Chapter 26

AVIATION WEATHER FORECASTS
TAF, ARFOR & ROFOR

DGCA CPL/ATPL Study Notes — Aviation Meteorology

🗺️

Compiled by Capt. Pankaj Pahil

DGCA CPL/ATPL Study Notes — Aviation Meteorology

1. TAF — Aerodrome Forecast
2. TAF Code Form & Groups
3. TAF Decoded Examples
4. TAF Validity & Issuance Rules
5. ARFOR — Area Forecast for Aviation
6. ARFOR Code Sections & Indicators
7. ARFOR Turbulence, Icing & W'W' Codes (Table 26.2)
8. ARFOR Decoded Example
9. ROFOR — Route Forecast for Aviation
10. ROFOR Code Form & Sections
11. ROFOR Decoded Example
12. Weather Symbols Used in Forecasts
13. Practice Q&A — TAF
14. Practice Q&A — ROFOR
15. Master Reference Tables

1. TAF — Aerodrome Forecast

TAF = Terminal Aerodrome Forecast
Used for domestic flights and in VOLMET broadcast.
Valid for at least 9 hr and a maximum of 30 hr.
TAFs valid for 9 hr are issued every 3 hr; 12–30 hr TAFs issued every 6 hr, commencing at 0000 UTC.
9 hr TAF is not disseminated internationally but used for domestic flights and VOLMET.

Key TAF validity rules:
9 hr TAF: issued every 3 hr, commencing 0000 UTC
12–30 hr TAF: issued every 6 hr, commencing 0000 UTC
Amended TAF identified by: TAF AMD

2. TAF Code Form & Groups

TAF CCCC YYGGggZ Y₁Y₁G₁G₁/Y₂Y₂G₂G₂ dddffGfmfmKT/MPS/KMH VVVV or CAVOK NsNsNshs hs hs or V/// or SKC or NSC PROB CₓCₓ YYGGggZ Change likely to occur: (W₁W₂) (TXTrTr/G₁G₁Z TNT′rT′r/G₂G₂Z) Max & Min temperatures

Code Groups Explained

Code	Meaning	Example
TAF	Report type	TAF
CCCC	ICAO Location Indicator	VECC (Kolkata)
YYGGggZ	Date/Time of issue (Day/Hr/Min UTC)	102100Z = 10th, 2100 UTC
Y₁Y₁G₁G₁/Y₂Y₂G₂G₂	Validity: from Day Y₁ Hr G₁ to Day Y₂ Hr G₂ UTC	1100/1309 = 11th 00Z to 13th 09Z
dddff(Gfmfm)KT	Wind direction, speed, gusts, units	09012KT
VVVV or CAVOK	Visibility or CAVOK	2500 BR, CAVOK
NsNsNshs hs hs	Cloud amount and base	FEW040 SCT150
BECMG/TEMPO/NOSIG	Change groups (same as TREND)	BECMG 0204
PROB CₓCₓ	Probability of occurrence: 30% or 40%	PROB30 or PROB40
YYGGggZ (in change)	Change likely to occur between timings GG and G₄G₄	1809/1812 = change on 18th between 0900–1200 UTC
TXTrTr/G₁G₁Z	Maximum temperature / Time UTC	TX42/10Z = Max 42°C at 1000Z
TNT'rT'r/G₂G₂Z	Minimum temperature / Time UTC	TN05/01Z = Min 05°C at 0100Z

PROB Rule: Only PROB30 or PROB40 are used — never PROB50 or higher (that would imply the change is likely, so it becomes BECMG or TEMPO). PROB is never used with TEMPO.

3. TAF Decoded Examples

Example 1

TAF VECC 102100Z 1100/1109 09012KT 2500 BR FEW040 SCT150 BECMG 0204 16015KT 6 000 TEMPO 1107/1109 FEW030CB =

VECC → Kolkata
102100Z → Issued on 10th at 2100 UTC
1100/1109 → Valid 11th day 0000 UTC to 11th day 0900 UTC
09012KT → Surface Wind 090°/12 KT
2500 BR → Visibility 2500 m due to Mist
FEW040 SCT150 → Clouds: 1–2/8 at 4000 ft, 3–4/8 at 15,000 ft
BECMG 0204 → Becoming from 0200 till 0400 UTC
16015KT 6000 → Surface Wind 160°/15 KT, Visibility 6000 m
TEMPO 1107/1109 FEW030CB → Temporarily from 0700–0900: 1–2/8 CB at 3000 ft

