What is severe weather?

Dense Fog Advisory

A dense fog advisory is issued when fog that reduces visibility
to 1/4 mile or less is possible in the advisory area.


Flood Warning

A flood warning is issued when flooding is occuring or is about to occur.


Flood Watch

A flood watch is issued when flooding is possible in the watch area.


Fire Weather Advisory

A fire weather advisory is issued when dry conditions in the advisory area result
in a situation where forest or brush fires are possible.


Heat Advisory

A heat advisory is issued when the heat index is expected to
exceed 105å¼ F (100å¼ F in New York City) or if nighttime lows are
expected to be greater than 80å¼ F for two or more nights.


Hurricane Local Statement

This statement is issued when it is necessary to inform the public
of hurricane or tropical storm watches and warnings. These statements
contain detailed information of when and what adverse conditions to
expect as a result of the tropical system affecting the statement area.


High Wind Advisory

A high wind advisory is issued when sustained winds of 31 mph or greater are expected to occur for at least
1 hour. This advisory can also be issued if winds of 46 mph or greater are expected for any length of
time.


Severe Thunderstorm Warning

A severe thunderstorm warning is issued when a storm with any
of these severe weather criteria is approaching the warning area:


  • hail 3/4 of an inch or greater

  • winds greater than 58 mph

  • recent history of tree, telephone pole, or other structural damage



Severe Thunderstorm Watch

A severe thunderstorm watch is issued when there is a possibility
that thunderstorms in and near the watch box area may produce the following
severe weather conditions:


  • hail 3/4 of an inch or greater

  • winds greater than 58 mph




Tornado Warning


A tornado warning is issued when a funnel cloud has been spotted or
a rotating thunderstorm has been indicated by doppler radar.


Tornado Watch

A tornado watch is issued when thunderstorms in and
near the watch box area may produce tornadoes.


Winter Weather Advisory

A winter weather advisory is issued when significant accumulations
of snow, sleet, or freezing rain may affect the advisory area.




Frequently asked questions about tornadoes



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