What are “DAM?” Or what are the units being used for the various meteorological parameters?
DAM is shorthand for decameters, or tens of meters. For example, 576 DAM is the same as 5760 meters. Why use some oddball unit like DAM? Because meteorologists use charts, and it saves a tiny bit of space and clutter by labeling the contours 576 or 564 rather than 5760 or 5640. You will most frequently encounter DAM when a forecaster is relating 500 millibar heights. Other units used are millibars (MB or mb), which is a measure of pressure and celcius (C) which is a measure of temperature. Meteorology is a science (despite the jokes about tea leaves, dice, chicken bones, trick knees, random number generators, etc. when discussing weather forecasting), and as such uses the base 10 MKS (or Meters, Kilograms, seconds) unit system rather than english units. Weather observations still have the aircraft altimeter setting in inches of mercury and the temperature in Fahrenheit in deference to our customers, but computer model forecast charts all use MB, C, and DAM.
