The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) warned of thunderstorms and rain showers affecting the entire country today as moisture-laden winds from the Pacific Ocean create unstable atmospheric conditions across the archipelago.
In its 24-hour forecast released at 4:00 AM April 21, 2026, and effective until 4:00 AM tomorrow, the state weather bureau attributed the widespread weather disturbances to easterlies—warm, humid air masses originating from the Pacific that are currently influencing Southern Luzon, Visayas, and Mindanao regions.
Nationwide Weather Pattern
Every region across the Philippines will encounter partly cloudy to overcast conditions accompanied by scattered rain showers and thunderstorm activity during the day. PAGASA's meteorological assessment reveals that while weather impacts remain similar throughout the country, the atmospheric mechanisms driving these conditions differ between northern and southern areas.
The weather agency issued particular warnings about potential flash flooding and landslide occurrences during intense thunderstorm episodes, stressing the importance of community vigilance and emergency preparedness across all vulnerable locations.
Luzon Regional Forecast
Metro Manila and surrounding areas including CALABARZON (Cavite, Laguna, Batangas, Rizal, and Quezon), MIMAROPA (Occidental Mindoro, Oriental Mindoro, Marinduque, Romblon, and Palawan), and Bicol Region will encounter partly cloudy to overcast skies with intermittent rain showers and thunderstorms driven by easterly wind patterns.
Northern Luzon provinces spanning the Cordillera Administrative Region, Ilocos Region, and Cagayan Valley will experience comparable weather conditions—partly cloudy to overcast skies with scattered rainfall and thunderstorm development. However, these atmospheric disturbances stem from localized convective activity rather than the easterly influence affecting southern territories.
Residents throughout Luzon should prepare for similar weather impacts and maintain equivalent levels of meteorological awareness regardless of the underlying atmospheric causes in their specific areas.
Visayas and Mindanao Conditions
The complete Visayas archipelago, covering Western Visayas, Central Visayas, and Eastern Visayas, will experience identical weather patterns. Provincial areas including Aklan, Antique, Capiz, Guimaras, Iloilo, Negros Occidental, Bohol, Cebu, Negros Oriental, Siquijor, Biliran, Eastern Samar, Leyte, Northern Samar, Samar, Southern Leyte, and Tacloban City should anticipate periodic rainfall and thunderstorm occurrences.
Throughout Mindanao, partly cloudy to overcast conditions with isolated precipitation and thunderstorm activity will prevail due to continuing easterly influences. Affected regions include Zamboanga Peninsula, Northern Mindanao, Davao Region, SOCCSKSARGEN, CARAGA, and the Bangsamoro Autonomous Region in Muslim Mindanao.
Marine and Coastal Conditions
PAGASA projects variable wind patterns and wave conditions across Philippine waters, with eastern coastal zones experiencing more pronounced effects from easterly wind influence.
Eastern coastlines of Southern Luzon, Visayas, and Mindanao will encounter moderate northeast to easterly winds, creating coastal wave conditions ranging from 1.5 to 2.5 meters in height. Maritime operators and fishing vessels should implement appropriate safety measures when navigating these waters.
Northern and Central Luzon areas will experience light to moderate easterly to southeasterly winds, producing slight to moderate coastal conditions with wave heights between 0.6 and 2.5 meters. These conditions present more favorable circumstances for marine operations compared to eastern coastal territories.
Remaining coastal areas nationwide will encounter light to moderate easterly to northeasterly winds, also creating slight to moderate wave conditions. While these areas should maintain manageable conditions for maritime activities, standard nautical safety procedures remain recommended.
Temperature and Atmospheric Data
PAGASA's monitoring station at Science Garden in Diliman, Quezon City, documented temperature variations during the 24-hour observation period concluding at 8:00 PM yesterday. Peak temperature measurements reached 33.3 degrees Celsius at 4:20 PM, while minimum readings dropped to 26.7 degrees Celsius at 5:00 AM.
Relative humidity measurements varied between 68 percent (recorded at 5:00 AM) and 45 percent (documented at 4:00 PM), demonstrating normal daily fluctuations in atmospheric moisture content.
Public Safety Guidelines
Considering the projected weather conditions, PAGASA stresses the critical importance of community preparedness, particularly concerning flash flood and landslide risks during severe thunderstorm events. Residents in flood-prone areas, riverside communities, and mountainous locations should exercise heightened caution.
Disaster management agencies and local government units should maintain close coordination with communities to ensure effective emergency response capabilities during extreme weather occurrences. Emergency evacuation procedures should undergo review while communication systems remain operational.
Vehicle operators should implement enhanced safety measures during rainfall periods, reducing travel speeds and increasing following distances. Pedestrians should seek appropriate shelter during thunderstorm activity and avoid traversing flooded roadways where water depth remains unknown.
Economic and Transportation Impact
Agricultural sectors should implement protective measures for crops and livestock where feasible, while construction operations and outdoor work environments should establish weather-appropriate safety standards.
The varying wind and wave patterns across different coastal regions require careful consideration from shipping operators. While eastern shorelines face moderate conditions with elevated wave heights, most remaining areas maintain acceptable conditions for maritime transportation.
Aviation operations and passenger travel may experience potential delays or route modifications due to thunderstorm activity, particularly during afternoon and evening periods when convective weather typically reaches peak intensity.
Fishing operations in eastern waters should monitor weather developments closely and consider modifying departure schedules or operational locations based on local conditions and wave predictions.
Extended Weather Outlook
Current atmospheric patterns demonstrate characteristic easterly influence typical for this seasonal period, transporting Pacific moisture across Philippine territory. While today's conditions indicate generally manageable weather overall, the possibility of severe localized thunderstorm development necessitates continuous monitoring.
Meteorological conditions may shift rapidly during thunderstorm formation, making persistent weather surveillance crucial for public safety and operational planning across all economic sectors.
Citizens should monitor official PAGASA bulletins at pagasa.dost.gov.ph for current weather updates and advisory warnings.