DOC Header
July 26, 2001

 

TO: All Holders of Operational Manual


SUBJECT: Transmittal Memorandum for Operations Manual Issuance



1. Material Transmitted:



WSOM Chapter D-39, Airport Weather Warnings.



2. Summary:



This is a new chapter, encompassing policy and procedure for Airport Weather Warnings (AWW). The responsibility for AWWs at an airport fall directly with the TAF-responsible Weather Forecast Office (WFO). The criteria for AWWs is airport specific, and WFOs should follow Appendix A to this chapter to ensure AWWs are established in accordance with customer needs.

 

3. Effect on Other Instructions:

 

None.



John J. Kelly, Jr.

NOAA Footer



Issue Date Org. Code NATIONAL WEATHER SERVICE

Operations Manual

Part Chap
07/26/2001 W/OS23 D 39



AIRPORT WEATHER WARNING




Table of Contents Page


1. Purpose


2. Background


3. Procedures


4. Issuance Criteria


5. Issuance Responsibility


6. Dissemination Responsibility


7. Training and Other Considerations


8. Verification


9. Product Appearance and Content


Appendices


A. Sample LOA...only the AWW...no other NWS products A-1


B. Sample LOA...Disseminating other NWS products including

the AWW B-1



C. AWW Info-sheet for the users C-1

1. Purpose. This chapter details National Weather Service (NWS) policy and procedures for the Airport Weather Warning (AWW) product/services issued by Weather Forecast Offices (WFO). The AWW replaces the local airport advisory (LAA). The LAA was discontinued effective with implementation of the AWW.



2. Background. The AWW was developed to address weather phenomena that may adversely impact ground operations at airports. This information has proved useful to airport managers, fixed-based operators, airline ground personnel and others responsible for the safety of ground operations. Ground decisions based on the AWW may include those associated with fueling delays during thunderstorms, de-icing frequency and other similar ground operations.



AWWs are not intended for use by in-flight operations.



3. Procedures. The AWW is issued based on airport specific weather criteria and/or the issuance of any NWS warning product that will affect the airport (5-mile radius from the center of the airport complex), as agreed upon between local airport management and the supporting WFO. A Letter of Agreement (LOA) determines the weather elements, dissemination mechanisms, and points of contact. Two sample LOAs are attached as appendices A and B.



The AWW complements existing NWS warnings and forecasts. Airport officials are encouraged to refer to other NWS warning and forecast products, such as Terminal Forecasts (TAF), Short Term forecasts (NOW), Zone forecasts (ZFP) and other public watches and warnings, which also contain information about conditions that may impact ground operations. Use of NOAA Weather Radio should be encouraged.

The AWW should normally be issued with a lead time of 30 minutes to one hour. Updates or cancellations will be issued if and when additional or different user action is required per locally established criteria.



The AWW is written in a plain language, free text format. It should include the triggering phenomenon, location, start time (end time as needed), and may include additional remarks.



Also, keep in mind the following:

a. Use KTS, not MPH, as ground operations are geared to knots.

b. Ground based users prefer location of the event with respect to the airport. Try to avoid using location of events based solely on towns and cities.



c. Keep the product concise.



4. Issuance Criteria. Issuance criteria are established according to local airport requirements and should be reviewed, and updated as necessary, or on an annual basis, whichever comes first. See examples of criteria below.



-surface wind gusts of 40 knots or greater.

-onset of freezing rain

-cloud to ground lightning within 5 miles of, and approaching, the airport.

-thunderstorms with hail of inch or greater

-onset of heavy snow



5. Issuance Responsibility. The NWS Forecast Office may enter into an agreement to issue AWWs for any airport in their area of responsibility, based on the need for such a product by airport personnel. All forecasters shall be trained on the procedures and criteria for AWW issuance. The AWW product and dissemination procedures will also be part of the service backup procedure with the service backup WFOs.



6. Dissemination Responsibility. The AWW will be disseminated via the NOAA port (Automated Weather Information Processor System (AWIPS) Satellite Broadcast Network (SBN)). In addition, or if no access to the NOAA data stream is available, a locally established communication system can be used. The NWS office's method of dissemination will vary depending on local communications options. Examples are listed below.



a. (Airport Operations Control Center) via (phone, pager, etc.).

b. (Airport control tower) via (SAIDS, or phone.)



Once the primary or backup point of contact at the airport is notified, it is the responsibility of that individual to use the information provided in the AWW to ensure the safety of ground based aircraft and personnel in airport operations areas.



7. Training and Other Considerations. The Norman Risk Reduction highlighted some issues and concerns of which WFOs need to be aware. The first is turnover of personnel at local airports. This can be a concern when there is a long interval between issuance of AWWs. The AWW information sheet at appendix C of this chapter can help train local users.





Another problem is communication. It will be up to the parties of the LOA to determine the best means of relaying information. A lead time of 30 minutes can be significantly reduced because of poor communication. Periodic tests of the AWW are recommended to ensure optimum communication.



8. Verification. Local verification and quality control of the AWW are required by the NWS. Periodic verification results, as agreed upon by each Region and issuing office, shall be provided to NWS Regional and National Headquarters.



