If the temperature/dewpoint spread is small and decreasing, and 
the temperature is 62°F, what type weather is most likely to 
develop? 





   ANSWER: Fog or low clouds. 

   The difference between the air 
   temperature and dew point is the temperature/dew point 
   spread. As the temperature/dew point spread decreases, fog 
   or low clouds tend to develop. 

In which situation is advection fog most likely to form? 





   ANSWER: An air mass moving inland from the coast in winter. 

   Advection fog forms when moist air 
   moves over colder ground or water. It is most common in 
   coastal areas. 

What situation is most conducive to the formation of radiation 
fog? 





   ANSWER: Warm, moist air over low, flatland areas on clear, calm 
   nights. 

   Radiation fog is shallow fog of which 
   ground fog is one form. It occurs under conditions of clear 
   skies, little or no wind, and a small temperature/dew point 
   spread. The fog forms almost exclusively at night or near 
   dawn as a result of terrestrial radiation cooling the ground 
   and the ground cooling the air on contact with it. 

What types of fog depend upon wind in order to exist? 





   ANSWER: Advection fog and upslope fog. 

   Advection fog forms when moist air 
   moves over colder ground or water. It is most common in 
   coastal areas. Upslope fog forms when wind blows moist air 
   upward over rising terrain and the air cools below its dew 
   point. Both advection fog and upslope fog require wind to 
   move air masses. 

Low-level turbulence can occur and icing can become hazardous in 
which type of fog? 





   ANSWER: Steam fog. 

   Steam fog forms in winter when cold, 
   dry air passes from land areas over comparatively warm 
   ocean waters, and is composed entirely of water droplets 
   that often freeze quickly. Low-level turbulence can occur 
   and icing can become hazardous. 

Convective circulation patterns associated with sea breezes are 
caused by 





   ANSWER: cool, dense air moving inland from over the water. 

   Sea breezes are caused by cool and 
   more dense air moving inland off the water. Once over the 
   warmer land, the air heats up and rises. Thus the cooler, 
   more dense air from the sea forces the warmer air up. 
   Currents push the hot air over the water where it cools and 
   descends, starting the cycle over again. This process is 
   caused by land heating faster than water. 

The development of thermals depends upon 





   ANSWER: solar heating. 

   Thermals are updrafts in small scale 
   convective currents. Convective currents are caused by 
   uneven heating of the earth's surface. Solar heating is the 
   means of heating the earth's surface. 

Which weather phenomenon is always associated with a 
thunderstorm? 





   ANSWER: Lightning. 

   A thunderstorm, by definition, has 
   lightning, because lightning causes the thunder. 

To get a complete weather briefing for the planned flight, the pilot 
should request 





   ANSWER: a standard briefing. 

   To get a complete briefing before a 
   planned flight, the pilot should request a standard briefing. 
   This will include all pertinent information needed for a safe 
   flight. 

Which type weather briefing should a pilot request, when 
departing within the hour, if no preliminary weather information has 
been received? 





   ANSWER: Standard briefing. 

   A pilot should request a standard 
   briefing anytime (s)he is planning a flight and has not 
   received a previous briefing or has not received preliminary 
   information through mass dissemination media (e.g., TWEB, 
   PATWAS, etc.). 

Which type of weather briefing should a pilot request to 
supplement mass disseminated data? 





   ANSWER: An abbreviated briefing. 

   An abbreviated briefing will be 
   provided when the user requests information to supplement 
   mass disseminated data, update a previous briefing, or to be 
   limited to specific information. 

A weather briefing that is provided when the information requested 
is 6 or more hours in advance of the proposed departure time is 





   ANSWER: an outlook briefing. 

   An outlook briefing is given when the 
   briefing is 6 or more hours before the proposed departure 
   time. 

When telephoning a weather briefing facility for preflight weather 
information, pilots should state 





   ANSWER: the aircraft identification or the pilot's name. 

   When requesting a briefing you 
   should provide the briefer with the following information: 
   VFR or IFR, aircraft identification or the pilot's name, aircraft 
   type, departure point, route of flight, destination, altitude, 
   estimated time of departure, and time en route or estimated 
   time of arrival. 

To update a previous weather briefing, a pilot should request 





   ANSWER: an abbreviated briefing. 

   An abbreviated briefing will be 
   provided when the user requests information (1) to 
   supplement mass disseminated data, (2) to update a 
   previous briefing, or (3) to be limited to specific information. 

When requesting weather information for the following morning, a 
pilot should request 





   ANSWER: an outlook briefing. 

   An outlook briefing should be 
   requested when the briefing is 6 or more hr. in advance of 
   the proposed departure. 

Transcribed Weather Broadcasts (TWEB's) may be monitored by 
tuning the appropriate radio receiver to certain 





   ANSWER: VOR and NDB frequencies. 

   Transcribed Weather Broadcasts 
   (TWEBs) are broadcast on selected VOR and NDB 
   frequencies. 

