In googling around a bit, I found the following:
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At:
http://www.weatherzone.com.au/misc/g...y.jsp?letter=V
"Video Integrator and Processor, which contours radar reflectivity (in
dBZ) into six VIP levels:
• VIP 1 (Level 1, 18-30 dBZ) - Light precipitation
• VIP 2 (Level 2, 30-38 dBZ) - Light to moderate rain.
• VIP 3 (Level 3, 38-44 dBZ) - Moderate to heavy rain.
• VIP 4 (Level 4, 44-50 dBZ) - Heavy rain
• VIP 5 (Level 5, 50-57 dBZ) - Very heavy rain; hail possible.
• VIP 6 (Level 6, 57 dBZ) - Very heavy rain and hail; large hail possible."
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At:
http://www.garmin.com/manuals/773_Ga...deAddendum.pdf
Ok, now, from the Nextrad intensity table on page 13 of the Garmin
"400/500 Series garmin Options Displays", I learned:
GREEN means 5-30 dBZ
YELLOW means 30-55 dBZ
RED means 55-75 dBZ
So...
Green is VIP Level 1
Yellow is VIP Levels 2,3,4
Red is VIP levels 5 and 6
The radar appears to come from an aggregation of ground NEXTRAD sites,
that is beamed up via satellite based on user request messages.
O. Sami Saydjari wrote:
As I was coming into Grand Rapids (KGRR) yesterday, the controller
announced that there was a "level 5" return (or perhaps she said "cell")
on final to runway 8, so I was vectored to 35 where there were mostly
"just level 4" stuff. So, forgive my ignorance, but where are these
levels defined? I assume they have to do with what sort of radar return
they get off a cloud and therefore has to do with rain intensity. Does
a level 5 return imply that a thunderstorm is likely to be generating it?
Also, I have a GDL-49 Satellite Data Link Transceiver linked to my
Garmin 430 display. I understand (and now have seen) that these things
just are not adequate to locate big cells. Rather, they show large
areas of showers. Are these based on satellite imagery, or from
aggregated ground station data or what?
Also, how to the radar levels (1 thru 6?) relate to the colors shown on
a GDL-49 display on a Garmin 430? Does red equal level 5 or level 6? I
think only have red, yellow and green...so it seems there are not
enough colors to show 6 levels.
-Sami, N2057M, Piper Turbo Arrow III