AIM

4/3/14

7−1−20

Meteorology

following weather products:  AWW, SIGMET,

Convective SIGMET, CWA, AIRMET (text [WA] or

graphical [G−AIRMET] products), and urgent

PIREP. HIWAS is available throughout the conter-

minous United States as an additional source of

hazardous weather information. HIWAS does not

replace preflight or inflight weather briefings from

FSS or real−time weather updates from Enroute

Flight Advisory Service (EFAS), radio call “Flight

Watch.” Pilots should call FSS or Flight Watch if

there are any questions about weather that is different

than forecasted or if the HIWAS broadcast appears to

be in error.

1.

Where HIWAS is available, ARTCC and

terminal ATC facilities will broadcast, upon receipt,

a HIWAS alert once on all frequencies, except

emergency frequencies. Included in the broadcast

will be an alert announcement, frequency instruction,

number, and type of advisory updated; for example,

AWW, SIGMET, Convective SIGMET, or CWA.

EXAMPLE

−

Attention all aircraft. Hazardous weather information
(SIGMET, Convective SIGMET, AIRMET 

(text [WA] or

graphical [G

−AIRMET] product)

, Urgent Pilot

Weather Report [UUA], or Center Weather Advisory
[CWA], Number or Numbers) for (geographical area)
available on HIWAS, Flight Watch, or Flight Service
frequencies.

2.

Upon notification of an update to HIWAS,

FSS will broadcast a HIWAS update announcement

once on all frequencies except emergency frequen-

cies. Included in the broadcast will be the type of

advisory updated; for example, AWW, SIGMET,

Convective SIGMET, CWA, etc.

EXAMPLE

−

Attention all aircraft. Hazardous weather information for
(geographical area) available from Flight Watch or Flight
Service.

3.

HIWAS availability is notated with VOR

listings in the Airport/Facility Directory (A/FD), and

is shown by symbols on IFR Enroute Low Altitude

Charts and VFR Sectional Charts. The symbol

depiction is identified in the chart legend.