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NCEP Home > NCEP Central Operations > ISDB > ON388 > Appendix a

Outline of WMO Bulletin Headers Used With NCEP GRIB

Revised 04/20/2020

Red text depicts changes made since 03/29/2019

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:

Octet Header Content
1

The character 'H' for GRIB bulletins sent to the NWS Family of Services, used for the WAFS program, and for general International Exchange
            or
The character ‘O’ for oceanographic GRIB bulletins intended for general International and National Exchange and for use in the NWS AWIPS program
            or
The character ‘E’ for oceanographic GRIB2 bulletins intended for general International and National Exchange and for use in the NWS AWIPS program
           or
The characters 'Y' or 'Z' for meteorological GRIB bulletins intended for the NWS AWIPS program.
          or
The characters 'Y' for WAFS GRIB2.

NOTE:

The characters 'L' and 'M' are used no more for the AWIPS products starting in August, 2014.
The character 'L' is the WMO official designation for new products in XML format.

2 A letter character specifying the type parameter as shown in Table A.1.
3 A letter character specifying the grid area as defined in Table A.2.
4 A letter or numeric character indicating the time difference between the reference time and valid time of the data as listed in Table A.3, i.e., the forecast length.
5-6 Numeric characters as defined in Table A.4.  Usually the pressure level, sometimes just a sequence number.  Some values have special level or layer meanings.
7 Blank (20)hex
8-11 Four characters identifying the originating center.  The first three characters are always ‘KWB’ for NCEP-produced messages.  The last character is a letter specifying the NCEP model as defined in Table A.5.
12 Blank (20)hex
13-14 Two numeric characters providing the reference day of the month (01-31) of the data.
15-18 Four numeric characters providing the reference hour and minute of the data.
19-22 Four OPTIONAL characters: one blank (20)hex, then 'Pxx', where xx=AA, AB, AC ... AY,AZ, BA, BB, BC ... etc.  Used to indicate sequential parts of a very long message that has been subdivided. The last  Example: a five part message would have the parts indicated by PAA, PAB, PAC, PAD, PZE. part of the message will have xx=Zn, where n is the next letter in the appropriate sequence.
19-21 or 23-25 Two ASCII carriage returns and a line feed, (0D0D0A)hex.

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" for Oceanographic GRIB bulletins intended for general International and National Exchange
                                           and for use in the NWS AWIPS program.
                                      "E"for oceanographic GRIB2 bulletins intended for general International and National Exchange
                                           and for use in the NWS AWIPS program
                                      "Y" or "Z" for GRIB bulletins destined for the NWS AWIPS program.
                                      "Y" for WAFS GRIB2.
                                      "L" for products in XML format.
     T2:   Type of data/parameter

     A1:  Grid

     A2:   Analysis or forecast hour

      ii:    Numeric.  Usually a 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, Y, or Z) indicates which entry to use.

NOTE:

The characters 'L' and 'M' are used no more for the AWIPS products starting in August, 2014.
The character 'L' is the WMO official designation for new products in XML format.

