Heavy showers are forecast through this evening for the Hawaiian Islands, according to the National Weather Service, due to unstable conditions associated with an upper-level disturbance and surface trough.

More stable conditions are expected — from east to west — starting Tuesday through the second half of the week.

This morning should be partly sunny, forecasters said, while this afternoon will be mostly cloudy, with highs ranging from 87 to 92 degrees Fahrenheit and easterly winds from 15 to 20 miles per hour.

The heat index, a measure of what it feels like when temperature and relative humidity are combined, is expected to reach as high as 99 degrees in Kapolei, 97 in Kahului, 96 in Lihue, 95 in Honolulu and 91 in Hilo this afternoon.

Forecasters say conditions will gradually begin to improve over the eastern end of the state by late tonight into Tuesday, as drier air and more stable conditions move in from the east. From Tuesday night through the second half of the week, forecasters expect a return of drier, more stable conditions.

However, more moisture is expected this weekend as a trough associated with a tropical disturbance to the south moves through. That, combined with an upper-level low setting up over the state, is expected to bring light winds and more rain.

More record highs and ties, meanwhile, were set over the weekend, this time bringing Hilo into the mix.

On Sunday, a record high of 94 degrees was set in Kahului, surpassing the previous record of 92 set in 1977, according to preliminary NWS data. A high of 93 degrees in Honolulu matched the record set in 1985, and a high of 90 in Hilo tied with an old record set in 1972.

On Saturday, a high of 88 degrees in Lihue tied with the previous record set in 2017. On Friday, a record high of 88 degrees in Hilo matched the previous one set in 2013.

Since the start of September, there have been daily record highs and ties in Lihue, Honolulu And Kahului. Hilo joined the records list this month with its first record high match on Friday.

A small craft advisory for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, and the windward, leeward and southeast waters of the Big Island, remains in effect until 6 p.m. today due to east winds of 15 to 25 knots and seas of 5 to 7 feet.

As of 11 a.m. today, Kiko, which is no longer a major hurricane, was 2,035 miles east of Hilo, according to the National Hurricane Center. Kiko is expected to continue on its current track through tonight, with gradual weakening expected during the next few days.