258 seamanship secrets
127 degrees magnetic – 110 degrees = 017 degrees magnetic
Apply variation to convert this answer to true degrees, then plot a line in that
direction from your position. It shows you are south and slightly behind the
low’s center.WIND AND BAROMETER SIGNALS
Winds may back, veer, or stay steady—depending on where you are in location to
a center of low pressure. Barometers fall slowly or rapidly to indicate where you
are relative to the low’s center. Below is an outline of the signals you are likely to
see if the low is bearing south, north, or west of your position.
Low-Pressure Center Bears South (Northern Hemisphere)
Wind signals
Winds are backing—i.e., shift ing counterclockwise.
If the winds are southeast, the system is approaching.
If the winds are easterly, the center is due south of you.
If the winds are northeasterly, the center has passed you.Barometer signals
Th e barometer will be lower than normal and dropping slowly.
If your track parallels an isobar, the barometer will be steady, with a slight drop.
When the barometer starts to rise, the low center has passed by.Action to take (Northern Hemisphere): Head farther north or hold position.
The counterclockwise winds will help drive you away from the storm path.
Low-Pressure Center Bears North (Northern Hemisphere)
Wind signals
Winds are veering—i.e., shift ing clockwise.
If the winds are southwest, the system is approaching.
If the winds are westerly, the center is due north of you.
If the winds are northwesterly, the center has passed by.Barometer signals
Th e barometer will be lower than normal and dropping slowly.
If your track parallels an isobar, the barometer will be steady, with a slight drop.
When the barometer starts to rise, the low center has passed by.Action to take (Northern Hemisphere): Make best speed and head south to
take yourself out of the storm path. Keep heading south until the winds shift
to the northwest and the barometer begins to rise.