The new DTN Flight Hazards GRIB2 data has the following naming convention:
Forecast Content
Below is a summary of the flight hazards data content provided for each forecast period and for each grid, where:
| Abbreviation | Description | Units | Interval |
|---|---|---|---|
|
Turb |
Turbulence |
Eddy Dissipation Rate (EDR) |
0.2, 0.3…..0.9 |
|
Ice |
Icing |
Percent Power Increase (PPI) |
Light (0 to 0.1 PPI ) Moderate (0.11 to 0.6 PPI ) Severe ( > 0.6 PPI) |
|
StormSp |
Max Updraft Speed |
Vertical Velocity (m/s) |
5, 10, 15, 20…..50+ |
|
StormTop |
Max Storm Tops |
Meters |
No interval |
| Level | FL | Turb | Ice | StormSP | StormTop |
|---|---|---|---|---|---|
|
980 |
010 |
X |
X |
|
|
|
900 |
030 |
X |
X |
|
|
|
850 |
050 |
X |
X |
|
|
|
750 |
080 |
X |
X |
|
|
|
700 |
100 |
X |
X |
|
|
|
650 |
120 |
X |
|
|
|
|
600 |
140 |
X |
X |
|
|
|
550 |
160 |
X |
|
|
|
|
500 |
180 |
X |
X |
|
|
|
475 |
200 |
X |
|
|
|
|
425 |
220 |
X |
|
|
|
|
400 |
240 |
X |
X |
|
|
|
375 |
260 |
X |
|
|
|
|
350 |
270 |
X |
X |
|
|
|
325 |
280 |
X |
|
|
|
|
300 |
300 |
X |
|
|
|
|
275 |
320 |
X |
|
|
|
|
260 |
330 |
X |
|
|
|
|
250 |
340 |
X |
|
|
|
|
230 |
350 |
X |
|
|
|
|
225 |
360 |
X |
|
|
|
|
215 |
370 |
X |
|
|
|
|
210 |
380 |
X |
|
|
|
|
200 |
390 |
X |
|
|
|
|
190 |
400 |
X |
|
|
|
|
180 |
410 |
X |
|
|
|
|
160 |
430 |
X |
|
|
|
|
150 |
450 |
X |
|
|
|
|
100 |
530 |
X |
|
|
|
|
Entire Atmosphere |
|
|
|
X |
X |
| Global | North America | |
|---|---|---|
|
Forecast Interval |
1 hour |
1 hour |
|
Forecast Length |
37 hours (0, 1, 2, 3, 4…..36 hour forecasts) |
North America – 19 hours (0,1, 2, 3, 4 ….18 hour forecasts) |
|
File Counts |
74 Thunderstorm files 1184 Icing files 1073 Turbulence files Total 2331 files for each forecast update |
38 Thunderstorm files 608 Icing files 551 Turbulence files Total 1197 files for each forecast update |
|
Update Period |
Turbulence – Every 6 hours |
Turbulence – hourly |
|
Icing – Every 6 hours |
Icing – hourly |
|
|
Thunderstorms – Every 6 hours |
Thunderstorm – hourly |
File Packaging and Bundling
The flight planning data is packaged as individual GRIB2 files. Each file contains one parameter for one particular forecast period and atmospheric level. These files are then bundled into TGZ files for distribution.
The GRIB2 compression is defined in the header information included in the data files. For further information review Section 4 Binary Data Section (BDS) found in the link below.
http://www.wmo.int/pages/prog/www/WDM/Guides/Guide-binary-2.html
TGZ File Bundle Naming Convention
The individual GRIB2 files are tar’ed together and then compressed by standard zip utility application for distribution. The naming convention of the tar’ed, zip file is:
Filename definition: <CCCC>_<MMM>2_<RR>_<DDHH>_<FF>.TGZ
Where:
CCCC= Issuing office identifier (DTN0)
MMM = Model (GFS or RAP)
RR= Resolution (02 for GFS / 13 for RAP)
DDHH = day and hour of model run
FF= Forecast hour (06, 09, 12,…36)
Individual GRIB File Naming Convention
Each TGZ file contains multiple files for each individual GRIB2 parameter and level.
File Names and Packaging
The flight planning data is packaged in individual files, with one file for each GRIB bulletin. This means that the same filenames are reused with every 6 hourly update.
