Here's why Tropical Storm Jenny didn't bring as much rain

MANILA, Philippines – Tropical Storm Jenny (Podul) did not bring as much rain to Luzon as earlier feared.

According to the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA), there are two reasons for this.

No. 1: Jenny was fast

When Jenny made landfall in Casiguran, Aurora, at 10:40 pm on Tuesday, August 27, it was moving at 35 kilometers per hour (km/h).

That is considered fast for a tropical cyclone, so Jenny did not linger over land. Around 3 am on Wednesday, August 28, or just 4 hours and 20 minutes after its landfall, Jenny had already left landmass.

"Naging mabilis po 'yung takbo nitong si Jenny, kaya 'yung mga impact natin ng ulan at tsaka ng hangin ay naging mabilis din. At mas naging kokonti lang, mas nag-concentrate po do'n sa mismong dinaanan ng bagyo," said PAGASA Weather Specialist Benison Estareja in a briefing late Wednesday morning.

(Jenny was moving fast, that's why the impact of the rain and the winds were felt for only a brief period too. And there was less rainfall, it became more concentrated in areas directly in the tropical cyclone's path.)

The following areas had the highest observed rainfall from 8 am on Tuesday to 8 am on Wednesday, in terms of millimeters (mm):

"Dito sa Metro Manila, kung mapapansin natin, nagkaro'n naman ng paulan tayo, but then more on light rain lang po kahapon (Tuesday)," Estareja said.

(Here in Metro Manila, if you noticed, we had some rain, but more on just light rain yesterday.)

No. 2: Jenny weakened when it hit land

As Jenny hit land, it weakened into a tropical depression. It remained in that category while crossing Northern Luzon and only re-intensified into a tropical storm when it was already over the West Philippine Sea.

Since it was in the weakest tropical cyclone category, its effect on the southwest monsoon or hanging habagat was also not that strong.

"From tropical storm, humina siya bilang tropical depression, so 'yung enhancement ng habagat or ng southwest monsoon dito sa area ng Batangas, Cavite, Metro Manila, Zambales, Bataan ay naantala," Estareja said.

(From tropical storm, it weakened into a tropical depression, so its enhancement of the southwest monsoon here in Batangas, Cavite, Metro Manila, Zambales, and Bataan was stalled.)

Estareja noted that many had asked about the rainfall, or the lack thereof.

Jenny eventually left the Philippine Area of Responsibility at 2 pm on Wednesday. It was the country's 10th tropical cyclone for 2019, and the 3rd for August. (READ: LIST: PAGASA's names for tropical cyclones in 2019– Rappler.com