Sign in

NDA Geography · Climatology, Atmosphere and Weather

Cyclones, Fronts and Local Winds

Cyclones are low-pressure storms with inward-spiralling winds — tropical ones born over warm seas, temperate ones born along fronts where air masses meet — and around them swirl the named local winds the NDA loves to test.

All Climatology, Atmosphere and Weather notesNDA Geography strategy

Why this matters

14 PYQs — tied for the largest subtopic, and rich in HARD multi-statement traps. Three blocks of marks: tropical vs temperate (extratropical) cyclones and their rotation/formation; fronts and air masses; and the named local winds (Mistral, Sirocco, Chinook, Santa Ana, Loo, Bora, Purga...). The local-wind names are pure recall — drill them to reflex.

Concept 1 of 3

Tropical vs temperate cyclones

Intuition

A cyclone is a low-pressure storm whose winds spiral INWARD — anticlockwise in the Northern Hemisphere, clockwise in the Southern (because Coriolis deflects to the left there). TROPICAL cyclones are compact, born over warm seas, and feed on ocean heat. TEMPERATE (extratropical) cyclones are larger, born in the mid/high latitudes along FRONTS where warm and cold air masses meet (the Polar Front Theory). Cyclones bring cloudy, rainy weather; anticyclones bring fair weather.

Definition

  • Cyclone rotation: winds spiral inward, anticlockwise in the Northern Hemisphere, CLOCKWISE in the Southern (Coriolis deflects left in the SH). Anticyclones rotate the opposite way.
  • Tropical cyclones — form over warm tropical seas (need warm water, Coriolis, upper-air divergence, LOW vertical wind shear). Called hurricanes (N Atlantic / E N Pacific), typhoons (NW Pacific / China), cyclones (Indian & S Pacific Oceans), Willy Willy (Australia), Baguio (Philippines).
  • Temperate / extratropical cyclones — form in mid and high latitudes along the Polar Front; they cover a much larger area than tropical cyclones and generally move WEST to EAST (NOT east to west).
  • Cyclones → cloudy/rainy weather; anticyclones → fair weather.
Eyecalm, clearEyewallstrongest winds + rainSpiral rain bandsInward spiralanticlockwise (N Hemisphere)

Worked example

Three claims: (1) in the Northern Hemisphere cyclones rotate anticlockwise and anticyclones clockwise; (2) cyclones bring rainy weather, anticyclones fair weather; (3) in the Southern Hemisphere the cyclonic spiral is clockwise because Coriolis acts to the left. How many are correct?
  1. NH cyclone = anticlockwise, anticyclone = clockwise — (1) correct.
  2. Cyclone = cloudy/rainy, anticyclone = fair — (2) correct.
  3. SH Coriolis deflects left, so the cyclonic spiral is clockwise — (3) correct.
Answer:All three statements are correct.
Practice this conceptself-check · 4 quick reps

Try it yourself

Which type of cyclone is essentially related to the 'Polar Front Theory'?

Practice — Level 1 (4 reps)

Quick reps to lock in the method. Try each, then check.

  1. 1.
    Which way do cyclones spiral in the Southern Hemisphere?
  2. 2.
    What is a Northwest-Pacific tropical cyclone called?
  3. 3.
    Do temperate cyclones move west-to-east or east-to-west?
  4. 4.
    Polar Front Theory explains which cyclone type?

From the bank · past-year question

Example 1Climatology, Atmosphere and WeatherMODERATE
Which of the following statements regarding cyclones and anti-cyclones is/are correct ? 1. In the Northern Hemisphere, cyclones rotate counter clockwise and anticyclones rotate clockwise. 2. Cyclones are often associated with cloudy or rainy weather, whereas anticyclones are often associated with fair weather. 3. In the Southern Hemisphere, the cyclonic spiral will be clockwise because the Coriolis force acts to the left. Select the answer using the code given below :

[Q112 · Apr · 2024]

Temperate cyclones move WEST to EAST

An extratropical-cyclone trap claims 'they move from east to west'. Mid-latitude (temperate) cyclones are steered by the westerlies and move west to east. They DO develop in mid/high latitudes and DO affect a larger area — those two claims are true.

