2008 REED’s East Coast Edition - Weather
Figure 2 The first key to decoding weather maps is a firm grasp of the symbols employed, the
basics of which are illustrated above.
the front. The temperature will remain passage of a cold front due to instability in
fairly constant before a cold front arrives the atmosphere, as mentioned above.
but will often fall rapidly behind the front, The dew point will hold steady or rise
sometimes at rates of 5º to 10º F per hour. slightly as a cold front approaches. Then it
The clouds accompanying a cold front are will likely fall quickly, sometimes even faster
cumulus in nature and, although some may than the temperature, as cold, dry air moves
advance some 50 to 100 miles ahead, most in behind the front. Showers at the cold front
are found close to the actual front. The cloud usually occur only in close proximity to the
pattern is not as regular as with a warm front. During winter in the mid-latitudes,
front. The time interval between the clouds’ precipitation may change from rain to snow
first appearance and the passage of the front and then snow flurries behind a cold front.
are usually shorter (measured in hours rath-
Recognizing Warm Fronts
er than days) than with a warm front. Small
cumulus clouds often appear just after the
A warm front introduces a low-pressure
area with its warmer, and usually moister, air.
The barometric pressure will usually drop at
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