"Dylan Smith" wrote in message
...
OK, I've never seen this before.

Take a look at the synoptic chart I've saved at
http://www.alioth.net/tmp/fronts.gif

There is a cold front, just south west of Ireland. The 'sharks teeth'
are outlines, rather than filled in. The other week I saw a warm front
drawn like this. What's the difference between this and a 'normal' cold
front?


http://www.msc-smc.ec.gc.ca/educatio...g167_e.cfm#193

Notwithstanding the rather bizarre structure which your chart-analyst
appears to see.....

..... what an unfilled cusp is *supposed* to indicate is an "upper" front".

An upper front is a *steepening* of the slope in the cold air, such that a
station at the surface does not notice any change in air mass per se, but it
notes the *effects* of a cold front passage (or a warm front passage)
because the structure *above* him corresponds to the classic cold-front or
warm-front scenario.

Note the cross-sections slightly higher up the same page, at "frame 188"