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High Density Observations (HDOB) Bulletin (Text)

The HDOB message is used to transmit High-Density/High Accuracy (HD/HA) meteorological data from hurricane reconnaissance aircraft. These are created automatically by the system software. Each message consists of a communications header line (Table G-3), a mission/ob identifier line (Table G-4), and 20 lines of HD/HA data (Table G-5).

Within an HDOB message, the time interval (resolution) between individual HD/HA observations can be set by the operator to be 30, 60, or 120 seconds. However, regardless of the time resolution of the HD/HA data, the meteorological parameters in the HDOB message always represent 30-s averages along the flight track (except for certain peak values as noted in Table G-5).

The nominal time of each HD/HA record is the midpoint of the 30-s averaging interval. This means that an HD/HA record at time t will include data measured at time t+15 s. For purposes of determining peak flight-level and SFMR winds, the encoding interval begins 15 s after the nominal time of the last HD/HA record and ends 15 s after the nominal time of the record being encoded.


Figure G-2.  Sample HDOB message (message begins with URNT15...)

0         1         2         3         4         5         6         7
01234567890123456789012345678901234567890123456789012345678901234567890
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URNT15 KNHC 281426
AF302 1712A KATRINA            HDOB 41 20050928
142030 2608N 08756W 7093 03047 9333 +192 +134 133083 089 080 999 00 
142100 2609N 08755W 7091 03054 9330 +166 +146 133106 115 103 999 00 
142130 2610N 08754W 7058 03040 9295 +134 +134 135121 124 111 999 00 
142200 2611N 08753W 7037 03060 9291 +124 +124 138129 136 122 999 00 
.
.
.
142230 2612N 08752W 7010 03057 9282 +102 +102 141153 166 148 999 00 
142300 2612N 08751W 7042 03010 9293 +088 +083 133159 164 147 999 00 
142330 2613N 08750W 6999 03064 9279 +088 +088 138158 161 144 999 00  
142400 2614N 08749W 7005 03046 9281 +080 +080 138155 158 142 999 00 
142430 2614N 08748W 6998 03048 9278 +078 +078 138151 153 137 999 00 
142500 2615N 08747W 7002 03048 9279 +084 +084 140146 148 133 999 00 
$$

WMO ID  CCID	 		OCEAN BASIN
------  ------------------   	------------------------
URNT15  KNHC | KBIX | KWBC   	Atlantic
URPN15  KNHC | KBIX | KWBC 	East and Central Pacific
URPA15  KNHC | KBIX | KWBC  	West Pacific

Note: KBIX is a backup CCID for KNHC.

0         1         2         3         4         5         6         7
01234567890123456789012345678901234567890123456789012345678901234567890
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IIIIIIIIIIIIIIIIIIIIIIIIIIIIII HDOB NN YYYYMMDD    

AF302 1712A KATRINA            HDOB 41 20050928  <--example

0         1         2         3         4         5         6         7
01234567890123456789012345678901234567890123456789012345678901234567890
-----------------------------------------------------------------------
hhmmss LLLLH NNNNNW PPPP GGGGG XXXX sTTT sddd wwwSSS MMM KKK ppp FF
142230 2612N 08752W 7010 03057 9282 +102 +102 141153 166 148 999 00

First column indicates status of positional variables as follows:
0   All parameters of nominal accuracy
1   Lat/lon questionable
2   Geopotential altitude or static pressure questionable
3   Both lat/lon and GA/PS questionable

Second column indicates status of meteorological variables as follows:
0   All parameters of nominal accuracy
1   T or TD questionable
2   Flight-level winds questionable
3   SFMR parameter(s) questionable
4   T/TD and FL winds questionable
5   T/TD and SFMR questionable
6   FL winds and SFMR questionable
9   T/TD, FL winds, and SFMR questionable