NOAA / NWS's Meteorological Development Laboratory
Degrib (NDFD GRIB2 Decoder)
Date: Wed, 02 Apr 2008 07:53:31 -0700 (PDT)
You are amongst the 3,054 people registered on the degrib mailing list.
Please email me if you wish to unregister. The latest version of the
program is on: (http://www.weather.gov/mdl/degrib).
The focus of release 1.91 is:
A) To handle the effective change to the encoding of Air Quality data,
B) Handle template 4.6 (percentile at a specific point in time),
C) Provide support for Alaska RTMA,
D) Handle the change in the NDFD Puerto Rico grid definition
------- General News:
1) (http://www.nws.noaa.gov/om/notif.htm#tin) TIN08-06: STREAMLINED DATA
PATHWAY FOR AIR QUALITY FORECAST GUIDANCE PRODUCTS: EFFECTIVE APRIL 1 2008
2) (http://www.nws.noaa.gov/om/notif.htm#tin) TIN07-90: CORRECTED:
ADDITION OF NCEP RTMA GRIDS FOR THE ALASKA REGION: EFFECTIVE MARCH 13 2008
3) Although I can't locate a TIN (Technical Implementation Notice), the
NDFD grid definition for Puerto Rico changed. This occurred around
3/17/2008 when NDFD started receiving data straight from the "IFPS
Service Backup" files. The new grid is finer (1.25 km spacing instead
of 2.5 km), and the lower left corner has shifted slightly.
------- Details about release: 1.91 (last one was 1.90 on 10/31/2007)
1) Due to (General News 1), the air quality grids will be sent directly
from NCEP instead of going through the NDFD central server. This causes
an effective change in the encoding of the smoke grids because the NDFD
central server was translating the NCEP encodings. For the smoke
parameters, NCEP follows the new GRIB2 (version 4) rule which states:
[92.6.2 To maintain orthogonal structure of GRIB2, parameter names
should not contains surface type and statistical process as part of the
This means that degrib now has to pay attention to the surface
parameters to differentiate the smoke variables when assigning them
abbreviations of "smokes" and "smokec".
NOTE: One consequence of rule 92.6.2 is that the WMO is deprecating
MaxTemp and MinTemp as parameter names in GRIB2. One would instead
label them Temperature, and use template 4.8 to specify whether it is a
Maximum or Minimum.
2) Updated the internal grid definition to allow the DWML code to
properly recognize the new NDFD Puerto Rico grid.
3) Updated the timezone/daylight savings methodology to no longer
require timezone files for the trivial cases of Hawaii, PR, and Guam.
4) Modified degrib to support template 4.6 (Percentile forecast at a
specific time or layer).
5) Updated meta data tables to reflect the current NCEP tables at
(http://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc.shtml), and to
reflect the GRIB2 Version-4 specification located at:
6) Updated the configuration files to allow for:
a) Downloading the Alaska RTMA.
b) The new locations of the Air Quality products.
c) Downloading probabilistic hurricane storm surge (psurge).
7) Incorporated a number of changes to the DWML code.
8) Fixed an interpolation bug when dealing with lat/lon grids and the
probed point is outside the grid (example the grid goes from 0 to 359.5
with a spacing of 0.5, but the point is at 359.6)
9) Changed the default install location from "c:/ndfd/degrib19" to
------- Please let me know if you have problems.
PS: Happy Power's of 2 day. (This morning at 1 am was the 1st hour of
the 2nd day of the 4th month of the 8th year of the current millennium)