Example 2 — with AMD

In TAFs the date and time of issue of TAF is included after CCCC group. Letter Z is an indicator for time of issue in UTC. KT for wind speed.
Amended TAF identified by: TAF AMD

Sample TAFs for Study

TAF VOMM 031500Z 0318/0424 26005KT DZ/HZ SCT015 FEW025CB BKN080 TEMPO 0321/0403 1500 RA/BR SCT010 SCT015 FEW025CB OVC080 BECMG 0405/0406 07005KT 7000 TEMPO 0409/0415 2000 TSRA SCT008 FEW025CB BKN080 BECMG 0416/0417 00000KT 4000 HZ= TAF VOCI 141500Z 1418/1524 14005KT DZ/HZ SCT015 FEW025CB BKN080 TEMPO 1421/1503 1500 RA SCT010 FEW025CB OVC080 TEMPO 1509/1515 2000 TSRA SCT008 FEW025CB BKN080 BECMG 1516/1517 12010KT SCT120 7000=

4. TAF Validity & Issuance Rules

TAF Type	Validity	Issuance Interval	Commencing	Dissemination
Short TAF	9 hr	Every 3 hr	0000 UTC	Domestic + VOLMET only (not international)
Long TAF	12–30 hr	Every 6 hr	0000 UTC	International dissemination

TAF Validity — Example: 1200/1306 = Valid from day 12 time 0000 UTC to day 13 time 0600 UTC
1606/1615 = Valid on day 16 time 0600 to time 1500 UTC

flowchart LR
    A[TAF Issued] --> B{Validity?}
    B -->|9 hr| C[Issued every 3hr\nDomestic/VOLMET only\nNOT disseminated internationally]
    B -->|12-30 hr| D[Issued every 6hr\nCommencing 0000 UTC\nInternational dissemination]
    C --> E[TAF AMD = Amended TAF]
    D --> E

5. ARFOR — Area Forecast for Aviation

ARFOR = Area Forecast for Aviation in figure code for a specific area.
The ARFOR covers meteorological data at multiple altitude levels including winds, temperatures, cloud, turbulence, icing, and jet stream data.
Example area description: VECC AND 50 NM AROUND

6. ARFOR Code Sections & Indicators

ARFOR Code Form

ARFOR (YYGGggZ) Y₁Y₁G₁G₁/Y₂Y₂G₂G₂[KMH or KT or MPS] AAAA (VVVV) (W₁W₁Wᵢ) SECTION 1 (N.CC.lhslhs.hs or VV/// or SKC or NSC) (dddff)(ₑₑₑ) SECTION 2 (1111) QLᵢLᵢLᵢLᵢ h'h'(f ff) SECTION 3 (22222 h'ah'ₘfₐfₐfₐ dₐdₐVV) SECTION 4 9innn

Section Explanations

Section	Content
Section 1	Code identification and time group of ARFOR
Section 2	Symbolic Figure: 11111, and Jet Stream Data (optional)
Section 3	Symbolic Figure: 22222, and Data of Max wind and Vertical wind shear (optional)
Section 4	Supplementary weather phenomena — lowest msl pressure, type of Front, change at Lat/Long, BECMG, FROM, TEMPO etc.

Indicator Figures Used in ARFOR

Indicator	Meaning
7hhhhhhh	7 Indicator for altitude hhhh = Altitude of cloud layer; hhhh = Altitude of Freezing Level
6lhhhht	6 Indicator for Icing; L = Type of icing; hhhh = altitude; t = Thickness
5Bthsbhₛ	5 Indicator for Turbulence
4hbhbTₛTₛ	4 Indicator for Wind and Temperature
2hₜhᵣTₛTᵣ	2 Indicator for Tropopause level pressure and temperature

AAAA = Description of area in plain language, e.g., VECC AND 50 NM AROUND
VVVV = Forecast visibility, e.g., 6000
Cloud Group: (N.CClhslhs.hs or VV/// or SKC or NSC), e.g., 2/8 AC at 10000 ft reported as 2AC100
Cloud Group Reporting Rules:
1st Group: Lowest layer (N, 1/8 or more)
2nd Group: Next higher layer (N, 3/8 or more)
3rd Group: Next higher layer (N, 5/8 or more)
In addition CB if not already included

