Vetus Meteoliner Anleitung Seite 42

9-6 A secondary low causes a disturbance
Secondary lows created by cold fronts are one of the banes of a
weather-man's life, upsetting even the best-made forecasts - quite
simply because there is no way of seeing them coming a day in
advance, bot only a very short time before they actually form.
The scenario begins harmlessly enough, with a cold front passing
over 'to plan'. All of a sudden, for no apparent reason. the front
stops in its tracks somewhere, sometimes even retreating a few
kilometres, before forming a new low of its own.
As the cold front passes over, there is the expected turn-around
in the pressure tendency, and the pressure starts rising rapidly.
After only half an hour or so, however, this welcome pressure rise
loses momentum and peters out. This is the first warning signal
on the baroscope!
If you don't want to spend the next 24 hours in the rain, now is the
time to act. Later on, if the pressure even starts dropping again.
it's definitely too late - you're already right in the middle of the bad
weather.
42
10.0801
Date
Time scale (past 24 hours)
N.B.: If the air pressure behind the cold front drops by more than
one hPa per hour, then a severe storm is brewing.
Pressure
Time
in hPa
Baroscope