Weather for Flying in Middle-East:

Saudi | Qatar | Oman

🌤 APPI Weather Manual – Combined Summary (Part I + Part II)

A practical meteorology guide for paraglider pilots.

1. The Atmosphere – Foundations of Weather

The troposphere (up to ~6 km at poles, ~11 km mid‑latitudes, ~16 km equator) is where all paragliding‑relevant weather occurs. Above it lies the tropopause, which blocks moisture and prevents cloud growth into the stratosphere.

Air is mostly 78% nitrogen, 21% oxygen, 1% other gases, including CO₂ which contributes to the greenhouse effect.
Air contains condensation nuclei (pollen, dust, smoke), essential for cloud formation.

2. Pressure, Density & Humidity

2.1 Pressure

Pressure decreases exponentially with altitude.
Standard pressure: 101.3 kPa at sea level.
High altitude = faster glider, faster takeoff/landing, slower human reactions.

2.2 Density

Warm air is less dense → rises.
Cold air is denser → sinks.
Density drops with heat & altitude → glider flies faster.

2.3 Humidity Concepts

Absolute humidity: actual water content.
Saturation humidity: max water air can hold at a given temperature.
Relative humidity (RH) = AH / SH × 100
Dew point: temp at which RH becomes 100% → cloud or fog formation.

3. Temperature & Lapse Rates

Air is heated mainly by Earth’s surface (not directly by the sun). Heat transfers via:

Conduction (ground to air)
Convection (vertical air movement)
Radiation
Advection (horizontal warm/cold air movement)

Lapse Rates

Environmental lapse rate: ~0.65°C / 100 m
Dry adiabatic: 1°C / 100 m
Moist adiabatic: 0.4–0.9°C / 100 m depending on dew point
Determines if atmosphere is stable, neutral, or unstable.

Unstable air → thermals, cumulus, storms
Stable air → stratus, inversions, weak or no thermals

4. Clouds – The Language of the Sky

Clouds form when rising air cools to its dew point. Formation triggers include:

Orographic lift
Thermal lift
Frontal lift
Radiation cooling
Advection of moist air over cold ground

Key Cloud Types and Meanings

Cumulus → thermal activity, good flying (Cu humilis)
Cumulus congestus → strong thermals, pre‑storm
Cumulonimbus (CB) → storms, hail, extreme danger
Stratus → stable air, poor soaring
Lenticularis → strong winds & wave lift (and rotor!)
Nimbostratus → steady widespread rain

5. Fog & Precipitation

Fog Types

Radiation fog → clear nights, calm winds
Advection fog → moist air over cold surface
Flying in fog is illegal (VFR rules) and extremely dangerous.

Precipitation

Formed when droplets become too heavy for updraft → rain, snow or hail (inside CBs).

6. Weather Fronts (Critical for Safety)

Fronts are boundaries between air masses.

6.1 Warm Front

Warm air glides over cold air
Produces layered clouds, long steady rain
Generally stable but not flyable

6.2 Cold Front

Cold air undercuts warm air
Produces rapid lift, CBs, storms, turbulence, strong wind shifts
VERY hazardous for flight

6.3 Occluded Front

Cold front overtakes warm front
Severe turbulence possible

7. Pressure Systems & Global Circulation

High Pressure (Anticyclone)

Air sinks, warms → stable weather, inversions, weak thermals

Low Pressure (Cyclone)

Air rises, cools → clouds, rain, storms
Wind flows inward & counter‑clockwise (Northern Hemisphere)

Coriolis effect

Deflects wind to the right in the Northern Hemisphere