The Weather and Climate in the Philippines

Weather is the condition of the atmosphere in a particular place at a specific time. Climate is the average weather condition in a region over a long or a number of years. Meteorology is the scientific observation and study of the atmosphere so that weather can be accurately forecast.

The Water Cycle

• Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. The surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other based on how they collide with each other.

• Condensation is the change of the physical state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle.

• Precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzling, rain, sleet, snow, ice pellets, graupel and hail.

The Weather Disturbances

The Philippines is known for the many cyclones (or low – pressure area) that come our way. Our country is located in the North Pacific Ocean where the greatest number of cyclones form. An average of 22 cyclones form in this area every year, about 19 of which enter the Philippine Area of Responsibility.

The Kinds of Cyclones

• Tropical depression – wind speed of less than 63kpph.

• Tropical storm – wind speed of 63 to 118 kph.

• Typhoon – wind speed of more than 118 kph.

The Naming of Tropical Cyclones

• Prior to 1890, the world’s tropical cyclones were named arbitrarily. An, Atlantic storm which dismasted a boat named “Antje” in 1842 became “Antje’s hurricane”, A typhoon which devastated Samar and Leyte on the 12th of October 1897 was called “El Baguio de Samar y Leyte” Before the end of the 19th Century, Clement Wragge, an Australian

• Weatherman, started giving tropical cyclones female names. Those which formed elsewhere were given male names. Normally Wragge was said to bestow this honor upon politicians who had incurred his disfavor.

• In 1941, a storm was named after Maria in the novel “storm” by George B. Stewart.

• Naming storms became quite popular in the United States during the Second World War. A number of air force and navy weather forecaster gave their wives and girlfriends the supposed distinction of having storms name after them.

• In 1942, a storm was named after the President Truman by the U.S press and later in the season another one was named after the president’s wife, Bess.

• In July 1946, a rare case occurred where in three storms develop most simultaneously in the western North Pacific basin where the Philippine territory is located. Instead of names, all three were identified based on their location (latitude- longitude). After sometime confusion prevailed over which storm was being reported.

• Early the next year, forecasters decided to identify storms using name in alphabetical order in which the first of the year will be dubbed Agnes, then Beverly, then Carmen, etc. Military communicators suggested female names for those forming in the Northern Hemisphere and male names for those in the southern half.

• Names issued by the US Air Force weather squadron station in Guam was then adopted by the Philippine Weather Service until 1963.

• Thus, in the 1963 tropical cyclone season, the Philippine Weather Bureau adopted four sets of Filipino women’s nickname ending in “ng” from A you Y to name all tropical cyclones occurring within the Philippine area of responsibility.

• These for groups of names have been prepared and arranged according to the Filipino alphabet. Names from each set group is accompanied by an auxiliary list from A to G just in case the number of tropical cyclones for the year always begin with A, the second begins with letter B and so forth. The said system of naming tropical cyclone is quite practical in many ways.

• Name selected cannot be confused with American name – they being unique and applicable only to Philippine Tropical Cyclones.

• The Filipino names will indicate that the storm is within the forecast responsibility of the Philippine Weather Bureau and would have a high probability of affecting the Philippines.

• The Filipino alphabet has 20 characters which is about the average number of tropical cyclones occurring in the Philippine area of responsibility in a year. Hence, at the end of the year one can tell the umber if storms occurring in the Philippine area of responsibility in a year.

• Hence, at the end of the year one can tell whether the number of storms occurring in the area is above or below normal by noting how far the name of that last cyclone of the year was from the first letter of the alphabet.

• Further, the name of the tropical cyclone will indicate how many cyclones have occurred within the area since the start of the year. Thus, for 1993 typhoon Tasing will be the 16th tropical cyclone of the year.

• In February 1979, the names of extraordinarily destructive storms were retired or decommissioned and a revised list of names for tropical cyclones entering the Philippine area of responsibility was adopted.

• A tropical cyclone causing a total damage of one billion pesos or greater and claiming three hundred or more lives was then classified as destructive and consequently decommissioned. The said list was again revised in 1985 to help minimize confusion in the historical records.

• Weather Advisory for Tropical Cyclones contains the general information on the presence of a cyclone even if it is still too far away from the country to pose a threat in the next three days. This gives the people ample time to become aware of a potential threat.

When is it issued?

