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READY logoCurrent HYSPLIT Volcanic Ash Forecast Guidance


NOTE: this web server is not maintained in an "operational" environment and should not be relied upon for 24/7 access.


Use one of the following National Weather Service (NWS) links to see the HYSPLIT model volcanic ash cloud forecast guidance for current eruptions in the Washington and Anchorage VAAC areas of responsibility .


These charts, with headers PHBE10 KWBC and PHBI10 KWBC, are issued by the NWS over WAFS. They are also made available by the NOAA Washington VAAC.

These HYSPLIT model output charts in VAFTAD-format consist of a series of maps showing the forecast ash cloud in time and space. The 4 panels in any column are for a single valid time after eruption. Individual panels are for layers applicable to aviation operations and are identified at the side of a panel with upper and lower flight levels (FL) in hundreds of ft. The bottom panel is a composite from the SURFACE to FL550. For each column, the forecast valid time separates the upper three panels from the composite panel. Volcano eruption information is at the lower left. A description of the input meteorology is at the lower right with a message to "SEE VOLCANIC ASH SIGMETS AND ADVISORIES". The ash cloud symbol and run description are at the lower center.

The HYSPLIT charts are NOT official forecasts; they are guidance only.

SIGMETs contain the official forecast: continental U.S., Alaska, Alaska-alternate, Hawaii, off-shore

Other official products are Volcanic Ash Advisories


Reference: Heffter, J.L. and B.J.B. Stunder, 1993: Volcanic Ash Forecast Transport And Dispersion (VAFTAD) Model. Wea Forecasting, 8 534-541.

Inquiries should be addressed to:
Barbara Stunder
Email: barbara.stunder@noaa.gov