What are 3 classic signs of a cold front passing that can be found on a meteogram?

Question

Just curious, what are 3 things you can find on a meteogram that indicate a cold front other than plummeting temperature and dew point?

Answer 1

1.  With an approaching cold front, surface pressure usually will be falling.  Once the front passes, the surface pressure will start rising again.   Reason...the air behind the cold front is usually associated with colder and denser sinking air.

2. The lowest surface air pressure readings are usually found along or very close to associated surface cold front.  So you will usually get a change in both the surface wind speed and wind direction as the front passes over your area.

3. Because the front represents the boundary between two different air masses with usually a different amount of moisture associated with it, you can usually expect a change in relative humidity too.

Answer 2

Excellent! Thanks for this great question!

PreFROPA you should look for:

Heightened Inversion

Shifting winds (usually coming from south. Pay particular attention to the 850MB to look for the Low Level Jet.)

Heightened SWEAT, CAPE and SSI indices

Increased lapse rates.

For FROPA or Frontal Passage, you should look for:

Other than the temperature and dew point, you should look for rising surface pressure trends,higher heights, veering winds throughout all layers. You should also be looking at a very shallow inversion, usually in the 750-800 mb area of the meteogram. Also, look for equal dew points and temperatures on the surface, because fog is often found on the front side of high pressure.

Those are the basics jists of what you should be looking for.

Hope I've Helped!