Hurricane vs typhoon by ocean

Tropical cyclones of the North Atlantic / eastern North Pacific are hurricanes; those of the NW Pacific are typhoons. A trap swaps these names. The Indian and South Pacific Oceans just call them 'cyclones'.
Drill 5 more on tropical vs temperate cyclones

Concept 2 of 3

Fronts and air masses

Intuition

An AIR MASS is a huge body of air with uniform temperature and humidity, formed over a large source region (tropical or polar, land or sea) — it forms under SETTLED conditions, not cyclonic ones. Where two air masses meet, the boundary is a FRONT. At a WARM front, advancing warm air rides gently up over cold air; at a COLD front, advancing cold air shoves under warm air, forcing it up steeply — which is why cold fronts spawn thunderstorms.

Definition

  • An air mass forms in a tropical OR polar source region, over continents OR oceans, and changes the weather of areas it moves into. It forms under stable/settled conditions — it does NOT 'develop in a cyclonic condition' (that claim is false).
  • A front is the boundary between two air masses.
  • Warm front — advancing warm air rides up OVER a retreating colder air mass (gentle slope, steady rain). This is the correct definition.
  • Cold front — advancing cold air undercuts warm air, lifting it steeply — associated with thunderstorms.
  • A front's passage usually brings a fairly rapid (not slow) change of weather — so 'a front causes a SLOW change in weather' is the false statement.
Warm frontCold airWarm air rises gentlysteady, widespread rainCold frontCold airWarm air lifted steeplythunderstorm

Worked example

Three claims about fronts: (1) a front's movement causes a SLOW change in weather; (2) cold fronts are associated with thunderstorms; (3) a warm front is where advancing warm air overrides and rises above colder air. Which are correct?
  1. A front usually brings a fairly rapid weather change, not a slow one — (1) wrong.
  2. Cold fronts lift warm air steeply, triggering thunderstorms — (2) correct.
  3. A warm front is exactly warm air overriding cold air — (3) correct.
Answer:Statements 2 and 3 are correct.
Practice this conceptself-check · 3 quick reps

Try it yourself

Which statement about air masses is NOT true: (a) they form in tropical or polar regions; (b) they develop over land and ocean; (c) they develop in a cyclonic condition; (d) they change weather conditions?

Practice — Level 1 (3 reps)

Quick reps to lock in the method. Try each, then check.

  1. 1.
    Which front is associated with thunderstorms?
  2. 2.
    At a warm front, does warm air rise over cold or shove under it?
  3. 3.
    Do air masses form in cyclonic or settled conditions?

From the bank · past-year question

Example 2Climatology, Atmosphere and WeatherHARD
Consider the following statements regarding 'fronts' : 1. The movement of a front causes a slow change in weather in the area over which it moves. 2. Cold fronts are associated with thunderstorms. 3. Warm front is the boundary between an advancing mass of warm air where it is overriding and rising above a mass of colder air. Which of the statements given above is/are correct ?

[Q74 · Apr · 2024]

A front's passage is a RAPID change, not slow

The statement 'the movement of a front causes a SLOW change in weather' is false — a passing front brings a comparatively abrupt shift (temperature, wind, cloud and rain all change quickly).

Air masses form in SETTLED conditions

An air mass needs a large, calm source region to take on uniform properties — it does NOT 'develop in a cyclonic condition'. That is the odd-one-out in 'which is NOT true' questions.
Drill 1 more on fronts and air masses

Concept 3 of 3

Named local winds

Intuition

Local winds are short-range winds with regional names, and the NDA tests the name-to-place pairing relentlessly. Group them by region — Mediterranean (Sirocco, Mistral, Khamsin), North America (Chinook, Santa Ana), the Middle East / Mesopotamia (Shamal), Siberia (Purga). The classic odd-one-out: the Harmattan blows in West Africa, NOT the Mediterranean.

Definition

Memorise the wind-to-place pairs:

