Vog Forecast Discussion for 11:00 AM HST Thursday, Feb 15th 2018

Summary:

Vog is limited in areal extent to the Island of Hawai'i through Friday (2/16). Late Friday night (2/16) into next week, vog is likely to affect the Island of Hawai'i and the rest of the island chain, beginning with Maui (2/16), then Molokai, Lanai, and Oahu (2/17) and eventually Kauai (2/18). In short, vog is expected to affect the entire island chain well into next week.

The primary pollutants in vog are sulfur dioxide gas and fine particulate matter. See the Vog Dashboard for information and protective measures for vog: www.ivhhn.org/vog

Current Measured Conditions:

As of 11:00 AM HST on Thursday, Feb 15th 2018, Hawaii Volcanoes National Park (HVNP) Visitor Center, Hilo and Mountain View each report 0.03, 0.04, and 0.01 ppm of SO2, respectively.
For current conditions, please see: http://weather.hawaii.edu/vmap/current/index.cgi.

Island of Hawai'i Forecast:

A breakdown in the trade winds means vog conditions may occur across the Hamakua coast of the Island of Hawai'i through early next week. Particularly affected are communities along the southern and eastern coasts, from Pahala to Hilo, the Hawaiian Volcanoes National Park (HVNP), lower Puna, and the entire Hamakua coast are the most likely to be affected. The Kona coast is likely to be affected as well from Saturday (2/17) into next week.

The primary pollutants in vog are sulfur dioxide gas and fine particulate matter. See the Vog Dashboard for information and protective measures for vog: www.ivhhn.org/vog

State-wide Forecast:

Widespread vog across the state is expected throughout the state. Maui will begin to be affected starting the night of 2/16. All of Maui county and Oahu will be affected the morning of 2/17. The entire island chain will be affected by 2/18. Vog conditions are expected to remain in place well into next week.

Forecast issued by: L. D. Holland

Revisit this page periodically for updates as forecast conditions change.

 

Visit Steven Businger's Hawaiian Weather Blog for discussions of recent vog episodes.

 

News and Items of Interest

Vog Climatology

The transport of volcanic aerosols, or volcanic smog (Vog), is primarily controlled by two factors - (1) the wind direction and (2) the height of the tradewind temperature inversion. The winds determine which direction the vog will be transported. Typically the winds in Hawaii are out of the northeast or east, as demonstrated by the graph below. This results in the vog being transported around the southern tip of the Big Island of Hawaii. The winds wrap around the westside of Hawaii and are often found over Kailua-Kona during these periods. When the winds are southerly, or are light, the vog is transported north over the northern end of Hawaii and across the northern islands of Maui, Molokai, Lanai, Oahu, Kauai, and Niihau. Again, from the graph below it can be seen that this will most likely occur during the winter months but can also happen in the spring and autumn. It is least likely to occur in summer (June, July, August) whenthe northeast trade winds are most persistent. The tradewind temperature inversion determines how high the vog can mix in the atmosphere. The trade wind inversion is typically between 2000 meters (6500 feet) and 2500 meters (8200 feet). Since the volcanic emissions are quite hot when they exit the vents the gas and aerosols rise quite rapidly, however, they mix with the surrounding air and cool just as fast. This results in large amounts of vog at higher elevations where it is trapped by the tradewind inversion, which it cannot mix across. Regions downwind of the volcano, be it to the south or north, are thus greatly effected near the base of the tradewind inversion and may experience high concentrations of vog periodically.

 

Photograph by M. Poland, November 13, 2008, USGS HVO.