NAM MOS Meteogram Details

This directory contains time series plots of data taken from the NAM MOS data. The plot represents a plot of forecasted data from a 6 hour forecast to 60 hours. These plots are updated once every 12 hours at around 12:15 EST.

This is a 60 hour forecast time series for a particular station location. The plot is divided up into several subplots described top to bottom:

Samples MOS Meteogram

Temperature and dewpoint chart
This shows temperature as the top line and dewpoint as the bottom line. The maximum and minimum temperatures are plotted below the chart at specific reporting times. 12Z is the low temperature and 0Z is the high temperature.

WX - present weather data
This shows the weather forecasted to be occurring at that time as a weather symbol.

SNOW - snow cover
This shows forecasted snow fall in inches for the previous 12 hours. A value of 1 indicated anywhere from a Trace to 2 inches. A value of 2 indicates snowfall of 2 to 4 inches. A value of 4 indicates 4 to 6 inches and 6 means more than 6 inches.

PREC - precipitation
This shows forecasted precipitation in inches for the previous 6 hours.

VIS - visibility
This shows the forecasted horizontal visibility in miles.

WINDS - 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 in millibars.

Time
This is the forecast time in universal time.