Understanding Hail Formation in Tropical Convective Systems:
Insights from the Cabiao, Nueva Ecija hail event on 08 May 2020
Marco Polo Ibanez1*, John A. Manalo1, Generich H. Capulo2, Lyndon Mark P. Olaguera3,4
1Department of Science and Technology, Philippine Atmospheric, Geophysical, and Astronomical Services Administration, Quezon City, Philippines
2Department of Earth and Space Science, Rizal Technological University, Mandaluyong City, Philippines
3Regional Climate Systems Laboratory, Manila Observatory, Quezon City, Philippines
4Department of Physics, School of Science and Engineering, Ateneo de Manila University, Quezon City, Philippines
* Presenter:Marco Polo Ibanez, email:marcopoloibanez@gmail.com
Hailstorms, though typically associated with mid-latitude climates, can also occur in tropical regions due to strong convective activity. In the Philippines, thunderstorms are frequent, driven by complex interactions between tropical dynamics and local geography, especially during monsoon transitions. Despite this, hail events remain understudied due to limited observations. This study investigates a severe hailstorm event on 08 May 2020 in Cabiao, Nueva Ecija, using satellite imagery, radar data, and atmospheric reanalysis soundings to analyze the atmospheric conditions and physical processes contributing to hail formation. Satellite data from HIMAWARI-8 showed deep convection with low brightness temperatures (~-85℃), while S-Band radar reflected large hydrometeors indicating hail formation. Proximity soundings from the European Center for Medium-Range Forecast (ECMWF) 5th generation of global reanalysis (ERA5) revealed an inverted V profile with high Convective Available Potential Energy (CAPE = 3241 J kg⁻¹) and strong low-level convergence, supporting intense updrafts. The presence of a low freezing level (~4 km) and CAPE within the Hail Growth Zone (HGZ) further facilitated hail development. Hodograph analysis indicated unidirectional easterly winds, enhancing persistent convection. The study emphasizes the role of thermodynamic and kinematic factors, such as elevated moisture, CAPE, and wind profiles, in hailstorm formation in tropical environments. These parameters can serve as early warnings for severe weather, contributing to improved forecasting and preparedness strategies for hail-producing storms in the Philippines.
Keywords: Severe Weather, Hail, Tropics, Philippines