There are 17 names in this directory beginning with the letter E.Easterly Wave
A wavelike disturbance in the tropical easterly winds that usually moves from east to west. Such waves can grow into tropical depressions.
Eddy
A small volume of air that behaves differently from the predominant flow of the layer in which it exists, seemingly having a life of its own. An example of such would be a tornado, which has its own distinct rotation, but is different than the large- scale flow of air surrounding the thunderstorm in which the tornado is born.
El Ni?o
A major warming of the equatorial waters in the eastern Pacific Ocean. El Ni?o events usually occur every 3 to 7 years, and are related to shifts in global weather patterns. (Spanish for the "Christ Child", named this because it often begins around Christmas.)
Enhanced greenhouse effect
The natural greenhouse effect has been enhanced by man's emissions of greenhouse gases. Increased concentrations of carbon dioxide, methane and nitrous oxide trap more infra- red radiation, so heating up the atmosphere.
Enhanced Wording
An option used by the SPC in tornado and severe thunderstorm watches when the potential for strong/violent tornadoes, or unusually widespread damaging straight- line winds, is high.
Entrance Region
The region upstream from a wind speed maximum in a jet stream (jet max), in which air is approaching (entering) the region of maximum winds, and therefore is accelerating. This acceleration results in a vertical circulation that creates divergence in the upper- level winds in the right half of the entrance region (as would be viewed looking along the direction of flow). This divergence results in upward motion of air in the right rear quadrant (or right entrance region) of the jet max. Severe weather potential sometimes increases in this area as a result.
Equilibrium Level (or EL)
On a sounding, the level above the level of free convection (LFC) at which the temperature of a rising air parcel again equals the temperature of the environment.
Excessive Heat Warning
Issued within 12 hours of the onset of the following conditions: heat index of at least 105 degrees Fahrenheit for more than 3 hours per day for 2 consecutive days or heat index more than 115 degrees Fahrenheit for any period of time.
Excessive Heat Watch
Issued for the potential of the following conditions within 12 to 36 hours: heat index of at least 105 degrees Fahrenheit for more than 3 hours per day for 2 consecutive days or heat index more than 115 degrees Fahrenheit for any period of time.
Exit Region
The region downstream from a wind speed maximum in a jet stream (jet max), in which air is moving away from the region of maximum winds, and therefore is decelerating. This deceleration results in divergence in the upper-level winds in the left half of the exit region (as would be viewed looking along the direction of flow). This divergence results in upward motion of air in the left front quadrant (or left exit region) of the jet max. Severe weather potential sometimes increases in this area as a result
Extratropical cyclone
A storm that forms outside the tropics, sometimes as a tropical storm or hurricane changes. See table below for differences between extratropical and tropical cyclones.
Eye
The low pressure center of a tropical cyclone. Winds are normally calm and sometimes the sky clears.
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Easterly Wave
A wavelike disturbance in the tropical easterly winds that usually moves from east to west. Such waves can grow into tropical depressions.
Eddy
A small volume of air that behaves differently from the predominant flow of the layer in which it exists, seemingly having a life of its own. An example of such would be a tornado, which has its own distinct rotation, but is different than the large- scale flow of air surrounding the thunderstorm in which the tornado is born.
El Ni?o
A major warming of the equatorial waters in the eastern Pacific Ocean. El Ni?o events usually occur every 3 to 7 years, and are related to shifts in global weather patterns. (Spanish for the "Christ Child", named this because it often begins around Christmas.)
Enhanced greenhouse effect
The natural greenhouse effect has been enhanced by man's emissions of greenhouse gases. Increased concentrations of carbon dioxide, methane and nitrous oxide trap more infra- red radiation, so heating up the atmosphere.
Enhanced Wording
An option used by the SPC in tornado and severe thunderstorm watches when the potential for strong/violent tornadoes, or unusually widespread damaging straight- line winds, is high.
Entrance Region
The region upstream from a wind speed maximum in a jet stream (jet max), in which air is approaching (entering) the region of maximum winds, and therefore is accelerating. This acceleration results in a vertical circulation that creates divergence in the upper- level winds in the right half of the entrance region (as would be viewed looking along the direction of flow). This divergence results in upward motion of air in the right rear quadrant (or right entrance region) of the jet max. Severe weather potential sometimes increases in this area as a result.
Equilibrium Level (or EL)
On a sounding, the level above the level of free convection (LFC) at which the temperature of a rising air parcel again equals the temperature of the environment.
Excessive Heat Warning
Issued within 12 hours of the onset of the following conditions: heat index of at least 105 degrees Fahrenheit for more than 3 hours per day for 2 consecutive days or heat index more than 115 degrees Fahrenheit for any period of time.
Excessive Heat Watch
Issued for the potential of the following conditions within 12 to 36 hours: heat index of at least 105 degrees Fahrenheit for more than 3 hours per day for 2 consecutive days or heat index more than 115 degrees Fahrenheit for any period of time.
Exit Region
The region downstream from a wind speed maximum in a jet stream (jet max), in which air is moving away from the region of maximum winds, and therefore is decelerating. This deceleration results in divergence in the upper-level winds in the left half of the exit region (as would be viewed looking along the direction of flow). This divergence results in upward motion of air in the left front quadrant (or left exit region) of the jet max. Severe weather potential sometimes increases in this area as a result
Extratropical cyclone
A storm that forms outside the tropics, sometimes as a tropical storm or hurricane changes. See table below for differences between extratropical and tropical cyclones.
Eye
The low pressure center of a tropical cyclone. Winds are normally calm and sometimes the sky clears.