Very funny weather station malfunction

[Jeroen Hoppenbrouwers]

KTMB 231153Z AUTO 02003KT 9SM -SN OVC044 A3016

[Jeroen Hoppenbrouwers]

Next METAR sort of shows what is going on:

KTMB 231253Z 35003KT 10SM BKN044 18/M02 A3018

[Hardy Heinlin]

I just woke up. Help me. I can't find the error ...

[Jeroen Hoppenbrouwers]

KTMB 231153Z AUTO 02003KT 9SM -SN OVC044 A3016
----                          ---
Miami                        SNOW?!?

The temperature sensor obviously gave up and the next, non-AUTO manual report fixed that. The negative dew point must have thrown the software off.

It is rare for Miami to have this kind of non-humidity at daybreak, so I think there is something more going on with that sensor.

[Hardy Heinlin]

Is the rain-or-snow info computed based on the sensed spread?

[Jeroen Hoppenbrouwers]

I have no clue, I  think it is mostly temperature, but this kind of malfunction gives you ideas... Hey Jose! Help!

[Will]

Good question about rain vs. snow. My guess is that the FAA-approved machine (let's call it the WeatherMatic 2000) has whatever sensors are necessary to say specifically what kind of stuff is in the air. I bet it it can sense the type of precip (or mist, or dust, or ash) and report it correctly without having to derive it based on other factors. That's just a guess, though.

[Will]

Oh, and one other thing... I saved a printed METAR from way back in the day when I was at Scottsdale, AZ and the weather was W0X0F, and that was actually what the METAR said. Although back in the day they didn't call them METARs, I think they called them Surface Observations or something like that. Anyway, it was (paraphrasing):

KSDL 1355Z 0000KT W0X0F 2992

It wasn't the "W0X0F" that was remarkable, it was that it happened in the desert.

[Hardy Heinlin]

As far as I recall from my flights in Arizona, "W0X0F" was the "battery empty" code from the WeatherMatic 100.

[IefCooreman]

when I was at Scottsdale, AZ

I'm curious... what year?

[Will]

I think it would have been 1992-1993. Aeromech.

[Jeroen Hoppenbrouwers]

According to the interwebs, W0X0F or WOXOF stands for Weather Obscured, Ceiling Zero, Visibility Zero, Due To Fog.  I've never seen it before despite a lot of METAR decoder writing over the decades.

[Will]

That is correct. Which is why I was so surprised to see it in Scottsdale.

W0X0F was retired when the old weather reporting format was replaced by METARs in 1996.

And even pre-1996, I only ever saw it the one time. Like CAVOK, it was one of the old abbreviations you had to memorize back in the day.