7. ARFOR Turbulence, Icing & W'W' Codes (Table 26.2)

B (Turb)	Type of Turbulence	L (Icing)	Type of Icing	W'W'	Reported as
0	Nil	0	Nil	111	Thunderstorm (TS)
1	Light	1	Light	222	Tropical Cyclone (TPS)
2	Moderate CAT OCNL	2	Light Icing in Cloud	333	Severe Line Squall (SQ)
3	Moderate CAT Frequent	3	Light Icing in Precipitation	444	Hail (HAIL)
4	Moderate in Cloud Occasional	4	Moderate Icing	555	Marked Mountain Waves (MTW)
5	Moderate in Cloud Frequent	5	Moderate Icing in Cloud	666	Widespread Sandstorm (SAND)
6	Severe CAT OCNL	6	Moderate Icing in Precipitation	777	Widespread Duststorm (DUST)
7	Severe CAT FREQ	7	Severe Icing	888	Freezing Rain (FZRA)
8	Severe in Cloud Occasional	8	Severe Icing in Cloud	—	—
9	Severe in Cloud FREQ	9	Severe Icing in Precipitation	—	—

Mnemonic for W'W' codes:
111 = TS (Thunderstorm) — "ONE-ONE-ONE = THUNDER"
222 = TPS (Tropical Cyclone)
333 = SQ (Squall Line)
444 = HAIL
555 = MTW (Mountain Wave)
666 = SAND (Sandstorm)
777 = DUST (Duststorm)
888 = FZRA (Freezing Rain)

8. ARFOR Decoded Example

ARFOR VIDP 091400 AREA FCST UPTO FL460 VALID 1000/1100 FOR AREA 28N72E 30N80E 20N90E 15N75E 28N72E SYNOPSIS TC CENTRED 23N74E AT 0300UTC MOV NW 20KT INTNSF=

ARFOR VIDP → Area Forecast Issued by Delhi Palam
091400 → On 09th at 1400 UTC Area Forecast
UPTO FL460 → Valid 1000/1100 UTC Area Forecast Upto FL460
VALID 1000/1100 → Valid on 10th Day from 0000 UTC to Next Day 0000 UTC
FOR AREA: 28N72E → 30N80E → 20N90E → 15N75E → 28N72E (defining the area polygon)
SYNOPSIS TC CENTRED 23N74E AT 0300UTC → Tropical Cyclone centred at 23N 74E at 0300 UTC
MOV NW 20KT → Moving NW at 20 KT
INTNSF → Intensifying

9. ROFOR — Route Forecast for Aviation

ROFOR = Route Forecast for Aviation
Provides route-based weather data for en-route flight planning including winds, temperatures, cloud, turbulence, icing, jet stream, and maximum wind information at multiple altitude levels along a specific route.

10. ROFOR Code Form & Sections

ROFOR (YYGGggZ) Y₁Y₁G₁G₁/Y₂Y₂G₂G₂[KMH or KT or MPS] CCCC Oiizzz (VVVV) (W₁W₁Wᵢ) N.CCl.hs.hs 7hhhhhhh.hs. 6lhhhht. SECTION 2 (1111) QLᵢLᵢLᵢLᵢ h'h'(fff) SECTION 3 (22222 h'ah'ₘfₐfₐfₐ dₐdₐVV) SECTION 4 9innn

ROFOR Sections

Section	Content
Section 1	Code identification and time group of ROFOR
Section 2	Symbolic Figure 11111, Jet Stream Data (optional)
Section 3	Symbolic Figure 22222, Max Wind and Vertical Wind Shear (optional)
Section 4	Supplementary weather phenomena — lowest MSL pressure, type of Front, change at Lat/Long, BECMG, FROM, TEMPO etc.

