METAR and Station plots

Meteorological Analysis

October 4, 2010

By Tom Collow

KSMQK = identifier for stations in the

continental United States

For stations located in Alaska and Hawaii

the first letter would be “P.”

SMQ = station abbreviation

SMQ = Somerset, NJ

For a detailed list of station abbreviations go

to http://www.nws.noaa.gov/tg/siteloc.shtml

031953Z AUTO

03 = Calendar Date

1953Z = 19:53 Z or UTC

UTC = EST + 5 hours, or

UTC = EDT + 4 hours

So 19:53 Z = 14:53 EST = 15:53 EDT

AUTO = automated station

could also have COR which means

correction to previous report.

02009G16KT

020 = wind direction from 20° (NNE)09 = wind speed of 9 knotsG16KT = wind gusts of 16 knots

If you see “00000” here, it signifies a calm wind.VRB is used to signify a varying wind direction. (ex. VRB02KT)

Your Turn

• KEWR 072305Z COR 22504KTS

• Where? Newark, NJ

• When? 7th at 23:05 UTC or 19:05 EDT

• Type? Correction to previous report

• Wind direction and speed?

from 225° or SW at 4 knots

3/4SM RA3/4SM = visibility of 3/4 of a statue mileRA = current weather term

RA = moderate rainsee sakai for complete list of terms

Note: RA alone denotes moderate rain-RA would mean light rain+RA would mean heavy rain

Observations can be combined, for example,+TSRA = thunderstorm with heavy rain

OVC010

Represents cloud cover in hundreds of feetIn the example above, it is overcast at 1000 feet1 octa = 1/8 of skySKC = Sky Clear CLR = Sky Clear below 12,000 feet FEW = 1–2 octas covered SCT = scattered = 3–4 octas coveredBKN = broken = 5–7 octas covered OVC = overcast = 8 octas covered

Ex. BKN021 FEW120 = Broken clouds at 2100 feet and few clouds at 12000 feet (sometimes more than 1 cloud layer is reported)

17/14 A2992

17/14 = Temperature of 17°C Dewpoint of 14°C

An “M” before the numbers denotes a “minus” sign

Ex. 05/M12 = temperature of 5°C and a dewpoint of -12°C

A2992 = altimeter pressure reading of 29.92 in. Hg

Altimeter setting = dependent on only station pressure and elevation, not temperature.

Remarks (RMK)SLP = Sea Level Pressure

Details on all of the different remarks are available on sakai, I will only have time for the most important ones

SLP851 = sea level pressure of 985.1 mbSLP134 = sea level pressure of 1013.4 mbAdd either a 9 or 10 to the front of the number and a

decimal point after the second number.General rule: add 9 if number is between 500 and 999

add 10 if number is between 000 and 499Except for extreme circumstances (hurricanes), the pressure

range is between 950 mb and 1050 mb.

Use the three digit number in the station plot

The 1 and 2 GroupsSix Hour Max/Min temperature

• 10ttt• Gives maximum temperature over the last 6 hours with

enough precision to be converted to the nearest whole degree Fahrenheit.

• ttt = temperature = tt.t degrees Celsius • A leading digit of 2 signifies the 6 hour minimum

temperature• If the temperature is negative, the “0” term will be

replaced by a “1.”• Ex. 10047 21011• 6 hour max temperature = 4.7°C• 6 hour min temperature = -1.1°C

The 5 Group: 3 hour pressure tendency

5XNNNX = code number 1 through 8 (see chart below)nnn = pressure tendency in tenths of millibarsWhether pressure is rising or falling depends on X

Ex. 53014

Pressure is 1.4 mb higher than it was 3 hours ago.

Ex. 56018

Pressure is 1.8 mb lower than it was 3 hours ago.

Temperature Conversion Term: T0ttt0ddd

• Gives Celsius temperature and dewpoint in enough precision to be converted to the nearest whole degree Fahrenheit.

• ttt = temperature (tt.t), ddd = dewpoint (dd.d)• Example T01720139• Temperature = 17.2°C = 63°F • Dewpoint = 13.9°C = 57°F• If the temperature is negative, the “0” term will

be replaced by a “1.”• Use these temperatures in the station plot

The P,6, and 7 Groups : Precipitation

Pnnnn

nnnn = precipitation in the last hour in hundredths of inches

Ex. P0023 = 0.23” of precipitation in the last hour

Instead of P, use 6 for total precipitation over the last 6 hours and 7 for total precipitation over the last 24 hours

Ex. 60082 = 0.82” of precipitation in the last 6 hours

Ex. 70145 = 1.45” of precipitation in the last 24 hours

Temperature, °F

Dewpoint , °F

Sea level Pressure, mb

Pressure Tendency

Wind Direction

Wind Speed

Cloud CoverCurrent Weather