METAR and Station plots
Meteorological Analysis
October 4, 2010
By Tom Collow
KSMQ
K = 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 knots
G16KT = 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? 7 at 23:05 UTC or 19:05 EDT
• Type?
Correction to previous report
• Wind direction and speed?
th
from 225° or SW at 4 knots
3/4SM RA
3/4SM = visibility of 3/4 of a statue mile
RA = current weather term
RA = moderate rain
see 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 feet
In the example above, it is overcast at 1000 feet
1 octa = 1/8 of sky
SKC = Sky Clear
CLR = Sky Clear below 12,000 feet
FEW = 1–2 octas covered
SCT = scattered = 3–4 octas covered
BKN = 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 mb
SLP134 = sea level pressure of 1013.4 mb
Add 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 499
Except 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 Groups
Six 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
5XNNN
X = code number 1 through 8 (see chart below)
nnn = pressure tendency in tenths of millibars
Whether 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
Wind Speed
Wind Direction
Temperature, °F
Current Weather
Dewpoint , °F
Sea level Pressure, mb
Pressure Tendency
Cloud Cover