The Weather Never Sleeps

Be weather wise

December 5, 2009 By Jack Williams

Help is at your fingertips

Before you take off for your first flight to a destination away from your home airport, your flight instructor will make sure you know how to prepare a flight plan. You’ll have to map your route, determine how you’ll navigate from place to place, calculate how long each leg of the trip should take, and estimate how much fuel you’ll need.

Before taking off you’ll also need to obtain a preflight weather briefing as required by both good judgment and the Federal Aviation Regulations (FARs). FAR 91.103 says that for a flight “not in the vicinity of an airport,” a pilot needs to obtain weather reports and forecasts.

Just as you need a flight plan before you can fly away over the horizon, you need a plan for learning how to obtain a weather briefing and then a plan for actually obtaining one.

A good plan for learning how to collect weather information for flights begins with becoming familiar with the FAA’s standard weather briefing (see sidebar). Meteorologists refer to the many different kinds of maps and text describing the current weather and forecasts for future weather as “products.”

The next step in your plan is to learn about the products used for a standard briefing by going to the National Weather Service Aviation Weather Center (AWC) “Standard Brief” section on the Web.

But, as the notice in red at the top of the AWC’s Standard Briefing page says, you shouldn’t try to use the Web site for a do-it-yourself briefing. However, the Web site is a good way to become familiar with weather information and to practice obtaining weather briefings. In fact, you can become more comfortable with obtaining preflight weather briefings by spending some time collecting weather data for imaginary flights—those dream trips you’d like to take when you’re a certificated pilot.

The next step is to begin digging out information for pre-preflight briefings. That is, you brief yourself before obtaining a formal briefing. You are more likely to understand a preflight briefing if you already know, in a general way, what the weather is doing over the part of the country where you plan to fly. Start doing this a day or so ahead of time. This can be no more complicated than watching The Weather Channel, the weather segment of local television news, or spending some time on weather Web sites, especially those that have maps showing the current and forecast weather. You want to learn things such as the possibility that a weather system could threaten your area when you want to go flying. Is your local television meteorologist forecasting rain for the day you plan to fly? If so, is the rain expected to be steady, covering most of the area, or will it fall as showers or thunderstorms for part of the day?

At this stage you should be most interested in what kinds of weather systems are affecting your weather. If a large storm is moving in, the local television meteorologist will probably talk about when it’s likely to pass.

You might find it more convenient to find the weather information you need on the Web. The National Weather Service (NWS) office in your area should be a good source of information; find links to local offices online.

The Weather Channel Web site has an aviation section with maps showing weather factors, such as forecast winds at 10,000 feet, that you won’t find on many other Web sites.

Another good way to obtain aviation weather maps and text information is to use the FAA’s Direct User Access Terminal (DUAT) system. The FAA contracts with two companies with slightly different URLs to operate the DUAT. They are CSC and DTC. Any pilot with a current medical certificate may register to use either or both of these sites.

See “The Weather Never Sleeps: Becoming a Weatherman” (January 2009 AOPA Flight Training) to learn how you can use DUAT to become proficient in obtaining and using weather data. DUAT offers not only data for preflight briefings but also for “outlook” briefings for flights more than six hours after you obtain the briefing. Once you are proficient at using weather text and maps to decide whether you should go flying, DUAT is a good way to obtain your weather briefing.

While do-it-yourself weather briefings are a good way to become comfortable with weather maps and text products, when it’s time to obtain a weather briefing for a real flight, you should definitely use the FAA’s flight service stations, which provide information by telephone when you’re on the ground and by radio in the air. On the ground you contact a flight service station by calling 800-WX-BRIEF. In the air, call Flight Watch on 122.0 MHz (for weather updates) or one of the other frequencies listed on aeronautical charts for additional information.

When you call a flight service station by telephone or radio, you’ll talk with a specialist who is trained and certified to help you interpret weather information, including how the weather and airspace regulations will affect you no matter what part of the country you are flying in. If you are a student pilot, be sure to tell the flight service briefer. The briefers are used to taking a little more time with students.

While talking with the flight service specialist, you might have difficulty visualizing the weather systems the briefer is talking about. To avoid this problem, before calling a flight service station on the phone you could print out a couple of weather maps and follow along.

One is a surface analysis, which shows the positions of areas of high and low air pressures and fronts at the surface. Another useful map is a surface prog, which is a map showing the forecast for a particular time. Obviously this should be the one that’s nearest to the time of your planned fight. You could find these maps on either on of the DUAT services or on the AWS Web site.

Before calling a flight service station you should take the AOPA Air Safety Foundation’s brief online course. The ASF courses are a good introduction to the system and will help you make the best use of it.

Jack Williams, a freelance science writer specializing in weather and climate, is an instrument-rated private pilot. The latest of his six books is The AMS Weather Book: The Ultimate Guide to America’s Weather. He answers questions about weather on his Web site.