DECODING FOR RECON REPORTS

Guide to Decoding Reconnaisance Schedules
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A = Requested on-station time for each complete pattern.

B = Mission identifier. Part of the aircraft's tail number is in that.

C = Estimated time of departure from originating station.

D = Departure Station (KHST is Homestead, Florida. I think that you and
the weather community has these.)

E = Forecast position of storm / hurricane.

F = Destination station (where aircraft is scheduled to return).

G = Pattern to fly. The only one he had time to tell me is that ALPHA
is an X pattern with 105 mile legs. They go in, fly about 105 miles,
exit, go counter-clockwise and then fly the other 105 mile leg.

H = The forecast movement to be used calculating each pattern location.

I = Comments.

(Information from Orville Bullitt)





Guide to Decoding Reconnaisance Reports
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The following information is presented for those who need a
comprehensive decoding of the topical recon and dropsonde
reports. The term 'vortex' data message actually represents
one vendors terminology for getting this data and should be
ignored for all practical purposes. I believe most of us
will be using the headers starting with URxxxx KMIA for
obtaining the majority of the observations.

Over that past few years, I've been able to get the info I
needed with the URNTxx and UZNTxx headers (all from KMIA).
This does not mean that there are not other headers.

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VORTEX DATA MESSAGE/RECON REPORT

The VORTEX message is actually a combination of three types of
reports: the vortex data message..the supplemental vortex data
message..and the reconassaince report. Each of these types of reports
will now be discussed, beginning with the vortex data message.

The following information is designed to aid in the interpretation
of the abbreviated and detailed vortex data messages. After a step
by step explanation, a sample message will be displayed.

Both the abbreviated and detailed vortex data messages are trans-
mitted in an alphabetical manner. In each report, a letter of the
alphabet is followed by information about the center of the
tropical circulation. This information includes such items as
lat/long of the center, temperatures inside and outside of the
eye of the storm, wind information, minimum pressures, etc.
Here is a breakdown of the message:

The first line of the report gives the mission identifier...this
consists of: 1-Agency; 2-aircraft number; 3-number of missions
in this storm system; 4-depression number; 5-storm name.
AF554 WX OB 03 KMIA means this mission is flown by the Air
Force, with aircraft number 554; observation number 3, reported
to Miami.

The second line gives the name of the type of report, either
ABBREVIATED VORTEX DATA MESSAGE or DETAILED VORTEX DATA MESSAGE

A. Date and time of fix...06/1634Z means the report is from the
sixth day of the month, at 1634Z.

B. Latitude of the vortex fix in degrees and minutes...26 DEG 00 MIN N
Longitude of the vortex fix in degrees and minutes...88 DEG 00 MIN W

C. Minimum height of a standard pressure level, given in meters...
700 MB 3150 M means the lowest height of the 700 mb level
was found to be 3150 meters above sea level.

D. Estimate of maximum surface wind observed in knots...30 KT means
the highest estimated surface wind is 30 kts with this
particular storm system.

E. Bearing and range from center of the maximum surface wind, given
in degrees and nautical miles...180 DEG 18 NM means the
30 kt wind mentioned in D above is 18 nm south of the center
of the storm.

F. Maximum flight level wind near storm center with direction from
center given in degrees, and speed in knots...110 DEG 45 KT
means that the wind is from 110 degrees at 45 knots.

G. Bearing and range from center of maximum flight level wind, given
in degrees and nautical miles from the storm center...180
DEG 15 NM means the maximum wind given in F above was found
15 nautical miles south of the storm center.

H. Minimum sea level pressure computed from dropsonde or extrapolation
from within 1500 feet of the sea surface, given in millibars...
1005 MB DROPSONDE means that the lowest pressure found was
1005 millibars and was determined from a dropsonde.

I. Maximum flight level temperature in Celcius / Pressure altitude
in meters, OUTSIDE the eye...09 C / 3082 M means that at
the flight level of 700 millibars, the highest temperature
outside the eye is 9 degrees C at a pressure altitude of
3082 meters.

J. Maximum flight level temperature in Celcius / Pressure altitude
in meters, INSIDE the eye...10 C / 3040 M means that at
the flight level of 700 millibars, the highest temperature
inside the eye is 10 degrees C at a pressure altitude of
3040 meters.

K. Dewpoint temperature in Celcius / Sea surface temperature in
Celcius inside the eye...08 C / 26 C means that the dewpoint
was 8 degrees C inside the eye, and the temperature of the
sea surface was 26 degrees C.

