Signal No. 1 up over 17 areas as Isang to traverse Northern Luzon

Tropical Cyclone Wind Signal (TCWS) No. 1 is raised over 17 areas as Tropical Depression Isang is expected to traverse Northern Luzon, state weather bureau PAGASA said on Friday.

In its 11 a.m. bulletin, PAGASA said the following areas are under TCWS No. 1:

• Batanes
• Cagayan
• Isabela
• Quirino
• Nueva Vizcaya
• Apayao
• Kalinga
• Abra
• Mountain Province
• Ifugao
• Benguet
• Ilocos Norte
• Ilocos Sur
• La Union
• Pangasinan
• the northern and central portions of Aurora (Casiguran, Dinalungan, Dilasag, Baler, Maria Aurora, Dipaculao, San Luis)
• the northern portion of Nueva Ecija (Lupao, Carranglan, Pantabangan, San Jose City)

Isang as of 10 a.m. was spotted in the vicinity of Casiguran, Aurora packing maximum sustained winds of 55 kilometers per hour near the center and gustiness of up to 90 kph.

The tropical depression was moving westward at 15 kph.

“It will traverse Northern Luzon in the next 12 hours, emerge over the West Philippine Sea tonight, and eventually exit the Philippine Area of Responsibility tomorrow (23 August) morning or afternoon,” PAGASA said.

“ISANG is forecast to intensify into a tropical storm tomorrow morning and may reach severe tropical storm category while approaching the waters south of Hainan, China. However, intensification into a tropical storm at a much earlier time (e.g., several hours after emerging over the West Philippine Sea) is not ruled out,” it added.

Heavy downpour causes flooding in Manila on Friday, August 22, 2025. Several cities in Metro Manila have suspended classes because of the bad weather. DANNY PATA

Classes for Friday, August 22, 2025, have been suspended in some areas due to bad weather.

Caloocan - All levels, public and private (starting 12 noon)

Las Piñas - All levels, public and private

Malabon - All levels, public and private (afternoon classes)

Manila - All levels, public and private (starting 12 noon)

Marikina - All levels, public and private (afternoon classes)

Muntinlupa - All levels, public and private

Navotas - All levels, public and private (afternoon classes)

Pasay - All levels, public and private (starting 12 noon)

Pasig - kindergarten to senior high school, public and private (starting 11 am)

Parañaque - All levels, public and private

San Juan - All levels, public and private (starting 12 noon)

Sta. Rosa, Laguna - preschool to senior high school (public)

Albay - All levels, public and private

Castilla, Sorsogon - All levels, public and private

Several roads in the National Capital Region (NCR) were flooded also Friday amid the heavy rains. 

'Blue alert' 

The National Disaster Risk Reduction and Management Center (NDRRMC) has upgraded its alert status from white to blue due to the effects of tropical depression Isang. 

In a Facebook post, it said this is to “closely monitor, consolidate and to ensure prompt coordination with concerned agencies and offices.”

The NDRRMC said the raising of the alert status is to prepare for a slow onset disaster or in anticipation of a situation escalation. —VAL, GMA Integrated News