Wind Direction And Wind Speed Measurement - La Crosse Technology WS-1611T Operation Manual

Professional weather center

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Air pressure

changes in inHg

The horizontal axis represents the last 12 hours air pressure recording (-12, -9, -6, -3

and 0 hour). The bars are plotted at each of the 5 steps and give the trend over the

recorded period. The scale on the right compares the result. The "0" in the middle of

this scale determines the current air pressure.

The vertical axis represents the air pressure changes in inHg (+0.12, +0.06, 0, -0.06, -

0.12. The "0" represents the current air pressure). The newly measured pressure was

compared to the previously recorded pressure reading. The pressure change

is expressed by the difference between the current ("0h") and the past readings in

division of ±2 hPa or ±0.06 inHg. If the bars are rising it indicates that the weather is

getting better due to an increase in air pressure. If the bars go down it indicates a drop

of the air pressure and the weather is expected to get worse from the present time "0".

At every full hour the current air pressure is used as a basis for the display of a new

graph bar. The existing graph is then moved one column to the left.

Note:

For accurate barometric pressure trend, the Weather Center should operate at the

same altitude. For example, it should not be moved. Should the unit be moved, for

instance from the ground to the second floor of the house, the readings for the next

12-24 hours shall be discarded.