ATC Basics: Current Weather - Temp, DP, ALT

What is the measure of the hotness or coldness of the air as measured by a thermometer?

Temperature

What is the temperature to which the air must be cooled at a constant pressure and constant water-vapor content in order for saturation to occur?

Dew point

If you see 18/16, what is the temperature?

18

If you see 18/16, what is the dew point?

16

How are temperatures/dew points less than 0 reported?

M

If dew point is unavailable, how is the block coded?

With temperature, /, and no entry

If temperature is unavailable, how is the block coded?

It’s not

If there’s a M in front of a number, how is that temperature of that said?

Minus

In temperature/dew point is 06, how is that reported

six

What is the pressure value to which an aircraft altimeter scale is set so that it will indicate above MSL of an aircraft on the ground at the location for which the value is determined?

Altimeter setting

If you see A3042, how is that said?

Altimeter 3042

What are plain language or coded data added to the body of the METAR/SPECI to report significant information not provided in the body of the report?

Remarks

What’s the 3 letter contraction used to separate remarks from the body of the report?

RMK

What happens if there aren’t any remarks?

Report is omitted

How is time coded for a remark whenever the event it’s referring to is in the same hour?

Minutes only

How is time coded for a remark whenever the event it’s referring to isn’t in the same hour?

Hours & minutes

What does DSNT mean?

Distant

What’s the abbreviation for distant?

DSNT

What is an explosion caused by the intense heating of subterranean rock that expels lava, ashes, etc?

Volcanic eruption

How are volcanic eruptions coded?

Plain language

What is a violent, rotating column of air that does not touch the surface?

Funnel cloud

What is a violent, rotating column of air touching the ground?

Tornado

What is a violent, rotating column of air that forms over a body of water and touches the water’s surface?

Water spout

What does the letter B denote in remarks?

Begins (at)

What does the letter E denote in remarks?

Ends (at)

What time zone is beginning & ending of all remarks in?

UTC

What is the maximum instantaneous wind speed that exceeded 25 knots since the last METAR?

Peak wind speed

What is the speed a gust of wind must exceed to be considered for peak wind speed?

25 knots

If you see PK WND 33048/22, what would you say?

Peak wind 330 at 48 occurred at 22 past the hour

What is the change in the wind direction of 45 degrees or more in less than 15 minutes with sustained wind speed of 10 knots or more throughout the wind shift?

Wind shift

What are the conditions for the wind to be considered shifting?

1. Shift of 45 degrees or more

2. Sustained wind of 10 knots or more

What is the remark identifier for wind shift?

WSHFT

What is the remark identifier for peak wind?

PK WND

What is the contraction for wind being the result of a frontal passage?

FROPA

If you see WSHFT 30 FROPA, what do you say?

Wind shifted at 30 due to frontal passage

What is the prevailing visibility determined from the usual point of observation?

Surface visibility

What is the abbreviation for surface visibility?

SFC VIS

What is the prevailing visibility for determined from the ATCT when the surface visibility is determined from another location?

Tower visibility

What’s the abbreviation for tower visibility?

TWR VIS

What is a condition when the prevailing visibility is less than 3 statute miles and rapidly increases & decreases by ½ mile or more during the period of observation?

Variable prevailing visibility

When you see VIS 3/4V1 1/2, what do you say?

Visibility variable between ¾ and 1 ½

What is the visibility in a specified direction that represents at least a 45 degree arc of the horizon circle?

Sector visibility

If you see VIS NE-SE 1/4 S-SW 3/4, what do you say?

Visibility northwest through southeast 1/4, south through southwest 3/4

How many degrees in a specified direction does sector visibility cover?

45

What generally includes all forms of visible electrical discharge produced by a thunderstorm?

Lightning

What are the 3 categories for the frequency of lightning?

1. Occasional

2. Frequent

3. Continuous

How often is lightning striking it it’s considered occasional?

Less than 1 flash/minute

How often is lightning striking it it’s considered frequent?

1-6 flashes/minute

How often is lightning striking it it’s considered continuous?

More than 6 flashes/minute

What is the contraction for occasional lightning?

OCNL

What is the contraction for frequent lightning?

FRQ

What is the contraction for continuous lightning?

CONS

What are the 4 types of lightning?

1. Cloud-to-ground

2. In-cloud

3. Cloud-to-cloud

4. Cloud-to-air

What is the contraction for cloud-to-ground lightning?

CG

What is the contraction for cloud-to-cloud lightning?

CC

What is the contraction for cloud-to-air lightning?

CA

What is the contraction for in-cloud lightning?

IC

What does ALQDS mean?

All quadrants

If you see SHRA B05 E30 SHSN B20E55 in the remarks, what do you say?

Rain showers begin at 05, ended at 30, snow showers began at 20, ended at 55

What is the contraction for thunderstorm?

TS

If you see GR 2, how do you say it?

Hailstones two inches in diameter

What are visible wisps of precipitation falling from clouds that evaporate before reaching the surface?

Vigra

Why is vigra important?

Could indicate a dry microburst or an icing hazard

What is a ceiling of less than 3,000 feet that rapidly increases/decreases in height during the period of observation?

Variable ceiling

What is the remark identifier for variable ceiling?

CIG

How many ranges must the sky be varying for it to be considered a variable sky condition?

2+ ranges

What are the 4 main types of clouds from the remark section?

1. Towering cumulus

2. Altocumulus castellanus

3. Standing lenticular or rotor

4. Cumulonimbus & cumulonimbus mammatus

What’s the remark identifier for cumulonimbus mammatus?

CMAM

What does PRESSRR mean?

Pressure rising rapidly

When you see PRESRR, what does that mean?

Pressure rising rapidly

What does PRESFR mean?

Pressure falling rapidly

What is the contraction for pressure falling rapidly?

PRESFR

What is the contraction for snow increasing rapidly?

SNINCR

If you see SNINCR 3/10, what do you say?

Snow increase 3 inches on the during the past hour, 10 inches on the ground