GLMP GRIB - MDL
Gridded LAMP GRIB2 Encoding Details
The GFS-based Gridded LAMP gridded guidance is provided on the 2.5km Lambert Conformal grid covering the same expanse as the National Digital Forecast Database (NDFD) CONUS grid in GRIB2 format. Beginning September 28, 2010, GRIB2 files will be available in the Experimental National Digital Guidance Database (NDGD). For current status of the files on the server, and descriptions of the file locations and names please refer to here. The files in NDGD contain multiple grids in each file, grouped by element.
This webpage seeks to provide users with some of the settings we are using to encode our products in GRIB2. Users should consult the NCEP WMO GRIB2 Documentation for the complete details on GRIB2 encoding.
Section 0 - Indicator Section
For all Gridded LAMP GRIB2 products we set octet 7, Discipline, to 0 for Meteorological. We use GRIB edition 2 in octet 8
Section 1 - Identification Section
| Octet No. | Value | Explanation |
|---|---|---|
| 6-7 | 7 | Originating Center - NCEP |
| 8-9 | 14 | Originating Sub-center - MDL |
| 10 | 1 | Initial operational version number |
| 11 | 0 | Version of local tables |
| 12 | 1 | Significance of date in Octets 13-19 |
| 13-19 | Year, Month, Day, Hr, Min, Sec | Date of model run on which guidance is based |
| 20 | 0 | Operational products |
| 21 | 1 | Forecast products |
Section 2 - Local Use Section
This section is not used in the LAMP Thunderstorm products.
Section 3 - Grid Definition Section
The Gridded LAMP guidance is presented on the 2.5-km NDFD grid. The following are the grid specifications used to pack the guidance into GRIB2.
| 2.5km CONUS Grid -- Image available here | ||
|---|---|---|
| Octet No. | Value | Explanation |
| 1-4 | 81 | Length of section in octets |
| 5 | 3 | Number of Section |
| 6 | 0 | Grid definition template defined in Octet 13-14 |
| 7-10 | 2953665 | Number of data points |
| 11 | 0 | Number of non-rectangular points |
| 12 | 0 | No appended list of points |
| 13-14 | 30 | Lambert Conformal GDT |
| 15 | 1 | Spherical earth, radius in Octet 16-20 |
| 16 | 0 | Scale factor of radius of spherical earth |
| 17-20 | 6371200 | Scaled value of radius of spherical earth |
| 21 | missing | |
| 22-25 | missing | |
| 26 | missing | |
| 27-30 | missing | |
| 31-34 | 2145 | NX |
| 35-38 | 1377 | NY |
| 39-42 | 20192000 | Latitude of first grid point |
| 43-46 | 238446000 | Longitude of first grid point |
| 47 | 48 | Resolution and component flags |
| 48-51 | 25000000 | Latitude where Dx and Dy are specified |
| 52-55 | 265000000 | Longitude of parallel meridian |
| 56-59 | 2539703 | Dx- grid length in x direction |
| 60-63 | 2539703 | Dy- grid length in y direction |
| 64 | 0 | Projection centre flag |
| 65 | 80 | Data scanned boustrophedonically |
| 66-69 | 25000000 | Latin 1 |
| 70-73 | 25000000 | Latin 2 |
| 74-77 | -90000000 | Latitude of southern pole |
| 78-81 | 0 | Longitude of southern pole |
Section 4 - Product Definition Section
The Gridded LAMP products are packed using Product Definition Template (PDT) 4.0. The following tables list the settings for each element for observations and forecasts.
