Tropical Depression Perla slightly strengthens

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MANILA, Philippines – Tropical Depression Perla slightly intensified and accelerated a bit on Thursday afternoon, October 17.

In a briefing at 5 pm on Thursday, the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) said Perla now has maximum winds of 55 kilometers per hour (km/h) from the previous 45 km/h and gustiness of up to 70 km/h from the previous 55 km/h.

The tropical depression is already 840 kilometers east of Aparri, Cagayan, now moving north northwest at 15 km/h from 10 km/h on Thursday morning.

PAGASA said Perla is less likely to intensify into a tropical storm, and may even return to being a low pressure area while still inside the Philippine Area of Responsibility.

There are also no areas under tropical cyclone wind signals, so far. (READ: FAST FACTS: Tropical cyclones, rainfall advisories)

But Perla could hit land or make a close approach to extreme Northern Luzon.

The tropical depression could trigger scattered rain and thunderstorms in the following areas beginning Saturday, October 19, or Sunday, October 20:

But there is already light rain currently being experienced in Batanes and Cagayan because of the northeasterly surface windflow.

Also due to the northeasterly surface windflow, travel is risky in the northern and western seaboards of Northern Luzon, especially for small vessels.

Forecast track of Tropical Depression Perla as of October 17, 2019, 5 pm. Image from PAGASA

Forecast track of Tropical Depression Perla as of October 17, 2019, 5 pm.

Image from PAGASA

Perla is the Philippines' 16th tropical cyclone for 2019, and the 1st for October. (READ: LIST: PAGASA's names for tropical cyclones in 2019)

The country gets an average of 20 tropical cyclones annually, but since 2019 is an El Niño year, only 14 to 18 tropical cyclones are expected.

Below is the estimated number of tropical cyclones from October to December:

Meanwhile, the intertropical convergence zone (ITCZ) will also bring scattered rainshowers and thunderstorms to these areas until Friday, October 18:

PAGASA defines the ITCZ as a "series of low pressure areas brought about by converging northeast and southeast winds that cause thunderstorms and rainshowers."

Other parts of the country, not affected by the ITCZ or the northeasterly surface windflow, will continue to have fair weather. There may just be isolated rainshowers or localized thunderstorms, mostly in the afternoon or evening.

PAGASA declared the start of the rainy season last June 14. – Rappler.com