Topic: Can someone clarify these NWS pressure readings for me?

[nincehelser]

See this page an an example: http://w1.weather.gov/data/obhistory/KSUS.html

It gives altimeter pressure as inHg, and sea level pressure in mb.

Is that a general convention usage or something unique to this NWS page?

In other words, if they give the pressure in inHg elsewhere, is it safe to assume that is an altimeter reading, and that a reading given in mb it is an MSL reading?

[ValentineWeather]

They use inHg almost always for altimeter in the States. Mesowest has an option for metric on the left side of page. Why NWS uses metric for MSLP not sure.   

http://mesowest.utah.edu/cgi-bin/droman/meso_base.cgi?stn=KSUS&unit=0&timetype=LOCAL

[Scalphunter]

use meteric for aviation. That came about several years ago

[floodcaster]

Mean Sea Level Pressure is almost always in millibars. Surface analysis maps and upper air charts use millibars (see attached). In aviation and media weather reports, pressure is normally reported (in the US) in inches of mercury (Hg).