Watches, Warnings and Advisories
     When and where severe or hazardous weather is either occurring or possible, the National Weather Service issues a forecast in the form of a watch or warning.  The
 public, however, is not always certain as to what this forecast actually means.  For example, a high wind warning indicates that there will be high winds–but how high
 and for how long?  The following table describes a few of the various watches, warnings, and advisories issued by the National Weather Service and the necessary
 precautions that should be taken during the event.
      In general, a watch is a NWS statement indicating that a particular hazard is possible, i.e., that conditions are more favorable than usual for its occurrence. A watch
 is a recommendation for planning, preparation, and increased awareness (i.e., to be alert for changing weather, listen for further information, and think about what to do
 if the danger materializes).  A warning is a NWS statement indicating that a particular weather hazard is either imminent or has been reported. A warning indicates the
 need to take action to protect life and property. The type of hazard is reflected in the type of warning (e.g., tornado warning, blizzard warning). An advisory is a NWS
 statement that discusses weather situations of inconvenience that do not carry the danger of warning criteria, but, if not observed, could lead to hazardous situations. 
 Examples include snow advisories stating possible slick streets, or fog advisories for patchy fog condition causing temporary restrictions to visibility.

 High Wind Warning–is issued when sustained winds
 are at least 40 mph, or wind gusts exceed 57 mph.
 Caution should be taken when driving high-profiles
 vehicles, such as trucks, trailers and motor homes.

 Wind-Chill Advisory–is issued for wind-chill
 temperatures of -30°F to -35°F or below.

 Heat Advisory/Warning–is issued when the daytime
 heat index is expected to reach 105°F for 3 hours or
 move and nighttime lows do not drop below 80°F.  A 
 Warning is issued when the heating index reaches
 115°F or higher.

 Flash-Flood Watch–is issued when heavy rains may
 result in flash flooding in the specified area.  Be alert
 and prepared for the possibility of a flood emergency
 that will require immediate action.

 Flash-Flood Warning–is issued when flash flooding
 is occurring or is imminent in the specified area. Move
 to safe ground immediately.

 Urban and Small Stream Advisory–is issued when
 flooding is occurring in small streams, streets, or in
 low-lying areas, such as railroad underpasses and
 urban storm drains.

 Severe Thunderstorm Watch–is issued when
 thunderstorms (with winds exceeding 57 mph and/or

 Severe Thunderstorm Warning–is issued when
 severe thunderstorms have been visually sighted or
 indicated by radar.  Be prepared for lightning, heavy
 rains, strong winds, and large hail.  (Tornadoes can
 form with severe thunderstorms.)

 Tornado Watch–is issued when tornadoes may
 develop within a specified area during a certain time
 period.

 Tornado Warning–is issued to alert people that a
 tornado has been spotted either visually or by radar. 
 Take shelter immediately.

 Snow Advisory–is issued in non-mountainous areas
 when a snowfall is expected of 2 inches or more in 12
 hours or 3 inches or more in 24 hours.

 Winter Storm Warning (formerly Heavy Snow
 Warning)–is issued in non-mountainous areas when
 a snowfall is expected of 4 inches or more in 12 hours
 or 6 inches or more in 24 hours.  (Where heavy snow
 is infrequent, a snow fall of several inches may justify
 a warning.)

 Blizzard Warning–is issued when falling or blowing
 snow and winds of at least 35 mph frequently restrict
 visibility to less than one-quarter mile for several hours.

 Dense Fog Advisory–is issued when fog limits
 

Warnings over the Water

Small Craft Advisory	Gale Warning	Storm Warning	Hurricane Warning

Small Craft Advisory–is issued to alert mariners that weather or sea conditions might be hazardous to small boats.  Expect winds of 18 to 34 knots (21 to 39 mph). The figure above displays the posted advisory and warning flags.

Gale Warning–is issued when winds may range
between 34 and 47 knots (39 to 54 mph) in the forecast area.

Storm Warning–is issued when winds in excess of 47 knots (54 mph) are expected in the forecast area.

Hurricane Watch–is issued when a tropical storm or hurricane becomes a threat to a coastal area.  Be prepared to take precautionary action in case hurricane warnings are issued.

Hurricane Warning–is issued when it appears that a hurricane will strike an area within twenty-four hours.  Expect wind speeds in excess of 64 knots (74 mph).