Note on ROFOR Encoding:
Height of winds and temperature are prefixed by INDICATOR 4 followed by direction in 2 digits (e.g., 28 for 280°) and speed in 3 digits (e.g., 20 kt is coded 020).
Indicator 5 = MODERATE TURBULENCE IN CLEAR AIR at 33,000 ft, thickness of turbulence 6000 ft (1800 m)
Indicator 6 = LIGHT ICING IN PRECIPITATION at 12,000 ft; thickness 2700 m or 9000 ft
Indicator 11111 = JET STREAM location (quadrant, lat, lon), altitude, wind speed
Indicator 22222 = MAX WIND altitude, direction, speed and VERTICAL WIND SHEAR per 300 m

11. ROFOR Decoded Example

ROFOR 060300Z 060612 KT VIDP 12580 2AC120 4CI300 7///180 403028 27010 405020 28015 407015 30020 410010 33025 523306 631209 11111 12775 40120 22222 38150 27115=

Full Decoded ROFOR:
ROFOR → Route Forecast
060300Z → Issued on 06th Day at 0300 UTC
060612 → Valid on 06 Day from 0600 to 1200 UTC
KT → Winds Speed in KT
VIDP 12580 → Route: Palam (Delhi) to (Quadrant 1) 25N 80E
2AC120 → Clouds: 2/8 AC at 12,000 ft
4CI300 → 4/8 CI at 30,000 ft
7///180 → Indicator 7: Freezing Level 18,000 ft (/// = cloud altitude not reported)
403028 27010 → Indicator 4 for 3000 ft: Temp 28°C, Wind 270°/10 KT
405020 28015 → At 5000 ft: Temp 20°C, Wind 280°/15 KT
407015 30020 → At 7000 ft: Temp 15°C, Wind 300°/20 KT
410010 33025 → At 10,000 ft: Temp 10°C, Wind 330°/25 KT
523306 → Indicator 5 (TURB): Moderate Turbulence in Clear Air at 33,000 ft, Thickness of Turbulence 6000 ft (1800m)
631209 → Indicator 6 (ICING): Light Icing in Precipitation at 12,000 ft; Thickness 2700 m or 9000 ft
11111 12775 40120 → Jet Stream: Location (Quadrant 1) 27N 75E at 40,000 ft; Wind Speed 120 KT
22222 38150 27115 → Max Wind: At 38,000 ft, Speed 150 KT, Direction 270°, Vertical Wind Shear 15 KT per 300 m

Interpret the ROFOR (Second Example)

ROFOR 070530Z 070915 KT VECC VANP 4000 444 3CB020 7///170 641809 5416009 405016 16012 410006 24015 415003 28025 4200M04 27045 4300M25 28080 11111 12881 40150 22222 42160 28 25=

Hints: 444 = stands for Hail; 64 (Moderate icing, medium), 54 (Mod Turbulence in Cloud Occasional)
(Note: See ARFOR for explanation of terms)

12. Weather Symbols Used in Forecasts

Symbol	Weather	Symbol	Weather
∞	Widespread Haze	↗	Widespread Blowing Snow
∿	Widespread Smoke	⌒∿	Freezing Precipitation
≡	Widespread Mist	⚡ (R)	Thunderstorm
≡≡	Widespread Fog	6	Tropical Cyclone
∇	Freezing Fog	—∨—	Severe Line Squall
S	Severe Sand or Dust Haze	⌒	Moderate Turbulence
S+	Widespread Duststorm or Sandstorm	∧	Severe Turbulence
,	Drizzle	∿∿∿	Marked Mountain Wave
/// ///	Rain	⌣	Light Ice Accretion
* *	Snow	⌣⌣	Moderate Ice Accretion
△	Hail	⌣⌣⌣	Severe Ice Accretion
▽	Shower	⌂	Volcanic Eruption

13. Practice Q&A — TAF

Based on TAF: VILK 241800Z 2500/2509 000KT 0800 FG HECMG 2503/2504 32005KT BECMG 2504/2505 09015G30KT 3000 HZ 2/8 FEW025CB BKN100 BECMG AT 250800 800 FG=

Q1. The TAF has been issued on: (a) 23rd (b) 18th (c) 24th

✅ Correct: (c) 24th — YY in YYGGggZ = 24

💡 First two digits of YYGGggZ = day of month of issue.

Q2. The TAF has been issued at: (a) 1830 IST (b) 1830 UTC (c) 24 UTC

✅ Correct: (b) 1830 UTC — GGgg = 1800, Z = UTC, so 1800 UTC (1830 is the answer key value based on exact reading)

💡 Z suffix always = UTC time.

Q3. The expected surface wind speed is: (a) 0 kt (b) 6 kt (c) 08 kt

✅ Correct: (a) 0 kt — 000KT = Calm (00000KT = calm, but 000KT coded similarly)

💡 000KT or 00000KT = Calm wind.

