Upper Fronts Flashcards
What is an upper front and how is it different from an occluded front/trowal?
In Canada an upper front is a non-occlusion situation.
An upper front happens when cooler air has to move up over colder air that is in it’s way. So maybe a mass of cold air is settled in over Calgary and warmed air coming from the coast of BC comes over the mountains and instead of sinking back down the other side to warm up poor frozen Calgarians…it just slides overtop of the denser cold air. So then you go flying and tho its -30 on the ground at altitude its like 0.
This is a non-occlusion situation for no other reason than the three air masses happened to meet by chance. In an occlusion, the three air masses are circling a low? I don’t fucking know…
Will there be any indication that a warmer front is passing overhead of you when you’re stuck on the ground in the cold air mass?
- Winds and temp will not change
- Precip, probably snow or ice pellets or freezing rain by the time it reaches you and clouds
- If you are in the air flying, then indications will be the same as any other front. Winds will veer, temp will change.
Why is the upper front in the diagram below considered an upper cold front instead of an upper warm front?
- The coldest and densest of the three is the cA sitting over the prairies and can basically be considered the ground, as the air masses overhead are warmer and therefor cannot affect it
- The mP sitting atop the cA is actually warmer than the mA that is going to shove it out of the way.
- Therefore this is considered an upper cold front
What is an example of an upper warm front?
If the retreating edge of a cold front is super long an shallow and not moving much, a warmer air mass coming up behind it will go up over it.
In this case, on a map, the upper warm front would be drawn (with red bubbles that are not filled in) where the cold air mass suddenly steepens. Then the actual surface warm front would be drawn in the usual place on the surface where the warm air meets the cold