9. Product Appearance and Content. The AWW product should be short and concise. This will ease dissemination of the product and help reduce confusion. See the following examples:





a.

WWUS84 KOUN 242145

OKC109-242245- (NOTE: Use of UGCs is optional)



AIRPORT WEATHER WARNING FOR WILL ROGERS WORLD AIRPORT

NATIONAL WEATHER SERVICE NORMAN OK

445 PM CDT SUN SEP 24 2000



EXPECT THUNDERSTORMS WITH HEAVY RAIN...HAIL...CLOUD TO GROUND LIGHTNING...AND SOUTHWEST WIND TO 40 KTS OVER THE AIRPORT FROM 505 PM TO 520 PM. (use only those elements that are in the LOA)



b.

WWUS84 KOUN 242145

OKC109-242220- (NOTE: Use of UGCs is optional)

AIRPORT WEATHER WARNING FOR WILL ROGERS WORLD AIRPORT

NATIONAL WEATHER SERVICE NORMAN OK

445 PM CDT SUN SEP 24 2000



WEST WIND GUSTS OF 50 TO 60 KTS WILL REACH THE AIRPORT BETWEEN 500 PM AND 510 PM. (use only those elements that are in the LOA)

c.

WWUS81 KBOX 241415

MAC025-241515- (NOTE: Use of UGCs is optional)



AIRPORT WEATHER WARNING FOR LOGAN AIRPORT

NATIONAL WEATHER SERVICE TAUNTON MA

915 AM EST FRI NOV 24 2000



FREEZING RAIN WILL DEVELOP AT AND AROUND THE AIRPORT BY 1000 TO 1030 AM AND END BETWEEN 200 TO 300 PM. (use only those elements that are in the LOA)



Appendix A

EXAMPLE OF A LETTER OF AGREEMENT

(Only involves AWW)

Letter of Agreement Regarding Airport Weather Warning Service

Between National Weather Service Forecast Office, (office name), (State)(name of airport authority) Airport Federal Aviation Administration (local tower, if applicable)



Parties to this Letter of Agreement (LOA) are the Meteorologist In Charge (MIC) of the National Weather Service (NWS) Forecast Office at ________, the Airport Management Official at ______________ Airport.

Airport Weather Warnings (AWW) are prepared and issued by selected NWS Forecast Offices, per agreement between airport operations personnel, and the NWS.

1. PURPOSE



This LOA defines the AWW service to be provided by the NWS Forecast Office at (location of WFO). It describes weather criteria necessary for the issuance of an AWW, identifies local dissemination responsibilities, and establishes procedures to provide warning for weather conditions that may adversely impact airport ground operations. This LOA supersedes a letter dated ____________, regarding Local Airport Advisory (LAA) service.

2. AIRPORT WEATHER WARNING



The AWW is issued by the NWS Forecast Office at (location of WFO) to advise airport officials that locally established hazardous weather criteria, which may adversely impact airport ground operations, have been met.



AWWs are not intended for use during in-flight operations. The AWW provides information useful to airport personnel, fixed-based operators, airline ground personnel and others responsible for the safety of ground operations. Ground operations may include tie-downs during high wind events, temporary holds for departing aircraft, and preparing snowplows.



AWWs complement existing NWS warnings and forecasts. Airport officials are encouraged to refer to other NWS warning and forecast products, such as terminal forecasts (TAF), Short Term Forecasts, public watches and warnings, which also contain



information important to ground based aviation users, especially those products issued for severe storms or high winds.



3. AWW ISSUANCE CRITERIA:



Issuance criteria are established between signers of this LOA and should be reviewed, and updated if necessary, on an annual basis.



For the (name of airport) Airport, the following criteria have been established for the issuance of the AWW:

For example....

-surface wind gusts of 40 knots or greater

-onset of freezing rain

-cloud to ground lightning within 5 miles, moving towards the airport

-thunderstorms with hail of inch or greater

-onset of heavy snow



4. ISSUANCE RESPONSIBILITY:



The NWS Forecast Office, (location of WFO), is responsible for issuing the AWW.

5. DISSEMINATION RESPONSIBILITY:



The AWW will be disseminated via the NOAA port (AWIPS SBN). In addition, or if no access to the NOAA port (AWIPS SBN) is available, a locally established communication system, as identified below, shall be used.



The NWS office will disseminate the AWW to:

Example...

a. (Airport control tower) via (SAIDS, or phone 555-1212.)



It is the responsibility of the individual receiving the AWW to forward information to other users, who should use the information for the safety of ground based aircraft and ground operations personnel.



6. EXAMPLE OF AWW:

AWW issued at 130 pm: Airport weather warning for ________airport. South winds 30 knots gusting 40 knots, beginning 200 pm, decreasing and shifting to northwest by 500 pm.



7. TERMS OF AGREEMENT:



All parties to this LOA should provide the NWS MIC with any changes to their requirements. The NWS MIC should discuss any requests for change with NWS Regional Headquarters and then arrange a meeting to address changes formally. This LOA will remain in effect until all parties agree on amending or revoking the LOA.



A review and update is mandatory after three (3) years have elapsed from the following date: (___________).