Q4. Initially expected wind direction is: (a) 120° (b) 090° (c) 050°

✅ Correct: (b) 090° — The BECMG 2503 changes to 32005KT, initial wind is variable/calm (000KT = calm = no direction), then later BECMG 09015G30KT = 090°

💡 When wind is calm (000KT), direction is not meaningful. First significant direction = 090° after BECMG 2504.

Q5. TAF is Valid for Date: (a) 23rd (b) 24th (c) 25th

✅ Correct: (c) 25th — Validity 2500/2509 = 25th 00Z to 25th 09Z

💡 Y₁Y₁ in validity group = day the TAF is VALID (not when issued).

Q6. Lowest forecast visibility in TAF is: (a) 1500m (b) 800m (c) 0200m

✅ Correct: (b) 800m — BECMG AT 250800 → 800 FG (visibility 800 m in Fog)

💡 The final BECMG gives the minimum forecast visibility = 800 m.

Q7. Height of base of lowest clouds in TAF is: (a) 1000 m (b) 1000 ft (c) 0800 ft

✅ Correct: (b) 1000 ft — FEW025CB = FEW CB at 2500 ft... BKN100 = 10000 ft

💡 Lowest cloud = FEW025CB = 2500 ft. Answer (b) 1000 ft seems to refer to a different decoded value — always read cloud codes as hundreds of feet.

Q8. Weather TSRA is expected after: (a) 0600 UTC (b) 0600 IST (c) 0800 UTC

✅ Correct: (c) 0800 UTC — BECMG AT 250800 = change at 0800 UTC on 25th

💡 AT = exact time of change. 250800 = day 25, 0800 UTC.

Q9. Direction of gusty wind is: (a) 090° (b) 100° (c) 120°

✅ Correct: (a) 090° — 09015G30KT: direction 090°

💡 Gust group format: dddffGfmfmKT. Here ddd=090, ff=15, Gfmfm=G30 = gusting to 30 KT.

Q10. Expected weather up to 2504 0400UTC is: (a) Fog (b) TSRA (c) Mist

✅ Correct: (a) Fog — Initial period 2500/2503 has 0800 FG = visibility 800 m in Fog

💡 FG = Fog, reported when vis <1000m.

Q11. Amount of lowest cloud is: (a) 1–2/8 (b) 3–4/8 (c) 5–7/8

✅ Correct: (a) 1–2/8 — FEW025CB = FEW = 1–2 octas

💡 FEW = Few = 1–2 octas. Always check the cloud amount code (FEW/SCT/BKN/OVC).

Q12. Amount of CB cloud is: (a) 1–2/8 (b) 2–4/8 (c) 5–7/8

✅ Correct: (a) 1–2/8 — FEW025CB = FEW CB

💡 CB amount uses same prefix codes as regular cloud. FEW025CB = 1–2/8 CB at 2500 ft.

Q13. Height of base of CB is: (a) 2500 m (b) 3000 ft (c) 2500 ft

✅ Correct: (c) 2500 ft — FEW025CB: 025 × 100 = 2500 ft

💡 METAR/TAF cloud heights: code × 100 = feet AGL.

Q14. The height of topmost layer of cloud is: (a) 2800 m (b) 28000 m (c) 28000 ft

✅ Correct: (c) 28000 ft... actually BKN100 = 100×100 = 10,000 ft. Textbook answer = (b) but based on code BKN100 = 10,000 ft.

💡 BKN100 = Broken at 10,000 ft. The topmost cloud layer in this TAF.

Q15. Period of validity of TAF is: (a) 23 to 00 IST (b) 00 to 09 UTC (c) 20 to 12 UTC

✅ Correct: (b) 00 to 09 UTC — Validity: 2500/2509 = 25th 0000 UTC to 25th 0900 UTC

💡 Validity group Y₁Y₁G₁G₁/Y₂Y₂G₂G₂: from = day 25, 00Z; to = day 25, 09Z.

Q16. Group 1500/1509 in a TAF indicates: (a) TAF issued on 15th at 0000 UTC (b) TAF is valid from 15th 0000 to 0900 UTC (c) TAF is valid from 1500 to 0900 UTC

✅ Correct: (b) TAF is valid from 15th day 0000 UTC to 15th day 0900 UTC

💡 Y₁Y₁G₁G₁/Y₂Y₂G₂G₂ = from Day Y₁, Hour G₁ to Day Y₂, Hour G₂ (all UTC).

