Yesterday, the Cook Islands Meteorological Service (CIMS) director Arona Ngari told CI News that the system was moving in the southerly direction at four knots.
The wind at the centre of the system was travelling at a speed of 35 knots, 10 knots higher than the recordings on Wednesday.
Yesterday, parts of the northern group including Penryhn and Manihiki experienced strong winds.
Residents on those islands posted videos of the effects of gale force winds which are expected to intensify, on Facebook.
Ngari said they were closely monitoring the system which he said could prove devastating for the Cook Islands, especially Rarotonga.
“The system is surrounded by the gale force winds and by the time CI News is out (today), it should be given a name.”
“At the centre of the system, the wind is travelling at 35 knots which is an indication that the system is intensifying.”
As of yesterday, the system was located about 150 miles northwest of Palmerston and was moving down a southerly track.
A weather bulletin from Regional Specialised Meteorological Centre for the Cook Islands after lunch yesterday advised a strong wind warning remained in force for all waters and land in the southern Cook Islands.
The forecast for the southern group including Rarotonga was for southeast winds of 25 to 30 knots, with gusts up to 40 knots. Rain and thunderstorms developing from the north were predicted for Rarotonga.
For Rakahanga, Manihiki, Penryhn and Suwarrow, the outlook was for damaging gale force winds with an average speed of 35 knots and gusting to 50 knots.
The bulletin also forecast periods of heavy rain and few squally thunderstorms, sea flooding in low-lying areas, high seas and moderate to heavy northerly swells for the northern group.
“An active trough of low pressure with associated clouds and rain affects Southern Cooks,” the bulletin said.
Ngari said if the system remained on track, Rarotonga was expected to face the brunt of the developing cyclone by this weekend.
The Met Service could not yet gauge the strength of the forming tropical cyclone but was asking island residents to get ready for the worst.
Meanwhile Emergency Management Cook Islands officers are on guard and ready to take appropriate actions when the weather worsens.
EMCI director Charles Carlson said his organisation was closely monitoring the system and would take necessary action as required
The Cook Islands is predicted to be hit with more cyclones than usual for this time of year because of the El Nino weather pattern which has also created widespread drought in the region.