What are coastal squalls (Chubascos / Rachas turbulentas) associated with convective clouds (Cumulonimbus), and what immediate seamanship precautions should a coastal skipper take upon sighting them?

1. Sudden, violent, localized increases in wind speed often accompanied by heavy rain showers; reduce sail area immediately, start the auxiliary engine, secure hatches, and ensure all crew don lifejackets and safety harnesses
2. Gentle warming trends with zero wind; hoist all light-air spinnakers immediately
3. Permanent ocean currents that flow in circles around lighthouses
4. Radio communication signals broadcast by the naval weather service