13
Part Two: Section 2
XM Weather
•
Winds Aloft (WINDS).
The Winds Aloft
selection provides the pilot with wind speed
and direction. The winds at a given altitude
are selected in the Winds Aloft Alt below the
WINDS selection. The selected altitude is
shown along with the product time.
•
Textual Meteorological Aerodrome Reports
(METARs)
. When you zoom in to show the
airport symbol associated with the colored flag
for a graphical METAR, and move the Map
Pointer to highlight that airport, you can then
press
ENT
to see the Textual METAR page for
that airport. The Textual METAR page is one of
the airport pages of the WPT page group.
•
Graphical Meteorological Aerodrome
Reports (METARs)
. The XM Weather page (in
the NAV page group) can show colored flags
to indicate the level of current weather condi-
tions at those airports for which textual METAR
reports are available. The flags are color-coded
to indicate the severity of the current weather at
the airport: cyan for VFR conditions, green for
Marginal VFR conditions, yellow for IFR condi-
tions, or magenta of Low IFR conditions.
•
Terminal Aerodrome Forecast (TAFs).
A
TAF page is added among the airport pages of
the WPT page group. The TAF page differs from
the Textual METAR page in that it describes
forecast future weather conditions rather than
current conditions.
•
Temporary Flight Restrictions (TFRs)
. The
boundaries of areas with TFRs are outlined in
yellow on the Map and XM Weather pages of
the NAV page group. In the 500W-series, TFR
boundaries are also shown on the NAV main
page. You can obtain more information about a
TFR by bringing up the map cursor, moving the
map cursor to within the yellow outlined area,
and pressing the
ENT
key.
Weather Product Age
The age of the displayed weather product—or the
effective time of Winds Aloft predictions—is shown
in the upper right corner of the display. For example,
if NEXRAD is displayed, “0:05” indicates that the data
are five minutes old. If Winds Aloft predictions are
being displayed, “10:00” indicates the effective time
for the displayed prediction is 10:00 AM.
The data for each XM Weather product are updated
regularly from the GDL 69/69A. XM Weather products
expire after the following intervals:
Product
Expiration Interval
METARs
90 minutes
NEXRAD/Radar Coverage
30 minutes
TFRs
60 minutes
TAFs
60 minutes
Lightning
30 minutes
SCITs
30 minutes
Winds Aloft Predictions
90 minutes
When the age of the displayed XM Weather prod-
uct reaches one half of its expiration time, the color
of the displayed time changes from green to amber.
Expired XM Weather products are never displayed. In
the unlikely event that the data should expire before
a fresh update is received, the time will be dashed out
and the data removed from the display.
XM NEXRAD Weather
The National Weather Service’s network of WSR-
88D Doppler weather surveillance radars—also called
NEXRAD, for Next Generation Radar—has greatly
improved the detection of meteorological events such
as thunderstorms, tornados, and hurricanes. An exten-
sive network of NEXRAD weather radars provides
190-00356-30 Rev H