The GRIB2 compression is defined in the header information included in the data files. For further information review Section 4 Binary Data Section (BDS) found in the link below.
http://www.wmo.int/pages/prog/www/WDM/Guides/Guide-binary-2.html
File Naming Convention
The flight planning files use a WMO Header file naming convention:
Filename definition: <M><P><G><I><LL>
Where:
M= Model Code
P = Parameter Code
G = Grid Code
I = Forecast Interval Code
LL = Level Code
| Model Code | Parameter Code | Grid Code | Forecast Interval Code | Level Code | |||||
|---|---|---|---|---|---|---|---|---|---|
| H (Always) | Code | Description | Code | Description | Code | Description | Code | Description | Flight Level |
|
|
L |
Turbulence |
Y |
NCEP GFS 1/4º Global Grid |
A |
0 hour forecast |
10 |
100 hPa |
FL530 |
|
|
I |
Icing |
D |
NCEP RAP 13km N. American Grid |
B |
1 hour forecast |
15 |
150 hPa |
FL450 |
|
|
1 |
Storm (Updraft Speed) |
|
|
C |
2 hour forecast |
16 |
160 hPa |
FL430 |
|
|
2 |
Storm (Storm Tops) |
|
|
D |
3 hour forecast |
18 |
180 hPa |
FL410 |
|
|
3 |
Small Aircraft Icing |
|
|
E |
4 hour forecast |
19 |
190 hPa |
FL400 |
|
|
4 |
Medium Aircraft Icing |
|
|
F |
5 hour forecast |
20 |
200 hPa |
FL390 |
|
|
5 |
Large Aircraft Icing |
|
|
G |
6 hour forecast |
21 |
210 hPa |
FL380 |
|
|
6 |
Helicopter Icing |
|
|
H |
7 hour forecast |
D1 |
215 hPa |
FL370 |
|
|
|
|
|
|
I |
8 hour forecast |
22 |
225 hPa |
FL360 |
|
|
|
|
|
|
J |
9 hour forecast |
23 |
230 hPa |
FL350 |
|
|
|
|
|
|
K |
10 hour forecast |
25 |
250 hPa |
FL340 |
|
|
|
|
|
|
L |
11 hour forecast |
26 |
260 hPa |
FL330 |
|
|
|
|
|
|
M |
12 hour forecast |
27 |
270 hPa |
FL320 |
|
|
|
|
|
|
N |
13 hour forecast |
30 |
300 hPa |
FL300 |
|
|
|
|
|
|
O |
14 hour forecast |
35 |
350 hPa |
FL270 |
|
|
|
|
|
|
P |
15 hour forecast |
40 |
400 hPa |
FL240 |
|
|
|
|
|
|
Q |
16 hour forecast |
50 |
500 hPa |
FL180 |
|
|
|
|
|
|
R |
17 hour forecast |
60 |
600 hPa |
FL140 |
|
|
|
|
|
|
S |
18 hour forecast |
70 |
700 hPa |
FL100 |
|
|
|
|
|
|
T |
19 hour forecast |
75 |
750 hPa |
FL080 |
|
|
|
|
|
|
U |
20 hour forecast |
85 |
850 hPa |
FL050 |
|
|
|
|
|
|
V |
21 hour forecast |
90 |
900 hPa |
FL030 |
|
|
|
|
|
|
W |
22 hour forecast |
D0 |
980 hPa |
FL010 |
|
|
|
|
|
|
X |
23 hour forecast |
00 |
Entire Atmosphere |
|
|
|
|
|
|
|
Y |
24 hour forecast |
|
|
|
|
|
|
|
|
|
Z |
25 hour forecast |
|
|
|
|
|
|
|
|
|
a |
26 hour forecast |
|
|
|
|
|
|
|
|
|
b |
27 hour forecast |
|
|
|
|
|
|
|
|
|
c |
28 hour forecast |
|
|
|
|
|
|
|
|
|
d |
29 hour forecast |
|
|
|
|
|
|
|
|
|
e |
30 hour forecast |
|
|
|
|
|
|
|
|
|
f |
31 hour forecast |
|
|
|
|
|
|
|
|
|
g |
32 hour forecast |
|
|
|
|
|
|
|
|
|
h |
33 hour forecast |
|
|
|
|
|
|
|
|
|
i |
34 hour forecast |
|
|
|
|
|
|
|
|
|
j |
35 hour forecast |
|
|
|
|
|
|
|
|
|
k |
36 hour forecast |
|
|
|
Each file is a single GRIB bulletin, with a marker at the head and at the end. The head marker is the ASCII text “GRIB”; the tail marker is a sequence of four ASCII 7’s, as in “7777”. See below.
[start of file]
…..
“GRIB” … [GRIB content] … “7777”
…
“GRIB” … [GRIB content] … “7777”
…
[end of file]