Page 278 - NS-2 Textbook

METEOROLOGY 273

EQUIVALENT WIND SPEHlS
nn Of WARNING D .... YTI~\E StG:-.tAl5 NIGHT SIGNALS
-------------r--------------
KNOTS I MPH

S\\-\ll CRAFl UP TO 33 UP TO lB

""

STO~\i 55-73

III

1[(1 &.I OR GREATER 74 OR CUATER

Storm warning signals.

Yucatan Peninsula with winds of 175 mph and a record cast presence of tmfavorable winds. These signals are now
low pressure of 26.13 inches of mercury, killing 500 peo- flown over most major marinas on the Great Lakes, other
ple and rendering 500,000 homeless as it swept across major recreational lakes in the nation, ocean beaches,
Latin America. coastal harbor marinas, and Coast Guard stations:
Cyclonic winds in the Northern Hemisphere circu- • Small craft warni1lg. One red pennant displayed by
late in a cotmterclockwise direction; those in the South- day, and a red light over a white light at night, in-
ern Hemisphere circulate clock"vise. Mariners must dicate that winds of up to 38 mph (33 knots) and
know this if it hecOInes necessary to maneuver out of a sea conditions dangerous to small craft are forecast
hurricane's path. in the area.
If you face in the same direction the storm in the • Gale warni1lg. Two red pennants displayed by day,
Northern Hemisphere is moving, winds in the right and a white light above a red light at night, indi-
semicircle are cU'culating so as to draw a vessel in that cate that winds ranging from 39 to 54. miles an
area into the path of the storm cente" This is called the haUl' (34-47 knots) are forecast.
dangerous semicircle. The wind also will tend to carry the • Storm warni1lg. A single square red flag with a
vessel along with the storm as it moves along its track. black center displayed during daytime, and two
On the other hand, winds in the left semicircle, called the red lights at night, indicate that winds of 55 mph
uavigable semicircle, tend to drive the vessel out of the (48 knots) and above are forecast.
path of the storm and help her to get behind it. • Hurrica1le wa1'lli1lg. Two square red flags with black
Maneuvering a vessel in a hun-kane consists mainly centers displayed by day, and a white light between
of determining whether she is in, or approaching, the two red lights at night, indicate that winds 74 mph
dangerous semicircle, and if she is, finding the best (64 knots) and above are forecast for the area.
method of working out of that tmdesirable position.
HURRICANE WARNING SYSTEM
STORM WARNING SIGNALS
The U.S. Hurricane Warning System was set up in 1938
Flags and pelmants hoisted at the National Weather Ser- as a cooperative effort of the National Weather Service, the
vice and other shore stations indicate the presence or fore- Navy, and the Army Air Corps. Up to that point, hurricanes