L. Eye character...brief verbal description such as poorly defined,
closed wall, open to NW, etc.

M. Eye shape orientation and diameter...Eye shapes are codes as
follows: C-circular; CO-concentric; E-elliptical. Orientation
of major axis of ellipse is transmitted in tens of degrees,
and all diameters are transmitted in nautical miles. Examples..
E09/15/5 means elliptical eye oriented with major axis thru
90 degrees (and also 270 degrees), with length of major axis
15 nm, and length of minor axis 5 nm. CO8-14 means concentric
eye with inner eye diameter 8 miles, and outer diameter 14
miles.

N. Confirmation of lat/long/time fix with format as in A and B above.

O. Fix determined by / fix level...There are five means of
determining fixes and nine means of indicating fix level.
The fix determination will be a series of one to five
numbers depending on how many items were used to determine
the position of the storm center. The coding is as follows:
1-Penetration, 2-Radar, 3-Wind, 4-Pressure, 5-Temperature.
The fix level will be either one or two numbers, depending
on whether or not the surface and flight level centers were
the same. The surface center will be given if visible,
both the surface and flight level centers will be indicated
only when they're the same. The coding is as follows:
0-surface, 1-1500 ft, 8-850 mb, 7-700 mb, 5-500 mb, 4-400 mb,
3-300 mb, 2-200 mb, 9-Other. Example: 1245/07 means the fix
was determined by four means..penetration, radar, temperature,
and pressure. The fix level was both at the surface and at
700 mb.

P. Navigation fix accuracy in nm / Meteorological accuracy in nm...
5/10 means the center is located within 5 nm of the lat-long
given for the center, with a meteorological accuracy to 10 nm.

Q. Remarks Section.


Sample report:

AF554 WX OB 03 KMIA
DETAILED VORTEX DATA MESSAGE

A. 06/1634Z
B. 26 DEG 00 MIN N
88 DEG 00 MIN W
C. 700 MB 3150 M
D. 30 KT
E. 180 DEG 18 NM
F. 110 DEG 45 KT
G. 180 DEG 15 NM
H. 1005 MB DROPSONDE
I. 09 C/ 3082 M
J. 10 C/ 3040 M
K. 8 C/ 26 C
L. POORLY DEFINED
M. C08-14
N. 26 DEG 00 MIN N
88 DEG 00 MIN W
O. 1245/07
P. 5/10
Q. NONE


--------------------
The supplemental vortex data message differs from many of the other
types of messages in that all data is from the flight level of the
aircraft.

The format for decoding these reports is quite similar to the
traditional RAOB decode. Height, temperature, dewpoint, wind
direction and speed are decoded almost identically.

The generic format of this type of report for the north Atlantic
is as follows:

URNT14 KMIA DDTTTT
AA ### MMXX NAME
SUPPLEMENTARY VORTEX DATA MESSAGE

01LaLaLa 1LoLoLoLo 1jHHH 1TTTdTd ddfff
02LaLaLa 2LoLoLoLo 2jHHH 2TTTdTd ddfff
03LaLaLa 3LoLoLoLo 3jHHH 3TTTdTd ddfff
04LaLaLa 4LoLoLoLo 4jHHH 4TTTdTd ddfff
05LaLaLa 5LoLoLoLo 5jHHH 5TTTdTd ddfff

etc...etc...etc

MFLaLaLa MLoLoLoLo MFfff


Some comments about the above code:

Data are collected at 15 nm intervals both approaching and departing
the storm. When approaching, data normally starts at 105 nm from
the center and at 15 nm intervals thereafter. When departing the storm,
data normally starts 15 nm from the center and at 15 nm intervals there-
after.

The indicator numbers at the beginning of each group are simply used
to distinguish one group from another. For example, the first data
report is labeled 01, and everything at that same lat/long location
has the number 1 in front. The next data sample (15 nm later) is
labeled 02/2, the next sample is 03/3, etc.

The line by line decode breaks down as follows:

UR 14 is the name of this report. Atlantic reports are coded URNT14
KMIA is the location of the recipient of the message (Miami)
DDTTTT is the day and time of the report in Greenwich
AA is the Agency providing the report. AF is Air Force, NOAA is NOAA
### is the aircraft number flying the mission
MM is the number of the mission for this storm
XX is the depression number, or simply XX if not a depression or greater
NAME is the name of the storm, if any
LaLaLa is the latitude of the report in degrees/tenths
LoLoLoLo is the longitude of the report in degrees/tenths
jHHH is the pressure height data in the following format:

j=0 means sea level data follows with HHH in whole millibars
j=1 means 200 mb data follows with HHH in geopotential decameters
j=2 means 850 mb data follows with HHH in geopotential meters
j=3 means 700 mb data follows with HHH in geopotential meters
j=4 means 500 mb data follows with HHH in geopotential decameters
j=5 means 400 mb data follows with HHH in geopotential decameters
j=6 means 300 mb data follows with HHH in geopotential decameters
j=7 means 250 mb data follows with HHH in geopotential decameters
j=8 D - Value in geopotential decameters; if neg, 500 is added to HHH
j=9 means no absolute altitude data available, or geopotential data
is not within 30 meters/4 mb accuracy requirements

