Weather: PAGASA February 2016 Rainfall Map

INTRODUCTION. The El Niño (lit. the little boy) is an unusual rise in the sea surface temperature along the Pacific Ocean, which brings changes in weather patterns across much of the countries facing the Pacific. In the Philippines, El Niño means lower amount of rainfall which may result in dry spell and drought. As early as 2014, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA, the Philippine official weather agency) has been warning the public of an imminent El Niño, only in mid-2015 did they confirm the country is experiencing “mild El Niño,” and is in danger of facing hotter and drier months.

The peak of this El Niño phenomenon was estimated to be between January-March of 2016. In order to give more detailed findings on the effects of El Niño, I obtained images/maps from PAGASA website and found the monthly rainfall maps. Rainfall maps are one of the most convenient ways of depicting how much rain a particular area received in a span of time. This is a way of easily informing the public of the actual amount of rainfall in the past days/months, so the public can use these to make inference on water security, irrigation, farm production, as well as floods and landslides.

I was not able to save the January 2016 Rainfall Map. So I decided to begin with what I have, the February 2016 map.

MAP BACKGROUND. Based on the rainfall observation gathered by the PAGASA from its numerous weather stations around the country for the duration of 1-29 February 2016, the weather bureau released its final rainfall map for February 2016.

The image shows the Normal Rainfall Rate (left map), Actual Rainfall observed for the period of Feburary 1-29, 2016 (middle), and the percent of normal for the same period (right map).
(obtained from PAGASA-DOST website)

The leftmost map shows the average rainfall rate received by each area in the Philippines based on its observations in every February between 1981 and 2010; the darker the color, the area shall expect more rain for this particular month. The actual monthly rainfall for February 2016 is shown at the middle column, while the percent of normal (%N) is at the rightmost column. The purpose of showing the %N is to give us an idea if the rain we received for the entire month is normal (just right) or not (excessive or deficient).

Simple computation for the %N is as follows:

For example, General Santos City in Mindanao is expected to receive around 75 millimeters (mm) of rain for Febraury. The actual observation for February 2016 for that city is only 20mm. We compute by stating that “Actual Observation” must be divided by the “Average Monthly Rainfall”. So, it will be 20mm divided by 75mm, and it will give us ~0.2667 as result. Remember, 0.2667 is also 26.67%. Therefore, this 2016, General Santos City only received 26.67% of the normal rainfall for the month of February.

According to PAGASA,

If you get…	Then, the actual rainfall for the month is…	PAGASA Color Code
0% - 40%	…way below normal, in other words, the area did receive little to nothing.	Red
41% - 80%	…below normal. The area is rain deficient.	Yellow
81% - 120%	…near normal, so a little more or a little less may not be big deal	Green
More than 120%	…above normal. The area received excessive amount of rain.	Blue

Citing the result we have above, General Santos City received rainfall that was way below the monthly normal/average. So, we expect PAGASA to put General Santos City and maybe some nearby towns in color red.

FINDINGS. If some of you do not comprehend the map, or maybe are lost in locating your area. The table that I made below will give you an easier understanding on what the map is trying to imply. The color coding is consistent with the standards from PAGASA, however, if you may notice some provinces in the map may have multiple colors, please note that the shading of each province in the table represents only the dominant color.

ILOCOS REGION (REGION I)

ILOCOS NORTE

ILOCOS SUR

LA UNION

PANGASINAN

CAGAYAN VALLEY (REGION II)

BATANES

CAGAYAN

ISABELA

NUEVA VIZCAYA

QUIRINO

CORDILLERA ADMINISTRATIVE REGION (CAR)

ABRA

APAYAO

BENGUET

IFUGAO

KALINGA

MOUNTAIN PROVINCE

CENTRAL LUZON (REGION III)

AURORA

BATAAN

BULACAN

NUEVA ECIJA

PAMPANGA

TARLAC

ZAMBALES

NATIONAL CAPITAL REGION (NCR)

FIRST DISTRICT (CAPITAL)

SECOND DISTRICT (EASTERN)

THIRD DISTRICT (NORTHERN)