As soon as a severe weather system is detected and the forecaster decide that this might affect the Philippines. The advisory is issued once a day at 3:30 pm except for the initial issuance which may come out any time when the severe weather system is detected

The Weather Advisory for Other Severe Weather System is an advisory for the occurrence of monsoons, active low-pressure area and a complex weather system which is a combination of two or more iterating systems. These systems are capable of causing floods because of the prolonged rains it may bring.

When is it issued?

There is, no lead time in these cases. It is issued only when there are indications that the rain may prolong and capable of causing floods. The Advisory is issued once a day at 3:30 pm except for the initial issuance which may come out at any time when a severe weather system is detected

The Severe Weather Bulletin

A severe weather bulletin is of two levels:

• Tropical Cyclone Alerts are alerts issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity.

• Tropical Cyclone Warning is the third stage of the cyclone warning. It indicates that there is real and immediate cy lone threat to a part or parts of the country from a cyclone. It provides detailed information about the tropical cyclone. This includes a description of the cyclone, current location, movement and intensity. Further, it indicates the areas where public storm signals are in effect. Finally, it advises the public to take appropriate safety. The warning includes a 24-hour forecast or outlook that gives more details in terms of future cyclones location and movement with respect to a particular area of reference.

When is it issued?

The warning is issued for times a day, at 5 AM, 11 AM, 5PM, 11Pm or at any time as conditions warrant.

What is a severe tropical cyclone?

A severe tropical storm is designated as a tropical cyclone when it reaches wind speeds of 64 knots (118 km/h, 74 mph). A very intense tropical cyclone is the highest category on the South-West Indian Ocean Tropical Cyclone scale, and has winds of over 115 knots (212 km/h, 132 mph).

What is meaning of PAG-ASA?

PAG-ASA is a Tagalog language word meaning "hope". It may refer to: PAGASA, Philippine Atmospheric, Geophysical and Astronomical Services Administration.

What are the effects of a tropical cyclone?

The effects of tropical cyclones include heavy rain, strong wind, large storm surges near landfall, and tornadoes. The destruction from a tropical cyclone, such as a hurricane or tropical storm, depends mainly on its intensity, its size, and its location.

How did PAG-ASA predict the weather?

The pressure, temperature, dew point temperature, wind direction and speed are observed at selected levels in the atmosphere using radiosondes which record these data by tracking helium -filled balloons attached to transmitters. Weather radars are also used to observe the cloud coverage within the range of the radar.

What happens when cyclone hits land?

When a tropical cyclone makes landfall, the eye usually closes in upon itself due to negative environmental factors over land, such as friction with the terrain, which causes surf to decrease, and drier continental air.

The Meaning and Description of the Modified Public Storm Signals

Public Storm Signal No. 1 | Meteorological Condition:

• A tropical cyclone will affect the locality

• Wind of 30-60 KPH may be expected in at least 36 hours.

The Impacts of the Winds:

• Twigs and branches of small trees may be broken.

• Some banana plants may tilt or land flat on the ground

• Some houses of very light material (nip and cogon) may be partially unroofed

• Very light or no damage at all may be unstained by the exposed communities.

• Rice in flowering stage may suffer significant damage.

The Precautionary Measure:

• People are advised to listen to the latest Severe Weather Bulletin issued by PAGASA every six hours.

• Business may be carried out as usual.

• When the tropical cyclone is strong, intensifying or is moving close, this signal may be gradually increase.

• Disaster preparedness is activated to alert status.

Public Storm Signal No. 2 | Meteorological Conditions:

• A moderate tropical cyclone will affect the locality

• Winds of greater than 60 KPH and up to 100KPH may be expected in at least 24hours

The Impacts of the Winds:

• Some coconuts trees may be tilted with few others broken

• Few big trees may be uprooted.

• Many banana plants may be destroyed

• Rice may be adversely affected

• Large number of nipa and cogon houses may be partially or totally unroofed

• Light to moderate damage to palay in flowering stage.

The Precautionary Measure:

• The sea and coastal water are dangerous to smaller sea craft.

• Fishermen are advised not to go out to sea.

• Avoid unnecessary risks. Travelling by sea or air is risky.

• Stay indoors.

• Secure Properties.

• Special attention should be given to the latest position, direction and speed movement and intensity of the tropical cyclone as it may intensify and move towards the locality.

• Disaster preparedness agencies and other organizations are alerted.

Public Storm Signal No. 3 | Meteorological Conditions:

A strong tropical cyclone will affect the locality.

