Cold Front Strength
What is a weak cold front? How can one determine the
trength of a cold front?
"Weak" and "strong" fronts (sometimes warm, sometimes cold) is determined
by the difference in atmospheric pressure across the direction of motion
of the atmosphere. "Weak" fronts refer to smaller pressure differences in
pressure. "Strong" fronts refer to larger differences in pressure.
Associated with such fronts is also the temperature difference. "Cold"
fronts refer to higher temperature in the direction of movement of the
front. "Warm" fronts refer to lower temperature in the direction of the
movement of the front. Large pressure/temperature differences also affect
the speed at which the pressure gradient moves with respect to the ground.
Large pressure/temperature differences usually result in faster moving
fronts. This is an oversimplification, however, because the "strength" of
a front is affected by moisture content as well as the vertical profile of
the air pressure and temperature. A front can have a larger or smaller
pressure difference depending upon the altitude. All of these atmospheric
mechanics are "feedback" mechanisms, that is, it is usually not possible
to separate the differences out -- one factor influences the affect of the
other factors -- and vice versa.
This is a great question! A weak cold front could be defined
in two ways (one or both conditions may occur):
1) When the difference in temperature in front of and behind
the front is only a few degrees.
2) When the movement of the front is very slow.
David R. Cook
Atmospheric Physics and Chemistry Section
Environmental Assessment Division
Argonne National Laboratory
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Update: June 2012