February Rainfall Totals Below Average
With just two months left of the rainy season, only December has so far provided wet conditions, according to a National Weather Service hydrologist. And the Big Island hasn’t escaped the dry conditions.
Since early January, the central North Pacific has been stuck in a weather pattern with the jet stream splitting to the north of the state, and the main Hawaiian Islands mostly under the dry and stable portion of the large scale circulation, reported Kevin Kodama, NWS senior service hydrologist, in his monthly precipitation summary for February.
“During the month of February, this has produced a higher than normal frequency of trade winds, but with wind speeds only at light to moderate intensities,” wrote Kodama in the summary. “The trade wind inversion has also been rather low during most of the days, which has restricted the vertical growth of clouds, resulting in lower than average amounts of rainfall across the state.”
February rainfall totals were below average at nearly all of the rain gages on the Big Island, according to the summary, with many of the totals less than 50% of average. Only isolated gauges in the South Kohala, Puna and Ka‘ū had near to above average totals.
Among the automated gauges, Waiākea Uka had the highest monthly total of 8.27 inches, or 65% of average. However, the highest overall total came from the Wainaku CoCoRaHS site with a manually recorded February total of 9.65 inches.
The highest daily total was from Glenwood, with 2.55 inches on Feb. 19. Kahua Ranch and Hakalau logged their lowest February totals since 2000 and 2010, respectively.
Rainfall totals for 2022 on the Big Island through the end of last month were below average at all gauge sites. The Pāpaʻikou Well gauge had the highest year-to-date total of 11.75 inches, or 41% of average.
There was some relief from the dry conditions last month, but only briefly.
During the middle of the month, a low pressure system aloft centered northeast of the state provided enough instability to enhance rainfall over portions of the Big Island and Maui County.
During the night of Feb. 13, heavy rainfall produced minor flooding along the Hāmākua Coast. According to the summary, rain gauges and radar data indicated 2-4 inches of rainfall from Laupāhoehoe to Honoka’a. A rock slide at Maulua Gulch near Laupāhoehoe briefly closed the Māmalahoa Highway.
Another bout of heavy rainfall occurred during the afternoon of Feb. 15, in this case along the slopes of the Ka‘ū District and over the ‘Ulupalakua area of Haleakalā on Maui. Rainfall amounts of 1-3 inches produced minor flooding, with no reports of significant impacts.
The prolonged dryness since early January also has resulted in the return of moderate to severe drought to most of the state because of very low rainfall, stream flow levels and deteriorating pasture conditions.
For the latest drought information throughout the state, refer to the Drought Information Statement.