Winder greater than 199KPH up to 185 KPH may be expected in at least 18 hours

The Impacts of the Winds:

• Almost all banana plants may be destroyed and a large number of trees may be uprooted

• Rice and corn crops may suffer heavy damage

• Majority of nipa and cogon houses may be unroofed or destroyed and there may be considerable damage to structure of light to medium construction

• There may be widespread disruption of electrical power and communication services

• In general, moderate to heavy damage may be expected in both the agricultural and industrial sectors.

The travel by sea and by air is very risky.

• Sea and coastal water will be dangerous to all sea crafts

The Precautionary Measure:

• People are advised to evacuate and stay in strong buildings

• Evacuate low lying areas.

• Stay away from coasts and river banks

• Watch out for the passage of the “EYE” of the typhoon

• During the passage of the “eye” do not venture away from the safety of the shelter

• Suspend classes in all levels and make sure children stay in the safety of strong buildings

• The disturbance is dangerous to threatened or affected communities.

• The passage of the “eye” of the typhoon is indicated sudden change from bad to fair weather.

• Fair weather, at last for one or two hours after which the worst weather will resume with very strong winds generally coming from the opposite direction.

• Disaster preparedness and response agencies or organizations are activated to respond appropriately.

Public Storm Signal No. 4 | Meteorological Conditions:

• A very intense typhoon will affect the locality

• Very strong winds of more than 185 KPH may be expected in at least 12 hours

The Impact of the Winds:

• Coconut plantations may suffer extensive damage

• Many large trees may be uprooted

• Rice and corn plantations may suffer severe damage

• Most residential and institutional building of mixed construction may be severely damaged

• Electrical power distribution and communications services may be disrupted

• Damage to affected communities can be very heavy

The Precautionary Measures:

• Cancel all travel and other outdoor activities

• Stay in the safety of houses or evacuation center

• The situation is potentially very destructive to the community.

• Disaster coordinating councils concerned and other disaster response organization must respond to emergencies very intense typhoon.

• The description of each signal is enhanced with the addition of statements pertaining to the perceived degree of associated damage based on typhoon passage surveys and empirical analysis

The New Public Weather Forecast

• In its continuing effort for enhance service delivery to the public, PAG-ASA recently modified the Public Weather Forecast. In line with this, it has set new guidelines for its issuance to sustain the improvement of weather forecasting services.

• Under the modified weather forecast, a brief statement of the synoptic situation that may influence the weather during the forecast period is included.

• It still contains the weather conditions, as normally had the in the past, expected in different areas of the country like Metro Manila, Baguio City, Metro Cebu and Metro Davao.

The Eclipse

• Eclipses are due to the revolution of the moon around the earth and the revolution of the earth around the sun, While the strong influence of the moon upon the earth’s water sphere produces tides.

• Solar Eclipse happens when the moon passes directly between the sun and the earth, the moon casts a shadow on earth. It happens during day time and during new moon.

• Perigee is the period when the moon must be at, or very near so that the darkest part of its shadow will touch the earth.

• Apogee is the period when the moon is very far from the earth

• Lunar eclipse occurs when the earth happens to be in the same line as the sun and the moon, then the earth casts a shadow on the surface of the moon. It happens at night time and during full moon. If the moon is covered by the earth umbra, a total lunar eclipse occurs. If the moon gets within the earths penumbra partial lunar eclipse occurs.

The Tides

• Tides are the effects of the rise and fall of the ocean level due to the strong influence of the moon upon the earths water sphere. During the new moon and the full moon every month, the sun, the earth and the moon are in line with one another.

• The tidal waves effects during such time are much stronger because the gravitational pulls of the sun and the moon are combined. This is the time when spring tide occurs.

• While a neap tide occurs when the high tides do not go up very high and the low rides do not go down very low.

The Solar System

The sun and all the other bodies held by its gravitational pull including the nine know planets make up the solar system

The Sun

The sun is a huge ball of hot gases 148,800,800 kilometers away from the earth it is the center of the solar system.

Planets

There are nine known planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Pluto. Among the other planets the earth is the only one that can sustain life because of the presence of oxygen in its atmosphere.

The Other Celestial Bodies

• Planetoids or asteroid are the tiny celestial bodies found between the orbits of mars and Jupiter

• Comets are celestial bodies composed of rocks and frozen gases and having very eccentric orbits.

• Halley comet has a “head” of burning gases believed to surrounding some loose rock fragments.

• Hyakutakes comet is scheduled to pass within 15 million kilometers of earth.

• Meteors are rock like particles in space. They are the smallest member of the solar system.

• Meteorite is a meteor which actually strikes the earth surface.

• Galaxy is a huge congregation of billions of stars.