atmoaggie

2 notes today concerning slight changes to the data found in Temp Drop Messages (TDM) and Vortex Data Messages (VDM).

TDM:
To minimize confusion and increase consistency with other storm-
related items, the changes detailed below will become effective
on May 15, 2013, for the Temp Drop Message (TDM). The TDM as
reported from Department of Defense (DOD) and NOAA aircraft
conducting reconnaissance missions for tropical cyclones. There
are no changes to WMO Headers or AWIPS IDs for the TDMs.

Currently, the Remarks Section (Data Identifer 62626) of the TDM
allows use of the word EYE. Dropsonde (sonde) operators have
been using the word EYE in the Remarks for all sondes released
in the center of all tropical cyclones; however, use of the word
EYE might suggest there is a partial or complete eyewall, when
this may not be the case.

Therefore, effective May 15, 2013, the EYE remark in the Remarks
section will no longer be used. The word CENTER may be used in
the Remarks section. The use of the word CENTER will indicate
the sonde was released in the center of a tropical cyclone,
regardless of whether an actual eye exists.

In summary, effective May 15, 2013, only the following remarks
will be used in the TDM: CENTER, EYEWALL XXX, MXWNDBND, or
RAINBAND.

Table G-6, Temp Drop Code, Identifier 62626 and Figure G-3,
Example Temp Drop Message for Tropical Cyclones, are provided in
the National Hurricane Operations Plan. The 2012 plan is
provided on line at:

OFCM Homepage

The 2013 NHOP will be posted on line by June 1, 2013, along with
the new TDM format for 2013 in Table G-6 and a new example in
Figure G-3.
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VDM:
To minimize confusion, provide greater precision to users, and
increase consistency with other storm-related items, the changes
detailed below will become effective on May 15, 2013. The changes
affect the Vortex Data Message (VDM) reported from Department of
Defense (DOD) and NOAA aircraft conducting reconnaissance
missions for tropical cyclones. There are no changes to WMO
Headers or AWIPS IDs for the VDMs.

Currently, the Remarks Section (Data Item P) of the VDM
identifies the location(s) of maximum flight level winds by the
relative quadrant of the storm, followed by the word QUAD.

Old format:

MAX FLT LVL WIND 77 KT N QUAD 01:23:40Z
MAX OUTBOUND FLT LVL WIND 77 KT N QUAD 01:23:40Z
MAX OUTBOUND AND MAX FLT LVL WIND 77 KT N QUAD 01:34:40Z

Beginning on May 15, 2013, the word QUAD will be removed from the
Remarks Section and replaced with the observed bearing (in
degrees) and range (in nautical miles), relative to the center
fix of the overall tropical cyclone maximum flight level winds.

New format:

MAX FLT LVL WIND 77 KT 357/12 01:23:40Z
MAX OUTBOUND FLT LVL WIND 77 KT 357/12 01:23:40Z
MAX OUTBOUND AND MAX FLT LVL WIND 77 KT 357/12 01:23:40Z

In addition, the reference to "the latest pass through any
portion of the storm" in the National Hurricane Operations Plan
(NHOP), Table 5-2, Data Item P, will be removed. For 2013, the
wording will be changed in the NHOP to refer to the latest pass
through any octant of the storm, i.e., 337.5-22.5 degrees, 22.5-
67.5 degrees, etc.

High-Density Observation Bulletins (HDOB) message formats are
provided in the National Hurricane Operations Plan (NHOP),
Chapter 5. The 2012 NHOP, along with the 2012 HDOB Message
Format, is online at:

OFCM Homepage

The 2013 NHOP will be posted on line by June 1, 2013, along with
the new HDOB message format for 2013 in Table 5-2. A new example
VDM will be provided in Figure 5-4.
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atmo:
Minor changes, sure. But you guys may find that some of the products out there for decoding these may not get updated by hurricane season. I can especially see the VDM changes breaking decoders if they aren't updated.