This document discusses signs of impending hydrometeorological hazards like tropical cyclones. It defines tropical cyclones as rotating storm systems that originate over tropical oceans and move westward. Tropical cyclones are classified based on wind speed into tropical depressions, tropical storms, severe tropical storms, typhoons, and super typhoons. Satellite images can track tropical cyclones based on their characteristic spiral shape and development of an eye, while weather radars track storm movement by detecting reflected signals from rain and clouds. Forecasters issue public storm warnings to notify citizens of expected wind strength.

1. SIGNS OF
HYDROMETEOROLOGICAL
HAZARD
RECOGNIZE SIGNS OF IMPENDING HYDROMETEOROLOGICAL HAZARDS
(AND PREPARE A HYDROMETEOROLOGICAL HAZARD MAP)
DRR11/12-IIC-D-33)

2. PAG-ASA WEATHER FORCAST

3. TROPICAL CYCLONE
• is a rotating, organized system of clouds and
thunderstorms that originates over the tropical waters.
Tropical cyclones rotate in a counterclockwise direction in
the northern hemisphere (conversely, clockwise in the
southern hemisphere). The term tropical cyclone
encompasses tropical depressions, tropical storms,
typhoons and hurricanes. ,

4. • After formation, tropical cyclones usually move to the
west and generally slightly poleward, then may "recurve,"
that is, move into the mid-latitude and back toward the
east. However, not all tropical cyclones recurve. It derives
its energy from the latent heat of condensation which
made them exist only over the oceans and die out rapidly
on land. The intensity of tropical cyclones vary, thus, we
can classify them based upon their degree of intensity.

5. THE CLASSIFICATION OF TROPICAL CYCLONES ACCORDING
TO THE STRENGTH OF THE ASSOCIATED WINDS AS ADOPTED
BY PAGASA (AS OF 01 MAY 2015) ARE AS FOLLOWS:
TROPICAL DEPRESSION (TD) - a tropical cyclone with maximum sustained winds of
up to 61 kph.
TROPICAL STORM (TS) - a tropical cyclone with maximum wind speed of 62 to 88
kph.
SEVERE TROPICAL STORM (STS) - a tropical cyclone with maximum wind speed of
89 to 117 kph.
TYPHOON (TY) - a tropical cyclone with maximum wind speed of 118 to 220 kph.
SUPER TYPHOON (STY), a tropical cyclone with maximum wind speed exceeding
220 kph.

7. THE TROPICAL CYCLONE
• A tropical cyclone can be seen in a satellite image due to its
characteristic spiral/circular shape. The stronger and more intense
a tropical cyclone becomes, the more symmetrical the inner clouds
or rainbands are and a distinctive “eye” at the center of circulation
becomes visible. This means that a tropical cyclone tends to be
more circular and it’s center will have a cloudless region. Weather
forecasters use satellite images like that in Fig. 2 to track the
movement and estimate the intensity of tropical cyclones.

9. THE WEATER RADAR
• Another way weather forecasters track the movement of
tropical cyclones is with the use of weather Radars.
RADAR is an acronym which stands for RAdio Detection
And Ranging. A Radar sends out electromagnetic waves
to the atmosphere that is then reflected by hydrometeors
(e.g. rain, clouds) present in the sky. An image is created
from the received signal and information on rain clouds
can be gathered. While radar images give more details of
a storm, it is limited to a range of approximately 400 km
from the radar site.

12. TOGETHER WITH THE FORECAST TRACK, PAGASA ALSO ISSUES THE PUBLIC STORM WARNING SYSTEM (PSWS) TO
WARN CITIZENS OF IMPENDING WIND STRENGTH. THE PSWS IS AS FOLLOWS:

13. GROUP ACTIVITY