Weather Tutorial FT Page

Aviation Weather

Tutorial

Terminal Forecasts (FT) is one of the best sources for predicting what the weather at a particular airport (terminal)will be in the future. These forecast predictions cover an area within 5 nautical miles of the center of the runwayfield. FTs are usually issued 3 times a day and are valid for accuracy up to 24 hours. The first section of theFT covers the expected weather for the upcoming 18-hour period. This includes information about ceiling, visibility,vision obstructions, wind and expected weather changes at that facility.

A sample Terminal Forecast (FT) is

JAN 251010 C5 X 1 S-BS 3325G35 OCNL CO X OS+ BS.16Z C30 BKN 3BS 3320 CHC SW-. 22Z 20 SCT 3315. 00Z CLR.04Z VFR WND . .

REPORT CODE INFORMATION GIVEN

JAN station/airport identifier

251010 date and time of report: day of the month followed by valid times

C5 X description of sky, clouds and ceiling level

1 number of statute miles of visibility; if no number given then visibility is greater than 6 statute miles

S-BS weather and obstructions to vision (see code from Surface Aviation report)

3325G35 wind description; absence of wind entry indicates that the wind is less than 6 knots; winds are given in relation to true north

OCNL CO X OS+ BS Specially coded remarks; OCNL = the conditions are expected to occur less than half of the time during the time period given

16Z C30 BKN 3BS 3320 CHC SW-. 22Z 20 SCT 3315. 00Z CLR. Expected changes over the next 18 hours at this terminal; a number followed by a "Z" indicates the time at which the change is expected to occur

04Z VFR WND . . Six-hour categorical outlook which gives the start time to which one adds 6 hours and gets the ending time for this time period; if the contraction "WND" is added to "VFR" it means that winds of 25 knots or stronger are expected during this time period; a double period indicates the end of the report . .

Terminal Forecast decoded below:

Jackson, Mississippi is valid beginning on the 25th day of the month at 1000Z until 1000Z on the 26th day of themonth. The ceiling is expected to be 500 feet, an obscurred sky with 1 statute mile visibility; light snow andblowing snow with wind from 330O at 25 knots gusting up to 35 knots; occasional conditions of zero ceiling withobscurred sky and zero visibility; accompanied by heavy snow and blowing snow; by 1600Z ceiling will be 3,000 feetin altitude and broken with visibility of 3 miles accompanied by blowing snow with wind from 330 degrees at 20knots with achance of light snow showers; by 2200Z scattered clouds at 2,000 feet with a visibility of more than6 miles, wind from 330 degrees at 15 knots; by 0000Z clear sky with visibility greater than 6 miles and wind lessthan 6 knots; outlook from 0400Z to 1000Z has a ceiling of more than 3,000 feet, visibility greater than 5 miles(VFR) and wind 25 knots or stronger; end of report.

REPORT CODE	INFORMATION GIVEN
JAN	station/airport identifier
251010	date and time of report: day of the month followed by valid times
C5 X	description of sky, clouds and ceiling level
1	number of statute miles of visibility; if no number given then visibility is greater than 6 statute miles
S-BS	weather and obstructions to vision (see code from Surface Aviation report)
3325G35	wind description; absence of wind entry indicates that the wind is less than 6 knots; winds are given in relation to true north
OCNL CO X OS+ BS	Specially coded remarks; OCNL = the conditions are expected to occur less than half of the time during the time period given
16Z C30 BKN 3BS 3320 CHC SW-. 22Z 20 SCT 3315. 00Z CLR.	Expected changes over the next 18 hours at this terminal; a number followed by a "Z" indicates the time at which the change is expected to occur
04Z VFR WND . .	Six-hour categorical outlook which gives the start time to which one adds 6 hours and gets the ending time for this time period; if the contraction "WND" is added to "VFR" it means that winds of 25 knots or stronger are expected during this time period; a double period indicates the end of the report . .

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