TABLE A.1   TYPE PARAMETERS - T2
(Header Octet 2)
Designator PARAMETER
  FOS & International (H) AWIPS (E or O) AWIPS (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   wave Steepness CAPE
X Surface Lifted Index Mixed Data Surface Parameters
Y UV Index Mean Period of Swell Waves CIN
Z Refer to GRIB2 - Production Definition Template (PDT) Refer to GRIB2 - Production Definition Template (PDT) Refer to GRIB2 - Production Definition Template (PDT)
Designator PARAMETER For Extra Tropical Storm Surge
KNHC and KWBM
C Extra Tropical Storm Surge Combined Surge and Tide
E Ocean Surface Elevation Relative To Geoid
G Hurricane Storm Surge
H Extra Tropical Storm Surge
Designator PARAMETER For World Area Forecast System (WAFS) - KWBC
B Horizontal Extent of Cumulonimbus (CB)
F In-Cloud Turbulence
H Geopotential Height of Standard Levels
H Maximum Wind Height (ICAO)
H Tropopause Height (ICAO)
I Icing
R Relative Humidity
T Temperature
T Tropopause Temperature
U U-component Wind
U Maximum U-component Wind
V V-component Wind
V Maximum V-component Wind
L Clear Air Turbulence (CAT)
Designator PARAMETER For Real-Time Ocean Forecast System (RTOFS) - KWBW
H Sea Surface Height Relative to Geoid
S Salinity
T Water Temperature
U U-Component of Current
V V-Component of Current
U Barotropic U velocity
V Barotropic V velocity
Designator PARAMETER For Wind Wave Forecast Model - KWBJ
C Significant Height of Combined Wind Waves and Swell
D Direction of Combined Wind Waves and Swell
F Inverse Mean Wave Frequency
I Ice Cover
J Primary Wave Mean Period
K Primary Wave Direction
L Significant Height of Wind Waves
M Mean Period of Wind Waves
N Direction of Wind Waves
O Significant Height of Swell Waves
P Direction of Swell Waves
Q Wind Speed
R Wind Direction
U U-Component of Wind
V V-Component of Wind
U U-Component of Current
V V-Component of Current
W Mean Period of Combined Wind Waves and Swell
Y Mean Period of Swell Waves
Z Current Direction
Z Current Speed
Designator LEVEL For Wind Wave Forecast Model - KWBJ
ii Sea Surface

TABLE A.2   GRID DESIGNATOR - A1
(Header Octet 3)

 

Designator Grid Number (See Table B in ON-388)
  FOS and
International (H) 		AWIPS (O) - For "CCCC" = KWBC AWIPS (E) - For "CCCC" = KWBJ AWIPS (Y, Z) - For "CCCC" = KWBC
A 21 228 - 2.5x2.5 deg Lat/Lon Global 11 - 0.5 deg - Lat/Lon Global grid 201 - 381 km Northern Hemisphere
B 22 218 - 12 km CONUS 12 - 0.167 deg - US East Coast 218 - 12 km CONUS
C 23 219 - N. Hemisphere High Res 13 - 0.167 deg - US West Coast 225 - 80 km National Double Resoulution - Hawaii
D 24 220 - S. Hemisphere High Res 14 - 0.167 deg - Eastern Pacific (includes Hawaii
and extends to the Pacific islands of Guam) 		130 - 13-km CONUS
E 25 221 - N. American High Resolution 15 - 0.25 x 0.167 deg - Alaska 185 - 12 km CONUS (DGEX)
F 26 229 - 1.0x1.0 deg Lat/Lon Global 16 - 0.133 x 0.167 deg - Alaska 186 – 12 km Alaska (DGEX)
G 50 230 - 0.5x0.5 deg Lat/Lon Global 17 - 0.067 deg - US West Coast 160 - 47.5 km Alaska NPS
H   231 - 0.5x0.5 deg Lat/Lon N.H. 18 - 0.067 deg - US East Coast 213 - 95 km CONUS
I 37 232 - 1.0x1.0 deg Lat/Lon N.H. 176 - .050 x .035 degree grid -
Great Lakes 		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 2.5 km - Lambert Conformal Great Lake
Wave High Resolution grid 		204 - 160 km Hawaii
L 40 235 - 0.5x0.5 deg Lat/Lon Global 0.25 deg - Lat/Lon Global grid 205 - 191 km Puerto Rico
M 41 238 - Western North Atlantic Lat/Lon 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 Atlantic Ocean - 0.16 deg Lat/Lon grid 254 - 40 km Mercator Pacific Region
P 44 251 - COFS Lat/Lon Eastern Pacific - 0.16 deg Lat/Lon grid 237 - 32 km Puerto Rico
Q   253 - Eastern North Pacific Lat/Lon 253 - Eastern North Pacific Lat/Lon 211 - 80 km CONUS
R   212 - 40 km CONUS 260 - 25 km North  Atlantic (OPC) 212 - 40 km CONUS
S   253 - Eastern North Pacific Lat/Lon   242 - 11.25 km Alaska
T 61 214 - 48 km Alaska Arctic 9km - North Polar Stereographic grid 161 - 0.5 degree Lat/Lon Puerto Rico
U 62 215 - 20 km CONUS 261 - 25 km North Pacific (OPC) 215 - 20 km CONUS
V 63 216 - 45 km Alaska   216 - 45 km Alaska
W 64 173 - 1/12 degree Global Lat/Lon West Coast - 0.16 deg Lat/Lon grid 236 - 40 km CONUS
X       243 - 0.4 degree NE Pacific
Y       217 - 22 km Alaska
Z Refer to GRIB2 - Production Definition Template (PDT)
Designator Grid Number For World Area Forecast System (WAFS) - KWBC
X 45 - Global Latitude/Longitude 1.25 degree Resolution

