Instructions for reading GAFOR charts
GAFOR (General aviation forecast) chart includes meteorological information for flight planning
along routes. GAFOR consists of three two hour forecasts for all air route.
Example of GAFOR forecast and its explanation:
PERIOD COVERED BY THE FORECAST
GAFOR date of issue is 2.5.2013 at 11.00 UTC, valid from 12 UTC till 18 UTC. Forecast is
divided in three 2-hours intervals 12/14 UTC, 14/16 UTC and 16/18 UTC.
GAFOR ROUTE CHART
GAFOR ROUTE
Identifier
Identification of the routes
10
11
12
13
14
15
16
17
18
20
30
31
40
Villach-Mojstrana-Lesce-LJLJ
LJLJ-Medvode-Vrhnika-Postojna
Razdrto-Divača-Črni Kal- Portorož
Razdrto-Ajdovščina-Nova Gorica-Udine
Divača-Mojstrana-Villach
Divača-Rijeka
Wolfsberg-Dravograd-Celje-Trebnje_Ponikve-Razdrto
LJLJ-Litija-Trebnje-Brežice-Zagreb
Trebnje-Kočevje-Delnice-Rijeka
Klagenfurt-Jezersko-LJLJ
LJLJ-Trojane-Celje-Maribor-Graz
Maribor-Zagreb
Maribor-Murska Sobota-Zalaegerszeg
Reference altitude
m (MSL)
FT (MSL)
1500
5000
820
2750
750
2500
600
2000
1500
5000
1100
3600
1100
3600
900
3000
1000
3300
1250
4100
900
3000
850
2850
500
1700
LEGEND
GAFOR forecast describes prevailing conditions of visibility and cloud ceiling (>4/8) along route
for three successive validity periods lasting two hours each.
X: CLOSED
M: MARGINAL
D: DIFFICULT
O: OPEN
Horizontal visibility less than 1.5 km or
cloud ceiling (>4/8) less than 1000 ft above reference altitude.
Horizontal visibility less than 5 km or
cloud ceiling (>4/8) less than 500 ft above reference altitude.
Horizontal visibility less than 8 km or
cloud ceiling (>4/8) less than 2000 ft above reference altitude.
Horizontal visibility more than 8 km or
cloud ceiling (>4/8) more than 2000 ft above reference altitude.
EXAMPLE 1
Reference route altitude : 3600 ft.
cloud amount and altitude of the cloud ceiling: 6/8, 5000 ft
horizontal visibility: 4 km.
Altitude of the cloud ceiling is 1400 ft above reference altitude. According to cloud ceiling the
weather category is D (difficult) but according to horizontal visibility weather category is M
(marginal). For the GAFOR forecast more rigorous condition is used, so GAFOR two hours
forecast is M (marginal).
EXAMPLE 2
reference route altitude: 3600 ft.
cloud amount and altitude of the cloud ceiling: 3/8, 4000 ft
horizontal visibility: 10 km.
Altitude of the cloud base is 400 ft above reference altitude and according to cloud base the
weather category is X (closed) but the cloud amount is less than 5/8 (no ceiling). According to
cloud amount the weather category is O (open) and according to vertical visibility weather
category is also O (open). GAFOR two hours forecast is O (open).
EXAMPLE 3
reference route altitude : 3000 ft.
cloud amount and altitude of the cloud ceiling: 8/8, 3600 ft
horizontal visibility: 7 km.
Altitude of the cloud ceiling is 600 ft above reference altitude and according to cloud ceiling the
weather category is M (marginal), according to horizontal visibility the weather category is D
(difficult). For the GAFOR forecast more rigorous condition is used, so the GAFOR two hours
forecast is M (marginal).
GAFOR BULLETIN
FBLJ31 LJLJ 111100
LJLJ 111218 AAAA 10OOD 11 12 13 15 16 17 20 OOO 30ODD 31 40 OOO=
FBLJ31 LJLJ 110800: GAFOR issued at 08 UTC on the 11th day of the month
h
LJLJ 110915 AAAA: GAFOR issued on the 11t day of the month, valid from 09 till 15 UTC
10OOD: route 10, forecasts for 2-hours intervals are O (open), O (open) and D (difficult)
11 12 13 15 16 17 20 OOO: routes 11, 12, 13, 15, 16, 17, 20, forecasts for 2-hours intervals are
open, open and difficult.