Coastal Watches and Warnings
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This display shows an approximate representation of coastal areas under
a hurricane warning (red), hurricane watch (pink), tropical storm
warning (blue) and tropical storm watch (yellow). The orange circle
indicates the current position of the center of the tropical cyclone.
The black line and dots show the National Hurricane Center (NHC)
forecast track of the center at the times indicated.
The letter inside the dot indicates the NHC's forecast intensity for that
NHC forecast tracks of the center can be in error; the average track
forecast errors in recent years were used to construct the areas of
uncertainty for the first 3 days (solid white area) and for days 4 and 5
(white stippled area). The historical data indicate the entire 5-day
path of the center of the tropical cyclone will remain within the outer
uncertainty area about 60-70% of the time. There is also uncertainty in
the NHC intensity forecasts. The intensity forecast chart and table
below provide intensity forecast and intensity forecast uncertainty
It is also important to realize tropical cyclones are not a point. Their
effects can span many hundreds of miles from the center. The area
experiencing hurricane force (one-minute average wind speeds of at least
74 mph) and tropical storm force (one-minute average wind speeds of
39-73 mph) winds can extend well beyond the white areas shown enclosing
the most likely track area of the center. The distribution of hurricane
and tropical storm force winds in this tropical cyclone can be seen in
the Cumulative Wind Distribution graphic displayed below.
This is an experimental product.
This display shows the probability, in percent, that the center of
the tropical cyclone will pass within 75 statute miles of a location during
the 72 hours beginning at the time indicated in the caption. The caption also
provides the name of the tropical cyclone and the advisory number from which
the probabilities were generated. Contour levels shown are 10%, 20%, 50%
This display shows how the size of the storm has changed, and the areas
potentially affected so far by sustained winds of tropical storm force (in
orange) and hurricane force (in red). The display is based on the wind
radii contained in the set of Forecast/Advisories indicated at the top of
the figure. Users are reminded that the Forecast/Advisory wind radii
represent the maximum possible extent of a given wind speed within
particular quadrants around the tropical cyclone. As a result, not all
locations falling within the orange or red swaths will have experienced
sustained tropical storm or hurricane force winds, respectively.
This is an experimental product. It shows the National Hurricane
Center (NHC) maximum 1-minute wind speed forecast as a broad blue line on a
chart of wind speed versus forecast period. The narrower lines, labeled 10%
and 20% (or 30%), indicate the probability that the maximum wind speed will
be some other magnitude than what the NHC has forecast. For example, the
cyclone could become stronger than the NHC has forecast, with there being a
10% chance that the wind speed will attain the level indicated by the 10%
line plotted above the NHC forecast. The probabilities are based on NHC
forecasts from 1988-1997. The data base excludes unnamed tropical
depressions. Current advisory information is shown near the bottom of the
chart. When applicable, the Saffir/Simpson Hurricane Scale is shown at
right. "Inland" is indicated for periods when the cyclone center is forecast
to be over land. "Ext" indicates that the NHC forecasts the cyclone to be
extratropical at that time.
This is an experimental product. The table shows the probability that
the maximum 1-minute wind speed of the tropical cyclone will be within any
of eight intensity ranges during the next 72 hours. It is based on the
outcomes of similar NHC wind speed forecasts during the period 1988-1997.
The data base excludes unnamed tropical depressions. NA indicates
data not available. TF indicates too few (<10) similar forecasts
during 1988-1997 to yield reliable results.