The
WMO abbreviated heading is used to identify the NCEP GRIB messages; however, it
is not a complete description of their content. The user is
cautioned against using the header as the sole
determiner of the record content; one should, of course, rely on
the Product
Definition Section for that purpose. Note: In the following, a hexadecimal number is enclosed in parentheses followed by the designation "hex". The information needed to identify the NCEP product is contained in 21 octets. The characters are encoded using the CCITT-ITA No. 5, also known (in the US) as ASCII characters, and are defined as follows:
The first six characters are commonly referred to as: T1 T2 A1 A2 ii In summary... Generic Meaning of T1 T2 A1 A2 ii: T1: Type of bulletin: "H" for GRIB messages for Family of Services, WAFS, and International Exchange; “O” and "E" for Oceanographic GRIB messages for National and International Exchange and for AWIPS GRIB messages; or "L", "M", "Y" or "Z" for AWIPS GRIB messages T2: Type of data/parameter A1: Grid A2: Analysis or forecast hour ii: Numeric. Usually the pressure level, sometimes just a sequence number. Some values have special level or layer meanings. In the following tables, the columns headed AWIPS are augmentations to the common Family of Services (FOS), National, and International Exchange variables. FOS, National and International GRIB messages (with H as the initial character) draw upon the left hand columns only. National, International, and AWIPS GRIB messages (with O as the initial character) draw upon the middle column only. AWIPS GRIB messages (with Y or Z as the initial character) use letters from both the left and right columns. If each column contains entries for the same designator, the T1 character (H, O, L, M, Y, or Z) indicates which entry to use. |
Designator | PARAMETER | ||
FOS & International (H) | AWIPS (E or O) | AWIPS (L, M, Y or Z) | |
A |
U-wind/current component | Cloud of non-conforming ICWF* parameters | |
B |
V-wind/current component | Vertical Wind Shear | |
C |
Vorticity | Total Significant Wave Height | Vorticity |
D |
Depth | Probability Parameters | |
E |
Total Precipitation | Ice Concentration | Total Precipitation |
F |
Long Wave Radiation | Ice Thickness | Precipitable Water |
G |
Convective Precipitation | Ice Drift | Convective Precipitation |
H |
Height (geopotential) | Ice Growth | Height (geopotential) |
I |
Ice Convergence | Non-Convective Precipitation | |
J |
Significant Wave Height | Period of Spectral Peak of the Ocean Waves | Precipitation Rate |
K |
Primary Wave Period | Direction of Spectral Peak of the Ocean Waves | Visibility |
L |
Primary Wave Direction | Height of Significant Wind Waves | Soil Parameters |
M |
Secondary Wave Period | Mean Period of Wind Waves | Catagorical Parameters (yes/no) |
N |
Secondary Wave Direction | Mean Direction of Wind Waves | Wind Speed or Gust |
O |
Vertical Velocity | Height of Significant Swell Waves | Vertical Velocity |
P |
Pressure | Mean Direction of Swell Waves | Pressure |
Q |
Wind Speed | Stability Index | |
R |
Relative Humidity | Wind Direction | Relative Humidity |
S |
