The Philippine Atmospheric, Geophysical and Astronomical Services Administration (Filipino: Pangasiwaan ng Pilipinas sa Serbisyong Atmosperiko, Heopisiko at Astronomiko,[4] abbreviated as PAGASA [pagˈasa], which means "hope" as in the Tagalog word pag-asa) is the National Meteorological and Hydrological Services (NMHS) agency of the Philippines mandated to provide protection against natural calamities and to ensure the safety, well-being and economic security of all the people, and for the promotion of national progress by undertaking scientific and technological services in meteorology, hydrology, climatology, astronomy and other geophysical sciences.

Angelo Seechi, SJ of the Vatican Observatory in Rome) which greatly aided the day and night observations of the weather.

On July 7, 1879, after data comparison with another Jesuit cleric in the West Indies, the observatory issued a warning indicating that a tropical cyclone was crossing northern Luzon.

[5][6] This reputation reached foreign shores, and other observatories began requesting for the monthly Boletin del Observatorio de Manila.

The bureau's published works on meteorology, terrestrial magnetism, and astronomy were well known and had later proven to be of great value to the American forces in the liberation of the Philippines from the Japanese during the Second World War.

[5][6] On October 4, 1943, with the establishment of the Second Philippine Republic as a puppet state of Japan during its occupation, the Weather Bureau was transferred to the Department of Public Works and Communications.

However, in the field, bureau personnel were instrumental in bringing accurate weather information over enemy-occupied territory to the combined liberation forces of the American and Filipino soldiers.

In February 1945, the Second World War brought the operations of the Weather Bureau to a halt when its offices were destroyed during the Battle of Manila.

[5][6] The rebirth of the Weather Bureau began on July 24, 1945, when it was reestablished by seven constituent personnel under the leadership of Edilberto Parulan as Officer-in-Charge.

[5] In the same year, temperature, relative humidity, and pressure observations in the upper atmosphere were made twice daily by the Laoag, Cebu and Zamboanga field stations.

Private radio systems and the then National Civil Defense Administration also helped to facilitate the reception of data and dissemination of the forecasts and warnings.

The institute provided technical in-service training at various levels while the Department offered a post-graduate course leading to a Master of Science degree in meteorology.

A telemetry system in the Marikina River Basin was then set up which led to the bureau's initial efforts in flood forecasting.

Called the "Typhoon Research Project, its launch in 1970 was made possible through the financial assistance of the National Science Development Board.

387, s. 1972, Marcos also established the Presidential Committee on Typhoon Moderation to coordinate, plan and implement programs intended to curb the severe effects of weather.

Results were inconclusive, but as with both Popeye and Stormfury, the data gathered ultimately proved helpful for meteorologists in future tracking of weather patterns and typhoon forecasts.

It sought to standardize the training of personnel and seismological equipment, as well as to improve the accuracy of determining the epicenters of earthquakes in the region.

[13] Following the re-establishment of the democratic government after the ouster of Ferdinand Marcos (see People Power Revolution) in 1986, President Corazon C. Aquino ordered the reorganization of the National Science and Technology Authority (now called Department of Science and Technology) and all agencies under its authority, pursuant to Executive Order 128, s. 1987[14] Five major branches (Weather, Flood Forecasting, Climatology & Agrometeorology, Astronomical, Geophysical & Space Science, and National Disaster Reduction) and three support divisions (Administrative, Finance & Management, and Engineering & Maintenance) now constitute PAGASA.

This organizational structure remained until October 2008, when the agency went under a Rationalization Program under Executive Order 366, s. 2004 issued by President Gloria Macapagal Arroyo.

The government initially spent ₱3 billion from Philippine Amusement and Gaming Corporation's (PAGCOR) revenues (with a three-year span) for the modernization fund of the state weather bureau, which included the upgrading and acquisition of equipment, a new salary scheme for the employees, manpower training for future weathercasters and the creation of PAGASA Data Center, among other plans.

PAGASA monitors daily rainfall and temperature data together with monthly observation of standard precipitation index, soil moisture, runoff and vegetation.

Specialized forecasts are also done by PAGASA like data gathering on regional rainfall outlook at locations of dams, watersheds, river basins, other important water reservoirs and flood-prone areas.

[20][21] PAGASA monitors tropical cyclone activity and issues warnings if they fall within the Philippine Area of Responsibility (PAR).

[27] Before Nilo's leave, an automated rain gauge was also installed in a telecommunications cellsite in Montalban, Rizal (in cooperation with Smart Communications) to monitor excess rainfall as a warning signal to avert the effects of flashfloods and landslides by using cellphones, the weather bureau plans to adopt its swift transfer of data from ground forecasting stations to main headquarters utilizing its automated data acquisition system modeled after Japan Meteorological Agency's AMeDAS in the near future as a solution to forecast inaccuracy and their problems.

The Japan International Cooperation Agency will provide modernization programs to enhance the services of PAGASA include meteorology and flood forecasting, and tornado warnings as precautionary measures.

[30] Pursuant to the Rationalization Program, PAGASA has five Regional Services Divisions (RSD) that provide localized forecasts in a select group of areas.

Under these RSDs, PAGASA disseminates regular thunderstorm advisories, heavy rainfall warnings, and special weather forecasts to more specific localities around the country, in line with the program's goal to increase its effectiveness and efficiency of public service.

Despite this, residents living in these areas were not informed of the forecast change, nor were they notified that public storm warning signal (PSWS) number 2 had been raised.

[35] As a result, Aquino criticized PAGASA for not warning the residents of Metro Manila about the strong tropical storm that struck the nation's capital.

[36] However, according to Dr. Nilo and PAGASA, the agency didn't have adequate equipment to "accurately" predict a movement of a storm and the weather forecasting instruments were too old and needed to be upgraded.