What Every Pilot Needs to Know About Weather
by Crista Worth
Life Is Risky; Flying Is Riskier
In life, we learn to mitigate risk: Look both ways before stepping off the curb so you won’t be hit by a bus. In flying, we mitigate risks by checking our personal physical and mental condition, maintaining our airplane, doing a pre-flight check and intelligently planning our route. Hanging over all this, literally, is the weather: clouds, fog, winds, ice — weather is probably the largest flight risk.
Preflight Action, §91.103(a), compels the PIC to be familiar with weather reports and forecasts.
Exactly what weather products you’re required to use isn’t spelled out for Part 91 pilots, although the regs require Part 121 and 135 operators to use products produced by the National Weather Service (NWS) or equivalent. The FAA’s preference is to use a standard weather briefing. It used to be that you had to call Flight Service to get your briefing and/or file a flight plan. Nowadays, websites and apps give you the same data FSS has — right at your fingertips. To effectively self-brief, you must know what’s needed, where to find it, and how to assess the risks posed by what you find.
What’s in a Standard Briefing?
An FSS briefer will organize your standard briefing as follows: adverse conditions, VFR flight not recommended, synopsis, current conditions, en route forecast, destination forecast, winds aloft, NOTAMs, prohibited areas, ATC delays, PIREPS and additional information. To dig up this information yourself, you’ll need to look at graphical forecasts for aviation, center weather advisories, convective SIGMETS, SIGMETs, AIRMETs, winds aloft, PIREPs, TAFs, METARs and NOTAMs. The charts you can peruse include surface analysis, forecast winds aloft, weather depiction, freezing level graphic, G-AIRMET graphic, high- and low-level significant weather progs, surface progs, constant pressure, visible and infrared satellite images, current and forecast icing products (CIP and FIP), graphical turbulence guidance (GTG), national/regional radar mosaics, radar echo tops and wind profiles. Don’t feel overwhelmed: Use the NWC’s convenient Standard Briefing page. Also, the friendly, highly trained briefers are still there for you at 800-WX-BRIEF.
I usually start with METARs and TAFs at the departure and destination airports. Red flags include low ceilings, poor visibilities, high winds or crosswinds, and poor runway conditions. Unacceptable conditions at the departure might mean delaying the flight or scrubbing it altogether. Bad weather at the destination might mean delaying the flight or finding an alternate route. The surface analysis and the weather depiction and radar charts give me the big picture. If temps aloft are high enough, I don’t need to look at icing. I’ll usually look at winds aloft across my route at different altitudes to look for wind shear. Winds in excess of 25 knots mean I’ll fly around the mountains rather than over them. If mountain ranges or passes are along my route, I’ll check the barometric pressure on either side. Major differences often lead to turbulence, rotors and mountain waves, which range from just no fun to downright deadly.
Monitor the Weather
If a long cross-country flight is in my near future, I’ll monitor the weather across the entire route (and perhaps across the entire country) for up to a week ahead. This gives me good situational awareness and a feel for what’s happening. Once in flight, the monitoring continues. I keep track of METARs ahead of time, to get an idea if the weather is changing or the forecast is holding.
It used to be that if the weather ahead looked iffy, I would call up Flightwatch on 122.0 MHz, but the FAA discontinued this service in October of 2015. These weather services are now provided via the same charted frequencies pilots use to open and close flight plans, as well as get updates on NOTAMs and TFRs. You can also call the universal FSS frequency of 122.2 MHz. So that several stations don’t answer you at once, include your location and the name of the FSS you are addressing on the initial call. For example: “Denver Radio, Cessna One-Two-Three-Four-Papa-Tango, over Thurman VOR, over.” Don’t include your specific request until two-way communications are established. The word "over" indicates the end of your transmission and that you expect a reply.
I can also ask ATC for PIREPs, and I always listen attentively to other pilots on frequency, in case any of them are having weather problems. If not on an IFR flight plan, I always ask for VFR flight following. This way I’m already in touch with ATC. They know who I am and what I’m flying. They might notify me of upcoming weather hazards or I can ask to deviate around clouds. Plus, I’m already in contact if I have an emergency. If available, I always pull up the ATIS at my destination as soon as possible, so I can form a mental picture of my approach and landing. Remember, the flight’s not over until the airplane is shut down and tied down. Proper aileron positioning during taxi will help prevent surface winds from upsetting your airplane — and you!
Want more info about weather in general? Check out the NWS Jetstream, an online school for weather. Then go out and fly!