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9 GXM 30 XM Radio Smart Antenna Owner’s Manual
The Storm Cells feature displays storms as well as the storm’s projected path in the immediate future.
Marine and Automotive units also show the size of the storm cell. The direction of the red cone indicates the projected path of the
storm cell. The red bars that appear in the cone indicate where the storm will be in the future. Each bar represents 15 minutes.
Aviation units show the direction of the storm with an arrow. The tip of the arrow indicates where the storm should be in 15
minutes. Critical information about the storm cell can be viewed by selecting the storm cell with the map pointer .
Automotive and MarineAviation
XM WEATHER FEATURES > STORM CELLS
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GXM 30 XM Radio Smart Antenna Owner’s Manual 10
The Hurricanes feature shows the current position of a hurricane, tropical storm, or tropical depression, as well as its projected
path (indicated by a red line). The darkened squares that appear along the red line display the projected locations received from the
National Hurricane Center. The Center provides four forecasts at 12-hour intervals as well as a ﬁfth forecast at a 24-hour interval.
XM WEATHER FEATURES > HURRICANES
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11 GXM 30 XM Radio Smart Antenna Owner’s Manual
Marine and Automotive units shows Surface Winds with a wind barb. The wind barb is a circle with a tail. The circle points into the
wind. Wind speed is indicated by the different combination of ﬂags that are attached to the tail.
XM WEATHER FEATURES > SURFACE WINDS
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GXM 30 XM Radio Smart Antenna Owner’s Manual 12
Aviation units display winds aloft using wind barbs or a wind streamline depending on the zoom range of the map. Similar to
Marine and Automotive units, the wind barbs indicate wind speed and direction. The wind streamline indicates wind direction with
XM WEATHER FEATURES > WINDS ALOFT
Wind BarbsWind Streamline
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13 GXM 30 XM Radio Smart Antenna Owner’s Manual
This feature displays pressure isobars and pressure centers. The isobars connect points of equal pressure. Pressure readings can help
determine weather and wind conditions in an area. High pressure areas are generally associated with fair weather . Low pressure
areas are generally associated with clouds and the chance of precipitation. Isobars that are packed closely together show a strong
pressure gradient. Strong pressure gradients are associated with areas of stronger winds. Pressure units can be displayed in Millibars
(mb), Inches of Mercury (in), and Hectopascals (hPa).
Strong Pressure Gradient
XM WEATHER FEATURES > SURFACE PRESSURE