1. SITUATION OVERVIEW
a. On-going El Nino in decaying stage; possibility of La Nina on the rise.
b. The current El Nino continues to weaken in the tropical Pacific. Majority of climate models suggest that El Nino is in its decaying stage, returning to ENSO-neutral condition by mid-2016.
c. Meanwhile, the possibility of a developing La Nina is favored during the second half of 2016. With this current state, La Nina Watch is now in effect. A La Nina event is characterized by a persistent cooler than average sea surface temperature anomalies (below -0.5 °C) over the tropical Pacific.
d. Rainfall assessment for the month of April showed that most parts of the country received way below to below normal rainfall except for the provinces of Compostela Valley, Agusan del Sur, North Cotabato, Pangasinan, Cavite, Rizal, and Metro Manila where above normal to near normal rainfall were observed. Further analysis showed that twenty-three (23) provinces were affected by dry spell while twenty-eight (28) provinces, mostly from Mindanao, experienced drought conditions in April.
e. Most parts of the country experienced warmer than average air temperatures due to the prevalence of ridge of high pressure area (HPA). The highest daytime temperature in the country was recorded at 40.1°C (Apr. 27) in Isabela State University-Echague. Two warmest daytime temperatures that surpassed their historical extremes were also observed: Malaybalay (36.4°C on Apr. 15, 2016 topped 36.2°C on April 24, 1998) and General Santos (39.4°C on Apr. 16, 2016 beat 39.0°C on April 5, 1988).
f. The month of May marks the weakening of the easterlies and gradual start of southwest windflow. Other weather systems that are likely to affect the country for May are the Intertropical Convergence Zone (ITCZ), easterlies, low pressure areas (LPAs), ridge of HPAs, and zero (0) or one (1) tropical cyclone to enter the Philippine Area of Responsibility. Afternoon or early evening thunderstorm activities are also expected to increase during the period.