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Wednesday, March 23, 2016

Weather Station Model

Temperature, pressure, moisture, and wind measurements are reported hourly at the surface (most are usually made 2 meters above the ground).

77: Temperature.

68: Dewpoint.

998: Pressure, to the nearest tenth of a millibar. Add either a 10 or 9 in front based on which would bring the value closer to 1000. The pressure here is 999.8 millibars (mb).

-03: Pressure tendency the last 3 hours, to the nearest tenth of a millibar. The pressure here has fallen .3 mb the last 3 hours.

Middle Circle (filled in w/ mostly black): Cloud cover. It's mostly black showing that this station is mostly cloudy. Technically, this represents a broken sky with 7/8 of the sky covered with clouds.

Black line, extending from circle: Wind barb. It points to where the wind is coming from. The wind here is from the southwest, hence a southwest wind. The two lines extending represent 20 knot winds with each line representing 10 knots.

Symbol between 77 and 68: This is the present weather field and in this case shows that there is a thunderstorm occurring at the station.

Symbol next to -03: That line is the pressure tendency. The 1st hour the pressure was steady, then fell the last two hours.

Triangle (with a dot above it): Previous weather, or the weather one hour ago. In this case it was a light rain shower.

How does the upper air station model differ from the surface station model?
─     Temperature is given in Celsius
─     Dewpoint depression is given not dewpoint temperature
─     Altitude of the pressure surface is given instead of pressure
─     Cloud cover is not noted

─     Circles indicating station locations are often omitted


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