Printed Reports and Forecasts

Chapter 9, Section C

Weather Source• Aviation Weather Center

– www.awc-kc.noaa.gov/ awc/aviation_weather_center.html

• DTC or Data Transformation Corp– http://www.duat.com– 1 800 245-3828

• DynCorp– http://www.duats.com– 1 800 767-9989

METAR

• Aviation routine weather reports

• METAR are routinely taken every hour at 50 past the hour. They are usually entered into the computer on the hour

• SPECI are special aviation weather report

Visibility

• Prevailing visibility is the greatest distance an observer can see and identify objects through at least half of the horizon

• RVR - Runway visual range is based on what a pilot in a moving aircraft should see when looking down the runway

Sky Condition

• Ceiling is defined as the height of the lowest layer of clouds or obscuring phenomena that is reported as broken or overcast

• If tops are know, your can find the thickness of clouds by adding the airport elevation to the height to the base of the clouds and subtract from the height of the cloud tops

Obscurations

• With obscurations such as fog, haze and smoke, the vertical distance that you can see is reported as vertical visibility

• VV008 would indicate that the sky is obscured with a vertical visibility of 800 feet

Obscurations

• FG - Fog is used when visibility is less than 5/8 of a mile

• BR - Mist is used when visibility is between 5/8 of a mile and 6 miles

• SQ - Squall indicates an increase of wind speed by 15 knots to a sustained speed of 20 knots or more for at least one minute

Remarks Codes

• A02 - automated station with precipitation discriminator

• RAE42SNB42 - rain ended and snow began at 42 past the hour

• PRESFR - Pressure falling rapidly• SLP - Sea level pressure 1004.5 millibars• T00081016 - Temperature .8o C and dewpoint

is -1.6o C

RADAR Weather Reports

• Defines areas of precipitation especially thunderstorms

• You must plot using Azimuth and range from reporting stations referencing true north

• Much easier to use RADAR Summary charts or doppler radar or national RADAR compostite

PIREPs

• Pilot weather reports - best reports for bases and tops of clouds, in-flight visibility, icing conditions, wind shear and turbulence

• PIREPs use a standard format Mandatory– UA routine report UUA urgent report– OV location in relation to a navaid– TM time in Coordinated Universal Time– FL Altitude or flight level– TP aircraft type

PIREPs

• SK Sky cover

• WX Flight visibility and weather

• TA temperature

• WV wind

• TB turbulence

• IC icing

• RM remarks

TAF

• Terminal Aerodrome Forecast - valid for a 24 hour period and scheduled four times a day

• Primary source of destination weather

• AMD means and amended forecast

• COR means a corrected forecast

• RTD indicates a delayed forecast

Contractions

• VRB - wind direction is variable• 00000KT - calm wind• P6SM - prevailing visibility expected to be

greater than 6 statue miles• SKC - sky clear• PROB40 2102 +TSRA - 40% probability of

thunderstorms with heavy rain between 2100Z and 0200 Z

Area Forecast FA

• Issued three times a day and include a forecast period of 18 hours

• We are in the Chicago region• Consists of four sections

– Heading– Precautionary statements– Synopsis– VFR Clouds and Weather

Area Forecast FA

• VFR Clouds and weather section summarizes sky condition, cloud heights, visibility, obstructions to vision, precipitation, and sustained surface winds of 20 knots or greater

• When winds are to be 20 knots or greater the categorical outlook includes the contraction WND

Wind and Temperature Aloft

• Usually given for nine level between 3,000 and 39,000 feet

• Winds are given in true direction and speed in knots

• Winds not forecast within 1,500 feet of station elevation

• Temperature not forecast for the 3,000-foot level or with 2,500 feet of the station elevation

Wind and Temperature Aloft

• Uses a four digit code for wind speed and direction, the first two digits are the wind direction in hundreds of degrees

• The second two digits indicate wind speed

• A two digit temperature code in degrees Celsius follows the wind speed and direction code

• All temperature above 24,000 feet are negative