Caribbean Weather systems

The various weather systems affecting the Caribbean region are discussed in this presentation. Their characteristics and weather conditions associated with each are described.

1. CARIBBEAN WEATHER SYSTEMS

2. WEATHER SYSTEMS WEATHER SYSTEMS AFFECTING THE CARIBBEAN

3. What is your weather like today? What is your weather like on any given day? This can be influenced by the weather systems affecting your area.

4. Caribbean weather systems A weather system is a large area of the atmosphere that has special temperature, pressure and moisture conditions . There are certain weather systems that are common to the Caribbean region

5. THERE ARE FIVE WEATHER SYSTEMS AFFECTING THE CARIBBEAN INTER TROPICAL CONVERGENCE ZONE (ITCZ) EASTERLY WAVES HURRICANES COLD FRONTS ANTICYCLONES Caribbean weather systems

6. I.T.C.Z The ITCZ is an area of low pressure lying east to west across the equatorial region. The hot air from the North East Trade Winds meet the hot air from the South East Trade Winds in this region. The hot moist air is forced to rise, resulting in rainfall. This belt of low pressure moves north and south of the equator with the seasons.

7. I.T.C.Z

8. I.T.C.Z In June it drifts northwards and may affect Trinidad and Tobago and the rest of the southern Caribbean. In December it drifts south and affects Guyana. It is also active in March and September when the hottest place is the equator.

9. Conditions associated with the I.T.C.Z Heavy rainfall Overcast skies with cumulus clouds Light and calm winds High temperatures

10. ITCZ

11. Easterly Waves They are weak, low pressure systems that lack a closed center. They are located at the outer fringe of the ITCZ. They form near Africa over the warm waters of the Atlantic Ocean and move westwards into the Caribbean. They affect most of the islands of the Caribbean during the months of June to December.

12. Easterly Waves

13. Conditions associated with Easterly Waves Moderate winds Heavy and continuous rainfall Overcast skies High temperatures. Tropical waves can eventually develop into tropical storms then hurricanes. They are not hurricanes since they don’t have a low pressure centre and strong winds.

14. Hurricanes

15. Hurricanes Hurricanes are intense, low- pressure systems with strong winds of > 120 km or 75 miles per hour. Winds converge in an anti-clockwise direction with heavy rainfall. They start off as tropical storms near West coast Africa and move westward into the Caribbean. The hurricane season in the Caribbean is from June to December . Usually has a low pressure center of around 996 mb .

16. Hurricanes Warm ocean water of at least 27degrees Celsius . Coriolis effect north and south of latitudes 10 degrees north and south, this causes the spiral motion of the hurricane and influences its path. Diverging upper level winds allows for updraughts of warm converging air. Latent heat is given off as the air rises and this increases temperature

17. Hurricanes CONDITIONS NECESSARY FOR THE DEVELOPMENT OF A HURRICANE

18. Hurricane PATH OF A HURRICANE

19. Hurricanes STRUCTURE OF A HURRICANE

20. Conditions associated with Hurricanes Wind speeds above 50 miles or120 km/ hour. Wind converge in an anti-clockwise direction towards a low pressure center in the northern hemisphere. Torrential rain Overcast skies with towering cumulonimbus clouds. Thunderstorms with lightning. High temperatures averaging 27 degrees Celsius.

21. Cold Fronts Formed when a cold air mass meets a warm air mass and pushes the warm air mass out of its way . Cold dry air called Northers moves south from the North American continent that pushes under the warm, moist Caribbean air. The rising warm air cools and condenses resulting in frontal rainfall. Cold front followed by cooler drier air and moderate to fresh breeze.

22. Cold Fronts

23. Cold Fronts

24. Conditions associated with Cold Fronts Cooler temperatures, 18 – 21 degrees Celsius. Moderate cloud cover Brings thunderstorms and rain . Moderate rainfall that lasts for days depending on the movement of the frontal system. Moderate speed winds from the north.

25. Anticyclones Anticyclones have opposite characteristics to Tropical Cyclones. They are high pressure systems. Winds blow out of them in an anti- clockwise direction. They form around mid- latitudes and may drift into the Caribbean. They are stable with sinking air blowing out of the centre. They affect most of the Caribbean north of Trinidad and Tobago.

26. Anticyclones C yclones vs Anticyclones. L

27. Anticyclones

28. Conditions associated with Anticyclones Dry and sunny Clear skies Moderate winds Moderate temperatures