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LOCATING A FRONTAL BOUNDARY

METEOROLOGIST JEFF HABY

The most common MISTAKES with labeling a front include:

1. Front is not drawn at the leading edge of the temperature gradient

2. Using temperature and wind direction shifts that are the result of topography and not a true front

3. Identifying outflow boundaries and other mesoscale boundaries as synoptic fronts

4. A dryline is not a true front and should not be labeled with a cold front symbol unless a cold front has overtaken the dryline

5. Drawing a stationary front that moves significantly when the maps are put into motion


Identifying a front: If you only had one parameter to go by when marking a front it would be to use surface synoptic wind patterns (not the result of topography or a mesoscale boundary). There is almost always an abrupt wind shift at the frontal boundary unless it is a front that is washing out or is stationary. The second parameter I would look at is the temperature gradient. A "fresh" front is easy to locate because there will be a remarkable temperature gradient just behind the frontal boundary. An older front may be more difficult to locate due to the temperature gradient washing out. Thirdly, the pressure trough can be used to locate the front. Surface air pressure is generally lowest at the frontal boundary since lifting is most pronounced there. Using these three parameters should give the frontal boundary. The front will be at the leading edge of the thermal gradient, there will often be a distinct synoptic wind shift at the front and the front will be in a pressure trough.