Frequency of Issuance
WEAX/AVWX service is available for both in port
and underway periods. In port WEAX/AVWX will only
be issued if requested and if the unit is not in a port
supported by one of the NAVMETOCCOM activities
listed in NAVMETOCCOMINST 3140.1. In port
WEAX/AVWX are issued once daily.
As a ship passes from one NAVMETOCCOM
centers area of responsibility to another, the forecast
responsibility is automatically passed between the
centers. Ships will be advised when this occurs in the
Remarks section of the WEAX/AVWX message.
When WEAX/AVWX service is requested,
forecasts will be provided at least once per 24-hour
period and updated whenever a significant change in the
forecast occurs, whether caused by atmospheric
changes or changes in the ships operating area or route.
WEAX/AVWX will be issued to a unit twice daily
when located within areas bounded by wind and high
sea warnings, and when conditions exceed those
specified by a unit involved in towing, salvage, or other
unique operations that require tailored support.
During minimize, only units experiencing
conditions listed in the previous paragraph will receive
routine WEAX/AVWX. All other units will receive an
initial WEAX/AVWX when minimize is imposed.
Updates will be provided only when conditions are
forecast to exceed those listed in the previous paragraph
during the 48-hour outlook period.
Wind, sea, and tropical cyclone warnings, and so
forth will be referenced in the WEAX/AVWX message
when applicable. For more information in this area, see
Table 10-3 shows the standard format used by
NAVMETOCCOM activities responsible for providing
The WEAX/AVWX meteorological situation will
include the locations of pertinent high-and low-pressure
centers. The bearing and range from a geographical
reference point or from the unit receiving the forecast
will be specified.
Appropriate items in subparagraph 2G of table 10-3
will be included when the MOVREP indicates an
aviation unit is embarked, or if otherwise requested.
Significant convective activity within 100 nmi of the
ship will be included. AVWX forecasts will be issued
twice daily when visibility and/or ceiling is at, or
decreases below 3 nmi or 1,000 ft. If the difference
between sea and swell direction and/or height is
significant, it will be indicated.
An Alfa index forecast will be included in
subparagraph 2H of table 10-3 for light airborne
multipurpose system (LAMPS) capable ships, When
refractivity data based on upper air soundings are
available, information regarding radar/radio
performance predictions and/or refractive index
structure data tailored to the ships radar configuration
may be included in this paragraph. Requests for
refractivity data should, when possible, include a
current upper air sounding. For more information on
WEAX and AVWX support, see the U.S. Navy
Oceanographic and Meteorological Support System
Manual, NAVMETOCCOMINST 3140.1. Refer to
NWPs 65-0-1 and 65-0-2, Characteristics and
Capabilities of U.S. Navy Combatant Ships, which list
the types and characteristics of radar on USN ships.
AIRCRAFT DITCH HEADING
LEARNING OBJECTIVES: Be familiar with
the procedures for obtaining the ditch heading
product. Recognize the characteristics of the
product. Identify its uses.
Navy aircraft are routinely involved in oceanic
flights. In the event of an in-flight emergency, a pilot
must make a decision on which direction to ditch the
The NODDS ditch headings product provides a
graphic depiction, using arrows, to show the
recommended direction into which an aircraft should
land on a water surface. Directions are calculated from
0 to 359 degrees relative to magnetic north.