Operation Manual

Red cones appear with a storm cell icon, and the widest part of
each cone points in the direction of the projected path of the
storm cell. The red lines in each cone indicate where the storm
will most likely be in the near future. Each line represents 15
minutes.
Lightning strikes are represented by . Lightning appears on the
weather precipitation chart if strikes were detected within the last
seven minutes. The ground-based lightning detection network
detects cloud-to-ground lightning only.
NOTE:
This feature is not available on all devices and in all
subscriptions.
Hurricane Information
The weather Precipitation chart can show the present position of
a hurricane
, a tropical storm, or a tropical depression. A red
line stemming from a hurricane icon indicates the projected path
of the hurricane. Darkened dots on the red line indicate the
projected locations through which the hurricane will pass, as
received from the weather data provider.
Weather Warnings and Weather Bulletins
When a marine weather warning, weather watch, weather
advisory, weather bulletin, or other weather statement is issued,
shading indicates the area to which the information applies. The
aqua lines on the chart indicate the boundaries of marine
forecasts, coastal forecasts, and offshore forecasts. Weather
bulletins may consist of either weather watches or weather
advisories.
To view information about the warning or bulletin, select the
shaded area.
Color Marine Weather Group
Cyan Flash Flood
Blue Flood
Red Marine
Yellow Severe Storm
Red Tornado
Forecast Information
The Forecast chart shows city forecasts, marine forecasts,
warnings, hurricane warnings, METARS, county warnings,
weather fronts and pressure centers, surface pressure, and
weather buoys.
Viewing Forecast Information for Another Time Period
1
Select Charts >
Forecast
.
2
Select an option:
• To view the weather forecast for the next 48 hours, in 12-
hour increments, select Next Forecast multiple times.
• To view the weather forecast for the previous 48 hours, in
12-hour increments, select Previous Forecast multiple
times.
Weather Fronts and Pressure Centers
Weather fronts appear as lines that indicate the leading edge of
an air mass.
Front Symbol Description
Cold front
Warm front
Stationary front
Occluded front
Trough
Pressure-center symbols often appear near weather fronts.
Pressure-
Center
Symbol
Description
Indicates a low-pressure center, which is a region of
relatively lower pressure. Moving away from a low-
pressure center results in increased pressure. Winds
flow counterclockwise around low-pressure centers in
the northern hemisphere.
Indicates a high-pressure center, which is a region of
relatively higher pressure. Moving away from a high-
pressure center results in decreased pressure. Winds
flow clockwise around high-pressure centers in the
northern hemisphere.
Viewing a Marine Forecast or an Offshore Forecast
1
Select Charts
> Forecast
.
2
Pan the chart to an offshore location.
The Marine Forecast or Offshore Forecast options appear
when forecast information is available.
3
Select
Marine Forecast or Offshore Forecast.
City Forecasts
City forecasts appear as weather symbols. The forecast is
viewed in 12-hour increments.
Symbol Weather Symbol Weather
Partly cloudy Fair (sunny, hot, clear)
Cloudy Rain (drizzle, sleet, showers)
Windy Foggy
Thunderstorms Snow (snow showers, flurries,
blizzard, blowing snow, sleet,
freezing rain, freezing drizzle)
Smoke (dusty, hazy)
Viewing Sea Conditions
The
Sea Conditions feature shows information about surface
conditions, including winds, wave height, wave period, and wave
direction.
Select
Charts
> Sea Conditions
.
Surface Winds
Surface wind vectors appear on the Sea Conditions chart using
wind barbs that indicate the direction from which the wind is
blowing. A wind barb is a circle with a tail. The line or flag
attached to the tail of the wind barb indicates the wind speed. A
short line represents 5 knots, a long line represents 10 knots,
and triangle represents 50 knots.
Wind Barb Wind Speed Wind Barb Wind Speed
Calm 20 knots
5 knots 50 knots
10 knots 65 knots
15 knots
Wave Height, Wave Period, and Wave Direction
Wave heights for an area appear as variations in color. Different
colors indicate different wave heights, as shown in the legend.
The wave period indicates the time (in seconds) between
successive waves. Wave period lines indicate areas that have
the same wave period.
Wave directions appear on the chart using red arrows. The
direction of each arrow pointer indicates the direction in which a
wave is moving.
38 SiriusXM Weather