Individual forecasts for specific routes of flight can be obtained 
from which weather source? 





   ANSWER: Transcribed Weather Broadcasts (TWEB's). 

   Forecasts for specific routes of flight 
   should be obtained from Transcribed Weather Broadcasts 
   (TWEBs) which are based upon specific routes. 

For aviation purposes, ceiling is defined as the height above the 
Earth's surface of the 





   ANSWER: lowest broken or overcast layer or vertical visibility into 
   an obscuration. 

   A ceiling layer is not designated in 
   the METAR code. For aviation purposes, the ceiling is the 
   lowest broken or overcast layer, or vertical visibility into an 
   obscuration. 

Figure 12 
(Refer to figure 12.) What are the current conditions depicted for 
Chicago Midway Airport (KMDW)? 





   ANSWER: Sky 700 feet overcast, visibility 1-1/2SM, rain. 

   At KMDW a special METAR (SPECI) 
   was taken at 1856Z and reported wind 320° at 5 kt., visibility 
   1½ SM in moderate rain, overcast clouds at 700 ft., 
   temperature 17°C, dew point 16°C, altimeter 29.80 in. Hg, 
   remarks follow, rain began at 35 min. past the hour. 

Figure 12 
(Refer to figure 12.) Which of the reporting stations have VFR 
weather? 





   ANSWER: KINK, KBOI, and KLAX. 

   KINK is reporting visibility of 15 SM 
   and sky clear (15SM SKC); KBOI is reporting visibility of 30 
   SM and a scattered cloud layer base at 15,000 ft. (30SM 
   SCT150); and KLAX is reporting visibility of 6SM in mist 
   (fog) with a scattered cloud layer at 700 ft. and another one 
   at 25,000 ft. (6SM BR SCT007 SCT250). All of these 
   conditions are above VFR weather minimums of 1,000-ft. 
   ceiling and/or 3-SM visibility. 

Figure 12 
(Refer to figure 12.) The wind direction and velocity at KJFK is 
from 





   ANSWER: 180° true at 4 knots. 

   The wind group at KJFK is coded as 
   18004KT. The first three digits are the direction the wind is 
   blowing from referenced to true north. The next two digits 
   are the speed in knots. Thus, the wind direction and speed 
   at KJFK are 180° true at 4 kt. 

Figure 12 
(Refer to figure 12.) What are the wind conditions at Wink, Texas 
(KINK)? 





   ANSWER: 110° at 12 knots, gusts 18 knots. 

   The wind group at KINK is coded as 
   11012G18KT. The first three digits are the direction the wind 
   is blowing from referenced to true north. The next two digits 
   are the wind speed in knots. If the wind is gusty, it is 
   reported as a "G" after the speed followed by the highest (or 
   peak) gust reported. Thus, the wind conditions at KINK are 
   110° true at 12 kt., peak gust at 18 kt. 

Figure 12 
(Refer to figure 12.) The remarks section for KMDW has RAB35 
listed. This entry means 





   ANSWER: rain began at 1835Z. 

   In the remarks (RMK) section for 
   KMDW, RAB35 means that rain began at 35 min. past the 
   hour. Since the report was taken at 1856Z, rain began at 35 
   min. past the hour, or 1835Z. 

Figure 14 
(Refer to figure 14.) If the terrain elevation is 1,295 feet MSL, what 
is the height above ground level of the base of the ceiling? 





   ANSWER: 505 feet AGL. 

   Refer to the PIREP (identified by the 
   letters UA) in Fig. 14. The base of the ceiling is reported in 
   the sky cover (SK) section. The first layer is considered a 
   ceiling (i.e., broken) and the base is 1,800 ft. MSL. The 
   height above ground of the broken base is 505 ft. AGL (1,800 
   - 1,295). 

Figure 14 
(Refer to figure 14.) The base and tops of the overcast layer 
reported by a pilot are 





   ANSWER: 7,200 feet MSL and 8,900 feet MSL. 

   Refer to the PIREP (identified by the 
   letters UA) in Fig. 14. The base and tops of the overcast 
   layer are reported in the sky conditions (identified by the 
   letters SK). This pilot has reported the base of the overcast 
   layer at 7,200 ft. and the top of the overcast layer at 8,900 ft. 
   (072 OVC 089). All altitudes are stated in MSL unless 
   otherwise noted. Thus, the base and top of the overcast 
   layer are reported as 7,200 ft. MSL and 8,900 ft. MSL, 
   respectively. 

Figure 14 
(Refer to figure 14.) The wind and temperature at 12,000 feet MSL 
as reported by a pilot are 





   ANSWER: 080° at 21 knots and -7°C. 

   Refer to the PIREP (identified by the 
   letters UA) in Fig. 14. The wind is reported in the section 
   identified by the letters WV and is presented in five or six 
   digits. The temperature is reported in the section identified 
   by the letters TA in °C, and if below 0°C, prefixed with an 
   "M." The wind is reported as 080° at 21 kt. with a 
   temperature of -7°C. 

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