PDA

View Full Version : TS direction of travel


73qanda
2nd Aug 2018, 19:34
What factors dictate the direction of movement of a line of TS ?
I am specifically thinking of YSSY and YBBN. My guess would be that it is mainly a combination of surface wind and winds up a bit higher, say 5000ft , but I’d like to know if there are other major factors, anyone know?
Cheers

Intruder
2nd Aug 2018, 20:50
Circulation around a low pressure system generally directs the path of cold fronts and their associated thunderstorms.

VH-MLE
3rd Aug 2018, 05:06
I recall from my Aviation Met book from years gone by that TS generally move in the direction of the 10,000ft wind...

Cheers.

VH-MLE

hikoushi
3rd Aug 2018, 06:59
While this comes from the other side of the planet and may or may not be applicable to the specific meteorology of the Australian east coast, in the USA the 18,000 winds are called the “steering winds” of storm systems. More specifically, meteorologists will look at the 500 millibar upper air chart (the winds following the 500 millibar constant pressure surface, which varies around an average of 18,000 feet-“ish”). This shows a good representation of the general vorticity (“spin”) in the atmosphere, since at that point roughly half the atmosphere is above and below.

212man
3rd Aug 2018, 08:00
This shows a good representation of the general vorticity (“spin”) in the atmosphere, since at that point roughly half the atmosphere is above and below. I assume mean half the atmpospheric pressure? Pretty sure there's some atmosphere above 36,000 ft :)

73qanda
3rd Aug 2018, 08:42
I recall from my Aviation Met book from years gone by that TS generally move in the direction of the 10,000ft wind...

in the USA the 18,000 winds are called the “steering winds” of storm systems.

Thanks for the replies everyone. The above responses are along the lines of what I’m seeking in that I am picturing small coastal systems effecting the airfield rather than cold front storms or large depressions.
ie, If I can see a line of cells 10nm west of the field on my radar while I’m holding and the surface wind is westerly, the 10,000ft wind forecast as northerly.....does that generally mean a SE direction of travel?
I understand every situation is different etc, just seeking others ideas, experience.
Thanks again

wiedehopf
3rd Aug 2018, 11:40
Having access to a radar history is your best bet.

So if you have a mobile phone you should be able to find an app for that.

Not sure where to get the data in New Zealand though, in the US you could use this: https://radar.weather.gov/Conus/Loop/northeast_loop.gif

hikoushi
4th Aug 2018, 00:04
I assume mean half the atmpospheric pressure? Pretty sure there's some atmosphere above 36,000 ft :)

Ha, good catch! Yes, that is what I meant.

underfire
4th Aug 2018, 14:08
https://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=153.15,-24.36,669

click on a location, this shows the windspeed
click on lower left 'earth' for settings

very handy for checking the jet stream at 250

73qanda
4th Aug 2018, 23:24
Thanks Underfire,
great site