From LPA to typhoon in just a day: PAGASA explains why 'Jolina' rapidly became a fierce cyclone


Typhoon "Jolina" (international name "Conson") strengthened from a tropical depression to a typhoon just on Monday, Sept. 6.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) first spotted a low pressure area (LPA) east of Mindanao over the weekend.

Then on Monday, it developed into a tropical cyclone and was assigned a local name "Jolina."

It was first classified by PAGASA as a tropical depression at around 2 a.m. then a tropical storm at 2 p.m.

After that, at around 5 p.m, Jolina intensified into a severe tropical storm packing maximum sustained winds of 95 kilometers per hour (kph) near the center and gustiness of up to 115 kph.

Just three hours after, at around 8 p.m., the cyclone exploded into a typhoon unleashing maximum sustained winds of 120 kilometers per hour (kph) near the center and gustiness of up to 165 kph along its path.

This has prompted PAGASA to raise tropical cyclone wind signal number 3 over several areas in Eastern Visayas.

PAGASA weather specialist Ariel Rojas said typhoon Jolina's rapid intensification can be attributed to the "favorable atmospheric and oceanic conditions" over the Philippine Sea.

The typhoon's "compact" structure also contributed to its rapid development.

Aside from its quick intensification, Rojas noted typhoon Jolina's "erratic movement that led to a high track uncertainty."

As it is a compact cyclone, Rojas said weather models and observation stations had difficulty capturing the weather system's movement.

It was initially projected to make landfall over northern Luzon but PAGASA had not ruled out the possible landfall over Eastern Visayas.

So far, Jolina has made landfall three times. These were in Hernani, Eastern Samar (10 p.m.) on Monday and in Daram, Samar (2 a.m.) and Sto Niño, Samar (3:40 a.m.) on Tuesday.

After crossing the islands of southern Luzon, Rojas said that Jolina may move towards mainland Luzon.

He said it is likely that Metro Manila, Cavite, Laguna, Batangas, Rizal, Quezon, Oriental Mindoro, Occidental Mindoro, Marinduque, Romblon, and Palawan may begin to experience "deteriorating" weather conditions around Tuesday noon.

"The threat of flooding and landslides is high in low-lying areas, riverbanks, and mountainous areas especially in Bicol, Calabarzon, and Mimaropa," Rojas said.

Due to the land interaction of the typhoon, he said that Jolina may weaken and could be downgraded into a severe tropical storm.

It will likely further weaken into a tropical storm while crossing Central Luzon.

"Jolina is forecast to emerge over the West Philippine Sea before noon on Thursday (Sept. 9). Re-intensification is forecast to occur beginning on Thursday afternoon as the tropical cyclone moves west-northwestward over the West Philippine Sea towards the southern China-northern Vietnam area," PAGASA said.

Rojas said that Jolina will likely leave the Philippine area of responsibility by Friday, Sept. 10.