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Have you ever experienced going out of your house to soak in the sun, only to be drenched by sudden rains hours later?
According to the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA), rain showers or thunderstorms usually occur in the afternoon or evening because of the heat accumulated from morning until the latter part of the day.
This scenario is not so strange; in fact it can be explained by one of the most basic weather processes called water cycle.
When the sun heats the earth’s surface, water from the ocean or a body of water evaporates and rises up to the atmosphere. Water vapor forms into clouds and undergoes condensation. When a cloud becomes massive, it can no longer sustain the moisture so it releases water through precipitation in the forms of rain, snow, or hail. The transformation of a cloud from white to a dark grayish color is brought by the lack of passing light from the sun. The cloud becomes thicker, making it hard for sunlight to penetrate.
During a thunderstorm, lightning and thunder also occur, along with gusty winds and moderate to heavy rains. Lightning is caused by the electric charges within the cloud and the ground. The charges at the top of the cloud are positive while negative charges form at the bottom. When these opposite charges connect, they produce a streak of light called lightning.
Meanwhile, thunder is caused by the vibration of air particles due to lightning. Since light travels faster than sound, thunder usually comes after lightning.
The Life Cycle of a Thunderstorm
According to the National Oceanic and Atmospheric Administration (NOAA), all thunderstorms originate from a thunderstorm cell which has a distinct life cycle lasting for about 30 minutes.
Towering Cumulus Stage
According to PAGASA, there are main ingredients to form a cumulonimbus cloud – moisture, lifting and unstable atmosphere. When the sun heats the ground, the warm air moves upward, condenses and begins to build clouds. The clouds will then grow vertically and densely.
Mature Cumulus Stage
The cloud continues to increase in size, width and height. In this stage, the affected areas start to experience heavy precipitation and gusty winds. NOAA considers this as the most dangerous stage wherein large hail, damaging winds, and flash flooding may occur.
Also called as the “decaying stage”, the cloud begins to collapse because it no longer has a supply of warm moist air to maintain itself and then it dissipates. The weather gradually calms down to light rains and weak wind flow. The top of the thunderstorm cloud usually flattens, spreads out or becomes less defined. Precipitation becomes light and clouds may also begin to evaporate.
How do we know if there’s an incoming thunderstorm?
PAGASA reminds the public of the higher chance of thunderstorms during the Hot and Dry season. As the temperature goes up, evaporation also speeds up. As evaporation becomes more active, the greater the chance of rain in a certain area.
The state weather bureau regularly issues thunderstorm warning levels:
This aims to make us aware that there is a slim chance of thunderstorm and that good weather will possibly prevail. However, since the weather keeps on changing, all are still advised to monitor updates.
Watch out! This one already urges the public to prepare as thunderstorm is more likely to occur or affect the area within the next 12 hours. Within the said span of time, it’s best to continuously monitor updates and take precautionary actions.
Thunderstorm starts to affect a specific place. This is also used to alert nearby areas that a possible thunderstorm may affect them within the next 2 hours.
What to do during a thunderstorm?
Keep in Mind…
A sunny morning does not always mean it’s going to be sunny all day long. Heat is one of the major factors of water cycle. Whenever clouds are present, there will always be a chance of rain.
We have to remember that the possibility of rain showers or thunderstorms are part of our everyday lives. What we have to do is to be prepared at all times by gearing up with umbrellas and staying updated on weather conditions.
NOAA – NWS