Ask A Scientist© Weather Archive

  >   name        Carol
  >   status      other
  >   age         50s

  >   Question -  What causes humidity to be so high in areas such as
  > Baltimore and lower in areas such as Maine or New England States?



 >Carol,
 >
 >The further north, the more likely that moist air
 >from the Gulf of Mexico or the gulfstream Atlantic
 >will not reach you. Baltimore and other coastal
 >locations are more likely to be humid because of
 >the proximity of the ocean (this can be true even
 >along the coastline of Maine during a Bermuda high
 >pressure event). However, high pressure areas
 >centered off of the east coast allow large amounts
 >of water vapor to accumulate, particularly in the
 >southeastern and middle Atlantic states, and along
 >the seaboard as wet air blows in off of the ocean.
 >More inland and northern areas receive mostly
 >continental air (from the landmass) and this air
 >has not normally accumulated as much moisture.
 >
 >You can get an idea of the amount of moisture in
 >the atmosphere by looking at an infrared water vapor
 >satellite view at either the Intellicast or Weather
 >Channel web sites. The water vapor shown is
 >throughout the depth of the atmosphere, but most
 >water vapor is in the lowest level, the Troposphere,
 >where we live.
 >
 >David Cook
 >meteorologist at Argonne Nat. Lab.
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