June 2015 Precipitation Summary

State of Hawaii

MONTH: June 2015

PREPARED: July 16, 2015

Note:  This summary uses the arithmetic mean, or average, for “normal” rainfall values.

State: [Text data table for rain gages]

Moderate trade wind conditions prevailed on most of the days in June across the main Hawaiian Islands.  Low pressure systems far north of the island chain pushed the subtropical ridge of high pressure southward closer to the state which weakened the large scale low level wind flow.  This occurred on June 5-6 and from June 26 through the end of the month allowing land and sea breezes to dominate local wind patterns.

Brief heavy showers along the Kona slopes of the Big Island produced minor flooding on the afternoon of June 10.  This was followed on June 14 by localized heavy showers enhanced from an upper level low over the state which caused minor flooding over the leeward slopes of the West Maui Mountains and the leeward Waianae slopes on Oahu. None of these events resulted in any significant property damage.

Island of Kauai : [June 2015 map] [year-to-date map]

June rainfall totals were in the below average range for most of the gages on Kauai.  The U.S. Geological Survey’s (USGS) Mount Waialeale rain gage had the highest monthly total of 21.38 inches (65 percent of average) and the highest daily total of 4.08 inches on June 15.  The Kalaheo and Hanapepe gages posted their lowest June totals in a data record going back to 1991 and 1993, respectively.

June rainfall totals were in the below average range for most of the gages on Kauai.  The U.S. Geological Survey’s (USGS) Mount Waialeale rain gage had the highest monthly total of 21.38 inches (65 percent of average) and the highest daily total of 4.08 inches on June 15.  The Kalaheo and Hanapepe gages posted their lowest June totals in a data record going back to 1991 and 1993, respectively.

Nearly all of the rain gages on Kauai had below average rainfall totals for 2015 through the end of June.  Over half of the totals were in the range of 40 to 70 percent of average.  Mount Waialeale had the highest year-to-date total of 121.11 inches (64 percent of average).

Island of Oahu: [June 2015 map][year-to-date map]

Many of the windward Koolau rainfall totals were in the near to above average range for the month of June.  The rest of the Oahu totals were mostly in the below average range.  As is usually the case, the U.S. Fish and Wildlife Service’s Oahu Forest National Wildlife Refuge (NWR) gage posted the highest monthly total of 15.24 inches (91 percent of average).  The USGS’ Moanalua rain gage had the highest daily total of 3.60 inches on June 28.

All of the rainfall totals on Oahu were in the near to below average range for 2015 through the end of June.  The Oahu Forest NWR gage had the highest year-to-date total of 80.73 inches (76 percent of average).

Maui County: [Maui June 2015 map] [year-to-date map] [Molokai/Lanai June 2015 map] [year-to-date map]

Maui County displayed a wide range of rainfall conditions with June totals ranging from 0 to 469 percent of average.  The highest monthly total was at Ulupalakua Ranch which recorded 6.75 inches (469 percent of average), making it the wettest June at this location since 1982.  The National Park Service’s Puu Alii gage on Molokai had the highest daily total of 1.10 inches on June 19.  The anomalously wet conditions from Ulupalakua Ranch to Kula is interesting considering that it is surrounded by drier than average totals at Pukalani, Kihei, and Kepuni.

Despite recent dryness is some areas, most of the rainfall totals for 2015 through the end of June were in the near to above average range across Maui County.  The USGS’ Puu Kukui gage had the highest year-to-date total through April but went out of service due to technical problems.  This difficult to reach site will hopefully be back in service soon.  The highest currently available year-to-date total was from Puu Alii on Molokai with 107.27 inches (182 percent of average).

Island of Hawaii: [June 2015 map] [year-to-date map]

Many of the gages on the Hamakua and South Kona slopes had near to above average rainfall totals for the month of June.  Pockets of near to above average rainfall also occurred in the North Kona District and in the Kau District from Pahala to Kapapala Ranch.  South Hilo, Puna, and South Kohala totals were mainly in the below average range.  The USGS’ rain gage at Kawainui Stream posted the highest monthly total of 19.10 inches (194 percent of average) while the Waiakea Uka gage had the highest daily total of 2.61 inches on June 1.  The rain gages at Kapapala Ranch and Waikii had their highest June totals since 1997 and 2005, respectively.

Rainfall totals for 2015 through the end of June fell into the near to below average range at most of the gages on the Big Island.  The rain gage at Kawainui Stream had the highest year-to-date total of 103.92 inches (133 percent of average).

Data Sources: Data used in this report are largely from National Weather Service sources including climate network weather observation stations at Lihue, Honolulu, Kahului, and Hilo, the Hydronet state network of automated rain gages, and selected Cooperative Observer sites.  Additional data come from automated rain gages operated by the State of Hawaii Department of Land and Natural Resources, the U.S. Geological Survey, the U.S. Bureau of Land Management, the U.S. National Park Service, the Department of Defense, the U.S. Fish and Wildlife Service, and the U.S. Department of Agriculture.  Averages come from the National Climatic Data Center (1981-2010 series) and the Rainfall Atlas of Hawaii (http://rainfall.geography.hawaii.edu/).  Data presented here are not certified and should be used for informational purposes only.

Kevin R. Kodama
Senior Service Hydrologist
NOAA/NWS Weather Forecast Office Honolulu