Aviation Weather Support
__ are governed solely by reference to outside visual cues such as horizon and terrain.
Visual Flight Rules (VFR)
When is low-level wind shear most hazardous to aviation?
During take-off and landing operations.
True or False. To find bases of stratus clouds caused by mechanical lift, use the LCL
True
The coldest temperatures behind a cold front will be found on the __ morning after passage
second
What are the favorable conditions for mixed icing?
-9°C to -15°C and DPD ≤ 3°C
__ and __ help determine whether flights are conducted using visual flight rules (VFR) or instrument flight rules (IFR).
Ceiling, Visibility minimums
An inversion will break when the inversion break temperature is __ than the forecast maximum temperature.
Lower
With a dew-point depression of 3-4°C and relative humidity of 70-80% what cloud amount can be forecast?
SCT
In a 24-hour period, when does the temperature increase and decrease the most?
Increase the most during the morning hours and decrease the most after midnight.
What are the favorable conditions for rime icing?
-16°C to -22°C and DPD ≤ 4°C & -22°C to -40°C and DPD < 6°C
TAF __ and __ criteria are designed around flight planning criteria.
specification, amendment
When the wind speed increases with height above the inversion, obtain the wind speed at __ feet and multiply by __.
5,000; 80%
What is the effect on clouds when moving into drier air?
If clouds upstream are moving into a forecast location that is drier, the amount of coverage will decrease and bases will increase in height.
The dew-point method only works if there is no __ change
air mass
What are the effects of aircraft icing on all aircraft types?
Increasing drag and weight while decreasing lift, reduces the effective power of aircraft engines, result in disastrous vibrations, creating foreign object damage (FOD), loss of aircrew’s vision, instrument failure, and loss of radio communication.
When the upper edge of the disk of the sun is 12° below the horizon.
Nautical Twilight
Geostrophic winds are obtained from the __, __, and/or __.
925mb upper air chart; Skew_T diagram; VAD wind profile
The surface wind speed method is used to calculate the height of __ clouds by multiplying the surface wind speeds by a value between __ and __.
stratus; 70 and 80
Forecast the maximum temperature to occur in __ and the minimum temperature to occur __ hour after sunrise.
mid-afternoon (1400-1600); one
List the accumulation and requirement for de-icing equipment for moderate icing...
Rate of ice accumulation is so great that even a short encounter can become hazardous to aircraft. Frequent use of de-icing or anti-icing equipment is necessary.
Contains a collaborative list of aircraft, ships, and weapon platforms thresholds
REA
What are the steps to determine when an inversion should break?
To determine if it will occur or not you must determine the inversion break temperature.
First find the temperature at the top of the inversion then extend a line dry adiabatically down to the surface and read the temperature.
This is the temperature required to break the inversion.
Compare the inversion break temperature to the forecast maximum temperature of the day.
What are the steps when using extrapolation to determine cloud amounts and bases?
Step 1. Identify the upstream area or location. Obtain source data (station elevation and cloud amounts and bases) from the station via METAR observations.
Step 2. Next, compute the station elevation from the upstream location and forecast location. (If the upstream station is lower than the forecast location, subtract the elevation change from the upstream cloud bases to account for the increase in the Earth’s elevation.)(If the upstream station is higher than the forecast location, add the elevation change to account for the decrease in the Earth’s elevation.)
Why does the diurnal temperature range decrease with stronger winds?
Due to increased heating of the air in the lowest levels, winds allow mixing of cooler air from aloft. The stronger the winds are, the more mixing occurs, thus the cooler the temperature.
Why is icing associated with cold fronts not as widespread as that with warm fronts?
Steep slope of Cold Front (1:50mi) when compared to the shallow slope of a Warm Front (1:150mi) makes the icing locations form more widespread and extend farther distances in association with the front.