Typhoon Betty slightly weakens; southwesterly windflow triggers heavy rain

MANILA, Philippines – Typhoon Betty (Mawar) slightly weakened over the Philippine Sea on Sunday afternoon, May 28, while the southwesterly windflow prompted rainfall warnings.

Betty’s maximum sustained winds decreased from 175 kilometers per hour to 165 km/h, said the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) in a bulletin issued at 5 pm on Sunday. Its gustiness went down from 215 km/h to 205 km/h.

As of 4 pm, Betty was located 630 kilometers east of Tuguegarao City, Cagayan. It shifted west northwest from west while maintaining its generally slow pace of 15 km/h.

Before rain from the typhoon, the southwesterly windflow had already been causing scattered rainshowers and thunderstorms, which may persist in Occidental Mindoro, Palawan, Western Visayas, Central Visayas, the Zamboanga Peninsula, Northern Mindanao, and the Bangsamoro Autonomous Region in Muslim Mindanao.

Rainfall warnings were issued for parts of the Visayas on Sunday as the southwesterly windflow dumped heavy rain.

In the coming days, Betty is expected to trigger heavy rain even though it is not seen to make landfall.

Monday afternoon, May 29, to Tuesday afternoon, May 30

100-200 millimeters (mm): eastern part of Babuyan Islands, northeastern part of mainland Cagayan
50-100 mm: Batanes, northwestern part of mainland Cagayan, northern part of Ilocos Norte, northern part of Apayao

Tuesday afternoon, May 30, to Wednesday afternoon, May 31

Greater than 200 mm: Batanes, Babuyan Islands, northern part of Ilocos Norte
100-200 mm: northern part of mainland Cagayan, rest of Ilocos Norte, Ilocos Sur, La Union, Abra, Benguet
50-100 mm: Pangasinan, rest of mainland Cagayan, rest of Cordillera Administrative Region

Wednesday afternoon, May 31, to Thursday afternoon, June 1

Greater than 200 mm: Batanes, Ilocos Sur, northern part of La Union, northern part of Benguet
100-200 mm: Babuyan Islands, Ilocos Norte, Abra, rest of La Union, rest of Benguet
50-100 mm: northern part of mainland Cagayan, Pangasinan, rest of Cordillera Administrative Region

PAGASA also maintained its forecast for the southwest monsoon or habagat, which will be enhanced by the typhoon.

Monday, May 29

monsoon rain possible in western parts of Mimaropa and Western Visayas

Tuesday, May 30

monsoon rain likely in western parts of Calabarzon, Mimaropa, and Western Visayas

Wednesday, May 31

monsoon rain likely in Western Visayas and western parts of Central Luzon and Southern Luzon

Affected areas must be on alert for floods and landslides.

For the past 24 hours, areas under Signal No. 1 have been unchanged:

Batanes
Cagayan including Babuyan Islands
Isabela
Apayao
Ilocos Norte
northern and central parts of Abra (Tineg, Lacub, Lagayan, San Juan, Lagangilang, Licuan-Baay, Malibcong, Danglas, La Paz, Dolores, Tayum, Bucay, Sallapadan, Daguioman, Bucloc, Boliney)
Kalinga
eastern and central parts of Mountain Province (Sadanga, Barlig, Natonin, Paracelis, Bontoc)
eastern and central parts of Ifugao (Mayoyao, Aguinaldo, Alfonso Lista, Banaue, Hingyon, Lagawe, Lamut, Kiangan, Asipulo)
northern and central parts of Aurora (Dilasag, Casiguran, Dinalungan, Dipaculao)
Quirino
northeastern part of Nueva Vizcaya (Kasibu, Quezon, Solano, Bagabag, Diadi, Villaverde, Bayombong, Ambaguio)

“Minimal to minor impacts caused by strong winds…are possible within any of the areas where [Signal No.1] is currently in effect. Such conditions may begin tonight or tomorrow (Sunday evening or Monday),” PAGASA said.

Signal No. 2 is the “most likely” highest wind signal to be raised due to Betty, though in a worst-case scenario, Signal No. 3 is possible.

PAGASA also said the enhanced southwest monsoon may bring occasional gusts starting Sunday evening or Monday morning to most of the Visayas, the eastern part of Central Luzon, the eastern and southern parts of Southern Luzon, and the northern part of Mindanao.

“The western portion of Luzon may also experience similar conditions beginning on Tuesday or Wednesday (May 30 or 31),” added the weather bureau.

PAGASA issued a new gale warning at 5 pm on Sunday, covering the following seaboards:

northern seaboard of Northern Luzon and eastern seaboard of Luzon – rough to very rough seas, with waves 3.7 to 6 meters high
eastern seaboards of Visayas and Mindanao – rough to very rough seas, with waves 3.4 to 5.5 meters high

The weather bureau advised small vessels not to sail and larger vessels to watch out for big waves.

Betty could head west northwest or northwest while gradually decelerating for the next 36 hours, then become slow-moving or almost stationary east of Batanes on Tuesday.

By mid-Wednesday, it could move north or north northeast toward the sea east of Taiwan. Taiwan remains within the Philippine Area of Responsibility (PAR).

Betty is expected to gradually weaken until Tuesday, and then weaken at a faster rate on Wednesday or Thursday, June 1. It could be downgraded to a severe tropical storm on Thursday.

At its peak, it was a super typhoon with maximum sustained winds of 215 km/h.

Betty, which entered PAR as a super typhoon at 2 am on Saturday, May 27, looks set to exit on Friday, June 2.

It is the country’s second tropical cyclone for 2023 and the first super typhoon of the year. – Rappler.com