Transcript Slide 1

Weather Reports and Forecasts
METAR
• METAR is the scheduled observation taken at
the end of each hour.
TYPE
ID
TIME
WIND
VIS
WX
SKY
T/TD
ALT
RE
MA
RK
METAR
KORD
041656Z
19020G26KT
6SM
-SHRA
BKN070
12/08
A3016
RMK
AO2
Type
• 2 Different Types:
– 1.) METAR, Standard Observation every hour
– 2.) SPECI is an observation taken at an
unscheduled time due to certain criteria that is
met such as low visibility, low clouds, frozen
precipitation, or thunderstorms.
ID
• Station identifier.
• KFNL
• KDIA
Time and Date
• 041656Z-Time and Date
• The 04 represents the day of the month.
• The 1656 represents the time at which the
observation went out.
• The Z represents that the time is in ZULU or
UTC (Coordinated Universal Time).
Wind
• 19020G26KT-Winds
• The 190 (the first three numbers) is the direction of the winds in
degrees from 0 to 360 degrees (although you will never see 360
because after 359, it goes back to 0).
• The 20 (next two numbers) is the speed of the winds in knots.
• the G26 represents the wind gusts. In this case the gusts are 26
knots.
• the KT simply means knots. It will always be at the end.
• For winds greater than 6 knots you might see 18015KT 150V210.
The winds are from 180 degrees at 15 knots, but the direction is
actually variable between 150 degrees and 210 degrees. In order to
be variable above 6 knots, the winds must have at least a 60 degree
variation.
Visibility
• The 6SM simply means 6 Statute Miles.
Occasionally you might see visibility up to 20
or 30 SM but for the most part it will go from
< 1/4 (vis below 1/4 SM) up to 10 SM.
Weather and Obscurations
• (-SHRA)-Present Weather and Obscurations
• - Light Moderate
• + Heavy
VC In the Vicinity
BC Patches
SH Shower(s)
MI Shallow
DR Low Drifting
TS Thunderstorm
PR Partial
BL Blowing
FZ Freezing
DZ Drizzle
UP Unknown Precipitation
PY Spray
RA Rain
BR Mist
PO Well-Developed
Dust/Sand Whirls
SN Snow
FU Smoke
SQ Squalls
SG Snow Grains
VA Volcanic Ash
FC Funnel Cloud Tornado
Waterspout
IC Ice Crystals
DU Widespread Dust
SS Sandstorm
GR Hail
SA Sand
SS Sandstorm
GS Small Hail and/or Snow
Pellets
HZ Haze
Sky Conditions
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BKN070-Sky Condition
BKN represents a broken sky. (The clouds cover 5/8 to 7/8 of the sky)
FEW (1/8 TO 2/8 cloud coverage)
SCT (SCATTERED, 3/8 TO 4/8 cloud coverage
OVC (OVERCAST, 8/8 Coverage).
110 represents the clouds are at 11,000 feet (simply add 2 zeroes to get
the height)
You will often have more than 1 designator (i.e. SCT035 BKN090 OVC140)
• An indefinate ceiling caused by fog, rain, snow, etc., will require a
designator as VV (Vertical Visibility). VV is the how high you can see
vertically into the indefinate ceiling.
• Significant Clouds such as TCU (Towering Cumulus), CB, (Cumulonimbus, or
a shower/thunderstorm), or ACC (Altocumulus Castellanus) will be found
on the en of a category (i.e. SCT035TCU)
Temp / Dew Point
• 12/08-Temperature and Dewpoint
– 12represents the temperature in Celcius
– 08represents the dewpoint in Celcius
• If the temperature or dewpoint falls below 0
there will be an "M" before it (i.e. 03/M02).
"M" means minus.
Remarks
• RMK AO2-REMARKS
• RMK simply means REMARKS and marks the end
of the standard metar observation and the
beginning of the remarks that are put in as
necessay.
• A02 means that the site is automated and HAS a
precipitation sensor. If it were AO1, there would
be no precip sensor.
– Note: there is a whole FAA handbook of the remarks
that can be stated.
TAF
Terminal Aedrome Forecast
• TAFs apply to a 5 statute mile radius from the
center of the airport complex
• TAFs complement and use similar encoding to
METAR
• Routine TAFs are valid for 24-hours.