MF means that maximum flight level wind data follows
TTTdTd is the temperature/dewpoint in degrees Celcius. Add 50 if
negative
ddfff is the true direction of flight level wind in tens of degrees
with fff being the speed of wind in knots
/ means data unknown or unobtainable


The following is a sample message with a partial decode following:


URNT14 KMIA 211730
AF 966 0411 FREDERIC OB 14
SUPPLEMENTARY VORTEX DATA MESSAGE
01178 10899 13107 10908 36027
02177 20895 23100 20908 35042
03178 30891 33092 30807 36052
04177 40887 43088 40907 35070
05178 50883 53070 50908 36088
06178 60880 63000 61010 35108
07178 70877 73882 71211 35120
MF178 M0877 MF120
OBS 01 AT 1530Z OBS 07 AT 1600Z
OBS 01 SFC WIND 36025
01177 10872 13000 11010 18120
02178 20868 23070 21009 17098
03178 30862 33088 30909 18080
04177 40858 43093 40908 17050
05177 50854 53102 50908 17048
06178 60850 63108 60905 18031
07177 70844 73114 70902 18025
MF177 M0872 MF120
OBS 1 AT 1630Z OBS 07 AT 1700Z
OBS 07 SFC WIND 16025
REMARKS HEAVY RAIN OUTBOUND


The first three lines identify the report in detail...

URNT14 is the report header
KMIA signifies the report is being sent to Miami
211730 means this is the 21st day...1730Z
AF means this mission is being flown by the Air Force
966 is the aircraft number
0411 means this is the fourth mission for this tropical system, and
this is the 11th tropical depression of the season
FREDERIC means that depression number 11 has gained tropical storm
status and is named Frederic
OB 14 means this is the 14th observation from this mission (4th)

The first data line decodes as follows:

01178...latitude is 17.8 degrees
10899...longitude is 89.9 degrees
13107...700 mb report at a height of 3107 meters
10908...temperature is 9 C / dewpoint is 8 C
36027...wind is 360 degrees at 27 kts

The second data line decodes as follows:

02177...latitude is 17.7 degrees
20895...longitude is 89.5 degrees
23100...700 mb report at a height of 3100 meters
20908...temperature is 9 C / dewpoint is 8 C
35042...wind is 350 degrees at 42 kts

...the remainder of the message for groups 03 thru 07 decodes
in the exact same manner...

MF178...maximum wind latitude is 17.8 degrees
M0877...maximum wind longitude is 87.7 degrees
MF120...maximum wind speed at these coordinates was 120 kts
OBS 01 AT 1530Z...first set of data taken at 1530Z
OBS 07 AT 1600Z...last set of data taken at 1600Z
OBS 01 SFC WIND 36025...surface wind at 1530Z was 360 degrees/25 kts


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Reconnaissance reports, provide valuable information
about the structure of tropical weather systems. This is the
raw coded report sent from the aircraft to the National Hurricane
Center. This message contains meteorological information including
pressure, temperature, wind, clouds and turbulence. In addition,
information about the capabilities of the aircraft are included,
such as radar ability, means of wind speed determination, etc.

Some of these reports are mandatory, and others are intermediate.
Also, some reports provide additional data at the end that is not
considered mandatory, but is useful.

The following is the generic code used in the reports. Each item
will be discussed separately, with a sample report decoded at the
end.

SYMBOLIC FORM

-------------------

Section One..Mandatory

9XXX9 GGggI YQLaLaLa LoLoLoBf hhhdd ddfff TTTdTdw /jHHH

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Section Two..Additional (appended to section one when available)

1kNsNsNs ChhHH ..... ..... 4ddff 6WsSsWdd 7IrItSbSe 7hhHH 8ddSrOe
8EwElci 9ViTwTwTw

-------------------

Section Three..Intermediate

9XXX9 GGggI YQLaLaLa LoLoLoBf hhhdd ddfff TTTdTdw /jHHH

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As can be seen above, each message consists of groups of five numbers.
The positioning of each number in a group, and also the indicator
numbers at the beginning of some groups, helps in the decode of the
report.

