[nws-changes] 20120305: grapical turbulence guidance update Fwd: ADMIN NOTICE NOUS41 KWBC

-------- Original Message --------

NOUS41 KWBC 052022

Technical Implementation Notice 11-58 Amended
National Weather Service Headquarters Washington DC
322 PM EST Mon Dec 27 2012

To       NWS Offices
         Federal Aviation Administration
         Family Of Services Subscribers
         Other Users of NWS Aviation Forecasts

From     Cynthia Abelmann
         Chief, Aviation Services Branch

Subject: Amended Graphical Turbulence Guidance To Be Updated effective
         April 5, 2012

The following changes have no impact on NOAA Weather Wire Service

Effective April 5, 2012, 1200 Coordinated Universal Time (UTC), the NWS
Aviation Weather Center (AWC) in Kansas City, Missouri, will update The
Graphical Turbulence Guidance (GTG) product in conjunction with the
implementation of the Rapid Refresh (RAP) model.  The following changes
potential impact to end users of this product include:

Resolution of the grid spacing will increase from 20KM to 13KM.  As a
result of increased resolution, the parameter Grid ID (PDS OCTET 7),
internal to the GRIB file, will change to 130. For more information see:


Additional forecast hours valid at 04, 05, 07, 08, 10 and 11 hours

This change will affect the following WMO headers for GTG:

WMO           FLIGHT


------------  -----
YVW*14 KKCI   FL450
YVW*15 KKCI   FL440
YVW*16 KKCI   FL430
YVW*17 KKCI   FL420
YVW*18 KKCI   FL410
YVW*19 KKCI   FL400
YVW*20 KKCI   FL390
YVW*21 KKCI   FL380
YVW*22 KKCI   FL370
YVW*23 KKCI   FL360
YVW*24 KKCI   FL350
YVW*25 KKCI   FL340
YVW*26 KKCI   FL330
YVW*27 KKCI   FL320
YVW*29 KKCI   FL310
YVW*30 KKCI   FL300
YVW*32 KKCI   FL290
YVW*33 KKCI   FL280
YVW*34 KKCI   FL270
YVW*36 KKCI   FL260
YVW*38 KKCI   FL250
YVW*39 KKCI   FL240
YVW*41 KKCI   FL230
YVW*43 KKCI   FL220
YVW*45 KKCI   FL210
YVW*46 KKCI   FL200
YVW*48 KKCI   FL190
YVW*50 KKCI   FL180
YVW*53 KKCI   170
YVW*55 KKCI   160
YVW*57 KKCI   150
YVW*60 KKCI   140
YVW*62 KKCI   130
YVW*65 KKCI   120
YVW*67 KKCI   110
YVW*70 KKCI   100
ZVW*50 KKCI   Composite

WHERE     *  = A    = 00 HOUR FORECAST
          *  = B    = 01 HOUR FORECAST
          *  = C    = 02 HOUR FORECAST
          *  = D    = 03 HOUR FORECAST
          *  = E    = 04 HOUR FORECAST
          *  = F    = 05 HOUR FORECAST
          *  = G    = 06 HOUR FORECAST
          *  = H    = 07 HOUR FORECAST
          *  = I    = 08 HOUR FORECAST
          *  = J    = 09 HOUR FORECAST
          *  = K    = 10 HOUR FORECAST
          *  = L    = 11 HOUR FORECAST
          *  = M    = 12 HOUR FORECAST

The GTG graphics are computer-generated 4-dimensional forecasts
of information related to the likelihood of encountering
atmospheric turbulence. The product provides forecasts for the
48 contiguous United States, much of Canada and Mexico, and their
respective coastal waters at flight altitudes from 10,000 MSL to
FL450 only. It does not provide forecasts from the surface
to 10,000 ft. Users should also be aware that turbulence is a
highly dynamic phenomenon and in case of rapidly changing
conditions, the product may not accurately convey a
significant hazard.

GTG may be used as a higher-resolution supplement to AIRMETs and
SIGMETs, but not as a substitute for the turbulence information
they provide. GTG-2 graphics are authorized for use as an
unrestricted, supplementary weather product. The GTG-2 does not
have the capability to be amended. See the definition of primary
and supplementary weather products below.

GTG is produced automatically from the 13 KM Weather Research and
Forecasting Rapid Refresh (RAP) model runs. GTG produces an
Analysis, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12-hour Turbulence
Forecast every hour in GRIB format. This product also provides a
composite field representing the maximum turbulence value between
10 and 45 thousand feet for each analysis and forecast.

The GTG graphics suite is automatically produced with no human
modifications. Information on the graphics is determined from
observational data, pilot weather reports, upper air soundings,
satellite soundings, automated aircraft reports, and surface
weather reports, all of which are integrated with computer
model output.

On January 24, 2012, GTG output in Gridded Binary (GRIB) format
will be available through

1. NWS FTP servers at:


2. The Family Of Services (FOS) High Resolution Data Service and
Server Access Service

3. Satellite Broadcast Network (SBN) NOAAPORT channel

To obtain sample gridded GTG data, contact:

Robert Sallee
Senior Software Engineer
Aviation Weather Center
Kansas City, MO 64153

For questions regarding the new GTG product contact:

M. Pat Murphy
Warning Coordination Meteorologist
Aviation Weather Center
Kansas City, MO 64153

National Technical implementation notices are online at: