QM-11

1. QM-11 Quartermaster Weather Instructors: George Crowl

2. Course Outline • a. Read and understand a local weather bulletin. Know how to obtain current marine and weather reports from the National Weather Service in your area by telephone, radio, or online. • b. Demonstrate your ability to read a barometer, thermometer, anemometer, psychrometer, and weather vane. Be familiar with the Beaufort Wind Force Scale. • c. Demonstrate your knowledge of the weather signs for your local area, including cloud types. Prepare a 48-hour forecast and compare your forecast with the actual weather that occurred.

3. QM-11a a. Read and understand a local weather bulletin. Know how to obtain current marine and weather reports from the National Weather Service in your area by telephone, radio, or online.

4. Local Weather Bulletin • The traditional typed weather bulletin is no longer available • A local forecast is available from nws.noaa.gov by entering city and state or ZIP code • It provides current conditions and a week's forecast • That page offers an option to select the marine forecast

5. Telephone Forecasts • http://www.nws.noaa.gov/om/marine/noaatel.htm is the web page to determine your local phone number for telephone weather forecasts • For Houston / Galveston, the phone number is 281-337-5074 • Select marine weather forecast

6. Radio • Marine VHF radios have weather channels specifically identified and selectable • One particular channel may be better reception or provide better coverage of the area you are interested in. • The forecast is repeated at regular intervals. It may take several minutes to get to your area of interest

7. Internet • Go to www.nws.noaa.gov • Select the area of interest by clicking, such as Houston/Galveston • That will give you current observations and the opportunity to click on such functions as radar, satellite, weather map, and marine • Other companies, such as weather.com and weather underground also have good sites

8. QM-11b b. Demonstrate your ability to read a barometer, thermometer, anemometer, psychrometer, and weather vane. Be familiar with the Beaufort Wind Force Scale.

9. Barometer • Barometer measures air pressure • Air pressure is an indication of current weather • Air pressure trends are an indication of future weather • Falling barometer = stormy weather • Rising barometer = clearing weather • Steady barometer = steady weather

10. Different Barometers • Original barometer – mercury • Newest barometer - digital

11. Different Barometers (2) • Common barometer – aneroid • Has a vacuum cham-ber, moves pointer • 30.04” mercury or1017 MB • Hand at 29.00” can be set to track trend

12. Thermometers • Outdoor - °C or °F • Note funny scale • Engine – highlights hightemperature • Digital – direct reading

13. Anemometer • Measures speed (and direction) of wind • Analog, vacuum and digital readouts • Normally shows relative wind direction & speed • Can be tied to GPS to provide true wind dir / vel • Mounted on highest mast

14. Wind Vane • Shows relative wind • Little red tabs show “eye of the wind” • Does not show velocity unless anemometer is tied into it • Does not show true winddirection • Mounted on highest mast

15. Psychrometer • Measures relative humidity • Two thermometers, one wet, one dry • “Sling” them around in the air, one is cooled by the wet bulb, shows a different temperature • Read a table of temperatures, tellsrelative humidity • New digital ones solve different ways

16. Beaufort Wind Scale • Invented by British Admiral Francis Beaufort in 1805 • Designed for open ocean, bay or lake will be less accurate • Relates wind speed (K) to sea state to wind names • Is still the basis of small craft warnings, gale warnings, storm warnings, etc • Force 5, 16-21K, “Fresh Breeze,” is usually the limit for Sea Scout sailing

17. Beaufort Scale • L

18. QM-11c c. Demonstrate your knowledge of the weather signs for your local area, including cloud types. Prepare a 48-hour forecast and compare your forecast with the actual weather that occurred.

19. Weather Cycle • Weather goes through regular cycles • Typical would be: clear in high pressure area, becoming cloudy, warm front with rain / snow in a low pressure area, some clearing, cold front with possible thunder-storms, clearing, and back to clear in a high pressure area • Winds and fronts generally go from west to east

20. Cloud Types • L

21. Cirrus • Cirrus, cirro... = high (18-50,000 ft) • Thin, wispy strands of water vapor or ice • “Mare's Tails” • Appears in advance of fronts, deteriorating weather

22. Cirrostratus • High, very thin, uniform • Ice crystals • Often can see through it

23. Cirrostratus Halo • Halo can form around the moon, perhaps the sun • Ice crystals are refracting light (as in a rainbow)

24. Cirrocumulus • High, small rounded puffs, usually in long rows • “Mackerel sky”, often clear, cold weather

25. Altostratus • Alto = middle altitude (6-18,000 feet) • Stratus = level, layered stable air mass • Dark clouds (thick, water inside) • May signal approach of a warm front

26. Altocumulus • Cloud has more vertical development • Weakening warm front or between a warm and a cold front

27. Stratus • Stratus = low level cloud (below 6000 ft), flat bottom and top, may be layered, stable air • May have light drizzle or snow

28. Nimbostratus • Low to middle cloud • Nimbo = precipitation = rain, sleet, hail, snow • Covers a wide area

29. Stratocumulus • Low, lumpy layer of clouds, little convection • Might have light precipitation • Common in polar and horse latitudes (30-38°)

30. Cumulus • Low clouds, flat bottoms, rounded bumpy tops • Unstable air, can grow in height, become cumulonimbus

31. Cumulonimbus • Dense clouds, unstable air, with cold fronts • Thunderstorms = rain, hail, sleet, even snow • Tornados and water-spouts come out bottom • Lightning, high wind gusts • Dangerous, get off the water

32. Cloud Types Summary • L

33. Sailors' Aphorisms • “Red sky at night, sailors' delight, red sky in morning, sailors take warning” • “When a halo rings the moon or sun, rain's approaching on the run” • “When the sun draws water, storms will follow” • “Rainbow to windward, foul fall the day,rainbow to leeward, rain runs away” • Mackerel skies and mares' tails,make tall ship take in their sails”

34. 48-Hour Weather Forecast • Watch the weather for a day or two • Write down what you see – wind direction and speed, precipitation, clouds types during period • Apply personal knowledge of weather cycle • Use history, cloud types, barometer if available • Predict for 48 hours – clouds, rain, relative temperature, etc. • Do NOT use a published forecast, make an honest prediction

35. Recommended Format • Date, time of day (morning, afternoon, evening) • Types of clouds, cloud cover • Rain possibilities • Temperature trend

36. Record Your Observations • Match your observations with your predictions (use the same sheet of paper, column for observations) • Highlight similarities, differences • Do not expect perfection (professional meteorologists sometimes get it wrong!) • This is an exercise in thinking

37. Questions?