Could somone please explain to me why the answer to this question is not Occluded Front?

Cheers
Richard

Richard

You have a point there. The lower portion of the system to the south of Tasmania is indeed an occluded front, although the occlusion has not progressed along the entire length of the system. I guess to be fair, I should accept either answer. Maybe I'll look at changing the wording of that question. Thanks for your feed-back.

Thanks Bob,

Makes sense. I figured that was the reason for your answer.

One more for you. Could you please explain the correct answer and logic to this one?

Thanks/Regards
Richard

Refer to MSL Analysis Fig 49 on page 44 of the VFR [Day] work booklet. The airstream most likely to suffer latitudinal heating is located at -
A S40 00 E160 00
B S40 00 E120 00
C S20 00 E120 00
D S35 00 E110 00

Hi Richard,

My answer to this one would be (D) and my reasoning is this:

Latitudinal heating is caused by an air mass moving north (in the Southern hemisphere) into warmer climes. This causes heating of the lower levels of the air mass which leads to instability in the lower levels where the heating is occurring.

So, let's look at each of the options in turn and see if we can spot this happening:

Option A: the wind at this position will be more a North Westerly or even westerly as it swings around the high at about S30 E160. The air is not moving northwards but rather southwards or even eastwards. No latitudinal heating will be occurring here.

Option B: S40 E120, we again have NW coming around off the low at S45 E110. Air is moving southwards over cooler waters. No latitudinal heating.

Option C: At S20 E120 the isobars are very widely spaced which means light winds. Not much rapid heating of the lower levels of the air mass happening here. Apart from that, following the isobars, you can trace the wind will be from the east/NE over central NT before it swings northwards off the coast of WA. The air mass isn't originating in colder lattitudes. It will already be quite warm. No lattitudinal heating here either.

Option D: Now this option is exciting. At S45 E110, a Low winding itself up quite nicely there. Check out the spacing of the isobars at S40 E105. That means strong winds. That Low is pulling cold polar air at high speed northwards up over warmer waters. There will be a good amount of warming up of the lower levels of the air mass with associated instability and bad weather in that area. That is where you are most likely to find latitudinal heating.

Cheers,

Rich

Thanks Richard,

I did some more reading and came to the same answer eventually, but your explanation is helpful.

I sat my Met exam last week and passed, so it is on to Navigation now.

Cheers
Richard