Topic

3.3 METARS & TAF’s

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METARS – Aviation Routine Weather Report

KJFK   162251Z   16007KT   10SM   FEW055   SCT190   BKN260   26/13   A2982   RMK   A02   SLP098   T02610128

 (KJFK)  This is the airport identifier.  K signifies the airport is in the 48 contiguous states.  PH is Hawaii and PA is Alaska.

(162251Z)  —  Issued time and date.  The first two numbers are the day (the 16th) and the rest is the time 2251 in Zulu time (denoted by the Z).

(16007KT) —  Wind direction and velocity.  Here the wind is coming from 160 degrees (or southeast) at 07 knots (KT=knots).

(10SM) — Visibility.  This shows visibility of 10 statue miles.

(FEW055 SCT190 BKN260) —  These are clouds and their levels (always add 00 to these numbers).  This says Few cloud at 5500, scattered at 19,000, and broken at 26,000.  A cloud ceiling is either broken or overcast (OVC).

(26/13)  —  Temperature and dewpoint.  These are always in Celsius.  The closer the numbers are the higher chance of lower clouds or fog.

(A2982)  —  Altimeter setting.  29.82 is the current setting here.

 REMARKS SECTION OF THE METAR

(RMK)  —  This signifies the start of the remarks section.  Not all METAR’s have remarks

(A02)  —  Type of station.  This is automatic weather with a precipitation discriminator.  That means it can tell if it’s rain or snow.  A01 is the other option and it won’t tell you the type of precipitation.

(SLP098) —  This is telling us the sea level pressure.  Completely useless to pilots.

TAF – Terminal Aerodrome Forecast

TAF contains the following sequence of elements in the following order:

Type of Report

Two Types of Forecasts

Routine Forecast  (TAF)

Amended Forecast (TAF AMD) 

ICAO Station Identifier

Four letter location identifiers.  Contiguous 48 states start with K, Hawaii is PH, and Alaska is PA

 Date and Time of Origin

The UTC date and time that the forecast is actually prepared.  Two digit date and four digit time, followed by the letter Z.

TAFs are scheduled for issuance four times daily at 0000Z, 0600Z, 1200Z, and 1800Z.

Valid Period Date and Time

Valid period of the forecast

Two digit date followed by two digit beginning hour and two digit ending hour.

Routine TAFs are valid for 24 hours.

Forecast Meteorological Conditions

Basic Format is as follows:

Wind

Forecast Surface Winds

Expected wind direction (first three digits)

Speed (last two or three digits)

Measurement (KT for knot)

Wind Gusts (denoted by the letter G and highest expected gust speed.

VRB = Variable wind

Weather

Visibility

½SM = Visibility one-half statute mile

2 1/4SM = Visibility two and one quarter statue miles

5SM – Visibility five statute miles

P6SM = Visibility more than six statute miles

Sky Condition Uses the METAR format.  Cumulonimbus clouds are the only cloud type forecast in TAFs.

Optional Data (Wind Shear) Wind Shear is the forecast of non-convective low level winds (up to 2000 feet) and is entered after the sky conditions whenever wind shear is expected.  The forecast includes the height of the wind shear followed by the wind direction and wind speed at the indicated height.