This code is developed to get as much weather information as possible in a 160-digit SMS message via the IRIDIUM website facility.
The different weather elements are:
Wind
Wind direction: in degrees: from 000° till 360°
Not in magnetic
The indicated direction is the direction where the wind comes from:

In code: three digits.
For example: wind from the sector 190-210° is indicated as 200
This means: the average wind comes from the sector between 240 and 260° with an average speed varying between 13 and 17 knots. The highest wind peak is 26 knots.

Visibility

Expressed in:
PR = Poor is less than 3km
MD= Moderate is between 3 and 10 km
UL= Unlimited, more than 10km

Clouds:

Amount: indicated in three letters:

SKC = sky clear
FEW = 1-2/8
SCT = 3-4/8
BKN = 5-7/8
OVC = 8/8
Height of cloud base:
indicated in three figures of hundreds of feet

Example:
001 = 100 feet
010 = 1000 feet
100 = 10000 feet
Example of cloud group: BKN160 this is 5-7/8 around 16000ft

Weather phenomena

sn = snow
snsh = snow shower
drsn = drifting snow (does not affect the visibility)
blsn = blowing snow (reduces the visibility significantly)
fg = fog
nsw = no significant weather
' - ' and ' + ' indicates the intensity;
example:
-sn = slight snow,
+blsn = heavy blowing snow

Surface contrast

Expressed in:
P = Poor: no elevations in the snow or ice surface are discernable
M= Moderate: one has to concentrate well to discern elevations
G = Good: elevations are easily discernable

The message

The message starts always with the determination of the day and the period:
Expressed in 6 digits: ddssee
dd = the day of the month
ss = hour of the start of the period in UTC (same as Z or GMT)
ee = hour of the end of the period in UTC

Example: 260422 is the 26th starts at 04utc and ends at 22utc

The next group is the wind group
Example of wind group: 25015g26
This means: the average wind comes from the sector between 240 and 260° with an average speed varying between 13 and 17 knots. The highest wind peak is 26 knots.

The next group is the visibility
Example of the wind group: PR
This means: the visibility is poor which is less than 3km

The next group is about the weather phenomena.
Example of this group: -drsn
This means: slight drifting snow

The next group is about the clouds.
Example of cloud group: bkn010
This means: there is 5-7/8 of clouds at a height of 1000 feet

The last group is about the surface contrast
Example: ctr = p
This means: the surface contrast is poor

The message starts always with these groups which indicate the conditions at the beginning of the forecast period.
Example: 260422 25015g26 PR -drsn bkn010 ctr=p (explanation see above)

Changes of the conditions

Sometimes only certain groups change. Groups that are expected to remain the same are not repeated in the next line.
Changes of the conditions are given in two possible ways:
When the changes will happen and not expected to return to the original conditions (most of the time):

BCM (abbreviation of BECOMING) and 4 digits
BCM ssee: 'ss' is the hour when the period, during which the change is expected to happen, starts.
'ee' is the hour when the period, during which the change is expected to happen, ends.
Example: 260422 25015g26 PR -drsn bkn010 ctr=p BCM 0810 20020g30

The original conditions are expected to change during the period 08utc-10utc: only wind conditions change, the rest remains the same
When the changes are expected to happen only temporarily:

TMP (abbreviation of TEMPO) and 4 digits
TMP ssee: 'ss' the start of the period
'ee' the end of the period during which the change happens and returns back to the original conditions.

Example: 260422 25015g26 PR -drsn bkn010 ctr=p TMP 0814 few020

Only the cloud conditions will change temporarily during 08 and 14utc.

Example of complete message:


200422 20008g14 UL nsw few200 ctr=g BCM 0913 18022g32 MD blsn bkn100 ctr=m TMP 1113 18028g40 PR ctr=p BCM 1519 14012g22 UL nsw few100 ctr=g/

The beginning conditions are 200422 20008g14 UL nsw few200 ctr=g:
200422: day and period: the 20th of the month, start at 04utc, ends at 22utc
20008g14: wind direction 190-210°, speed average 6-10kt and gust 14kt
UL: the visibility is unlimited
nsw: no significant weather
few100: cloud amount 1-2/8, height 10000ft
ctr=g: the surface contrast is good
BCM 0913 18022g32 MD blsn bkn100 ctr=m

The original conditions will change during 09 and 13utc and will remain like that unless otherwise indicated.
TMP 1113 18028g40 PR ctr=p
During 11utc and 13utc conditions will changes temporarily
BCM 1519 14012g22 UL nsw few100 ctr=g/

After 15 utc conditions change again into following condition and will remain the same for the rest of that period.

Remarks: / indicates the end of the message.

Sometimes when we expect that the likelyhood of something to happen is pretty small we add a percentage, and this as follows: prob30 which means a percentage of 30 that the following changes will happen.
Example:
200422 20008g14 UL nsw few200 ctr=g prob30 BCM 0913 18022g32 MD blsn bkn100 ctr=m There is 30 percent chance that the change (18022g32 MD blsn bkn100 ctr=m) will happen.