Weather forecasters continue to look to Monday as a quite literally pivotal moment in Kilo’s progress through Hawaiian waters.

In the meantime, Hawaii residents can expect at least another day of moist, sweltering conditions as tradewinds continue to diminish through Sunday and a mass of warm tropical moisture settles over the island chain.

Kilo remained a tropical depression through Saturday but was expected to intensify back into a tropical storm by late Sunday or early Monday. Forecasters at the Central Pacific Hurricane Center said the storm could further intensify into a hurricane by the time it reaches the islands around midweek.

At 11 p.m. Saturday, Kilo was about 510 miles south-southwest of Honolulu and moving west-northwest at 16 mph. Maximum sustained winds were 35 mph with higher gusts.

Kilo has been following a ridge of high pressure, which has steered it in a west-northwesterly direction.

Forecasters say the storm will remain on its current course through Sunday with some decrease in forward speed. However, the storm is expected to take a sharp turn to the northwest and up the island chain on Monday as it hits a weakness in the ridge.

"Although Kilo has been struggling to organize thus far, the environment certainly appears to be conducive for strengthening," the Central Pacific Hurricane Center said.

A "very moist" air mass to the northeast of Kilo is spreading across the islands, which will cause rainfall that may lead to flash flooding, the National Weather Service said.

The Weather service predicted possible rainfall totals of 2 to 4 inches, with higher amounts possible in isolated areas. Flooding is possible where heavy rains fall on ground that is already saturated, particularly areas near or around mountain ranges.

A flash flood watch is in effect for all islands until 6 p.m. Monday.

On Saturday afternoon, outer rain bands from Kilo brought thunderstorms, heavy rain and localized flooding to the northern areas of Hawaii island. According to the National Weather Service, the heaviest rainfall occurred over the leeward slopes of Mauna Loa.

On Oahu, lingering showers dampened the ridges of the Koolau Mountains, extending to Manoa Valley and downtown Honolulu.

With trades diminishing throughout the day, warm and humid conditions pushed heat index values (how hot it feels based on actual air temperature and humidity) past 100 degrees Fahrenheit.

Meanwhile, Hilo set a high temperature record Saturday. The high of 90 for the date topped the previous record of 87 set in 2007.