FOURTH DISTRICT (SOUTHERN)

·      NCR Second District covers Quezon City and the cities of San Juan, Mandaluyong, Marikina, and Pasig ·      NCR Third District covers the cities of Caloocan, Malabon, Navotas, and Valenzuela ·      NCR Fourth District covers the cities of Pasay, Parañaque, Las Piñas, Makati, Taguig, Muntinlupa, and the municipality of Pateros

CALABARZON (REGION IV-A)

BATANGAS

CAVITE

LAGUNA

QUEZON

RIZAL

MIMAROPA (REGION IV-B)

MARINDUQUE

OCCIDENTAL MINDORO

ORIENTAL MINDORO

ROMBLON

PALAWAN

BICOL REGION (REGION V)

ALBAY

CAMARINES NORTE

CAMARINES SUR

CATANDUANES

MASBATE

SORSOGON

WESTERN VISAYAS (REGION VI)

AKLAN

ANTIQUE

CAPIZ

GUIMARAS

ILOILO

NEGROS ISLAND REGION (NIR)

NEGROS OCCIDENTAL

NEGROS ORIENTAL

·      Newest region created only last year 2015.

CENTRAL VISAYAS (REGION VII)

BOHOL

CEBU

SIQUIJOR

EASTERN VISAYAS (REGION VIII)

BILIRAN

EASTERN SAMAR

LEYTE

NORTHERN SAMAR

SAMAR

SOUTHERN LEYTE

ZAMBOANGA PENINSULA (REGION IX)

ISABELA CITY

ZAMBOANGA DEL NORTE

ZAMBOANGA DEL SUR

ZAMBOANGA SIBUGAY

·      Isabela City is geographically attributed to an ARMM province, Basilan. Voted not to be included in the ARMM in 2001.

NORTHERN MINDANAO (REGION X)

BUKIDNON

CAMIGUIN

LANAO DEL NORTE

MISAMIS OCCIDENTAL

MISAMIS ORIENTAL

DAVAO REGION (REGION XI)

COMPOSTELA VALLEY

DAVAO DEL NORTE

DAVAO DEL SUR

DAVAO OCCIDENTAL

DAVAO ORIENTAL

SOCCSKSARGEN (REGION XII)

COTABATO

COTABATO CITY

SARANGANI

SOUTH COTABATO

SULTAN KUDARAT

·      Cotabato City is geographically attributed to an ARMM province, Maguindanao. Voted not to be included in the ARMM in 2001.

CARAGA REGION (REGION XIII)

AGUSAN DEL NORTE

AGUSAN DEL SUR

DINAGAT ISLANDS

SURIGAO DEL NORTE

SURIGAO DEL SUR

AUTONOMOUS REGION IN MUSLIM MINDANAO (ARMM)

BASILAN

LANAO DEL SUR

MAGUINDANAO

SULU

TAWI-TAWI

MAJOR CITIES

LAOAG

BAGUIO

TUGUEGARAO

ANGELES

LEGASPI

PUERTO PRINCESA

ILOILO CITY

BACOLOD

DUMAGUETE

CEBU CITY

TAGBILARAN

TACLOBAN

ZAMBOANGA CITY

CAGAYAN DE ORO

BUTUAN

MARAWI CITY

DAVAO CITY

GENERAL SANTOS

My summary will be: Most of Luzon received near normal to above normal amount of rainfall, although some parts like Pangasinan, northern part of Region III, portions of Mindoro Island, and majority of Palawan province may have experienced dry spell or even drought. Much of the Visayas had sufficient amount of rain as most areas registered near normal to above normal values, only the island province of Siquijor and southernmost part of Negros Island experienced rain deficiency. Mindanao, on the other hand, had started to feel the effects of El Niño, as red and yellow shades dominate the island group. Only the easternmost provinces of Surigao del Sur and Davao Oriental benefitted from the rains brought about by either the Northeast Monsoon or the Easterlies.

PIE CHARTS. The pie charts below are based on the table above, it may not reflect the rainfall observation of the entire Philippines. These are made just to give an "in a nutshell" idea.