Is it true that the VAAC's do not issue VAFTAD's, but use them as guidance, like the PUFF and AVHRR?
If I wanted to see your forecast, then would need to look up your bulletin and the attached VAAC
chart along with the SIGMETS bulletin, or do you send the VAFTAD out as a graphic?
From
http://www.arl.noaa.gov/ready-bin/vaftadalt.pl
"Official VAFTAD guidance charts [graphics] are issued by NOAA over WAFS under
headers PHBE10 KWBC and PHBI10 KWBC. These products are available on the
Internet from NWS sites such as the
Office of Operational Systems
and the Aviation Weather Center
(AWC). The Washington VAAC also provides the charts.
SIGMETs contain the official forecast. Some domestic and U.S. Offshore
SIGMETS are issued from the AWC.
Other official volcanic ash products are the
Volcanic Ash Advisories, issued
from Volcanic Ash Advisory Centers (e.g. Washington and Anchorage)."
VAFTAD and PUFF are both dispersion models. The model output is not the
official forecast, but, analogous to meteorological model output (e.g.
AVN, ETA, MM5), provides guidance in developing the forecast. AVHRR
imagery is not a forecast, but an analysis.
Please also see a description of the Washington VAAC at
http://www.ssd.noaa.gov/VAAC/program.html,
that includes links to past VAFTAD products and Volcanic Ash Advisories.
Barbara Stunder