10 



UNITED STATES COAST GUARD 



In order for clouds to form in the 

 atmosphere, what must be present be- 

 sides water vapor? 



Why do clouds always appear thick- 

 er, darker, and closer together near 

 the horizon? 



Why do thunderstorms occur most 

 frequently from midnight to early 

 morning at sea, whereas, on land they 

 occur frequently in the late afternoon? 



What sequence of cloud types is char- 

 acteristic of the approach of a cold 

 front? 



What is a "growler"? 



What is meant by : 



(a) Hummocked ice; 



(b) Ice jamming; 



(c) Icebergs? 



A vessel's true course is 175° and 

 speed is 18 knots. The apparent wind 

 is from SSW with a 15 knot apparent 

 wind velocity. 



Required: 



(a) The direction from which the 

 true wind is blowing. 



(b) The velocity of the true wind. 

 To what wind force on the Beaufort 



Scale do the following conditions cor- 

 respond? 



Wind Speed less than 1 knot; 



Sea Condition smooth and min-or 

 like. 



What is a squall? 



What is a tropical cyclone? 



How may clouds provide early in- 

 dication of a tropical cyclone? 



Interpret the wind rose, sketched as 

 it would be shown on a Pilot Chart to- 

 gether with the scale of wind percent- 

 ages. 



When a tornado moves out over the 

 water from land, what name is applied 

 to the resulting phenomenon? 



State the usual sequence of winds, 

 clouds, precipitation, pressure and tem- 

 perature which will be observed on the 

 line of direction of movement of the 

 depression illustrated. 



Wrection of 

 Movement 



Front 



What is the usual sequence of direc- 

 tions in which a tropical cyclone in the 

 Northei'n Hemisphere moves? 



State the rule for determining the 

 dangerous and navigable semicircle of 

 tropical cyclones. 



What is the general direction in 

 which storms move in the temperate 

 zones? 



10 



20 30 ho iO 60 70 80 90 100 



SCALE OF WIND PERCENTAGES 