| Observation Guidance Valid at a Point in Time - PDT 4.0 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Octet No. | 2-M Temp Obs (K) | 2-M Temp Obs Err Est. (K) | 2-M Dew Point Obs (K) | 2-M Dew Point Obs Err Est. (K) | Ceiling Hgt Obs (m) | Visibility Obs (m) | Wind Speed Obs (m/s) | Wind Direction Obs (degrees) | Opaque Sky Cover Obs (%) | Wind Gust Obs (m/s) |
| 1-4 | Length of section in octets | |||||||||
| 5 | 4 | |||||||||
| 6-7 | 0 | |||||||||
| 8-9 | 0 | |||||||||
| 10 | 0 | 0 | 0 | 0 | 6 | 19 | 2 | 2 | 6 | 2 |
| 11 | 0 | 0 | 6 | 6 | 13 | 0 | 1 | 0 | 1 | 22 |
| 12 | 0 | 7 | 0 | 7 | 0 | 0 | 0 | 0 | 0 | 0 |
| 13 | missing | |||||||||
| 14 | 108 | |||||||||
| 15-16 | missing | |||||||||
| 17 | missing | |||||||||
| 18 | 1 | |||||||||
| 19-22 | hours from reference time to valid time (i.e. projection) | |||||||||
| 23 | 103 | 103 | 103 | 103 | 215 | 1 | 103 | 103 | 1 | 103 |
| 24 | 0 | |||||||||
| 25-28 | 2 | 2 | 2 | 2 | 0 | 0 | 10 | 10 | 0 | 10 |
| 29 | missing | |||||||||
| 30 | 0 | |||||||||
| 31-34 | 0 | |||||||||
| Forecast Guidance Valid at a Point in Time - PDT 4.0 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Octet No. | 2-M Temp Fcst (K) | 2-M Dew Point Fcst (K) | Ceiling Hgt Fcst (m) | Visibility Fcst (m) | Wind Speed Fcst (m/s) | Wind Direction Fcst (degrees) | Opaque Sky Cover Fcst (%) | Wind Gust Fcst (m/s) | Ceiling Height Probabilities Fcst (%) | Visibility Probabilities Fcst (%) |
| 1-4 | Length of section in octets | |||||||||
| 5 | 4 | |||||||||
| 6-7 | 0 | |||||||||
| 8-9 | 0 | 5 | 5 | |||||||
| 10 | 0 | 0 | 6 | 19 | 2 | 2 | 6 | 2 | 6 | 19 |
| 11 | 0 | 6 | 13 | 0 | 1 | 0 | 1 | 22 | 13 | 0 |
| 12 | 2 | 5 | 5 | |||||||
| 13 | missing | |||||||||
| 14 | 108 | |||||||||
| 15-16 | missing | |||||||||
| 17 | missing | |||||||||
| 18 | 1 | |||||||||
| 19-22 | hours from reference time to valid time (i.e. projection) | |||||||||
| 23 | 103 | 103 | 215 | 1 | 103 | 103 | 1 | 103 | 215 | 1 |
| 24 | 0 | |||||||||
| 25-28 | 2 | 2 | 0 | 0 | 10 | 10 | 0 | 10 | 0 | 0 |
| 29 | missing | |||||||||
| 30 | 0 | |||||||||
| 31-34 | 0 | |||||||||
| 35 | N/A | 2 for < 500ft, 3 for < 1000ft, and 5 for <= 3000ft | 2 for < 1mi, 4 for < 3mi, and 5 for <= 5mi | |||||||
| 36 | N/A | 7 | 6 | |||||||
| 37 | N/A | 0 | 0 | |||||||
| 38 | N/A | 2 | 2 | |||||||
| 39-42 | N/A | 15240 for < 500ft, 30480 for < 1000ft, and 91450 for <= 3000ft | 160934 for < 1mi, 482803 for < 3mi, and 804673 for <= 5mi | |||||||
| 43 | N/A | missing | missing | |||||||
| 44-47 | N/A | missing | missing | |||||||
Section 5 - Data Representation Section
We use Data Representation Template 5.3: Gridpoint data - complex packing and spatial differencing.
For decimal scaling, we use the following decimal scaling factors:
| Temperatures | Ceiling Height | Visibility | Wind Speed | Wind Direction | Opaque Sky Cover | Wind Gust | Ceiling Height Probabilities | Visibility Probabilities |
|---|---|---|---|---|---|---|---|---|
| 1 | 0 | 0 | 1 | -1 | 0 | 1 | 0 | 0 |
Binary scaling is used on selected Gridded LAMP 2.5 km grids. Learn more about binary scaling. The following binary scaling factors are used:
| Temperatures | Ceiling Height | Visibility | Wind Speed | Wind Direction | Opaque Sky Cover | Wind Gust | Ceiling Height Probabilities | Visibility Probabilities |
|---|---|---|---|---|---|---|---|---|
| 2 | 3 | 7 | 2 | 0 | 0 | 2 | 0 | 0 |