CH 16 Weather Reports, Forecasts and graphics (INCOMPLETE)

METAR 151955Z

DDHHMMZ
DD = day of month, HH = hour, MM = Minute, Z = zulu
15 → 15th day of the month

• 19 → 19:00 (7 PM) UTC

• 55 → 55 minutes

METAR 32020G35KT 280V350

• 320 → wind is coming from 320° (northwest)

• 20 → sustained wind speed is 20 knots

• G35 → gusts up to 35 knots

• KT → units are knots

• 280V350 → wind direction is variable between 280° and 350°

METAR TSRA BKN009CB 16/14 A2987

• TS = thunderstorm

• RA = rain

• BKN = broken clouds (5/8 to 7/8 of the sky covered)

• 009 = cloud base at 900 feet AGL

• CB = cumulonimbus clouds (thunderstorm clouds)

• 16 = temperature 16°C

• 14 = dew point 14°C

• A = altimeter setting (in inches of mercury)

• 2987 = 29.87 inHg

METAR RMK SLP001

REMARK
SLP = sea-level pressure (in hectopascals / millibars)

• 001 = coded value

To decode:

• If the number is 000–499, add 1000

• If 500–999, add 900

For SLP001:

• 001 is between 000–499 → add 1000

• 1000.1 hPa

• Sea-level pressure is 1000.1 millibars (hPa)

METAR CODE Weather Phenomena

+TSRA = thunderstorm with heavy rain
-SHRA = light rain shower
MI = shallow
DR = low drifting (dust, sand, snow)
BL = Bloweing low drifting (dust, sand, snow)
TS = Thunderstorm
BC = Patches
FZ = Freezing
SH = Showers
PR = Partial

METAR CODE Precipitation

DZ = Drizzle
SN = Snow
IC = Ice Crystals
GR = Hail
RA = Rain
SG = Snow grains
PL = ice pellets (illegal)
GS = small hail
UP = unknown

METAR CODE phenomena that reduce visability

BR = Mist
FU = Smoke
SA = Sand
PY = Spray (ocean spray)
FG = Fog
VA = Volcanic Ash
HZ = Haze
DU = Dust

METAR CODE Obscuration

SS = Sand storm
SQ = Squall
DS = Dust Storm
FC = Funnel Cloud
+FC = Tornado/water spout
PO = well developed dust/sand whirls

METAR CODE Sky Conditions

Below is not ceiling:
SKC or CLR = Clear sky
Few = Few clouds
SCT = Scattered

Below are ceiling:
BKN = Broken
OVC = Overcast
VV = Vertical Visibility
CB = Cumulonimbus
TCU = Towering Cumulus

METAR CODES Lightning

Frequency:
OCNL = Occasional (less than 1 flash/min)
FRQ = Frequent (1-6 flashes/min)
CONS Continuous (More than 6 flashes/min)

Types of Lightning:
CG = cloud to ground
IC = in cloud
CC = cloud to cloud
CA = cloud to air

METAR CODE Ceiling

BCAT1 = celing below min (200ft) or vis less than ½ sm
LIFR = ceiling less than 500ft and or vis less than 1 sm
IFR = ceiling less than 1000 ft or vis less than 3 miles
MVFR = ceiling 1000 - 3000 ft or vis 3 - 5 sm
VFR = no ceiling or greater than 3000 ft and vis greater than 5 sm

METAR CODE special (SPECI)

special non routine aviation weather report if wind direction change by 45 degrees or more in less than 15 min, visibility decrease, runway visibility, tornado, thunderstorm, hail, freezing precipitation, ice pellets, volcano, squall

Squall

A squall is a sudden, sharp increase in wind speed lasting at least 1 minute, often accompanied by precipitation or storms.

Key characteristics:

• Wind speed increases by at least 16 knots

• Reaches 22 knots or more

• Lasts at least 1 minute

• Often associated with:

  • Thunderstorms

  • Heavy rain, snow, or hail

  • Rapid wind shifts

METAR

METAR = routine aviation weather report

• Issued hourly (or half-hourly at busy airports)

• Describes current weather conditions at an airport

Includes:

• Wind

• Visibility

• Weather (rain, snow, etc.)

• Clouds

• Temperature/dew point

• Pressure

✅ Simple: “What’s the weather right now at the airport?”

TAF

TAF (Terminal Aerodrome Forecast) = forecast of airport weather

• Covers 24–30 hours into the future

• Updated 4 times daily (typically)

Includes forecasts of:

• Wind

• Visibility

• Weather

• Cloud ceilings

• Significant changes over time

✅ Simple: “What will the weather be at the airport?”

PIREP

PIREP (Pilot Report) = real-time weather report from a pilot

• Given in-flight by pilots

• Reports actual conditions experienced in the air

Includes:

• Turbulence

• Icing

• Cloud tops/bases

• Winds

• Visibility

✅ Simple: “What is a pilot actually experiencing up there?”

METAR CODE Method

Nothing = Human
A01 = Automated station without precipitation discriminator
A02 = Automated station with precipitation discriminator
AUTO = automated (not specified)

AWOS

An Automated Weather Observing System (AWOS) is a, typically airport-based, suite of sensors and computers that provides real-time, minute-by-minute weather data for aviation safety, including wind, temperature, dew point, altimeter setting, visibility, and sky conditions

METAR SLP993

SLP993

• Sea-level pressure (SLP) in millibars (hPa).

• Formula: SLP = 1000 + 993 / 10 = 999.3 hPa

  • Actually, in standard decoding: SLP993 → 999.3 hPa

Weather conditions expected to occur in the vicinity of the airport, but not at the airport, are denoted by the letters “VC.” When VC appears in a TAF, it covers an area of

5-10 sm radius of airport

What weather is predicted by the term VCTS in a Terminal Aerodrome Forecast?

