This is a cross section across the cold front layed
from cold to warm air. Backward inclined crowded isentropes represent the
frontal zone. However, the appearance of the isentropes in the cross-section
is not typical for a cold front. If the cross section is studied carefully
it can be seen that the cold front is actually found in upper layers whereas
near the ground (under 700 hPa) the isentropes indicate the presence of
warmer air.
Coldest cloud tops (depicted here as orange line representing IR pixel values) are clearly connected to the upper level cold front. Notice also the unstable layer in the left of the cross-section, between 750 and 650 hPa level. Very common and important feature that can be seen here is the lowering of the tropopause behind the cold front. In the upper left corner og the cross-section it can be seen that the tropopause is lowered down to 300 hPa, whereas ahead of the front (in the upper right corner) the tropopause is obviously outside the scope of the cross-section (above 200 hPa). |
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