AEROGRAPHER'S MATE 3 & 2 



a wide area. This type fog is also very deep, 

 because it extends from the ground to the frontal 

 surface. The clouds above the frontal surface 

 also slow down the dissipating effect of solar 

 heating. All these factors make the warm-front 

 fog the worst possible type to encounter. (See 

 fig. 15-11.) 



DEW 



Dew is a deposit of waterdrops on objects 

 at or near the ground. It is produced by conden- 

 sation of water vapor from the surrounding 

 clear air and occurs on relatively calm, clear 

 nights. 



White Dew 



White dew consists of a deposit of white, 

 frozen dew drops. It first forms as liquid dew, 

 then freezes. 



FROST 



Frost, or hoarfrost, is a deposit of ice 

 having a crystalline appearance. It generally 

 assumes the form of scales, needles, feathers, 

 or fans. Hoarfrost is the solid equivalent of 

 dew and should not be confused with white dew, 

 which is dew frozen after it formed. Frost 



(A) WEATHER MAP 

 WARM-FRONT FOG 



PRECIPITATION AREA 



WARM FRONT 



(B) VERTICAL CROSS 

 ALONG A A 



COLD AIR 



209.31 



Figure 15-11. — Warm-front fog. 

 362 



