Training Guide in Surface Weather Observations - Multiple Choices

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layer aloft will be considered as midway between the time the balloon begins to fade until the time the balloon completely disappears. Once you have determined the amount and height of each layer present at the station you will know what layer the ceiling will be. If you have learned to evaluate the sky cover and record it correctly, then determining the ceiling is relatively easy. The ceiling is the lowest layer reported as broken or overcast, or if the sky is totally obscured, the height of the vertical visibility shall be the ceiling. When the cloud height is varying rapidly while you are trying to obtain a height, report the average of all observed values as the height of the layer. If it is the ceiling layer and the average height is less than 3,000 feet and the amount of change is according to the criteria given in your station’s WSOH, a remark shall be included in column 14 of MF1M-10 giving the range of variability. For example, “CIG 005V010” would indicate a ceiling that was varying between 500 and 1,000 feet. 5.3.1 Methods Used When Determining Cloud and Ceiling Heights Determination of heights should be supplemented by visual observations and not left solely to instruments themselves. To determine the height of layers aloft and the vertical visibility into surfacebased phenomena, the following methods can be used. a. Ceiling Light and Clinometer. At night, sky cover height and vertical visibility values may be determined with a clinometer and a projector by using the following procedures: 1. Allow the pendant to swing freely; sight through the clinometer centering the intersection of the cross-hair: (a) Upon the brightest portion of the light beam spot when the sky cover layer is aloft (see Figure 5-13), or (b) On the upper limit of the light beam penetration when the sky is completely obscured by a surface-based layer (see Figures 5-12 and 5-14). 2. When the pendant has come to rest, lock it in position without moving the clinometer. 3. Read the indicated angle to the nearest whole degree and release the pendant clutch. 4. Repeat steps 1 through 3 three times, then determine an average angular reading. 5. Refer to a table appropriate for the baseline used for the equivalent height value of this average reading. 5-18
Figure 5-13. Measured Cloud Height. Figure 5-14. Vertical Visibility. b. Ceiling Balloons. In daytime, sky cover height and vertical visibility values may be determined with a ceiling balloon using the following procedures: 1. Choose the appropriate color of balloon; red balloons are usually best with thin clouds, blue or black balloons with other conditions. 2. Inflate the balloon using the following instructions: The balloon should be dry inside, and relatively dry outside, especially during freezing weather. Remove any trapped air by folding and squeezing the balloon in your hand, then stretch the neck sufficiently to insert the inflation nozzle. Place the nozzle so that the tubing connecting the nozzle to the regulator rests on a support and is not suspended from the nozzle. Inflate the balloon slowly and turn off the gas as soon as the balloon begins to lift the nozzle. Add or remove gas from the balloon until the nozzle is suspended just above the support when any motion of the balloon has stopped. Listen for leaks in the balloon. Tie the neck of the balloon securely just above the nozzle and remove the balloon from the nozzle. Double the end of the neck over the tied portion and either tie it or secure it with a rubber band. 3. Release and watch the balloon continuously. Determine with a stop watch (or any watch having a second hand) the length of time that elapses between release of the balloon and entry into the base of the layer. The point of entry will be considered as midway between the time the balloon first begins to fade and the time of complete disappearance. 4. Determine the reportable height above the surface corresponding to the elapsed ascent time in the tables found in WSOH. The accuracy of the height obtained by the balloon will be decreased when the balloon: (a) Does not enter a representative portion of the cloud base. (b) Is used during the occurrence of hail, ice pellets, any intensity of freezing rain, or moderate to heavy rain or snow. 5-19
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Training Guide in Surface Weather O
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PREFACE METAR/SPECI is the internat
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CHAPTER 7 - PRESSURE ..............
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1.2 Content and Format of the Manua
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1.6 Report Modifier - COR An observ
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1-6
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12. A METAR observation contains se
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25. At no time shall an observation
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2.1.4 Estimated Winds Though winds
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2-4
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Code the following wind situations
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19. Which of the following wind par
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3.1 Visibility 1 CHAPTER 3 VISIBILI
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3.2.3 Surface and Tower Visibility
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SUR- FACE VISIBILITY PRESENT WEATHE
Page 32 and 33: 3.3 Visibility Chart As an aid for
Page 34 and 35: OUTLINE DETERMINING VISIBILITY From
Page 36 and 37: REVIEW QUESTIONS Select the best an
Page 38 and 39: 11. 12. At the time of observation,
Page 40 and 41: 23. Weather conditions being equal,
Page 42 and 43: 38. Visibility of 2 3/8 miles is re
Page 44 and 45: When more than one type of present
Page 46 and 47: 4.1.2 Descriptors Descriptors are q
Page 48 and 49: Obscurations that stand alone, i.e.
