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NIFE Weather Review With 100% Correct
Answers
Composition of the Atmosphere - correct answers ✔✔78% nitrogen, 21% oxygen, 1% other (Stays mostly constant regardless of altitude) Troposphere characteristics - correct answers ✔✔28k-55k (36k average over U.S.) Nearly all weather occurs here Temperature decrease with increase in Alt Wind increase with altitude Water Vapor composition - correct answers ✔✔0-5% What is standard pressure lapse rate & standard day conditions - correct answers ✔✔1 Hg. lost per 1000ft of alt 29.92Hg. 15°C, sea level Atmospheric Circulation - correct answers ✔✔Constant heating and cooling of earth's surface leads to ascending/descending air PGF (Pressure Gradient Force) - correct answers ✔✔Air wants to flow from high to low Force acts perpendicular to Isobars
What is Temperature Inversion and when they occur? - correct answers ✔✔Temperatures increase with altitude Occurs on cool, calm nights or warm fronts over a cool air mass What is an airmass? - correct answers ✔✔A large body of air w/ the same characteristics in a horizontal plane (Temp & Moisture) Cold AM: Unstable Warm AM: Stable What is dew point - correct answers ✔✔Direct indication of the amount of moisture present in the air.
- Air is considered saturated when dew point = temperature What is indicated altitude? - correct answers ✔✔Alt directly read from the altimeter What is true altitude? - correct answers ✔✔Actual height above sea level (MSL) What is absolute altitude? - correct answers ✔✔Actual height above the ground (AGL) What is pressure altitude? - correct answers ✔✔Height above the standard datum plane (29.92) What is density altitude? - correct answers ✔✔Where the airplane thinks it is flying What kind of air does low pressure areas have? - correct answers ✔✔Warm descending air
Usually occurs 1500 - 3000ft. AGL @ 15-20kts What is a land breeze? - correct answers ✔✔Land cools faster than water, so breeze reverses and flows from land to ocean. What are stratiform clouds? - correct answers ✔✔Moist stable air, associated with steady precipitation. Widespread with no define-able shape What are cumuliform clouds? - correct answers ✔✔Comes from moist unstable air, associated with showery precipitation. Large puffy clouds with more definite shape What are special clouds? - correct answers ✔✔Nimbo/Nimbus: Violent or heavy Cumulonimbus (Thunderstorms): Severe to extreme turbulence, hail, lightening, icing etc. Nimbostratus: Thick, uniform, widespread clouds that build downward, associated with heavy rain showers and moderate turbulence Four lifting methods - correct answers ✔✔"You're FOCT" Frontal: Cold fronts
Orographic: Lifting of air mass from wind pushing again mountain forcing air upward Converging: Two air masses (or parts of one) force air up because it has no where else to go Thermal: Cool air over a warm surface, heightened by intense solar heating Stability of Air - correct answers ✔✔Determined by the temperature of the surrounding air. What is stable air? - correct answers ✔✔Cold air that settles when lifting action is removed What is neutral air? - correct answers ✔✔Air that is the same temp remains at the same level after lifting action is removed What is unstable air? - correct answers ✔✔Warm are that continues to rise when lifting action is removed What is a front? - correct answers ✔✔Discontinuities between contrasting air masses Located in troughs of low pressure "TouchDowns Win Playoffs" Temperature Dew Point Wind Pressure
Classifications:
- Light
- Moderate
- Severe
- Extreme (declare emergency/exit ASAP) Reporting level for turbulence? - correct answers ✔✔Occasional: Less than 1/3 of the time Intermittent: 1/3 - 2/3 of the time Continuous: More than 2/3 of the time What is clear air turbulence and when is it most severe? - correct answers ✔✔Air turbulence that is harder to see because it outside of clouds; it is most severe near jet streams What are the aircraft icing requirements and what are the two kinds? - correct answers ✔✔Must have supercooled water droplets/visible moisture; free air temp and aircrafts surface temp must be below freezing. Structural and Engine icing What effect does structural icing have on an aircraft performance? - correct answers ✔✔Increase drag, reduced lift, increase stall speeds What effect does engine icing have on aircraft performance? - correct answers ✔✔Engine flame out, FOD, compressor stalls What are the types of ice formations and at what temps do they form? - correct answers ✔✔Clear: 0° to -10°C, Unstable conditions in cumulus clouds
RIME: -10° to -20°C, Stable conditions in stratus clouds Mixed: -8° to -15°C, combo of the two and the most common type of icing What are the intensity levels of Icing? - correct answers ✔✔Trace Light Moderate Severe When is visibility reported as obscured? - correct answers ✔✔Reported as obscured when visibility is less than 7 miles. What are the characteristics of fog formation and name the two types? - correct answers ✔✔Cloud base is w/in 50ft from the ground, greater than 20ft thick, visibility is reduced to less than 5/8 of a SM (favorable conditions is temp & dew point spread is near or less than 2°C). Radiation: the sun will dissipate Advection: sun will not dissipate, wind can What are the characteristics of thunderstorms and the recommendations when encountering one? - correct answers ✔✔H.I.M.E.L.T Hail Icing Microbursts Extreme Turbulence
What is a TAF? - correct answers ✔✔Terminal Aerodrome Forecast, 24 hours of forecast conditions, used to determine destination weather and are also updated hourly What does FM mean on a TAF/METARs Report? - correct answers ✔✔FM means "from"
- Indicates rapid, permanent change
- From time listed until next change or next day forecast What does BECMG mean on a TAF/METARs Report? - correct answers ✔✔BECMG means "Becoming"
- Gradual change in predominant conditions by end time listed
- To end of previous forecast What does TEMPO mean on a TAF/METARs Report? - correct answers ✔✔TEMPO means "Temporary"
- Temporary conditions
- Only certain times updated
- Expires @ end of period listed What does V stand for on TAF/METARs Reports? - correct answers ✔✔V stands for Variable What does G stand for on TAF/METARs Reports? - correct answers ✔✔G stands for Gust What does information does NEXRAD give/display? - correct answers ✔✔H.T.M.L Hail Tornado
Microbusts Low-Level Wind Shear What is a severe weather warning (WW) and what are the requirements? - correct answers ✔✔Severe weather conditions and often indicate a thunderstorm. DO NOT FLY IN WW. Requirements: (Only needs one of the following)
- Tornados/Funnel clouds/ Lightning
- 50 knot winds or greater
- 3/4" diameter hail or larger What is a non-convective SIGMET (Significant Meteorological Conditions)? - correct answers ✔✔Not thunderstorm related and valid for 4 hours Criteria:
- Severe or extreme non-convective turbulence, not associated w/ thunderstorms
- Sever icing not associated with thunderstorms
- Dust/Sand storms lowering visibility to <3 miles
- Volcanic Ash What is a convective SIGMET (Significant Meteorological Conditions)? - correct answers ✔✔Implies severe or greater turbulence, severe icing, low level wind shear and issued hourly @ +55 minutes & valid for up to 2 hours. Criteria:
- Hail >= 3/4 in diameter
- Wind gusts >= 50 kts
