951219: METAR/TAF ChangesNOUS (fwd)

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: 951219: METAR/TAF ChangesNOUS (fwd)
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Tue, 19 Dec 1995 13:46:25 -0700 (MST)

057 
NOUS41 KWBC 191911
PNSNMC

NATIONAL TECHNICAL INFORMATION MESSAGE 95-55...PART 2 OF 4
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
815 AM EST TUE DEC 19 1995

TO:         USERS OF NWS INTERNATIONAL AVIATION FORECASTS

FROM:       THERESE PIERCE
            CHIEF...INTEGRATED HYDROMETEOROLOGICAL CORE

SUBJECT:    METAR/TAF PROJECT:  CHANGES TO THE INTERNATIONAL
            AVIATION AERODROME FORECASTS (TAFS)...EFFECTIVE
            JANUARY 1 1996 AT 0000 UTC

NOTE:  THIS IS PART 2 OF A 4 PART MESSAGE.  PART 1 WAS JUST SENT.
PARTS 3 AND 4 WILL BE TRANSMITTED TOMORROW.

5) FORMATTING CHANGES
IN ADDITION TO THE CHANGES DESCRIBED IN PART 1...FORMATTING
CHANGES WILL BE IMPLEMENTED SIMILAR TO THOSE MADE TO THE FTS IN
1993.  SPECIFICALLY...THE FOLLOWING FORMAT CHANGES WILL BE
IMPLEMENTED IN THE TAF...EFFECTIVE 0000 UTC ON JANUARY 1...1996:

   - EACH FM GROUP SHALL BEGIN ON A SEPARATE LINE...INDENTED 5
     SPACES FROM THE LEFT MARGIN;
   - CONTINUATION LINES SHALL BE INDENTED 6 SPACES FROM THE LEFT
     MARGIN.  NOTE: SOME NWS-PREPARED TAFS MAY INCLUDE CONTINUA-
     TION LINES WHICH ARE INDENTED 5 SPACES RATHER THAN 6 BETWEEN
     JANUARY 1 1996 AND JUNE 1 1996.  THIS IS DUE TO A LIMITATION
     IN THE SOFTWARE SOME NWS OFFICES USE TO PREPARE THE TAFS
     BASED ON FTS.  AFTER JUNE 1 1996...ALL CONTINUATION LINES IN
     THE TAF SHALL BE INDENTED SIX SPACES.
   - AN END-OF-REPORT SEPARATOR ("=") SHALL BE INCLUDED AT THE
     END OF EACH TAF

   EXAMPLE INCLUDING FORMATTING CHANGES:
   TAF
   PAOM 071045Z 071212 14004KT P6SM FEW030
        FM2100 14010KT P6SM SCT030 PROB40 2106 2SM -RA
         OVC020
   FM0600 21015KT P6SM SCT035

*****************************************************************
OPERATIONAL DOCUMENTATION ASSOCIATED WITH THE TAF IMPLEMENTATIONS
<
FOR HOLDERS OF THE WEATHER SERVICE OPERATIONS MANUAL (WSOM)
CHAPTERS...AN OPERATIONS MANUAL LETTER (OML) FOR WSOM D-37...
ENTITLED "INTERNATIONAL AVIATION AERODROME FORECASTS"...WILL
BECOME EFFECTIVE ON JANUARY 1...1996.  A DRAFT VERSION OF THIS
CHAPTER HAS BEEN REVIEWED BY THE NWS...AND A FINAL UNSIGNED
DRAFT WILL BE DISTRIBUTED LATER THIS WEEK.  THIS UNSIGNED DRAFT
IS WHAT WILL BE IMPLEMENTED UNTIL THE OML HAS BEEN SIGNED.  THE
SIGNED D-37 OML WILL BE DISTRIBUTED AS SOON AS IT IS AVAILABLE.

ON JUNE 1...1996...D-37 (AND D-21..."AVIATION TERMINAL
FORECASTS") WILL BE SUPERSEDED BY A NEW TAF CHAPTER...D-31...
ENTITLED "AVIATION TERMINAL FORECASTS".

****************************************************************
ADDITIONAL CHANGES TO BE IMPLEMENTED AT 0000 UTC ON JUNE 1 1996:

WITH THE COMPLETE IMPLEMENTATION OF THE METAR AND TAF CODES IN
THE U.S. ON JUNE 1 1996...ONE ADDITIONAL GROUP WILL BE
IMPLEMENTED IN THE TAF CODE -- THE FORECAST OF NON-CONVECTIVE
LOW-LEVEL WIND SHEAR -- IN THE FORMAT DESCRIBED BELOW.

THE NON-CONVECTIVE LOW-LEVEL (UP TO 2000 FEET ABOVE THE GROUND)
WIND SHEAR GROUP (WSHWSHWSHWS/DDDFFKT) SHALL BE INCLUDED IN NORTH
AMERICAN TAFS ONLY.  THERE IS NO PROVISION IN THE INTERNATIONAL
TAF CODE FOR NON-CONVECTIVE LOW-LEVEL WIND SHEAR (LLWS).  IN THE
UNITED STATES...THE NON-CONVECTIVE LLWS GROUP WILL BE INCLUDED...
WHEN CONDITIONS ARE EXPECTED...IMMEDIATELY FOLLOWING THE CLOUD
FORECAST GROUP IN THE TAF.  IN CANADIAN TAFS...THE NON-CONVECTIVE
LLWS GROUP...WHILE CODED IN THE SAME FORMAT AS IN THE U.S....
WILL APPEAR IN A DIFFERENT LOCATION -- IMMEDIATELY FOLLOWING THE
SURFACE WIND FORECAST.

IN BOTH THE U.S. AND CANADA...THE NON-CONVECTIVE LLWS GROUP SHALL
BE CODED AND DECODED AS FOLLOWS:
                       WSH  H  H  /DDDFFKT
                          WS WS WS
WS        - AN INDICATOR MEANING WIND SHEAR;
H  H  H   - FORECAST HEIGHT...IN HUNDREDS OF FEET ABOVE GROUND
 WS WS WS   LEVEL...OF THE WIND SHEAR;
DDD       - FORECAST WIND DIRECTION...TENS OF DEGREES TRUE...
            ABOVE THE SHEAR;
FF        - FORECAST WIND SPEED...IN KNOTS...ABOVE THE SHEAR; AND
KT        - UNITS INDICATOR...MEANING KNOTS

EXAMPLE:              EXPLANATION:
WS015/30035KT         FORECAST WIND SHEAR AT 1500 FEET AGL...WIND
                      FROM 300 DEGREES AT 35 KNOTS

SAMPLE U.S. TAF:
TAF
KGEG 231051Z 231212 12012KT 4SM -RA BR OVC008 WS005/27050KT
     FM1930 09012KT 1SM -DZ BR VV003
     FM2100 23020KT P6SM BKN020
     FM0000 24015KT P6SM SCT050

***************************************************************
IF YOU HAVE QUESTIONS ABOUT THE TAF CODE CHANGES... CALL
CHRISTINE ALEX AT (301)-713-1726 X 142 OR SEND E-MAIL TO HER AT
CALEX@xxxxxxxxxxxxxxxxxxxxxx

FOR UPDATES AND CHANGES REFER TO THE NWS METAR/TAF HOME PAGE:
HTTP://WWW.NWS.NOAA.GOV/OSO/OSO1/OSO12/METAR.HTM

THIS IS THE END OF PART 2 OF THIS MESSAGE.  PARTS 3 AND 4
CONTAINING THE LIST OF NWS-PREPARED TAFS WILL BE SENT TOMORROW.
END