, but you can't rule out a mistake was made.

I looked on GPSjam.org and didn't notice any interference for 10/9/22 in New Zealand.

spacenews.com/.../

If you think it's a problems with your device, then the only thing I can suggest is connecting to Garmin Express via USB cable on your laptop and making sure you have all of the updates. And call Garmin Support if the issue persists. I use GPS+Galileo on my 66i and haven't had any problems.

Here's another website for GPS interference.

https://www.navcen.uscg.gov/gps-problem-report-status

And lastly, there's always the possibility that there was weather server error/problems. And that might be the most likely reason. Server problems happen even to Google, Amazon, etc...pretty much everyone. It might have been just a case of bad luck.

0 twolpert over 2 years ago

The most likely reason for this is bad data from the weather provider. I guess Garmin is still using DarkSky, but I do not know for sure. Even in the best of circumstances, the data is only approximate - because the provider may not have data for your exact location. Also unable to find any data on how long the Dark Sky forecast is good for...

0 Jordan249 over 2 years ago in reply to twolpert

Yes, much more likely to be related to the weather forecast model was off than spoofing.

Anytime you're in a location that sees extreme weather changes...they're going to get it wrong sometimes. That forecast you got might have been accurate for 20 to 40 miles south of you.

Polar air that doesn't move quite as far as they forecasted (computer generated forecast model) can make a big difference.