Beginning with section one, the mandatory reports, here is the
breakdown of the code:

9XXX9...The 9's on either end of this group are simply indicator
numbers. The XXX can be any of three possibilities depending
on the aircraft.
222..means this is a mandatory report without radar
capability.
555..means this is an intermediate report with or
without radar capability.
777..means this is a mandatory report with radar
capability.

GGggI...GG is the hour of the report; gg is the minute of the report;
I is an indicator regarding aircraft height and dewpoint
sensing capability.
0..No dewpoint capability / aircraft below 10000 meters
1..No dewpoint capability / acft at or abv 10000 meters
2..No dewpoint cap / acft blo 10000 m / fl temp blo -50C
3..No dewpoint cap / acft aoa 10000 m / fl temp blo -50C
4..Dewpoint capability / aircraft below 10000 meters
5..Dewpoint capability / acft at or above 10000 meters
6..Dewpoint cap / acft below 10000 m / fl temp blo -50C
7..Dewpoint cap / acft aoa 10000 m / fl temp blo -50C

YQLaLaLa...Y is the day of the week..Sunday=1...Saturday=7
Q is the quadrant of the globe the aircraft is located
using the following decode...
0..0-90N / 0-90W
1..0-90N / 90W-180
2..0-90N / 180-90E
3..0-90N / 90E-0
4..Not used
5..0-90S / 0-90W
6..0-90S / 90W-180
7..0-90S / 180-90E
8..0-90S / 90E-0
LaLaLa is the latitude in tenths of degrees. 268 would
be 26.8 degrees

LoLoLoBf...LoLoLo is the longitude of the aircraft in tenths of degrees.
880 would be 88.0 degrees, 110 would be 11.0 or 111.0
depending on the quadrant of the globe indicator in the
last group.
B..Turbulence group as follows..
0..No turbulence
1..Mdt turbulence..in clear air..infrequent
2..Mdt turbulence..in clear air..frequent
3..Mdt turbulence..in cloud..infrequent
4..Mdt turbulence..in cloud..frequent
5..Severe turbulence..in clear air..infrequent
6..Severe turbulence..in clear air..frequent
7..Severe turbulence..in cloud..infrequent
8..Severe turbulence..in cloud..frequent
f..Conditions along route of flight as follows..
0..In the clear
8..In and out of clouds
9..In clouds all the time
/..Impossible to determine due to darkness or some
other cause.

hhhdtda...hhh gives the pressure altitude of the aircraft to the
nearest decameter
dtda..gives information about the wind group that follows.
dt specifies if the wind is 0) Spot wind; 1) Average wind; or
/ meaning no wind report.
da specifies how the winds were obtained, with 0) Winds obtained
using doppler radar or inertial systems; 1) Winds obtained
using other navigation equipment / techniques; / Navigator
unable to determine wind or wind not compatible.

ddfff...Wind direction and speed at the flight level of the aircraft.
This is coded using the standard meteorological conventions.

TTTdTdw...The temperature, dewpoint, present weather group at flt lvl.
TT is the temperature in Celcius. If the temperature is
negative, 50 is added to the absolute value of the temperature,
and any hundreds digits are omitted. For example, a temperature
of -60 would be coded as 10 (60=110 with hundreds omitted)
To determine if the temperature is really or -110, see
the indicator number in the time group above. Msg temps are
denoted as //.
TdTd is the dewpoint at flight level. Dewpoints are encoded the
same as temperature. When the dewpoint is colder than -49.4C,
it is reported as // and a plain language remark is added with
the actual dewpoint, i.e. DEW POINT -53C.
w is the present weather group with the following meanings..
0..Clear
1..Scattered clouds
2..Broken clouds
3..Overcast / Undercast
4..Fog, thick dust or haze
5..Drizzle
6..Rain (continuous or intermittent from stratoform
clouds)
7..Snow, or rain and snow mixed
8..Rain (continuous or intermittent from cumuliform
clouds)
9..Thunderstorm
/..Unknown for any cause, including darkness

/jHHH.../ is an indicator for this group
j is the code for the level being reported by HHH in this
group. The code is as follows...
0..Sea level pressure in millibars (1000's omitted)
1..200 mb lvl in geopotential decameters (1000s omitted)
2..850 mb lvl in geopotential meters (1000's omitted)
3..700 mb lvl in geopotential meters (1000's omitted)
4..500 mb lvl in geopotential decameters
5..400 mb lvl in geopotential decameters
6..300 mb lvl in geopotential decameters
7..250 mb lvl in geopotential decameters (1000s omitted)
8..D value in geopotential decameters (if negative, 500
is added to HHH)
9..No absolute altitude available, or geopotential
data not within or - 30 meters / 4 mb accuracy
requirements.
HHH..Geopotential height or sea level pressure of the level