  • Mediterranean winds — Sirocco (hot, from the Sahara), Mistral (cold, down the Rhone), Khamsin (hot, Egypt). The Harmattan is NOT Mediterranean — it blows over West Africa.
  • North America — Chinook (warm, dry; 'snow-eater', raises winter temperatures fast), Santa Ana (hot, dry; fuels Southern California wildfires).
  • Mesopotamia / Middle East — Shamal (warm, dry).
  • Siberia — Purga (cold blizzard wind blowing out of Siberia).
  • The doldrums (equatorial low) is a belt of calm winds, NOT a local wind.
Local windRegionCharacter
HarmattanWest AfricaNOT Mediterranean (the odd one out)
NDA 2024 — Harmattan is the one NOT related to the Mediterranean.
SiroccoMediterranean (from Sahara)Hot, dusty
MistralMediterranean (Rhone valley)COLD, dry
KhamsinEgypt / MediterraneanHot
ChinookNorth America (Rockies)Warm, dry 'snow-eater'
Santa AnaSouthern CaliforniaHot, dry; causes wildfires
NDA 2026 — Santa Ana wind drives Southern California wildfires.
ShamalMesopotamia / Middle EastWarm, dry
NDA 2019 — Shamal is found in Mesopotamia.
PurgaSiberiaCold blizzard wind
NDA 2018 — Purga blows out from Siberia.
Practice this conceptself-check · 5 quick reps

Try it yourself

Which local wind is NOT related to the Mediterranean Sea: Harmattan, Khamsin, Sirocco, Mistral?

Practice — Level 1 (5 reps)

Quick reps to lock in the method. Try each, then check.

  1. 1.
    Which wind causes Southern California wildfires?
  2. 2.
    Which cold blizzard wind blows out of Siberia?
  3. 3.
    The Shamal is a local wind of which region?
  4. 4.
    Chinook is what kind of wind?
  5. 5.
    Is the doldrums a local wind?

From the bank · past-year question

Example 3Climatology, Atmosphere and WeatherMODERATE
Which one among the following local winds is NOT related to Mediterranean Sea ?

[Q80 · Sep · 2024]

Harmattan is West African, not Mediterranean

Grouped with Khamsin, Sirocco and Mistral (all Mediterranean), the Harmattan is the outsider — a dry, dusty West African wind.

Chinook is HOT-DRY, the doldrums is CALM

The Chinook is a warm, dry descending wind that raises temperatures quickly in winter (true). The doldrums is a belt of calm equatorial winds — a pressure belt, not a local wind.
Drill 6 more on named local winds

Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Reference tables (1)

Named local winds8 rows
Local windRegionCharacter
HarmattanWest AfricaNOT Mediterranean (the odd one out)
NDA 2024 — Harmattan is the one NOT related to the Mediterranean.
SiroccoMediterranean (from Sahara)Hot, dusty
MistralMediterranean (Rhone valley)COLD, dry
KhamsinEgypt / MediterraneanHot
ChinookNorth America (Rockies)Warm, dry 'snow-eater'
Santa AnaSouthern CaliforniaHot, dry; causes wildfires
NDA 2026 — Santa Ana wind drives Southern California wildfires.
ShamalMesopotamia / Middle EastWarm, dry
NDA 2019 — Shamal is found in Mesopotamia.
PurgaSiberiaCold blizzard wind
NDA 2018 — Purga blows out from Siberia.

Watch out for (6)

Mastery check — 5 interleaved questions

Try each one before clicking. Questions are interleaved across the concepts above, not grouped — interleaving sharpens transfer.

Example 1Climatology, Atmosphere and WeatherHARD
Consider the following conditions favourable for the formation and intensification of Tropical Storms : 1. Presence of the Coriolis force 2. Upper divergence above the sea level system 3. High variations in the vertical wind speed Which of the conditions given above is/are correct ?

[Q121 · Sep · 2025]

Example 2Climatology, Atmosphere and WeatherMODERATE
Which one of the following is NOT true in reference to Air mass?

[Q66 · Apr · 2019]

Example 3Climatology, Atmosphere and WeatherHARD
Match List-I with List-II and select the correct answer using the code given below the Lists : List-I (Local Wind) A. Yamo B. Black Roller C. Bise D. Haboob List-II (Place) 1. Sudan 2. France 3. Japan 4. North America

[Q97 · Sep · 2018]

Example 4Climatology, Atmosphere and WeatherMODERATE
Match List I with List II: List I (Tropical Cyclone): A. Hurricanes B. Willy Willy C. Baguio D. Typhoons List II (Country): 1. China 2. Philippines 3. Australia 4. USA Code :

[Q108 · Sep · 2024]

Example 5Climatology, Atmosphere and WeatherHARD
Which one of the following is a local wind that blows out from Siberia?

[Q114 · Apr · 2018]

Drill every past-year question on this subtopic

16 questions from the bank — paginated, with cart and Word-export support.

Drill the 16 questions