I.C Weather Information

Name some examples of sources of weather data for flight planning purposes

Foreflight

WX Brief

Aviation Weather Center

ASOS, ATIS, AWOS

Flight Service Station

National Weather Service

What’s a METAR? How long is it valid for?

French. Aviation Routine Weather Report

tells current surface weather conditions

Issued 55 mins after the hour

Good for 1 hour

What is a TAF

Terminal Aerodrome Forecast

Forecast for 5 SM from airport

valid for 24 or 30 hour time

issued 4 times; 0000Z, 0600Z, 1200Z, 1800Z

What kind of weather product will be released in place of a METAR in the event of a significant weather change?

SPECI - for drastic changes in the weather

What is a TEMPO on a TAF mean? What is this an indication of?

expected to change Temporarily between the forecasted time

What is an AIRMET?

Hazardous weather that affects small planes and VFR pilots

good for 6 hours

S - IFR conditions, ceilings <1000 ft, < 3 SM

T - Turbulence (30+ knots)

Z - Icing

What is a SIGMET?

Non-convective weather, that affects all aircrafts, good for 4 hours

severe icing, severe/ extreme turbulence, dust or sandstorm, volcanic ash

hurricane = 6 hours

What’s a Convective SIGMET?

Hazardous for all flight, good for 2 hours

Winds >50 knots, Hail >3/4 in, tornados, embedded thunderstorms, Squall Lines affecting 40% or more in a 3000 sq mile area

What are the different types of turbulence intensity classifications?

Light - slight

Moderate - postive control at all times

Severe - large, mometarily out of control

Extreme - structural damage

What are the different types of turbulence

Convective - rising/ sinking air

Mechanical - wind that comes over trees, buildings, mountains, creating eddies

Windshear

What is a CWA?

Center Weather Advisory

unscheduled in-flight weather advisory for hazardous wearher

a “nowcast” for weather developing in the next 2 hours

What is a 9900 on a winds loft chart?

winds are light and variable

What’s a PIREP?

Pilot Report - gives in-flight weather conditions

What gases make up the atmosphere?

78% N, 21% O2, 1% trace gases

What are the layers of the atmosphere

Tropshere

Stratosphere

Mesosphere

Thermosphere

Exosphere

What is considered standard atmospheric temperature and pressure?

15*C, 29.92, or 1013.25 milibars

What’s the lapse rate?

1000 ft = -2*, -1.00

What are some indications of stable air?

Poor visibility, no turbulence

stratiform clouds, continuous precipitation

What are some indications of unstable air?

Good visibility, turbulent air, Thunderstorms

Cumuliform clouds, scattered precipitation

What is convection?

up and down movement of air

What is wind?

horizontal convection

What are the three forces affecting wind heading and speed?

Coriolis Force

Fricition

Pressure Gradient Force (PGF) - pushes air from area high pressure to low pressure

How does pressure travel?

from High to Low, and left to right

What is the Coroilis Force effect?

because of the earth rotational force on its axis, wind is deflected from left to right

How does air in low pressure system move? What kind of weather is associated with low pressure zones?

in, up, ccw

updrafts, cloudiness and precipitation

How does air in high pressure system move? What kind of weather is associated with high pressure zones?

out, down. cw

light surface winds, clear skies

What is a Jet Stream?

narrow band of strong winds near the tropopause

What is a Valley Wind?

Cold air falling in a valley and pushes warm air up

What is Mountain Wind?

Cold air falls down the mountainside

What is Katabatic wind?

any wind blowing down an incline, when the incline is influential in carrying that wind

What is land breeze

at night, cool air moves from land to the warmer water

What is Sea Breeze

Day, cooler air moves from the sea to the warmer land

What is Wind Shear?

sudden shift in wind speed, direction

What is inversion?

air temperature increase with altitude.

common on clear, calm, cool nights

the land cools more rapidly than air, cooling the air directly above it faster than the air aloft

What is relative humidity?

saturation level of the air, expressed in %

What is the Dew Point?

where the air would become 100% saturated by moisture currently present

What is a front?

boundary between two different air masses

What is a cold front?

depicted by blue trangles

advancing cold air mass

moves faster than warm air, up to 40 kts

sudden temp dorps, rain, gusty winds, TS or squall lines

What is a warm front?

depicted by red circles

advancing warm air mass

moves half as fast as cold fronts due to less dense air

warmer, more humid weather

a blanket over the cold front

What is a stationary front?

Neither the cold or warm front are able to overpower the other

speeds of 5 kts

prolonged, persistent weather

What is an Occluded Front?

purple circles and triangles

fast moving cold frornt catches up with warm front and pushes warm air up

widespread clouds, persistent precipitation, and shifting winds

What is a squall line?

A narrow band of thunderstorms (10-20 mi wide) covering up to 100s of miles

Often accompanied by high winds and heavy rain

What is a dry line?

low level boundary separating most air from dry air

orange half circles

What is a cloud?

visible gathering of water or ice

What are the cloud families based on altitude?

High Clouds - 20,000 ft

Middle Clouds - 6,500 - 20,000 ft

Low Clouds - SFC - 6,500 ft

What are the cloud classifications?

Cumulus Clouds - due to convection, unstable atmosphere

Stratus Clouds

Cirrus

Lenticular

Nimbus Clouds

Fractus Clouds

Alto

What clouds can you find in the high altitude family?

Cirris, Cirrocumulus, Cirrostratus

What clouds can you find in the mid- altitude family?

Altocumulus, Altostratus

What clouds can you find in the low altitude family?

Nimbostratus, Stratus, Stratocumulus

What is the most dangerous cloud type to pilots?

