Weather Endorsement Standard (119)

Prerequisites: None

General Description: Understand and demonstrate the proper use of weather information in planning and adapting navigation during local and passage-making voyages.  Demonstrate the ability to use both the latest technological tools as well as traditional maritime skills to forecast weather conditions.

SAILING KNOWLEDGE

A Certified Sailor has successfully demonstrated his or her understanding of:

1. Basic Concepts

• The role of marine weather in your boating plans, particularly wind forecasting
• The relationship of temperature, precipitation, visibility, wind, and waves and their impact on forecasting
• Wind terminology and units used in speeds, distances, temperatures and pressures
• Utilizing data from the Ocean Prediction Center, National Data Buoy Center, and Marine Weather Services Charts

2. Pressure and Wind

• Pressure and wind, including the flow of wind around highs, lows, ridges and troughs
• Conversion of apparent wind to true wind
• Calibration and setting of barometers, both aneroid and digital
• Pressure distributions and related labeling practices on weather maps
• Predicting wind speed and direction from isobars on a weather  map

3. Global Winds and Currents

• The basic properties of the atmosphere and their influence on wind and weather
• Air mass classifications and vertical stability basics
• The role of equatorial heating in establishing the doldrums, horse latitudes, trade winds and prevailing westerlies
• The role the polar front plays in generating low fronts, and how these subsequently cross the mid-latitudes of the globe
• The origins and behavior of the winds aloft and how they contribute to the development and transport of surface systems around the globe
• The distribution of ocean currents around the globe and how to predict their values in voyage planning

4. Strong Wind Systems

• Forecasting conventions and warnings available for strong wind systems
• The distinctions between lows and fronts, and between tropical and extra-tropical storms
• Predicting squall behavior
• Finding and using Quick Scat satellite wind measurements
• Typical behaviors of tropical depressions, storms, and hurricanes

5. Clouds, Fog, and Sea State

• The ten basic cloud types and what they can indicate
• Cloud sequences at frontal passage
• Fog formation and forecasting
• Practical distinctions between sea fog and radiation fog and between swells, wind waves and ripple
• Predicting wave height and speed based on wind speed, duration, and fetch
• The Beaufort Wind Force scale that relates wind speed to sea state

6. Wind and Terrain

• Presence and topography of land and how it affects the wind flow over adjacent waters
• Prominent local winds such as: sea breezes, land breezes, channeling and gap winds, blocking and lifting and downslope winds
• The interaction between thermal winds and pressure system winds

7. Weather Maps Review

• The types of weather maps available and how to access them at home and underway
  The process of weather routing, including sequencing of analyses and forecasts to confirm the forecasts
• Accessing and utilizing GRIB forecasts, taking into account their pros and cons compared to analyzed products prepared by meteorologists
• Using the 500-mb maps and weather discussions to help evaluate surface forecasts
  Utilizing shipboard observations of wind and pressure to evaluate analyses and the subsequent forecasts

8. Sources of Weather Data

• The use of both traditional and modern sources of climatic data for planning the time and route of voyages-for inland and coastal voyaging, as well as ocean crossings
• The latest sources for weather data underway and the wireless options for obtaining it
• The distinctions and pros and cons of commercial weather services compared to free public services from the National Weather Service
• The role of professional weather routing services and how they might fit into your voyaging plans

  9. On-board Forecasting and Tactics

• Proper use of barometer, wind speed, wind direction, clouds, and sea state for shipboard forecasting
• Gauging the direction of the winds aloft from cirrus cloud patterns
• Know which weather-related old maritime sayings have some value in forecasting
• The role of weather routing in improving sailing tactics

10. Southern Hemisphere Weather

• Which aspects of weather are unique, and which are and are not reversed in the Southern Hemisphere
• The sources for weather information specific to the Southern Hemisphere

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