Garmin 795 Manual

A SERVICE OF

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Garmin aera 795/796 Pilot’s Guide

190-01194-00 Rev. C

86

Hazard Avoidance

OverviewGPS NavigationFlight PlanningHazard AvoidanceAdditional FeaturesAppendicesIndex

NEXRAD data is not real-time. The lapsed time between collection, processing, and

dissemination of NEXRAD images can be signiﬁcant and may not reﬂect the current

radar synopsis. Due to the inherent delays and the relative age of the data, it should

be used for long-range planning purposes only. Never use NEXRAD data or any radar

data to maneuver in or near areas of hazardous weather. Rather, use it in an early-

warning capacity of pre-departure and enroute evaluation.

Composite data from all the NEXRAD radar sites in the United States is shown. This

data is composed of the maximum reﬂectivity from the individual radar sweeps. The

display of the information is color-coded to indicate the weather severity level.

The display of radar coverage is always active when NEXRAD is selected. Areas

where NEXRAD radar coverage is not currently available or is not being collected are

indicated in grayish-purple. Radar capability exists in these areas, but it is not active

or is off-line.

neXrAD AbnorMAlItIeS

There are possible abnormalities regarding displayed NEXRAD images. Some, but

not all, of those include:

•Groundclutter

•Strobesandspuriousradardata

•Sunstrobes,whentheradarantennapointsdirectlyatthesun

•Militaryaircraftdeploymetallicdust(chaff)whichcancausealterationsinradar

scans

•Interferencefrombuildingsormountains,whichmaycauseshadows

neXrAD lIMItAtIonS

Certain limitations exist regarding the NEXRAD radar displays. Some, but not all, are

listed for the user’s awareness:

•NEXRADbasereectivitydoesnot providesufcientinformation todetermine

cloud layers or precipitation characteristics (hail vs. rain). For example, it is not

possible to distinguish between wet snow, wet hail, and rain.