 

TABLE A.2   GRID DESIGNATOR - A1 (continued - 1)
(Header Octet 3)

For All NCEP GRIB products have a CCCC that starts with KWB(?)

 

Designator Grid Number (See Table B in ON-388)
  For "CCCC" = KWBS For "CCCC" = KWBR For "CCCC" = KWBE For "CCCC" = KWBT For "CCCC" = KWBM For "CCCC" = KWBW
  AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (E) AWIPS (E)
A HIRES - 5 km Eastern US 198 (RTMA) 6 km  Alaska 198 - 6.0 km Alaska   198 - 6.0 km Alaska RTOFS - 0.3 km Alaska
B HIRES - 5 km Western US   218 - 12 km CONUS     RTOFS - 0.08 km Bering
C HIRES - 5 km Alaska 195 (RTMA) 2.5 km Puerto Rico 195 - 2.5 km Puerto Rico     RTOFS - 0.08 km Western CONUS
D HIRES - 5 km Pacific Hawaii 92 (RTMA) 1.488 km  Alaska     184 - 2.54 km CONUS-Pacific RTOFS - 0.08 km Arctic
E HIRES - 5 km Puerto Rico RTMA - 1.25 km Puerto Rico NAM Smartinit - 1.25 km Puerto Rico      
F HIRES - 5 km Pacific Guam          
G   199 (RTMA) 2.5 km Guam   199 (GFS DNG) 2.5 km Guam 199 (ESTOFS) 2.5 km Guam RTOFS - 0.08 km Guam
H   196 (RTMA) 2.5 km Hawaii 196 - 2.5 km Hawaii   196 - 2.5 km Hawaii RTOFS - 0.08 km Honolulu
I   184 (RTMA) 2.54 km CONUS 184 - 2.54 km CONUS   184 - 2.54 km CONUS-Atlantic RTOFS - 0.5 km Gulf of Alaska
J   90 (RTMA) 1.27 km CONUS       RTOFS - 0.25 km Hudson-baffin
K   91 (RTMA) 2.976 km Alaska 91 - 2.976 km Alaska     RTOFS - 0.08 km Western Atlantic
L            
M   197 (RTMA) 5 km CONUS 227 - 5 km CONUS   ESTOFS - 10.0 km Micronesia RTOFS - 0.05 km Atlantic
N   188 (RTMA - NWRFC) 2.5 km 207 - 95 km Alaska      
O     197 (NAM DNG) 5 km CONUS      
P   189 (RTMA - JUNEA) 1.5 km 237 - 32 km Puerto Rico   1.25 km - Puerto Rico  
Q   184 (URMA) 2.54 km CONUS   211 - 80 km CONUS    
R   188 (URMA - NWRFC) 2.5 km 212 - 40 km CONUS      
S     242 - 11.25 km Alaska     RTOFS - 0.08 km Samoa
T           RTOFS - 1.0 km Tropical Pacific
U     215 - 20 km CONUS      
V     216 - 45 km Alaska      
W - Y Reserved for Future Use          
Z Refer to GRIB2 - Production Definition Template (PDT)

 

TABLE A.2   GRID DESIGNATOR - A1 (continued - 2)
(Header Octet 3)

For All NCEP GRIB products have a CCCC that starts with KWB(?)

