Printed Reports and Forecasts Chapter 9, Section C

Weather Source Aviation Weather Center DTC Duats GTE Duats www.awc-kc.noaa.gov/ awc/aviation_weather_center.html DTC Duats http://www.duat.com 1 800 245-3828 GTE Duats http://www.gtefsd.com/aviation/GTEaviation.html 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 veriable 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