One last thing to worry about with regards to changing and moving air masses: elevation. Even if no heat is being added to or taken away from an air mass, it can still warm and cool just from changes in elevation. That's because changes in elevation correspond to changes in pressure. As air moves to higher pressure without the addition or subtraction of heat ("adiabatically"), both its density and temperature increase. The temperature change is a known constant: about 10 degrees Celsius per kilometer.

Let's go back to our Rapid City example and change it around a bit. Rapid City and Goodland are both about the same elevation. Suppose instead that the wind is from the southeast at 15 knots and that a temperature of 77 degrees is found upstream at Omaha, Nebraska (MAP.) That 77 degree air from Omaha would make it to Rapid City the next day. But Rapid City is higher than Omaha: the air mass will cool a bit from the elevation change. How much?

Use the STATIONS command in Weather to find out the height (in meters) of the two stations:

CD  STATION         ICAO  IATA  SYNOP   LAT     LONG   ELEV   S  T  U  F  H
NE OMAHA/EPPLEY     KOMA  OMA   72550  41 18N  095 54W  299   X  X        A
SD RAPID CITY       KRAP  RAP          44 03N  103 04W  970   X  X        A