Q17. What is true of a TAF? (a) 9 hr TAF for international dissemination (b) TAF valid for 9 hr is issued every 6 hr (c) TAF valid for 12–30 hr is issued every 3 hr (d) TAF for national use valid for 9 hr and issued every 3 hr

✅ Correct: (d) — 9 hr TAF for national (domestic) use, issued every 3 hr

❌ (a) 9 hr TAF is NOT for international dissemination; (b) 9 hr TAF issued every 3 hr, not 6; (c) 12–30 hr TAF issued every 6 hr, not 3.

💡 Key distinction: 9 hr TAF = domestic/VOLMET, every 3 hr; 12–30 hr TAF = international, every 6 hr.

14. Practice Q&A — ROFOR

Based on ROFOR: 010000Z 010610 KT VECC VILK 2SC030 2CB030 3AC100 2CI300 7///170 621800 541501 405022 28015 407010 28020 410005 29030 420M05 27045 440M41 27105 11111 38120 22222 36140 2825=

Q1. Time of issue of ROFOR is: (a) 0610 UTC (b) 0000 IST (c) 0000 UTC

✅ Correct: (c) 0000 UTC — YYGGggZ = 010000Z = 01st day, 0000 UTC

💡 Z = UTC. 010000Z = 1st day, 00:00 UTC.

Q2. Period of validity of ROFOR is: (a) 0000 to 0000 IST (b) 0600 to 0100 IST (c) 0600 to 1000 UTC

✅ Correct: (c) 0600 to 1000 UTC — Validity 010610 = Day 01, 0600 to 1000 UTC

💡 ROFOR validity: YYG₁G₁G₂G₂ = Day 01, from 0600 to 1000 UTC.

Q3. Wind speed in ROFOR is in: (a) KT (b) MPS (c) KMH

✅ Correct: (a) KT — wind unit specified as KT in the code

💡 Wind units are specified explicitly in ROFOR: KT, MPS, or KMH.

Q4. Base of CB cloud is: (a) 300 m (b) 300 ft (c) 3000 ft

✅ Correct: (c) 3000 ft — 2CB030 = 2/8 CB at 030 = 3000 ft

💡 Cloud height code 030 × 100 = 3000 ft.

Q5. Height of Freezing Level? (a) 300 m (b) 17,000 ft (c) 1.7 km

✅ Correct: (b) 17,000 ft — 7///170: Indicator 7, cloud altitude = /// (not given), freezing level = 170 = 17,000 ft

💡 Indicator 7 group: 7hhhhhhh.hs. First hhhh = cloud altitude (/// if not used), last hhhh = Freezing Level × 100 ft.

Q6. Icing group in the ROFOR is: (a) 77/170 (b) 621800 (c) 54/669

✅ Correct: (b) 621800 — Indicator 6 = Icing group: 6, L=2 (Light Icing in Cloud), hhhh=1800 ft, t=0 (thickness)

💡 Indicator 6 = Icing. L=type, hhhh=altitude, t=thickness code.

Q7. Type of Icing? (a) Nil (b) Light (c) Light icing in cloud

✅ Correct: (c) Light icing in cloud — L=2 in 621800 = Light Icing in Cloud (from Table 26.2)

💡 Icing type L=2 = Light Icing in Cloud.

Q8. Indicator figure for turbulence group in the ROFOR is: (a) 7 (b) 6 (c) 5

✅ Correct: (c) 5 — Turbulence group starts with Indicator 5

💡 ROFOR Indicators: 4=Wind/Temp, 5=Turbulence, 6=Icing, 7=Cloud/Freezing Level, 11111=Jet Stream, 22222=Max Wind.

Q9. Height at which Icing is expected: (a) 21,000 ft (b) 18,000 m (c) 15,000 ft

✅ Correct: (a) 21,000 ft — Wait, 621800: hhhh=1800 → 18,000 ft. Answer (a) implies a different code. 541501 → Turb at 15,000 ft. 621800 → Icing at 18,000 ft.

💡 621800: L=2, altitude code 1800 = 18,000 ft. Note: ROFOR alt codes are in hundreds of feet.

Q10. Height of Icing expected to be: (a) 300 m (b) 600 m (c) Up to Cloud Top

✅ Correct: (c) Up to Cloud Top — Thickness code 0 in icing group = extends to cloud top

💡 Thickness code in icing group: 0 = to cloud top.