1. ______________________________________

Meteorologist In Charge

National Weather Service, (City, State)



2. ______________________________________

(Name).

Manager, FAA/ATCT

(City, State)



3. _____________________________________

(Name)

(Title, eg: Director of Airports)

(Name of airport)



"The NWS undertakes the activities under this Agreement, pursuant to and in accordance with 15 U.S.C. & 313 et seq"




Appendix B

2ND EXAMPLE OF A LETTER OF AGREEMENT

(Involves AWW and other NWS products) Letter of Agreement Regarding Weather Services Between National Weather Service Forecast Office, (office name), (State)

and (name of airport authority) (local tower if applicable)



Parties to this Letter of Agreement (LOA) are the Meteorologist In Charge (MIC) of the National Weather Service (NWS) Forecast Office at ________, the Airport Management Official at ______________ Airport., and the (air traffic control tower) Manager, Federal Aviation Administration (FAA).



1. PURPOSE



This LOA lists and defines the NWS warning and advisory service to be provided by the NWS Forecast Office at ________, It describes weather criteria necessary for the issuance of weather warnings, identifies local dissemination responsibilities, and establishes procedures to provide warnings for weather conditions that may adversely impact airport ground operations. This LOA supersedes a letter dated January 1, 2000, regarding Local Airport Advisory (LAA) service.

2. WEATHER WARNINGS PRODUCTS AND CRITERIA



The following products will be issued by the NWS Forecast Office at ________, when the associated weather is expected to affect the ______________ Airport:

a. Tornado Warning

b. Severe Thunderstorm Warning

-Hail 3/4 inch diameter or greater

-Wind gusts 58 mph or greater

c. Heavy Snow Warning

-6 inches or more within 12 hours

-9 inches or more within 24 hours.

d. Winter Storm Warning

-Heavy snow combined with wind or wind chills

e. Blizzard Warnings

-Winds 35 mph or more with blowing snow and visibilities less than 1/4 mile (for 3 hours)

f. Flash Flood Warning

g. High Wind Warning

-Sustained 40 mph or higher (for 1 hour), or gusts 58 mph (no time limit)

h. Airport Weather Warning

-Lightning within 5 nautical miles

-Sustained winds of 20 knots or greater or winds gusts over 30 knots



Issuance criteria for the Airport Weather Warning product are established between signers of this LOA and should be reviewed and updated when necessary.

3. DISSEMINATION RESPONSIBILITY:



The AWW will be disseminated via the NOAA port (AWIPS SBN). In addition, or if no access to the NOAA port (AWIPS SBN) is available, a locally established communication system, as identified below, shall be used.



NWS Forecast Office at ___________, will notify the Airport Communications/Control Center via phone at xxxxxx when any of these warnings are issued. When possible, the NWS will advise the Airport Communications/Control Center of the length of time that the weather phenomena can be expected in the area.



The Airport Communications/Control Center personnel will then notify the airport duty Manger and make any other required Airport Notifications.



4. TERMS OF AGREEMENT:



All parties to this LOA should provide the NWS MIC with any changes to their requirements. The NWS MIC should discuss any requests for change with NWS Regional Headquarters and then arrange a meeting to address changes formally. This LOA will remain in effect until all parties agree on amending or revoking the LOA.



A review and update is mandatory after three (3) years have elapsed from the following date: (___________).



1. ______________________________________

Meteorologist In Charge

National Weather Service, (City, State)



2. _____________________________________

(Name)

(Title, eg: Director of Airports)

(Name of airport)

"The NWS undertakes the activities under this Agreement, pursuant to and in accordance with 15 U.S.C. & 313 et seq"



Appendix C



Airport Weather Warnings (AWW)

From your National Weather Service

AWWs:



- Are local products (5-mile radius of the center of the airport complex) issued for weather hazardous to Airport Ground Operations which may not be apparent in other NWS forecasts or warnings.

* Complement existing NWS warnings and forecasts.

* Are issued for specific weather criteria, negotiated by local airport management and the NWS office.

* Issued for the onset of the weather event.

* Issued with lead times up to 1 hour.

* Dissemination methods are negotiable.

* Examples:

AIRPORT WEATHER WARNING FOR __________AIRPORT.

NATIONAL WEATHER SERVICE ___________

900 PM EST THU JAN 13 2000



FREEZING RAIN...BEGINNING 1000 PM...CHANGING TO SNOW BY MIDNIGHT.

------------------------------------------------------------------------

AIRPORT WEATHER WARNING FOR __________AIRPORT.

NATIONAL WEATHER SERVICE ___________

130 PM MDT SUN AUG 13 2000



SOUTH WINDS 30 KTS GUSTING 40 KTS...BEGINNING 200 PM...DECREASING AND SHIFTING TO THE NORTHWEST BY 500 PM

------------------------------------------------------------------------



AIRPORT WEATHER WARNING FOR __________AIRPORT.

NATIONAL WEATHER SERVICE ___________

430 PM MDT SUN AUG 13 2000



CLOUD TO GROUND LIGHTNING WITHIN 5NM...BEGINNING 500 PM THROUGH 515 PM.



Contact:_________________________________

For more details