Low Pressure System
A Low Pressure System is an area of relative pressure minimum that has
converging winds and cyclonic spin in the Northern Hemisphere. It is the
opposite of an area of high pressure or an anticyclone.
A
wave and/or an upper-level trough, often along an old, trailing frontal
boundary generally sets off low development in the Gulf along the coasts
of Texas or Louisiana. The most intense systems are associated with a pronounced
jet maximum off the Texas/Mexico border.
These
low pressure systems usually move northeasterly, bringing low ceilings
and heavy, steady rainfall ahead of the low. The rainfall potential of a well developed Gulf Low may should not be underestimated. Low pressure systems moving toward
Pensacola from the southwest pick up tremendous amounts of moisture and
can produce as much rainfall as a moderate tropical system. These lows
have been responsible for record rainfall amounts and widespread flooding
in the local area.
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