Cumulonimbus clouds

Volatile nature = turbulence, windshear, thunderstorms, microburst

What is an Anvil cloud and what does it mean if one forms?

a cumulonimbus cloud that has reached stratospheric stability. Thunderstorm in its mature stage

What is turbulence?

fluid dynamics, chaotic changes in pressue and flow velocity

What is wake turbuluence?

wingtip vortices that fall down and outward

What is convective turbulence?

occurs in convective storms (TS) that are felt by the aircraft.

Strong up/down drafts due to uneven heating

The greater temperature difference, the greater the turbulence.

Barren surfaces heat up more quickly

What is Mechanical Turbulence

wind over trees, mountains, building, creating eddies

the higher the wind speed/ more rough the obstruction, the greater the turbuluence

What are Mountain Waves?

Wind hitting perpendicular to mountain at med-high speeds and over to the other side in stable air

This creates rotors waves (low altitude) or breaking waves (high altitude) that affect how an aircraft performs.

low level wave - rotor clouds

high level wave - lenticular clouds

What must be present in order for a thunderstorm to form?

Sufficient water vapor (high dew points)

Unstable laspe rate

Initial lifting action

What are the 3 stages of a thunderstorm?

Cumulus

Mature

Dissipating

Describe the 3 stages of a Thunderstorm

Cumulus - updrafts, 3,000 ft/ min

Mature - up/downdrafts, 2,500 ft/ min, mircoburst, TS hazards

Dissipating - downdrafts, storm dies rapidly

What are some weather phenomena that come along with a thunderstorm?

rain, lightning, hail

Turbulence, wind shear, microburrst, tornadoes

What should you do if you accidentally end up in a thunderstorm

find the quickest course out of the storm

disengage autopilot

maintain attitude

scan instruments

adjust power

What is a Microburst?

powerful downdrafts.

6,000 ft/ min

What temperature range is icing likely to occur?

0 to -20*C

What are the three areas where icing can occur?

Induction Icing

Instrument Icing

Strucutural Icing

What is Induction Icing

Ice that blocks air from reaching the engine

Results: blocking air filter. Carburetor icing as the air pressure (and temp) in the venturi drop

What is Instrument Icing

icing of the pitot tube and/or static source

error on ASI, Altimeter, VSI

What is Structural Icing

occurs in visible mositure

and hits the aircraft at 0*C or less

and OAT is between 0 and -20*C

What are the 3 types of Structural Icing?

Clear

Rime

Mixed

What is fog?

visible aerosol consiting of tiny water droplets near the Earth’s surface

What are the different types of fog? (6)

SURAPI

Steam

Upslope

Radiation

Advection

Precipitation

Ice

Explain the different types of fog: SURAPI

Steam - cold air moves over warm water

Upslope - pushed up a mountain

Radiation - night, from cooling ground cools the air above it (5kts)

Advection - moist air moves over colder ground or water (15kts)

Precipitation - as warmer precipitations falls through colder air

Ice - fog composed of ice crystals (-40*C)

What is mist?

intermediate point between haze and fog and consists of minute water droplets suspended in the atmosphere

What is frost? When does it occur?

thin ice crystals.

on solid objects (0*C), near the surface in clear, calm and stable air

How can it affect pir performance? What can we do about it?

lead to winds over the wing to slow and increase stall speed.

Prevent aircraft from becoming airbornce at normal takeoff speed

Use de-icing spray

What are examples of obstructions to vision?

(ground/ ice) fog

blowing sand, snow, dust

haze, smoke, dust, blowing spray

What is haze?

small dry particles suspended in stable air

downward visibility (air-to-ground) is greatly reduced

What is smoke?

found aroud fire or industrial areas due to the combustion process

Whart is ADS-B and how does it work?

Automatic Dependent Surveillance - Broadcast

precise tracking via satellite, shows ident, position, altitude and velocity

Required: 10,000’ + MSL

within 30 NM of B & C airspace

What is a TIS-B and how does it work?

Traffic Information Service Broadcast

Equipped with ADS-B, shows other aircrafts in flight

Aids in collision avoidance

What is FIS-B and how does it work?

Flight Information Service Broadcast

provides Meterological and Aeronautical Information

available on Universal Access Transceiver (UAT) Network (978 MHz)

advisory only

What are go/no-go decisions?

determinatation of whether or not to fly.

Using ADM (3P, DECIDE Model, PAVE, IMSAFE)

What is PAVE?

Pilot - IMSAFE

Aircraft - Airworthy

EnVironment - Weather conditions

External Pressures - IM AIR

What are the most common causes for diversions?

Significant Weather

Medical Emergency

Using Pilotage and Dead Reckoning - Use 3 to 1 Rule

What are personal mimimums? Why are they important

an individual’s set of procedures and guidelines for deciding under what conditions to operate or continue operating an aircraft

Used to make go/no-go or continue/ divert decision

What is a diversion and when would a diversion be necessary?

A landing at an airport, other than the intended destination airport, for reasons beyond the control of the pilot.

Weather, medical reasons, change of plans, mechanical

How does one develop and use personal minimums?

Assess experience and comfort level

Consider the conditions

Adjust for conditions

Stick to the plan

What is the most prominent limitation of our onboard weather?

Considered “near real time”, delayed by 1 - 30 mins

What are some NEXRAD shortcomings

Can’t distinguish between heavy rain and hail

only lower altitudes are detected

may be outdated up to 20 mins

What are the limitations of weather reports and forecasts?

Use both to get a full picture.

What is a limitation of a MOS weather report?

uses raw historical data to compute future weather conditions

What is a limitation of a TAF?

only issued every 6 hours and valid for 5 SM

What type of weather product is a METAR and how can that be a limitation?

An observation

Outdated weather due to hourly updates

What are the limitations of inflight weather resources?

Range of only 300 miles

CWA - only gives weather information as it occurs, not for planning

FSS - can only communicate with 1 aircraft, aka delays