Lesson 5

• Philippines- is prone to typhoons formed in the Northwest Pacific Basin
• earth's changing climate brought about by the effects of global warming contributes to the worsening storms that

  wreak havoc in the country
• HYDROMETEOROLOGIAL HAZARDS: Tropical Cyclones, Thunderstorms, Hailstorms, Tornados, Blizzards, Heavy Snowfall, Avalanches, Coastal storm surges, Flash floods, Drought, Heatwaves, Cold Spells
• Tornados, rotating colum of air
• Blizzards, cold wind /w heavy snowfall
• Avalanches large mass of snow tumbling down a mountain
• Coastal storm surges, abnormal rise in seawater caused by storm's wind pushing water onshore
• Flash floods, flood caused by heavy excessive rainfall in a short period of time
• Drought, dry period in the natural climate cycle
• Heatwaves, a period of unusually hot weather
• Classifications of Typhoon (5): Tropical Depression (TD), Tropical Storm (TS), , Severe Tropical Storm (STS), Typhoon (TY), Super Typhoon (STY)
• Tropical Depression (TD) - less than 62 km/h- highest TCWS: 1
• Tropical Storm (TS) - 62-88 km/h - highest TCWS: 2
• Severe Tropical Storm (STS) - 89-117 km/h - highest TCWS: 3
• Typhoon (TY) - 118-184 km/h - highest TCWS: 4
• Super Typhoon (STY) - 185 km/h - highest TCWS: 5
• Formation of Typhoons:

  Typhoons that enter the Philippine area of responsibility (PAR) typically form at the Northwestern Pacific Ocean. It is known to be the most active tropical cyclone basin on the planet, producing almost a third of the world typhoons, annually. The number of typhoons that form in this basin rises steadily from February until June. September is considered to be the most active month in the formation of typhoons.
• Conditions in order for storms to be generated:

  1. Heat from the sea
  2. Presence of Intertropical Convergence Zone (ITCZ)
  3. Presence of Low-Pressure Area (LPA) in the ITCZ
  4. Light wind or weak vertical wind shear in the upper atmosphere
• TYPHOONS those that develop at the Western North Pacific Ocean Basin
• HURRICANES those which develop east of the International Date Line up to the Western Atlantic Ocean
• CYCLONES those which develop in other basins like the North Indian Ocean and South Indian Ocean,Bay of Bengal, Sout Pacific Ocean, and Northern and Western Australia
• TYPHOON YOLANDA - destroyed 90B php worth of property, took 6K human lives - PAGASA was tasked to provide flood and typhoon warnings so that the loss of life and property can be lessened. - Government should continue to invest on the agency
• THUNDERSTORMS, A violent short-lived weather disturbance that is almost always associated with lightning,thunder, dense clouds, heavy rain or hail, and strong gusty winds
• Requirements for thunderstorms to form: moisture or humidity, rising unstable air, lifting mechanism to keep the air rising
• Stages of Thunderstorms: Developing Stage, Mature Stage, Dissipating Stage
• Developing Stage, thunderstorm is marked by a cumulus cloud that is pushed by a rising column of air
• Mature Stage precipitation begins to fall out of the storm, creating a column of air that pushes downward known as downdraft
• Dissipating Stage, the gust front moves far away from the storm and cuts the warm moist air that feeds the thunderstorm, and the intensity of the rainfall decreases, although there is still the danger brought about by lightning
• Thunderstorm Warnings: Advisory, Watch, Information
• Advisory - thunderstorm threatens specific area within the next 2h
• Watch- thunderstorm is likely to occur within the next 12h
• Information- thunderstorm is less likely to occur within the next 12h
• Flood- occurs when a normally dry piece of land is covered by large amounts of water
• Flood- can be brought by excessive rainfall or when the sea level rises
• Flood- usually affect areas which are low-lying, and where the land meets the sea or another body of water
• Flood- are one of the most common natural disasters, second only to fires
• Storm Surges- the abnormal rise of the water level in coastal areas brought about by the strong winds, waves, and low atmospheric pressure of storm
• Storm Surges- higher than the normal or regular astronomical tide
• Storm Surges- the result of the push of wind and pressure on the water towards the shore
• El Nino & El Nina- are weather phenomena, together called El Nino Southern Oscillation (ENSO) cycle, describes the fluctuations is the atmosphere occurring in the area between the International Date Line and 120 Degrees West referred to as the East-Central Equatorial Pacific