 

Designator Grid Number (See Table B in ON-388)
  For "CCCC" = KWBK For "CCCC" = KWBF For "CCCC" = KWBV For "CCCC" = KWBY For "CCCC" = KWBD For "CCCC" = KWB?
 For "CCCC" = KWB?
  AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z) AWIPS (Y, Z)
A 3 - Global Lat/Lon 1.0 deg   3 - Global Lat/Lon 1.0 deg   198 (DGEX) 6 km Alaska    
B              
C   Global Gaussian Lat/Lon T126 Resolution   2.5km NDGD grid for CONUS      
D              
E 221 - N. American High Resolution            
F - N Reserved for Future Use            
O         197 (DGEX) 5 km CONUS    
P - Y Reserved for Future Use            
Z Refer to GRIB2 - Production Definition Template (PDT)

 

Table A.3 FORECAST HOUR DESIGNATOR - A2
(Header Octet 4)

 

DESIGNATOR FORECAST HOUR
FOS, International (H) and AWIPS (Y)
For KWBC 		National, International (O) and AWIPS (E or O) AWIPS (Z)
For KWBC
For KWBC For KWBJ or KWBU or KWBM or KWBW
A 00 hour analysis 00 hour analysis 00 hour analysis 02 hour fcst
B 06 hour fcst 01,02,..,12 hour fcst 01,02,03 hour fcst 03 hour fcst
C 12 hour fcst 13,14,..,24 hour fcst 04,05,06 hour fcst 04 hour fcst
D 18 hour fcst 25,26,..,36 hour fcst 07,08,09 hour fcst 08 hour fcst
E 24 hour fcst 37,38,..,48 hour fcst 10,11,12 hour fcst 09 hour fcst
F 30 hour fcst 49,50,..,60 hour fcst 13,14,15 hour fcst 10 hour fcst
G 36 hour fcst 61,62,..,72 hour fcst 16,17,18 hour fcst 14 hour fcst
H 42 hour fcst 73,74,..,84 hour fcst 19,20,..,23 hour fcst 15 hour fcst
I 48 hour fcst 85,86,..,96 hour fcst 24,25,..,29 hour fcst 16 hour fcst
J 60 hour fcst 108 hour fcst 30,31,..,35 hour fcst 20 hour fcst
K 72 hour fcst 120 hour fcst 36,37,..,41 hour fcst 21 hour fcst
L 84 hour fcst 144 hour fcst 42,43,..,47 hour fcst 27 hour fcst
M 96 hour fcst 168 hour fcst 48,49,..,59 hour fcst 54 hour fcst
N 108 hour fcst 192 hour fcst 60,61,..,71 hour fcst 66 hour fcst
O 120 hour fcst 216 hour fcst 72,73,..,83 hour fcst 33 hour fcst
P 132 hour fcst 240 hour fcst 84,85,..,95 hour fcst 39 hour fcst
Q 144 hour fcst 264 hour fcst 96,97,..,119 hour fcst 45 hour fcst
R 156 hour fcst 288 hour fcst 120,121,..,131 hour fcst 51 hour fcst
S 168 hour fcst 312 hour fcst 132,133,..,143 hour fcst 57 hour fcst
T 180 hour fcst 336 hour fcst 144,145,..,155 hour fcst 78 hour fcst
U 192 hour fcst 360 hour fcst 156,157,..,167 hour fcst 90 hour fcst
V 204 hour fcst 384 hour fcst 168,169,..,174 hour fcst 102 hour fcst
W 216 hour fcst - 175,176,..,180 hour fcst 114 hour fcst
X 228 hour fcst - 181,182,...,203,204 hour fcst  
Y 240 hour fcst - 205,206,...,239,240 hour fcst  
Z Refer to GRIB2 - Production Definition Template (PDT) Refer to GRIB2 - Production Definition Template (PDT) Refer to GRIB2 - Production Definition Template (PDT) Refer to GRIB2 - Production Definition Template (PDT)
Designator FORECAST HOUR For World Area Forecast System (WAFS) - KWBC
C 06 Forecast hour
D 09 Forecast hour
E 12 Forecast hour
F 15 Forecast hour
G 18 Forecast hour
H 21 Forecast hour
I 24 Forecast hour
J 27 Forecast hour
K 30 Forecast hour
L 33 Forecast hour
M 36 Forecast hour

The WMO headings for NAM model products generated on grid 237 (Puerto Rico) and HRRR and RAP model products generated on grid grid 130 (CONUS 13 km) use a special table for the FORECAST HOUR DESIGNATOR - A2 (Header Octet 4). 

