Garmin GPSMAP 8700 Black Box Owners Manual - Page 61

Weather Data Broadcasts Weather data is broadcast at different intervals for each weather feature. For example, radar is broadcast at five-minute intervals. When the Garmin receiver is turned on, or when a different weather feature is selected, the receiver must receive new data before it can be shown. You might experience a delay before weather data or a different feature appears on the chart. NOTE: Any weather feature can change in appearance if the source that provides the information changes. 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 Changing the Weather Chart 1 From a combination screen or SmartMode layout with a weather chart, select Menu > Weather Menu > Change Weather. 2 Select a weather chart. Viewing Precipitation Information Precipitation ranging from very light rain and snow, up to strong thunderstorms, is indicated in varying shades and colors. Precipitation is shown either independently or with other weather information. Select Charts > Precipitation. The time stamp in the upper-left corner of the screen indicates the elapsed time since the weather data provider last updated the information. Storm Cell and Lightning Information Storm cell are represented by the icon on the weather precipitation chart. They indicate both the present position of a storm and the projected path of that storm in the immediate future. 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 the icon. 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. 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 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. 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 12hour increments, select multiple times. • To view the weather forecast for the previous 48 hours, in 12-hour increments, select 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. PressureCenter Symbol Description Indicates a low-pressure center, which is a region of relatively lower pressure. Moving away from a lowpressure 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 highpressure center results in decreased pressure. Winds flow clockwise around high-pressure centers in the northern hemisphere. City Forecasts City forecasts appear as weather symbols. The forecast is viewed in 12-hour increments. Symbol Weather Fair (sunny, hot, clear) Partly cloudy Cloudy Rain (drizzle, sleet, showers) Thunderstorms Windy Smoke (dusty, hazy) Foggy Snow (snow showers, flurries, blizzard, blowing snow, sleet, freezing rain, freezing drizzle) SiriusXM Weather 53