U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL WEATHER SERVICE 1325 East-West Highway Silver Spring, Maryland 20910-3283

W521 August 8, 1975

SUBJECT : Transmittal Memorandum for Operations Manual Issuance 75-19

TO            : All Holders of Operations Manual

1. Material Transmitted:

New Chapter B-13, Standards and Procedures for Surface Observing Programs at FAA Facilities.

2. Summary:

This chapter describes the standards, procedures, and NWS/FAA responsibilities for weather observing programs at FAA facilities. Many of these policies are based on the 1965 FAA/ESSA (NOAA) Memorandum of Agreement.

3. Effect on Other Instructions:

        a. Observing program type at Combined Station Towers, stated in paragraph 3.2, chapter B-10, WSOM,
                should be changed from basic observations to aviation observations.

        b. Cancels OML 68-46, 11/17/68 filed with B-13, which should be destroyed.

George P. Cressman
Director, National Weather Service

Issue Date Org. Code                 NATIONAL WEATHER SERVICE         Part      Chap.
8-8-75         W521x1                                       Operations Manual                   B        13

Table of Contents:

1. General

1.1 Purpose
1.2 Policy

2. FAA Observing Facilities and Observing Programs

2.1 FAA Flight Service Stations (FSS)
2.2 Air Traffic Control Towers (ATCT) and Combined Station Towers (C/ST)
2.3 Definitions

3. Responsibilities of NWS

3.1 Standards
3.2 Quality Control
3.3 Certification

4. Equipment, Maintenance, Operation, and Supply Support

4.1 Minimum Equipment at Basic Weather Observing Stations
4.2 Minimum Equipment for Limited Aviation Weather Reporting Stations (LAWRS)

5. Contents of Observations

Exhibits:

        B-13-1 Certificate
 

1. General.

1.1 Purpose. This chapter establishes standards and procedures for the surface weather observing program at FAA facilities. These standards and procedures have been coordinated and approved by the FAA.

1.2 Policy. Whenever an NWS aviation weather observing staff is stationed at an airport, the NWS will be responsible for the observation programs. At parttime NWS stations, the FAA may jointly share this responsibility if mutually agreed. At facilities staffed by the FAA but not by NWS, the FAA, subject to mutual agreement, will be responsible for the observational functions.

2. FAA Observing Facilities and Observing Programs.

2.1 FAA Flight Service Stations (FSS). Observation programs at FSS facilities usually fulfill needs of both NWS and FAA in that the observations satisfy both network and aviation requirements. Therefore, Basic Weather Observations and in some cases Synoptic Observations, are normally required from these facilities.

2.2 FAA Air Traffic Control Towers (ATCT) and Combined Station Towers (C/ST). Observation programs at these facilities are normally aviation oriented and contain only those elements which can be either observed from within the confines of the control tower or remoted into the control tower. Where an Automatic Meteorological Observation Station (AMOS) is installed, tower personnel will provide visually observed elements to supplement those from AMOS. Limited Aviation Weather Reporting Stations (LAWRS) are those FAA designated ATCT and C/ST.

2.3 Definitions. Detailed definitions of Basic Weather Observations and Limited Aviation Weather Observations and their uses are contained in chapter B-10, WSOM.

3. Responsibilities of NWS.

3.1 Standards. It's the responsibility of NWS to set standards for weather observing. When observations are used wholly or in part for aviation purposes, standards shall reflect consultation and coordination with the FAA insofar as aviation aspects are concerned.

3.2 Quality Control. NWS will maintain a quality control program to measure conformance of the observational program to established standards, and to take follow-up action as necessary.

3.3 Certification.

        a. NWS will test and certify all FAA personnel that take observations, in accordance with chapter B-61, WSOM.

        b. The Regional Director or his designated representatives shall issue a certificate to each LAWRS meeting NWS standards for weather observations. Terms of the certificate will be reviewed during each visit made to the facility. A remark should be included in each visit report as to whether or not the terms of the certificate remain valid. The certificate, example attached as B-13-1, is to be used for this purpose.

4. Equipment, Maintenance, Operation, and Supply Support. Observational equipment that is used exclusively for aviation observations will be procured, installed, operated, maintained, and supply supported by the FAA. Observational equipment such as the sling psychrometer and rain gage, serving multiple NWS/FAA purposes, will be procured, installed, maintained, and supply supported by the NWS unless otherwise agreed to. To the maximum extent possible, each agency should.avail itself of the facilities offered by the other in contracting for, installing, maintaining, and supply supporting observational equipment on a non-reimbursable basis where appropriate.

4.1 Minimum Equipment at Basic Weather Observing Stations. FSS making Basic Weather Observations shall have:

a. a ceilometer or balloons and ceiling light,

b. a hygrothermometer and sling psychrometer,

c. a wind direction and speed system with gust recorder,

d. a standard 8-inch rain gage (if station reports precipitation), and

e. an altimeter setting indicator, mercury barometer, and barograph.

The above criteria applies to any new establishments. At existing stations, upgrading of equipment standards should be made as equipment and resources become available. NWS regional headquarters should be consulted before any changes are made.

4.2 Minimum Equipment for Limited Aviation Weather Reporting Stations (LAWRS). ATCT and C/ST making Limited Aviation Observations shall have:

        a. a ceilometer or cloud height indicator (CHI). This requirement can be satisfied by a ceiling light for night and a ceiling balloon capability for day operations or, an FAA negotiated contract with a certified observer who would obtain cloud measurements using NWS approved procedures,

b. a hygrothermometer (if terminal forecasts are required),

c. a wind direction and speed system, and

d. an altimeter setting indicator routinely compared as stated in Federal Meteorological Handbook #1.

5. Contents of Observations. The observed elements required for Basic Observations and Limited Aviation Observations are contained in Exhibit B-10-1 chapter 10, WSOM.