Surface Meteogram Details

A meteogram is a time cross-section of data for a specific surface reporting station. The data plotted include temperatures, winds, pressure, clouds and present weather. These data are updated hourly at around 50 minutes past the hour.

Meteograms

This is a 25 hour time series for a particular station location. The plot is divided up into several subplots described top to bottom:

Meteogram for Pittsburgh during the blizzard of 1993

Temperature and dewpoint chart

This shows temperature as the top line and dewpoint as the bottom line.

EXTT - extreme temperature
The maximum and minimum temperatures are plotted below the chart at specific reporting times. 12Z and 18Z are generally low temperatures and 0Z and 6Z are high temperatures.

WX - present weather data
This shows the weather being reported at that time as a weather symbol.

SNWDP - snow depth
This shows reported snow cover in inches.

PREC - precipitation
This shows precipitation totals in inches. The values are 24 hour totals generally at 12Z, 6 hour totals at 0Z, 6Z and 18Z, 3 hour totals elsewhere.

VIS - visibility
This shows the horizontal visibility in miles.

WGST - wind gusts
This reports wind gusts in knots if the winds are strong and gusty. This is generally the maximum wind reported over a several minute period during the observation of data.

WIND - winds and cloud cover
This is the standard wind and cloud cover symbols used in the surface data plots. Up is north.

Cloud chart

This chart gives cloud layer information. The vertical axis is height of cloud base in feet and is logarithmic. The layers are plotted as horizontal lines. Clear skies are plotted as a 'C'. Scattered cloud layers (1/8th to 3/8th coverage) are plotted as a single short dash. Broken cloud layers (4/8th to 7/8th coverage) are plotted as two short dashes. Overcast layers are plotted as a single long dash. The actual cloud ceiling is displayed below the chart in 100s of feet if the ceiling is below 10,000 feet.

Pressure chart

This chart plots sea level pressure (or altimeter setting if pressure not reported) in millibars.

Time
This is the reporting time in universal time.