Strange weather today

[robert41]

At KATW. Using real weather. A very low pressure reading. So low I could not set the altimeter low enough on several aircraft. Airport elevation is about 900ft.

 

[orionll]

Looks like the METAR reported for KATW today at 1345Z had erroneous data: KATW 131345Z 29018G23KT 10SM BKN020 09/05 A2062

Edit: How were the flight characteristics for your flight? Given the METAR reported altimeter setting (20.62 inHg), the pressure altitude should've been 9300 ft + field elevation (918 ft at KATW). Did it seem like you were flying at 10,200 ft?

 

[robert41]

Flights characteristics were normal, just the higher altimeter reading. I went up to 3-4000ft from the shift z data. Once close to OSH, the pressure read more normal.

Adding. I took up the A2A182 and did act like being at 4000ft.

 

[srgalahad]

Erroneous would be a good bet...

"The lowest non-tornadic atmospheric pressure ever measured was 870 hPa (25.69 inHg), set on 12 October 1979, during Typhoon Tip in the western Pacific Ocean."

Now, it's possible there was a tornado over the airport but in that case the winds would be a lot higher than reported, so best guess is a typo in the source report.

The alternative is to set the altimeter to show field elevation for departure and then correct it once information is available.

 

[robert41]

Was unable to set the altimeter any lower on several aircraft. Maybe a gauge limit? Interesting that the shift z data shows the correct altitude. Also the AI had no problems with this.
All back to normal readings today.