Q201: Which factor can prevent radiation fog from forming? ^t50q201

• A) Low spread
• B) Calm wind
• C) Overcast cloud cover
• D) Clear night, no clouds

Correct: C)

Explanation: Radiation fog forms on clear, calm nights when the ground radiates heat to space, cooling the surface air to its dew point. An overcast cloud cover prevents the necessary radiative cooling of the ground surface by acting as an insulating blanket, reflecting long-wave radiation back to the ground. Calm wind (option B) is actually a prerequisite for radiation fog formation. A clear night (option D) and low spread (option A) are also favourable, not preventative, conditions.

Q202: Through what process does advection fog form? ^t50q202

• A) Extended radiative cooling on clear nights
• B) Warm, humid air moving across a cold surface
• C) Mixing of cold, humid air with warm, humid air
• D) Cold, moist air flowing over warm ground

Correct: B)

Explanation: Advection fog forms when warm, moist air is transported (advected) horizontally over a cold surface and cooled from below to its dew point. This is most common over cold ocean currents or cold land surfaces in spring. Option D reverses the temperature relationship. Option C describes mixing fog (a different type). Option A describes radiation fog. The defining factor in advection fog is the movement of warm moist air over cold ground.

Q203: What process leads to the development of orographic fog (hill fog)? ^t50q203

• A) Warm, humid air being forced over hills or a mountain range
• B) Mixing of cold, moist air with warm, moist air
• C) Extended radiation on cloudless nights
• D) Evaporation from warm, wet ground into very cold air

Correct: A)

Explanation: Orographic fog (hill fog) forms when moist air is forced to rise over terrain, cooling adiabatically until it reaches its dew point; the result is a cloud base that sits on the hillside or mountain top. Option C describes radiation fog. Option D describes steam fog (evaporation/mixing fog). Option B describes mixing fog. The key process is forced lifting of moist air over elevated terrain.

Q204: What weather phenomena are associated with an upper-level trough? ^t50q204

• A) Development of showers and thunderstorms (Cb)
• B) Light winds and shallow cumulus formation
• C) High stratus layers with ground-covering cloud bases
• D) Calm weather and formation of lifted fog layers

Correct: A)

Explanation: An upper-level trough is a region of cold air aloft with positive vorticity advection, which promotes divergence aloft and convergence at the surface, triggering strong convective uplift. This instability favours the development of showers and thunderstorms (Cumulonimbus). Options B and D describe stable, anticyclonic conditions. Option C (high stratus) would require stable, moist conditions near the surface, not the convective instability associated with a cold upper trough.

Q205: On the windward side of a mountain range during Foehn, what weather should be expected? ^t50q205

• A) Cloud dissipation with unusual warming and strong gusty winds
• B) Layer clouds, mountain peaks obscured, poor visibility, and moderate to heavy rain
• C) Scattered cumulus with showers and thunderstorms
• D) Calm winds and formation of high stratus (high fog)

Correct: B)

Explanation: On the windward (stau) side of a mountain range during Foehn, moist air is forced to rise and cool, producing dense cloud, obscured peaks, poor visibility, and moderate to heavy rain or snow — the classic 'Stau' weather. Option A describes the lee side of the Foehn (warm, dry, gusty). Option D describes stable, fog-prone conditions unrelated to Foehn. Option C describes conditions more typical of frontal convective activity.

Q206: Which chart presents observed MSL pressure distribution and the corresponding frontal systems? ^t50q206

• A) Significant Weather Chart (SWC).
• B) Prognostic chart.
• C) Surface weather chart.
• D) Hypsometric chart

Correct: C)

Explanation: The surface weather chart (also called the synoptic chart or analysis chart) displays actual measured pressure values reduced to MSL as isobars, along with the positions of frontal systems. It represents the observed state of the atmosphere at a specific time. A prognostic chart (option B) shows forecast conditions. The hypsometric chart (option D) shows upper-level contour heights on constant-pressure surfaces. The SWC (option A) focuses on hazardous weather phenomena, not comprehensive pressure analysis.

Q207: In METAR, how is heavy rain encoded? ^t50q207

• A) SHRA
• B) .+SHRA.
• C) .+RA
• D) RA.

Correct: C)

Explanation: This question is identical to question 120. In METAR, precipitation intensity modifiers are '+' for heavy and '-' for light. 'RA' is the METAR code for rain; therefore '+RA' (shown as '.+RA' in the options) denotes heavy rain. 'RA' (option D) alone means moderate rain. 'SHRA' (option A) is shower of rain. '+SHRA' (option B) is heavy shower of rain — a different precipitation type.

Q208: In METAR, how are moderate rain showers encoded? ^t50q208

• A) .+RA.
• B) TS.
• C) .+TSRA
• D) SHRA.

Correct: D)

Explanation: In METAR, the descriptor 'SH' (shower) is added before the precipitation code to indicate convective precipitation from cumuliform clouds. Moderate showers of rain are therefore coded 'SHRA'. '+TSRA' (option C) means heavy thunderstorm with rain. 'TS' (option B) means thunderstorm without precipitation modifier. '+RA' (option A) means heavy continuous rain from stratiform clouds, not a shower.

Q209: Under what conditions does back-side weather (Ruckseitenwetter) occur? ^t50q209

• A) After the passage of a warm front
• B) During Foehn on the lee side
• C) After the passage of a cold front
• D) Before the passage of an occlusion

Correct: C)

Explanation: Back-side weather (Rückseitenwetter) describes the weather in the cold air mass following the passage of a cold front: cold, unstable polar or arctic air with scattered showers, good visibility, and gusty winds — often excellent soaring conditions for gliders in the convective back-side air. It occurs after, not before, frontal passages. An occlusion (option D) combines warm and cold front characteristics. Foehn (option B) is a separate orographic phenomenon. After a warm front (option A) brings the warm sector, not cold back-side air.

Q210: In the International Standard Atmosphere, how does temperature change from MSL to approximately 10,000 m altitude? ^t50q210

• A) From +15° to -50°C
• B) From -15° to +50°C
• C) From +30° to -40°C
• D) From +20° to -40°C

Correct: A)

Explanation: In the International Standard Atmosphere (ISA), the temperature at MSL is +15°C, and the temperature decreases at 6.5°C per 1000 m (2°C per 1000 ft) through the troposphere. At approximately 11,000 m (the tropopause), the temperature reaches -56.5°C, rounding to approximately -50°C at 10,000 m. Options C and D give incorrect MSL starting values (+30°C and +20°C). Option B reverses the sign convention, implying temperature increases with altitude.

Q211: What weather should be expected during Foehn conditions in the Bavarian region near the Alps? ^t50q211

• A) Nimbostratus on the northern Alps, rotor clouds on the windward side, warm and dry wind
• B) High pressure over the Bay of Biscay and low pressure over Eastern Europe
• C) Nimbostratus on the southern Alps, rotor clouds on the lee side, warm and dry wind
• D) Cold, humid downslope wind on the lee side of the Alps with a flat pressure pattern

Correct: C)

Explanation: Classic Bavarian Foehn is driven by low pressure over the Gulf of Genoa and high pressure over the North Sea, forcing air southward over the Alps. Nimbostratus forms on the south (windward) side of the Alps, while on the north (lee) Bavarian side, warm and dry air descends, often accompanied by Föhnmauer (Foehn wall) and rotor clouds along the Foehn boundary. Option A incorrectly describes the lee-side wind as cold and humid and places the Ns on the wrong side. Option B describes the synoptic pressure setup only partially. Option A places the Ns on the north (lee) side, which is incorrect.