Page 50 and 51: Question: What does an observer do
Page 52 and 53: Footnotes for Weather Phenomena Mat
Page 54 and 55: 9. +FZRA a. Severe freezing rain b.
Page 56 and 57: 23. Volcanic ash is reported: a. wh
Page 58 and 59: 37. Match the following present wea
Page 60 and 61: 46. Which of the following precipit
Page 62 and 63: 59. Steady rain is observed 4 miles
Page 64 and 65: 72. Rain showers of an unknown inte
Page 66 and 67: 5.2 Sky Cover Figure 5-2. Weather O
Page 68 and 69: Example 5-2. One Layer with Single
Page 70 and 71: Figure 5-4. Advancing Layer (sky co
Page 72 and 73: 5-8
Page 74 and 75: Figure 5-10. Surface-base Layer Sur
Page 76 and 77: Example 5-5. Four Layers. The follo
Page 78 and 79: Example 5-8. One Layer. Example 5-9
Page 80 and 81: 1 CU - Cumulus 1 Example 5-12. Mult
Page 84 and 85: 5. When a balloon is used for deter
Page 86 and 87: OUTLINE DETERMINING SKY COVER AMOUN
Page 88 and 89: Select the correct answer. REVIEW Q
Page 90 and 91: 20. If a layer aloft has less than
Page 92 and 93: 40. Match the following reportable
Page 94 and 95: 6.1 Temperature and Dew Point - T
Page 96 and 97: 6. Obtain the difference between th
Page 98 and 99: Other examples of determining wet-b
Page 100 and 101: The conversion from ice to water ca
Page 102 and 103: a. Read right end of index in minim
Page 104 and 105: Figure 6-8. Reading a Thermometer t
Page 106 and 107: TIME G LST G UTC (2) TEMP. (°C) DE
Page 108 and 109: Method II: Centrifugal Force A shor
Page 110 and 111: INSTRUCTIONS: Select the best answe
Page 112 and 113: 16. Under what conditions is the de
Page 114 and 115: 6-21 +130 129 128 127 126 +125 124
Page 116 and 117: 6-23
Page 118 and 119: The altimeter setting shall be repo
Page 120 and 121: 7-4
Page 122 and 123: 7. Sea-level pressure is an adjustm
Page 124 and 125: 2. Additive Data [NA SAWRS] 3- and
Page 126 and 127: 8.2.2.2 24-Hour Precipitation Amoun
Page 128 and 129: When finished, put the emptied meas
Page 130 and 131: 8.3.3.1 Depth of New Snow (Snowfall
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8-10
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10. A thunderstorm is overhead, mov
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26. A 6-hourly maximum temperature
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CHAPTER 9 REVIEW EXERCISES OBSERVIN
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Exercise #3 Lower layer has ____/8t
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Exercise #5 Surface based layer has
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Exercise #7 Total sky coverage is _
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Exercise #9 Lower layer has ____/8t
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Exercise #11 Total sky coverage is
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QUALITY CONTROL EXERCISE Each of th
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21. METAR KKKK 282045Z E29006KT 7SM
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42. METAR KFFF 302250Z 03008KT 40SM
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16. a. METAR 17. b. second 18. d. f
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11. - a change in wind direction of
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...unfocused lights of moderate int
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22. b precipitation occurring not a
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52. b. decreasing dominance. 53. b.
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24. 8 VV 25. 8 OVC 26. 7 BKN 27. as
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A-14
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A-16
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A-18
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18. 1200 UTC or other time modified
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9. Lower layer has 1 /8ths coverage
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16. METAR KFFF 312148Z 36005KT 1 1/
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43. METAR KGGG 052145Z 05009KT 4SM
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WET BULB TEMPERATURES 31 32 33 34 3
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WS Form B-11 (12-96) Pres. by WSOH
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C-3
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. If an altimeter setting indicator
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Training Guide in Surface Weather Observations - Multiple Choices

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