Wind Speed Measurement; Rainfall Measurement - La Crosse Technology WS-1912 Instruction Manual

Weather center

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will not mistake the new location as being a possible change in air-pressure when really it

is due to the slight change of altitude.

WEATHER TENDENCY INDICATOR

Working together with the weather icons is the weather tendency indicators (located on the

left and right sides of the weather icons). When the indicator points upwards, it means that

the air-pressure is increasing and the weather is expected to improve, but when indicator

points downwards, the air-pressure is dropping and the weather is expected to become

worse.

Taking this into account, one can see how the weather has changed and is expected to

change. For example, if the indicator is pointing downwards together with cloud and sun

icons, then the last noticeable change in the weather was when it was sunny (the sun icon

only). Therefore, the next change in the weather will be cloud with rain icons since the

indicator is pointing downwards.

Note:

Once the weather tendency indicator has registered a change in air pressure, it will remain

permanently visualized on the LCD.

AIR PRESSURE HISTORY (ELECTRONIC BAROMETER WITH

BAROMETRIC PRESSURE TREND)

The bottom section of the LCD also shows the relative air pressure value and the air

pressure history.

The bar graph of the electronic barometer shows the air pressure history of the past 12

hours in five 3-hour steps.

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.

Air pressure

changes in hPa

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 48-60 hours shall be

discarded..