Barometric pressure in Easter Mediterranean

[Amari]

On the UK shipping forcast last week barometric pressures ranged from 950 to 1035 but when we are liveaboard in the Med spring and autumn our 20 year old barometer never varies 5 units either side of 1020. Is this the way of things, or is the barometer caput?

 

[peteandthira]

I don't think it varies much in lower latitudes. I spent 4 years in Oman and my barograph drew a straight line for almost the whole time.

Not sure about the med though, perhaps a google will help?

Pops

 

[Roberto]

IIRC, the historically lowest pressure ever recorded in the whole med has been in the region of 975/980mb..

 

[jimbaerselman]

Variations in pressure are much less, generally around 1005 to 1015 in Greece in the winter, slightly lower in the summer. And there's a general summer gradient, dropping by about 5 as you travel east from Italy to Turkey, which creates the persistent northerlies of Greek waters.

Lows may only be 2 or 3 mb less than the average, but can create very strong winds. Something to do with the differing cyclostrophic and geostrophic ratios in lower latitudes - don't ask - they're lovely words though.

 

[peteandthira]

Jimbo

Hope you don't mind me calling you that, but I can never remember how to spell it by the time I get to type a reply!

It is well known that lower latitudes get wind forces from much lower pressure differences.

For those who get UK met office pressure charts, there is a scale at the top left which shows the latitude vs isobar spacing.

Down in the Med, what seems like a calm day in Scotland can easily whip up a f6 or f7.

Likewise, those horrific looking dartboards in northern latitudes are often only a similar f6 or f7.

It is all to do with rotation of the earth, which despite the equator being the fattest bit, it is subject to much less geostrophic force and so needs very little pressure differences to produce a gale.

As I have often said, the above words are not neccessarily in the right order, but much can be gained from them especially if corrected!

Pops