I notice this is only available if you select a personal weather station, not 
history at an airport station.  I am a little mistrustful of PWS as they are 
not calibrated and maintained as the airport sites are.  The airport sites 
already have a good metric page available There is a °F/°C switch near the 
upper right of the page to switch units.

The PWS page makes three errors which the main page does not.  Since they 
already "know better" on the main page, the question is why change for these 
PWS pages. (s/b is shorthand for "should be")
Wind: kph s/b km/h
Precip. Rate: mm/hr s/b mm/h
Pressure: mb s/b hPa

The main page uses too much resolution for readings that come out of the 
automated airport box already quantized.  Other than that, their metric 
conversion is quite good.  These items are not available from a PWS.

Visibility: 0-3 miles, various resolutions 1/16 - 1/2 mile, vary for manual and 
automated observation.  0.1 km resolution would adequately represent them all.
>3 miles, quantized to 1 mile resolution, in metric should be to 1 km 
>resolution.  For max 10 mile visibility, they use 16.1 km, but 16 km would be 
>more consistent with the resolution of the data and not imply false precision.

Ceiling: Data is quantized 0-5000' by 100' increments, 5000-10000' by 500' 
increments, >10000 by 1000' increments.  It makes no sense to convert to 
nearest meter.  I would suggest rounding to 10 m resolution for lower 
altitudes, 100 m resolution above 3000 m.

(Quantizations above are from explanation of METAR, the automated current 
conditions statement for pilots.  The averaging and preprocessing of the data 
taken in the airport box is defined in FMH-1.)
 

________________________________
 From: "[email protected]" <[email protected]>
To: U.S. Metric Association <[email protected]> 
Cc: Don Hillger <[email protected]>; Gary Brown <[email protected]>; 
Lorelle Young <[email protected]>; Valerie Antoine 
<[email protected]> 
Sent: Friday, December 13, 2013 1:08 PM
Subject: [USMA:53437] New Weather Underground PWS Metric Dashboard in Beta
  

Weather Underground, which is the most metricated and most detailed weather 
site, has rolled out a beta version of its Personal Weather Station (PWS) 
display and has asked for feedback.  USMA's Don Hillger was instrumental in 
getting Weather Underground to display correct metric usage.

Don (and others), you may wish to check out the beta and make comments as 
appropriate.  In order to see the beta display, you have to click on a Weather 
Station name on the main page.  You will then be taken to a page headed Weather 
History for [Name of Weather Station].  In the heading of that page, you will 
see the New Dashboard link to click on.  On the beta page, you will see a 
Feedback button about half-way down on the left side.

Note that in order to see the metric display, when you first go into the site, 
you need to click Settings in the upper right-hand corner, and in the Units 
pull-down menu, select Metric.

I noticed one correction to be made and have submitted it:  to use "km/h" 
instead of the deprecated "kph".

--Martin Morrison, METRIC TODAY Training & Education Columnist

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