Snow | Salinity | Snow |
T |
Air Temperature | Ocean Temperature | |
U |
U Wind Component | Vessel Icing | U Wind Component |
V |
V Wind Component | Visibility | V Wind Component |
W |
Ocean Temperature Warming | CAPE | |
X |
Surface Lifted Index | Mixed Data | Surface Parameters |
Y |
UV Index | Mean Period of Swell Waves | CIN |
Z |
Refer to GRIB PDS | Refer to GRIB PDS | Helicity |
Designator | Grid Number (See Table B) | ||
FOS and International (H) | AWIPS (O) | AWIPS (L, M, Y or Z) | |
A |
21 |
228 - 2.5x2.5 deg lat/lon global | 201 - 381 km Northern Hemisphere |
B |
22 |
218 - 12-km CONUS | 218 - 12-km CONUS |
C |
23 |
219 - N. Hemisphere High Res | 175 - 10 km lat/lon Guam |
D |
24 |
220 - S. Hemisphere High Res | 130 - 13-km CONUS |
E |
25 |
221 - N. American High Res | 185 - 12 km CONUS (DGEX) |
F |
26 |
229 - 1.0x1.0 deg lat/lon global | 186 – 12 km Alaska (DGEX) |
G |
50 |
230 - 0.5x0.5 deg lat/lon global | 160 - 47.5 km Alaska NPS |
H |
231 - 0.5x0.5 deg lat/lon N.H. | 213 - 95 km CONUS | |
I |
37 |
232 - 1.0x1.0 deg lat/lon N.H. | 202 - 191 km CONUS |
J |
38 |
233 - 1.25x1.00 deg lat/lon global | 203 - 191 km Alaska |
K |
39 |
234 - 0.25x0.25 deg lat/lon ECGM regional | 204 - 160 km Hawaii |
L |
40 |
235 - 0.5x0.5 deg lat/lon global | 205 - 191 km Puerto Rico |
M |
41 |
238 - Western North Atlantic lat/lon | 227 - 5 km CONUS |
N |
42 |
239 - Alaska Regional lat/lon | 207 - 95 km Alaska |
O |
43 |
244 - North Atlantic lat/lon | 254 - 40 km Mercator Pacific Region |
P |
44 |
251 - COFS lat/lon | 237 - 32 km Puerto Rico |
Q |
253 - Eastern North Pacific lat/lon | 211 - 80 km CONUS | |
R |
212 - 40 km CONUS | 212 - 40 km CONUS | |
S |
253 - Eastern North Pacific lat/lon | 242 - 11.25 km Alaska | |
T |
61 |
214 - 48 km Alaska | 161 - 0.5 degree lat/lon Puerto Rico |
U |
62 |
215 - 20 km CONUS | 215 - 20 km CONUS |
V |
63 |
216 - 45 km Alaska | 216 - 45 km Alaska |
W |
64 |
173 - 1/12 degree global lat/lon | 236 - 40 km CONUS |
X |
243 - 0.4
degree NE Pacific |
||
Y |
217 - 22 km Alaska | ||
Z |
Refer to GRIB PDS |
DESIGNATOR | FORECAST HOUR | |||
FOS, International (H) and AWIPS (L or Y) | National,
International
(O) and AWIPS (E or O) |
AWIPS (M or Z) | ||
Octet 8-11
= KWBM |
Octet 8-11 = KWBJ | |||
A |
00 hour analysis | 00 hour analysis | 00 hour analysis | 02 hour fcst |
B |
06 hour fcst | 12 hour fcst | 03 hour fcst | 03 hour fcst |
C |
12 hour fcst | 24 hour fcst | 06 hour fcst | 04 hour fcst |
D |
18 hour fcst | 36 hour fcst | 09 hour fcst | 08 hour fcst |
E |
24 hour fcst | 48 hour fcst | 12 hour fcst | 09 hour fcst |
F |
30 hour fcst | 60 hour fcst | 15 hour fcst | 10 hour fcst |
G |
36 hour fcst | 72 hour fcst | 18 hour fcst | 14 hour fcst |
H |
42 hour fcst | 84 hour fcst | 21 hour fcst | 15 hour fcst |
I |
48 hour fcst | 96 hour fcst | 24 hour fcst | 16 hour fcst |
J |
60 hour fcst | 108 hour fcst | 30 hour fcst | 20 hour fcst |
K |
72 hour fcst | 120 hour fcst | 36 hour fcst | 21 hour fcst |
L |
84 hour fcst | 144 hour fcst | 42 hour fcst | 27 hour fcst |
M |
96 hour fcst | 168 hour fcst | 48 hour fcst | 54 hour fcst |
N |
108 hour fcst | 192 hour fcst | 60 hour fcst | 66 hour fcst |
