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Weather stations in the Upper Tanana Valley and Copper River BasinWeather stations in the Upper Tanana Valley and Copper River Basin

The FAA has announced it intends to close the contract weather services in Big Delta and Gulkana, leaving only automated weather stations at these locations critical to VFR flight routes in Alaska. The accompanying map, produced by the Alaska Airmen's Association and the Alaskan Aviation Safety Foundation, shows the distribution and nature of weather reporting stations that service this region.

Green circles: Stations with this symbol report weather 24 hours a day. An ASOS or AWOS is located at these sites but are augmented by human weather observers between 16 and 24 hours per day, who fill in details missed by the automated machines. Most importantly, they add or correct the sky condition, visibility, and types of weather that the machine either doesn't detect or may only sense after the weather has changed. Examples of these conditions are storm cells, rain and snow squalls, and fog banks and mountain cloud formations that signal high winds.

During their daily hours of operation, observers maintain a continual weather watch, updating their reports as conditions develop, and issuing specials when changes break specified thresholds. They also provide a mike-in-hand service to talk with pilots directly to convey weather information.

Orange circles: This symbol represents stations that are only served by an automated device, without human augmentation. These stations are not able to see many details important to pilots. They broadcast the automated observation and have no dialog with pilots. Those stations with an ASOS will issue special observations when conditions change beyond specified criteria. Those with the AWOS units only report weather three times per hour, regardless of weather changes.

Yellow diamonds: Stations with this symbol represent part-time human observers and are known as A-Paid stations. They provide valuable information to help fill in the weather picture but are only scheduled to report on a part-time basis. In actual practice, the stations often report less frequently than scheduled. At least one of these stations went for months with no weather reports filed last summer. These are valuable stations but cannot be relied upon as the basis for operational decision making by the aviation community. These stations do not issue specials to warn pilots of weather changes and have no mike-in-hand for contact with pilots.

Yellow lines: The lines on this map correspond to routes routinely flown by VFR pilots. In addition to these routes, many pilots fly to other airstrips, river bars, and lakes in the region not shown on the map. These routes see significant travel within the region and are used by pilots flying to and from Alaska via the Alaska Highway, used by summer visitors and residents alike.

Scale: Even with the scale bar on the map, the size of this region may not be appreciated. The entire state of Oregon is slightly larger than area depicted on the map.

Shaded relief: The shading on these maps comes from a digital elevation data set, derived from topographic maps. It shows the nature of the terrain, particularly the mountainous areas that pilots must fly through along VFR routes in this region. The dramatic effects of terrain on weather further illustrate how variable conditions encountered by pilots may be and the sparseness of weather reporting stations.

Today's status: The map on the left shows the distribution of stations operationally in use today. These stations also provide the surface observations used by the National Weather Service to generate our aviation forecasts.

After closures: After the FAA closes the weather observation services, currently scheduled to occur at the end of September 2001, Gulkana and Big Delta will be downgraded to stand-alone stations, as is depicted on the map on the right. The Alaska Airmen's Association and the Alaskan Aviation Safety Foundation feel this change would be detrimental to aviation safety.

What to do: Write the FAA, and let them know your concerns on regarding these weather services.

Send your letters to:

Clarence Goward, AAL-536, 222 W. 7th, #14, Anchorage, AK 99513
E-mail: [email protected]

In view of the nature of this notice, and the short time period before the stations are lost, we suggest you copy the FAA regional administrator on this matter.

Pat Poe, FAA Regional Administrator, 222 W. 7th, #14, Anchorage, AK 99513
E-mail: [email protected]

We would also appreciate a copy of your letter so that we may track this issue.

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