NOUS41 KWBC 131400 AAA



Service Change Notice 18-19 Corrected

National Weather Service Headquarters Silver Spring MD

1000 AM EDT Fri Apr 13 2018


To:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners and NWS Employees


From:     Allison Allen

          Chief, Marine, Tropical and Tsunami Services Branch


Subject:  Updated: Format for the Reconnaissance Vortex Data

          Message changing on or around May 15, 2018


Updated to correct for "Changes to the Vortex Message" number

"5" listed below to reflect that the current flight level wind

block begins with Vortex Message Item D. A correction was also

made to the "New Format Definitions" for "Bearing, Range and

Time of Wind observed." Items M and O below to refer to the

correct items in the message for the "Estimate of Maximum

Outbound Surface Wind Observed" and the "Maximum Outbound Flight

Level Wind," respectively.


After soliciting comments during the 2017 hurricane season, the

Office of the Federal Coordinator for Meteorology Working Group

for Tropical Cyclone Operations and Research Forum (WG/TCORF)

has approved changes to the Reconnaissance Vortex Data Message

format beginning on or around May 15, 2018. This product is

transmitted from NOAA and Air Force Hurricane Hunter aircraft.


This product is issued under the following AWIPS and WMO



AWIPS Header      WMO Header





The format changes will enhance the utility of the Vortex

Message by including important parameters previously not

provided or provided optionally in the comment section. The

change also will improve the organization of the message.


Changes to the Vortex Message include:


1. The current format has a formal entry only for inbound wind

maxima, with any outbound wind maxima appearing in the comment

section.  In the new format, Items L through O comprise a new

mandatory outbound wind maxima section to simplify data decoding

and to ensure no data are missed. The new outbound wind maxima

section appears in a similar format to the inbound maxima data

(Items H through K).


2.  The latitude and longitude will be listed in decimal degrees

instead of degrees and minutes to better accommodate NOAA's

National Hurricane Center and other users' needs.


3.  The new message format includes a new tropical cyclone

center data block section (Items C through G).  The surface wind

reported by dropsonde at the system's center is now given in

Item E. Center/eye shape and size characteristic lines are moved

up to Items F and G from Items L and M.


4.  The current message lacks most wind observation times; the

proposed format appends the observation times to the bearing and

range location Items.


5.  To better collect similar data together, the inbound maximum

surface and flight-level wind block (Items D through G in the

current format) is shifted downward to Items H through K.


A comparison of the current and new format is provided below.


Current format:


URNT12 KNHC 241133


A. 24/11:12:50Z

B. 10 deg 58 min N

  082 deg 46 min W

C. 700 mb 2927 m

D. 90 kt

E. 144 deg 5 nm

F. 253 deg 78 kt

G. 158 deg 8 nm

H. 977 mb

I. 10 C / 3042 m

J. 18 C / 3045 m

K. NA / NA


M. C20

N. 12345 / 7

O. 0.02 / 1 nm

P. AF301 0616A OTTO                 OB 13

MAX OUTBOUND AND MAX FL WIND 108 KT 349 / 14 NM 11:17:00Z




New format:


URNT12 KNHC 241133


A. 24/11:12:50Z

B. 10.97 deg N 082.77 deg W

C. 700 mb 2927 m

D. 977 mb

E. 210 deg 11 kt


G. C20

H. 90 kt

I. 144 deg 5 nm 11:07:00Z

J. 253 deg 78 kt

K. 158 deg 8 nm 11:07:30Z

L. 95 kt

M. 314 deg 5 nm 11:17:00Z

N. 033 deg 108 kt

O. 349 deg 14 nm 11:17:30Z

P. 10 C / 3042 m

Q. 18 C / 3045 m

R. NA / NA

S. 12345 / 7

T. 0.02 / 1 nm

U. AF301 0616A OTTO OB 13

MAX FL WIND 108 KT 349 / 14 NM 11:17:00Z


Current format definition can be found at:


Under Figure 5-3, page 5-6


New format definition:

A.    Date and Time of Fix

B.    Latitude and Longitude of Vortex Center Fix

C.    Minimum Height at Standard Atmospheric Level

D.    Minimum Sea-Level Pressure from Dropsonde or Extrapolation

E.    Dropsonde Center Wind Speed and Direction

F.    Eye Character

G.    Eye Shape/Orientation/Diameter

H.    Estimate of Maximum Inbound Surface Wind Observed

I.    Bearing, Range and Time of Wind observed in Item H

J.    Maximum Inbound Flight-Level Wind

K.    Bearing, Range and Time of Wind observed in Item J

L.    Estimate of Maximum Outbound Surface Wind Observed

M.    Bearing, Range and Time of Wind observed in Item L

N.    Maximum Outbound Flight-Level Wind

O.    Bearing, Range and Time of Wind observed in Item N

P.    Maximum Flight-Level Temp/Pressure Altitude Outside Eye

Q.    Maximum Flight-Level Temp/Pressure Altitude Inside Eye

R.    Dewpoint Temp/Sea Surface Temp Inside Eye

S.    Fix Determined By (Codes for Observation Type)

T.    Navigation Fix Accuracy/Meteorological Accuracy

U.    Aircraft ID, Mission Number, Cyclone Name, and Observation



End Remarks include: Maximum Flight-Level Wind, Bearing, Range

and Time


For questions regarding this notice, please contact:


Jessica Schauer

NWS Tropical Services Program Leader

NWS Marine, Tropical and Tsunami Services Branch

Miami, FL 



National Service Change Notices are online at: