Date of Issue:     December 27, 1984              Effective Date:   February 4,1985

In  Reply Refer To: W/OM13x2                     File With:     D-36

Subject:   International Aviation Service Arrangements

Reference(s):

WSOM Chapter D-36, transmittal issuance 78-23, dated 12/12/78

Effective 1800 GMT, February 4, 1985, forecasts of winds and temperatures aloft will be issued within the U.S., its territories and possessions in a new World Meteorological Organization (WMU) code (WINTEM) which has replaced the WMU ARMET code. Data in the WINTEM format, along with significant weather forecasts in plain language, will serve as backup for standard flight documentation charts or for departures from airports where such charts are normally not available. An exception to the replacement will be the continued issuance of 10 ARMET bulletins at the request of the Federal Aviation Administration (FAA) for air traffic control purposes.

The WINTEM forecasts are to be distributed as required via Automation of Field Operations and Services and stored at the FAA's Weather Message Switching Center for further distribution. In addition, the WINTEM forecasts will be distributed domestically via the NWS Family of Services and internationally via meteorological or aeronautical circuits.

NWS WINTEM bulletins are prepared for two categories: low-level, including grid-point data for flight levels 50 (850 hPa), 100 (700 hPa), 180 (500 hPa), and 240 (400 hPa); and high level, including grid-point data for flight levels (300 hPa), 340 (250 hPa), 390 (200 hPa), and 450 (150 hPa). The high-level bulletins also include tropopause height and level-of maximum-wind information.

Attachment 1 gives an example of (1) a low-level WINTEM bulletin, with a brief explanation and (2) a high-level WlNTEM bulletin, with a brief explanation of the features not included in the low-level bulletins.

Attachment 2 is a geographical depiction of the low-level WINTEM bulletins included in this program; attachment 3, of the high-level bulletins. These attachments are to be used in lieu of Appendix F to WSU Chapter D-36.

Richard E. Hallgren
Assistant Administrator
  for Weather Services

Attachments

Attachment 1

(1) FBNT11 KWBC 081940

(2) WINTEM 090600

(3) 650N 0350W 0300W 0250W 0200W 0150W 0100N 0050W

(4) F240 34028M40 34025M42 33015M43 3300JM43 14002M43 13003M42 07007M41

F180 34025M30 34021M32 34011M33 03003M33J 12005M33 11005M32 05011M31

F100 35019M14 35015M16 01007M16 09007M17 11011M17 10011M17 06011M18

F'050 01015M09 010131109 04009M10 09011M11 12017M13 11015M15 08011M17

(5) 600N

F240 28054M36 28061M36 28065M37 29065M37 29055M38 30044M39 320J4M40

Explanations:

(1) Bulletin heading, including date and hour of preparation.

(2) Code type and date and hour of forecast valid time.

(3) Latitude coordinate (65.0N) followed by longitude coordinates (35.0W, 30.0W, 25.0W, etc.) of grid points.

(4) Indication of flight level (F) followed by flight level (for example, 240, i.e., 24,000 feet) followed by wind and temperature forecasts at intersections of 65.0N with 35.0W, 30.0W, 25.0W, etc. First two digits of forecast are direction related to true north, in tens of degrees, for example, 340 degrees at 65.ON-35.0W. Next three digits are wind speed in knots, for example, 28 knots. M is sign of temperature (negative). (Temperatures of zero degrees Celsius or above are indicated as P, for positive). Last two digits are temperatures, for example, minus 40 degrees Celsius.

(5) Latitude coordinate (60.0N) related to the group of forecasts that follows.

FBPA39 KWBC 081940

WINTEM 090600

300N 1100E 1150E 1200E 1250E 1300E 1350E

(1) TROP 470 470 480 480 490 510

(2) MAXW 46026108 42028108 37029106 34029092 38028084 40027081

F450 26106M68 28092M64 28081M64 26075M63 26075M62 27075M62

Explanations:

(1) Tropopause heights in flight level, for example, 47,000 feet at 30.ON-110.OE and 51,000 feet at 30.ON-135.OE.

(2) Level-of-maximum-wind information. In each eight-character group, the first 3 digits are height of the maximum wind in flight level, next 2 digits are directions in tens of degrees related to true north, and last 3 digits are maximum wind forecast speed in knots. For example, the maximum wind at 30.0N-110.0E is forecast to be at 46,0C0 feet, true direction 260 degrees, and speed 108 knots.

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