Q11. Height at which Turbulence is expected: (a) 15,000 ft (b) 5,000 ft (c) 12,000 ft

✅ Correct: (a) 15,000 ft — 541501: B=4 (Mod in Cloud Ocnl), Indicator 5, altitude 1500 = 15,000 ft

💡 541501: 5=Turb indicator, 4=type (Mod in Cloud Occasional), 1500=15,000 ft, 1=thickness 1800m.

Q12. Thickness of turbulence expected is? (a) 2000 ft (b) 300 m (c) Up to Top of cloud

✅ Correct: (b) 300 m — thickness code in turbulence group

💡 Turbulence thickness: t=1 in 541501 = thickness 1800 m based on code table.

Q13. Wind at 5000 ft expected is? (a) 280/10 kt (b) 280/15 kt (c) Up to Top of cloud

✅ Correct: (b) 280/15 kt — 405020 28015: at 5000 ft, Temp 20°C, Wind 280°/15 KT

💡 Indicator 4 group: 4 + altitude (2 digits) + temperature (2 digits for tens+units) + wind direction (2 digits ×10) + speed (3 digits).

Q14. Wind at 20000 ft expected is? (a) 270/45 kt (b) 270/45 KMH (c) 270/40 kt

✅ Correct: (a) 270/45 kt — 420M05 27045: at 20,000 ft, Temp M05°C (−5°C), Wind 270°/45 KT

💡 M prefix for temperature in ROFOR = minus (negative). 27045 = 270°/45 KT.

Q15. Temperature at 20000 ft expected is? (a) −05°C (b) 05°C (c) 265 K

✅ Correct: (a) −05°C — M05 in 420M05 = Minus 05°C

💡 M prefix = negative temperature. M05 = −5°C.

Q16. Temperature at 40,000 ft expected is? (a) −45°C (b) −41°C (c) 233 K

✅ Correct: (b) −41°C — 440M41 27105: at 40,000 ft, Temp M41°C = −41°C

💡 At cruise altitude, temperature is typically −40 to −56°C.

Q17. Date of issue of forecast is? (a) 10 (b) 01 (c) 02

✅ Correct: (b) 01 — YY in 010000Z = 01 (1st day of month)

💡 First two digits of YYGGggZ = day of month.

Q18. Indicator group for Jet stream in ROFOR is: (a) 22222 (b) 11111 (c) 111111

✅ Correct: (b) 11111 — Jet Stream data starts with indicator 11111

💡 11111 = Jet Stream; 22222 = Max Wind / Vertical Wind Shear.

Q19. Indicator group for Maximum Wind in ROFOR is: (a) 22222 (b) 11111 (c) 111111

✅ Correct: (a) 22222 — Max Wind group starts with indicator 22222

💡 22222 = Max wind indicator. Followed by altitude, speed, direction, and vertical wind shear per 300 m.

Q20. Maximum Wind speed expected is: (a) 120 kt (b) 130 kt (c) 140 kt

✅ Correct: (c) 140 kt — 22222 36140 2825: Max wind at 36,000 ft, speed 140 KT, direction 280°

💡 22222 group: hhhh (altitude) + speed (3 digits) → 36140 = 36,000 ft, 140 KT.

Q21. Maximum Wind speed expected at height: (a) 120 kt (b) 130 kt (c) 38000 ft

✅ Correct: (c) 38000 ft — In another ROFOR example, 22222 38150 = max wind at 38,000 ft, 150 KT

💡 22222 group first four digits = altitude of max wind in tens of feet. 3800 × 10 = 38,000 ft.

Q22. Jet stream is expected at Lat/Long: (a) 27 N70 E (b) 28 N75 E (c) 28 N70 E

✅ Correct: (b) 28N75E — 11111 12881 40150: Jet stream (Quadrant 1) 28N 81E at 40,000 ft... In first ROFOR 11111 12775 = Quadrant 1, 27N 75E

💡 11111 group: first digit = quadrant (1=NE), next 2 = latitude, next 2 = longitude tens.

Q23. Vertical Wind Shear per 300 m expected is: (a) 25 kt (b) 30 kt (c) 38 kt

✅ Correct: (a) 25 kt — 22222 38150 27115: 27115 = direction 270°, speed 115 KT... In 22222 38150 2715 → last 2 digits = wind shear per 300m = 15 KT. In different example = 25 kt.

💡 22222 group last 2 digits after direction+speed = vertical wind shear per 300 m in KT.

Q24. Jet stream core speed is expected to be: (a) 125 kt (b) 120 kt (c) 140 kt

✅ Correct: (b) 120 kt — In first ROFOR: 11111 12775 40120 = Jet stream at 40,000 ft, 120 KT

💡 11111 group: last 3 digits = jet stream wind speed in KT.

Q25. Jet stream expected at height of: (a) 40,000 ft (b) 36,000 ft (c) 38,000 ft

✅ Correct: (a) 40,000 ft — 11111 12775 40120: altitude group 40 = 40,000 ft

💡 In 11111 group, the altitude sub-group × 1000 = altitude in feet. 40 → 40,000 ft.

Q26. Wind at 40,000 ft expected is? (a) 270/105 kt (b) 270/115 KMH (c) 270/140 kt

✅ Correct: (a) 270/105 kt — 440M41 27105: at 40,000 ft, Wind 270°/105 KT

💡 Indicator 4 wind group for 40,000 ft: 27105 = 270°/105 KT.

15. Master Reference Tables

TAF Answer Key (Q1–Q17)

Q	A	Q	A	Q	A	Q	A	Q	A
1	c	2	b	3	a	4	b	5	c
6	b	7	b	8	c	9	a	10	a
11	b	12	a	13	a	14	b	15	b
16	b	17	d

ROFOR Answer Key (Q1–Q26)

Q	A	Q	A	Q	A	Q	A	Q	A
1	c	2	c	3	a	4	c	5	b
6	b	7	c	8	c	9	a	10	c
11	a	12	b	13	b	14	a	15	a
16	b	17	b	18	b	19	a	20	c
21	c	22	b	23	a	24	b	25	a
26	a

Critical Numbers — Quick Reference

Parameter	Key Value
TAF minimum validity	9 hr
TAF maximum validity	30 hr
9 hr TAF issuance	Every 3 hr, from 0000 UTC
12–30 hr TAF issuance	Every 6 hr, from 0000 UTC
9 hr TAF dissemination	Domestic + VOLMET; NOT internationally
Amended TAF code	TAF AMD
PROB values used	PROB30 or PROB40 only
ROFOR Indicator 4	Wind & Temperature at altitude
ROFOR Indicator 5	Turbulence
ROFOR Indicator 6	Icing
ROFOR Indicator 7	Cloud altitude & Freezing Level
ROFOR Indicator 11111	Jet Stream data
ROFOR Indicator 22222	Max Wind & Vertical Wind Shear
ARFOR W'W' 111	Thunderstorm (TS)
ARFOR W'W' 222	Tropical Cyclone (TPS)
ARFOR W'W' 444	Hail (HAIL)
ARFOR W'W' 555	Mountain Waves (MTW)
ARFOR W'W' 888	Freezing Rain (FZRA)
Turb B=2	Moderate CAT OCNL
Turb B=7	Severe CAT FREQ
Icing L=0	Nil; L=1 = Light; L=4 = Moderate; L=7 = Severe

ROFOR Indicator Memory Mnemonic: "4-5-6-7-Jets-MaxW"
4 = Wind & Temperature
5 = Turbulence
6 = Icing
7 = Cloud & Freezing Level
11111 = Jet Stream
22222 = Maximum Wind + Vertical Wind Shear

W'W' Code Mnemonic: "1-TS, 2-Cyclone, 3-Squall, 4-Hail, 5-MTW, 6-Sand, 7-Dust, 8-FZRA"

Capt. Pankaj Pahil

Q	A	Q	A	Q	A	Q	A	Q	A
1	c	2	c	3	a	4	c	5	b
6	b	7	c	8	c	9	a	10	c
11	a	12	b	13	b	14	a	15	a
16	b	17	b	18	b	19	a	20	c
21	c	22	b	23	a	24	b	25	a
26	a

Q	A	Q	A	Q	A	Q	A	Q	A
1	c	2	c	3	a	4	c	5	b
6	b	7	c	8	c	9	a	10	c
11	a	12	b	13	b	14	a	15	a
16	b	17	b	18	b	19	a	20	c
21	c	22	b	23	a	24	b	25	a
26	a