qBands may be as long as
500 km (300 mi) usually about
300-500 km (180-300 mi) in advance of
cold fronts.
qStrong vertical wind
shear is essential to the development of
these prefrontal waves as it ensures
that updrafts will be positioned ahead of
the downdrafts.
qThis feeds moisture
into the system which is also aided by
gust front propagation ahead of
the situation.
q