NZ Weather Forum

Hello All. Is anyone able to provide a good definition of what Synoptic Circulation is? Also from a national perspective whether currently with these systems passing through there is a link between surface and upper level circulation ( effects of upper level divergence and vorticity advection on the development of surface level weather systems?)

Much Appreciated for any reponses!

when a surface low has upper level support then it will be alot stronger
same for a surface high
thats one thing

but you can also get a upper level trough too!
(something that used to be often described in weather forecasts, not so much now it seems?)

a good definition of what Synoptic Circulation is?

Its the movement of air around highs, lows....

is there a link between surface and upper level circulation

I recommend this URL. http://www.theweatherprediction.com/habyhints/
Have a read of 25,26.

Thanks Guys. Just a bit of a weather project that i got to do with the weather for this week. Much appreciated

One Last Question: Could someone please explain the statement below in a more understanding way -( perhaps explaing why would be great)

Links between surface and aloft last week:

"Development of Rossby (Planetary) wave activity over NZ vaired last week.
27-29th Sept: Started with only minor rossby wave activity over NZ region at 200hpa. However, a strong wave developed to the south and southwest of the country extending northward over SE australia. This was sonsistent with the developement of the large complex trough and secondary low observed at the surface.
30 Sept to 1 Oct: The plantery wave at 200hPa weakened and shifted eastwards, as the complex trough at the surface moved across the south island.
2-3 oct: weak wave activity returned to the region, while suggestion of a split jet pattern occurred at 200hpa, consistent with the development of a slow moving high pressure system at the surface (over the Tasman sea)"

Maybe explaining how or where this caused diuvergence or convergence aloft etc etc , Or maybe something about the jet stream and its effects?

Cheers!! Much appreciated!

Leighton - you will find this MUCH easier to understand (particularly in terms of the relationships between features) if you look at maps for each day. Find yourself a surface chart and a 200hpa chart which shows height and wind speeds. That will give you a visual representation of the upper level troughs and ridges (waves), the surface features (highs and lows) and the jetstreams which will be a lot easier to take in.

also jet streams can spawn /intensify troughs , especially at the bottom most part of the curve (not sure if that is what is known as the exit area?)

I think of a jet streams effect in this way as helping the cooling aloft by getting rid (venting) of the rising air
(not sure if it can be thought of as like though)

The Wyoming gfs allows you to plot an upper level chart over the surface pressure chart.

NZstorm wrote:The Wyoming gfs allows you to plot an upper level chart over the surface pressure chart.

How do I do that? Whats the liink?