• TAFs are scheduled for issuance 4 times daily
at 0000Z, 0600Z, 1200Z, and 1800Z.
TAF example
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TAF
KOKC 051130Z 051212 14008KT 5SM BR BKN030 TEMPO 1316 1 1/2SM BR
FM1600 16010KT P6SM SKC
BECMG 2224 20013G20KT 4SM SHRA OVC020 PROB40 0006 2SM TSRA OVC008CB
BECMG 0608 21015KT P6SM NSW SCT040 =
• A TAF report contains the following sequence
of elements in the following order:
• 1. Type of Report
• 2. ICAO Station Identifier
• 3. Date and Time of Origin
• 4. Valid Period Date and Time
• 5. Forecast Meteorological Conditions
Type
• There are 2 types of reports:
– 1.) TAF, standard
– 2.) TAF AMD, an amended TAF
Station Identifier
• The ICAO four letter station identifier.
• KOKC
• KSEA
Date and Time
• (051130Z)
– This element is the UTC date and time the forecast
is actually prepared. The format is a two-digit date
and four-digit time followed, without a space, by
the letter Z. Routine TAFs are prepared and filed
approximately one-half hour prior to scheduled
issuance times. TAFs are scheduled for issuance
foure times daily at 0000Z, 0600Z, 1200Z, and
1800Z.
Valid Period
• (051212)
• The UTC valid period of the forecast is a two-digit
date followed by the two-digit beginning hour
and two-digit ending hour. Routine TAFs are valid
for 24-hours. Valid periods beginning at 0000Z
shall be indicated as 00. Valid periods ending at
0000Z shall be indicated as 24. The 24 indication
applies to all time group ending times.
– 091212 - Forecast valid from the ninth at 1200Z til the tenth at
1200Z.
Probability Forecast
• (PROB40 0006)
– The probability or chance of thunderstorms or other
precipitation events occuring, along with associated
weather conditions (wind, visibility, and sky conditions).
• Examples: PROB40 = 40% chance
– PROB40 2102 1/2SM +TSRA - Chance between 2100Z and
0200Z of visibility one-half thunderstorm, heavy rain.
– PROB40 1014 1SM RASN - Chance between 1000Z and
1400Z of visibility one rain and snow.
– PROB40 2024 2SM FZRA - Chance between 2000Z and
0000Z of visibility two freezing rain.
From Group
• (FM1600)
– The FM group is used when a rapid change,
usually occuring in less than one hour, in
prevailing conditions is expected.
• Examples:
– FM0100 SKC - After 0100Z sky clear
– FM1430 OVC020 - After 1430Z ceiling two
thousand overcast
Becoming Group
• The BECMG group is used when a gradual
change in conditions is expected over a longer
time period, usually two hours.
• Example:
– OVC012 BECMG 1416 BKN020 - Ceiling one
thousand two hundred overcast. Then a gradual
change to ceiling two thousand broken between
1400Z and 1600Z.
Temporary Group
• The TEMPO group is used for any conditions in
wind, visibility, weather, or sky condition which
are expected to last for generally less than an
hour at a time
• Examples:
– SCT030 TEMPO 1923 BKN030 - Three thousand
scattered with occasional ceilings three thousand
broken between 1900Z and 2300Z.
– 4SM HZ TEMPO 0006 2SM BR HZ - Visibility four in
haze with occasional visibility two in mist and haze
between 0000Z and 0600Z.
AWOS
• Automated Weather Observing System
– is a highly sophisticated data sensing, processing
and dissemination system.
– Updated weather reports are produced once each
minute, however, observations are only
transmitted every 20 minutes to the Flight Service
and NWS. Other ways of receiving the information
are over a radio frequency or by phone.
ASOS
• Automated Surface Observing System
– Designed to support weather forecast activities
and aviation operations
– ASOS works non-stop, updating observations
every minute, 24 hours a day, every day of the
year.
– The ASOS reporting is available through the
aircraft radio and Over the telephone.
RVR
• The horizontal distance a pilot may see down
the runway.
• RVR is measured in increments of 100 feet up
to 1,000 feet, increments of 200 feet from
1,000 feet to 3,000 feet, and increments of
500 feet above 3,000 feet to 6,000 feet