O |
120 hour fcst | 216 hour fcst | 72 hour fcst | 33 hour fcst |
P |
132 hour fcst | 240 hour fcst | 84 hour fcst | 39 hour fcst |
Q |
144 hour fcst | 264 hour fcst | 96 hour fcst | 45 hour fcst |
R |
156 hour fcst | 288 hour fcst | 120 hour fcst | 51 hour fcst |
S |
168 hour fcst | 312 hour fcst | 132 hour fcst | 57 hour fcst |
T |
180 hour fcst | 336 hour fcst | 144 hour fcst | 78 hour fcst |
U |
192 hour fcst | 360 hour fcst | 156 hour fcst | 90 hour fcst |
V |
204 hour fcst | 384 hour fcst | 168 hour fcst | 102 hour fcst |
W |
216 hour fcst | - |
- |
114 hour fcst |
X |
228 hour fcst | - |
54 hour fcst | |
Y |
240 hour fcst | - |
66 hour fcst | - |
Z |
Refer to GRIB PDS | Refer to GRIB PDS | 108 hour fcst | Refer to GRIB PDS |
DESIGNATOR | FORECAST HOUR AWIPS (Y or Z) |
DESIGNATOR | FORECAST HOUR AWIPS (Y or Z) |
A |
00 Hour Analysis | N |
18 Hour Forecast |
B |
01 Hour Forecast | O |
24 Hour Forecast |
C |
02 Hour Forecast | P |
30 Hour Forecast |
D |
03 Hour Forecast | Q |
36 Hour Forecast |
E |
04 Hour Forecast | R |
42 Hour Forecast |
F |
05 Hour Forecast | S |
48 Hour Forecast |
G |
06 Hour Forecast | T |
60 Hour Forecast |
H |
07 Hour Forecast | U |
72 Hour Forecast |
I |
08 Hour Forecast | V |
84 Hour Forecast |
J |
09 Hour Forecast | W |
96 Hour Forecast |
K |
10 Hour Forecast | X |
108 Hour Forecast |
L |
11 Hour Forecast | Y |
120 Hour Forecast |
M |
12 Hour Forecast | Z |
Refer to GRIB PDS |
DESIGNATOR | LEVEL or LAYER |
99 |
1000 hPa |
98 |
Air Properties at the Surface of Earth |
97 |
Level of the Tropopause |
96 |
Level of the Maximum Wind |
94 |
Level of the 0 deg. C isotherm |
93 |
975 hPa |
92 |
925 hPa |
91 |
875 hPa |
89 |
Any Parameter Reduced to Sea Level |
88 |
Land/Water Properties at the Surface of the Earth/Ocean |
87 |
1000-500 hPa thickness |
86 |
Boundary Layer |
82 |
825 hPa |
77 |
775 hPa |
74 |
Cloud Top Level |
73 |
Cloud Bottom Level (high, med, or low) |
72 |
725 hPa |
67 |
675 hPa |
62 |
625 hPa |
57 |
575 hPa |
52 |
525 hPa |
47 |
475 hPa |
42 |
425 hPa |
37 |
375 hPa |
32 |
325 hPa |
27 |
275 hPa |
22 |
225 hPa |
17 |
175 hPa |
12 |
125 hPa |
01 |
Refer to GRIB PDS |
00 |
Entire
Atmosphere |
Note: The following levels are used to indicate geometric height for aviation flight levels, not pressure levels | |
81 |
6000 ft FL (approximately 810 hPa) |
73 |
9000 ft FL (approximately 730 hPa) |
64 |
12000 ft FL (approximately 640 hPa) |
51 |
18000 ft FL (approximately 510 hPa) |
DESIGNATOR | NCEP MODEL |
A |
Reserved for Future Use |
B |
Reserved for Future Use |
C |
Global Forecast System Model |
D |
Downscaled GFS using Eta eXtension (DGEX) |
E |
North American Mesoscale (NAM) Model |
F |
Nested
Grid Model (NGM) |
G |
Rapid Update Cycle |
H |
Medium Range Forecast (MRF) |
I |
Sea Surface Temperature Analysis |
J |
Wind-Wave Forecast Model |
K |
Global Ensemble Forecasts |
L |
Regional Ensemble Forecasts |
M |
Ocean Models |
N |
Used
by
NDFD Program |
O |
Merge of Models |
P |
EPA/CMAQ |
Q |
Reserved for Future Use |
R |
Real
Time Mesoscale Analysis / Analysis of Error |
S-Y |
Reserved for Future Use |
Z |
Refer to GRIB PDS |