Wali (2014)

A small circulation that had been embedded in disorganized thunderstorm activity in the central North Pacific tightened up into a tropical depression on 17 July 2014 and was named Tropical Storm Wali shortly afterward. Wali moved slowly northwest between 17 and 19 July. It reached its peak intensity late on 17 July and early on 18 July, then began weakening later on 18 July as wind shear increased and the center became exposed. The system lost tropical cyclone status by 0000 UTC 19 July and its low-level remnant swirl dissipated soon after.

Wali did not make landfall as a tropical cyclone and there were no coastal watches or warnings issued. The center remained well southeast of the main Hawaiian Islands throughout its life and the storm dissipated over the central North Pacific on 19 July. After dissipation, a plume of remnant moisture spread westward and reached the main Hawaiian Islands on 19–20 July, producing significant weather impacts there.

The storm’s maximum sustained winds were 40 knots (about 46 mph) with a minimum central pressure of 1003 mb, corresponding to a minimal tropical storm at peak intensity. Wali was a tropical storm for only about a day and a half (four best-track points indicating tropical storm strength).

The remnant moisture produced heavy rain and flooding on windward Oahu. Multiple gauges from Kahuku to Waimanalo recorded more than 12 inches of rain over a 12-hour period ending 1900 UTC 20 July, and the Punaluu Pump gauge reported an intense rainfall rate of 4.16 inches per hour at 1015 UTC 20 July. Rough seas from convective outflow north of Maui also caused hazardous conditions in Maalaea Bay.

There were no reports of damage or casualties while Wali was a tropical cyclone. After dissipation, one fatality was reported when a swimmer was killed near Molokini Island south of Maui on 19 July due to rough seas generated by a collapsing thunderstorm. Numerous road closures and stalled vehicles were reported on windward Oahu, including sections of the Kamehameha Highway, but no flood fatalities occurred.

Forecasters initially expected more rapid intensification than occurred; the Central Pacific Hurricane Center’s short official forecasts overestimated intensity by up to 20 kt at 24 hours, and no tropical storm-force winds were observed in ship reports. Track forecasts were generally accurate for this short-lived system, and the remnant moisture that produced the heavy Hawaiian rains arrived as expected.