This table is defined as follows:
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 GRIB2 - Production Definition Template (PDT)

 

The above table is maintained by the NWS Office of the Chief Information Officer and can be found online at:

https://www.weather.gov/tg/tablec10

TABLE A.4   LEVEL DESIGNATORS - ii
(Header Octets 5 and 6)

The following version of Table A.4 contains changes implemented by the WMO on November 3, 1993. Unless indicated in
Table A.4 below, the designator given is the hundreds and tens digits of the hPa level in the atmosphere, e.g. 70=700hPa; 03=30hPa, etc.

 

DESIGNATOR LEVEL or LAYER
99 1000 hPa
98 Air Properties at the Surface of Earth or 2 m above ground
97 Level of the Tropopause
96 Level of the Maximum Wind
95 950 hPa
94 Level of the 0 deg. C isotherm
93 975 hPa
92 925 hPa
91 875 hPa
90 900 hPa
89 Any Parameter reduced to Mean Sea Level
88 Land/Water Properties at the Surface of the Earth/Ocean
87 1000-500 hPa thickness
86 Boundary Layer
85 850 hPa
82 825 hPa
80 800 hPa
77 775 hPa
75 750 hPa
74 Cloud Top Level
73 Cloud Bottom Level (high, med, or low)
72 725 hPa
71 Cloud Ceiling Level
70 700 hPa
67 675 hPa
65 650 hPa
62 625 hPa
60 600 hPa
57 575 hPa
55 550 hPa
52 525 hPa
50 500 hPa
47 475 hPa
45 450 hPa
42 425 hPa
40 400 hPa
37 375 hPa
35 350 hPa
32 325 hPa
30 300 hPa
27 275 hPa
25 250 hPa
22 225 hPa
20 200 hPa
17 175 hPa
15 150 hPa
12 125 hPa
10 100 hPa
08 80 m above ground
01 Refer to GRIB2 - Production Definition Template (PDT)
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)
65 12000 ft FL (approximately 650 hPa)
50 18000 ft FL (approximately 510 hPa)

 

TABLE A.5   MODEL IDENTIFIERS
  (Header Octet 11)

All NCEP GRIB products have a CCCC that starts with KWB(?). 
The fourth letter (?) of this identifier is defined as follows:

 

DESIGNATOR NCEP MODEL
A Reserved for Future Use
B Reserved for Future Use
C Global Forecast System Model (GFS)
D Downscaled GFS using NAM eXtension (DGEX)
E North American Mesoscale (NAM) Model
F Climate Forecast System (CFS)
G Rapid Refresh (RAP)
H High Resolution Ensemble Forecast (HREF)
I Sea Surface Temperature Analysis (SST)
J Wind-Wave Forecast Model
K Global Ensemble Forecasts
L Regional Ensemble Forecasts
M Ocean Models/Extratropical Storm Surge Model
N Used by NDFD Program
O Merge of Models
P AQM/AIR Quality Model
Q MDL Gridded MOS Products
R Real Time Mesoscale Analysis / Analysis of Error
S Hires Window Model (ARW, NMM); Five Domains (West/East US, AK, HI, PR)
T GFS Downscale Numerical Guidance
U Hurricane Wave Model
V North American Ensemble Forecast System (NAEFS) - CMC
W Real-Time Ocean Forecast System - RTOFS
X European Center for Medium range Weather Forecasting (ECMWF)
Y High Resolution Rapid Refresh (HRRR)
Z Refer to GRIB2 - Production Definition Template (PDT)
Note: The identifiers KWBA, KWBB and KWD(A-Z) are reserved for future use.

Page last modified: 19 May 2025.