Thunderstorms are expected in the vicinity. (5-10 SM, but not at airport)

Only cloud types forecast in the Terminal Aerodrome Forecast?

Cumulonimbus.

A calm wind that is forecast in TAF

00000KT

TAF KEY CODES

Code Meaning
FM1200 From 1200Z onward, conditions change (usually wind, weather, cloud)
TEMPO Temporary changes expected (less than 1 hour at a time)
BECMG Gradual change expected over a period
TX / TN Maximum / Minimum temperature forecast during period

What is the single source reference that contains information regarding volcanic eruption, turbulence, and icing conditions for a specific region?

In-Flight Weather Advisories.

What information is provided by a Convective Outlook (AC)

It provides prospects of both general and severe thunderstorm activity and specific severe weather threats during the following 8 days.

Maximum turbulence potential charts (GTG-3) are issued

hourly (06, 09, 12 hour forcasts which are update every 3 hours)

Isobars on a surface weather chart represent lines of equal pressure

reduced to sea level.

A prognostic chart depicts the conditions

forecast to exist at a specific time in the future.

U.S. High-Level Significant Weather Prognostic Chart is prepared for use

between 25,000 feet and 63,000 feet pressure altitude.

Forecast winds and temperatures aloft for an international flight may be obtained by consulting

Wind and Temperature Aloft Charts prepared by the U.S. National Centers for Environmental Prediction (NCEP).

What sources reflect the most accurate information on current and forecast icing conditions?

PIREP’s, AIRMET Zulu’s, and SIGMET’s.

A public severe thunderstorm watch implies

58 mph winds or greater and/or surface hail of 1 inch or more in diameter.

Analysis Heights/Temperature Chart, what is 500mb, 300mb, 200mb

MB stands for “millibars”, which is a unit of atmospheric pressure.

• 500 mb → about 18,000 feet

• 300 mb → about 30,000 feet

• 200 mb → about 39,000 feet

Constant Pressure Analysis Charts contain contours, isotherms, and some contain isotachs. The contours depict

ridges, lows, troughs, and highs aloft.

The vertical wind shear that is critical for probability of turbulence is

5 knots or more per 1,000 feet.

horizontal wind shear, critical for turbulence (moderate or greater) per 150 miles is

greater than 18 knots.

If a SIGMET alert is announced, how can information contained in the SIGMET be obtained?

By contacting the nearest FSS.

Which type weather conditions are covered in the Convective SIGMET?

Embedded thunderstorms, lines of thunderstorms, and thunderstorms with 3/4-inch hail or tornadoes.

SIGMETs may be issued for the contiguous U.S.

as convective SIGMETs when obscured thunderstorms are forecast.

Convective SIGMETs are issued for a line of thunderstorms at least

60 miles long with thunderstorms affecting 40 percent of its length.

Convective SIGMETs are issued for severe thunderstorms

occurring for more than 30 minutes of the valid period.

A SIGMET is issued when weather affects

3,000 square miles or more.

SIGMETs (other than domestic convective SIGMETs) may be valid for not more than

4 hours for other phenomena.

A SIGMET may be issued

for an area where conditions are deemed to have a significant effect on the safety of aircraft operations.

The Mid-Level Significant weather (SIGWX) Chart is used to determine an overview of flying weather conditions between what altitudes?

10,000 feet MSL and FL 450.

The Federal Aviation Administration’s Flight Information Service Data Link (FISDL) is designed to provide data on a common frequency to flight crews from

17,500 feet MSL down to 5,000 feet AGL.

The Federal Aviation Administration’s Flight Information Service Data Link (FISDL) provides what products?

METARs, SIGMETs, PIREPs, and AIRMETs.

The Federal Aviation Administration’s Flight Information Service Data Link (FISDL) products, such as ground radar precipitation maps, are

not appropriate for finding a path through a weather hazard area.

What weather database can a dispatcher access concerning wind shear activity at an airport?

TWIP

En route weather advisories should be obtained from an FSS on

122.2MHZ

What info is provided by a convective Outlook (AC)?

It provides prospects of both general and severe thunderstorms activity and specific severe weather threats during the following 8 days

The Federal Aviation Administration’s Flight Information Service Data Link (FISDL) is designed to provide data on a common frequency to flight crews from

17,500 feet MSL down to 5,000 feet AGL.

What wind direction and speed aloft are forecast by this WINDS AND TEMPERATURE ALOFT FORECAST (FB) report for FL 390 - “731960”?

731960
73 = wind direction
19 = wind speed
60 = temp
if first two is 50 - 99, subtract 50 from direction and add 100 knots to speed
73 - 50 = 23, 19 + 100 = 119
Wind direction = 230 degrees and wind speeds 119 knots

A station is forecasting wind and temperature aloft to be 280° at 205 knots; temperature –51°C at FL 390. How would this data be encoded in the FB?

But for winds ≥ 100 knots, use the special rule:

• Add 50 to the wind direction (DD)

• Subtract 100 knots from the speed (SS)

• Temperature is always included at FL390
  

• Direction: 280° → 28 → 28 + 50 = 78

• Speed: 205 − 100 = 105 → last two digits = 05

• Temperature: −51 → 51
  
  780551

What approximate wind direction, speed, and temperature (relative to ISA) are expected for a flight over TUS at FL 270?

24,000 30,000
0505-17 330533
010° true; 5 knots; ISA +13°C.

WILL ADD INFO FOR TAF AND PIREP!!!!!!!

WILL ADD INFO FOR TAF AND PIREP!!!!!!!