FORECAST CONDITIONS
Turbulence Ceiling & Visibility
Place Time Wind Visibility Weather Ceiling
KLUK FM1800Z 16004KT P6 SM BKN040
KDAY TEMPO 1519Z -- 4SM -SHRA BKN025
FM1900Z 16007KT P6 SM -- BKN035
KCMH FM1800Z 17006KT P6 SM -- BKN040
TEMPO 1922Z -- 4SM -SHRA, BR --
WINDS ALOFT
Turbulence Visibility & Performance
Place Altitude Wind Temp
CVG 6000 260/07 16 C
CMH 6000 210/08 15 C
1. Ceiling & Visibility. First, look at the weather data elements that report ceiling and visibility.
In the case of the proposed VFR flight from KLUK to KCMH, current visibility at your departure and destination airports is marginal, and the small temperature/dew point spread should trigger a mental red flag for potentially reduced visibility. The forecasts call for conditions to improve at your departure airport, KLUK, by the time you plan to launch (1830Z).
Note, however, that you could encounter marginal conditions,
including light rain showers, en route and also at your destination (KCMH). Since the forecast ceilings will probably not allow you to fly VFR at the planned altitude (5,500 MSL), this part of the analysis tells you that terrain and obstacle avoidance planning (discussed in the next section) will be necessary for this flight if you choose to depart at the originally scheduled time.
2. Aircraft Performance. Next, carefully review current and forecast temperatures – departure, en route, and destination
– for possible adverse impact on aircraft performance. If the temperatures are high, you need to know and plan for the effects of high density altitude, especially on takeoff, climb,
and landing. If temperatures are low and you plan on flying in the clouds, you should pay special attention to known or forecast icing and freezing levels.
In the sample VFR flight from KLUK to KCMH, temperatures on the surface and at your planned altitude are moderate, so performance problems associated with density altitude or icing are not likely to occur on this flight.
3. Turbulence: Review wind conditions for departure airport, en route, and destination airport. You will also need a mental picture of vertical wind profiles, so as to select the best altitude(s) for cruise flight, and to determine whether wind shear is present.
For the sample flight from KLUK to KCMH, the chart format allows
you to see quickly that you will encounter light southerly surface winds at your departure and destination airports. Winds aloft will also be light, but from a westerly direction. There are no indications for wind shear or convective activity (thunderstorms), so you can conclude that turbulence is not likely to be a hazard for this particular flight.
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本文链接地址：General Aviation Pilot’s Guide to Preflight Weather Planning, Weather Self-Briefings, and Weather Decision Making(8)
