UKH

Hi Everyone

I'm trying to work out the weather for today from the Synoptic Chart, there's a high pressure (1027mb) well North of the UK and two low pressure areas (984mb) NE of UK and W of UK.

My question is, if you look at the low that's NE of the UK, the Mb's are building up towards the 1027Mb high to the W, so with the anticyclone which rotates clockwise and the cyclone that rotates anticlockwise, at what point between 984Mb and 1027Mb do you define an area that's a low and high ? is it a particular point in pressure ?

many thanks

L

"Highs" and "Lows" are points rather than areas.  I.e. they are maxima and minima on the synoptic chart.  High and low pressure systems will always be defined relative to the surrounding atmosphere rather that at absolute values of pressure.

Thanks, makes sense. I'm getting there

1013 is the ‘standard atmosphere’ anything bigger is technically high pressure and anything smaller is low pressure. 

However, you can have a low (cyclone) that is at more than 1013, as it is lower pressure than the atmosphere around it.

Its easier to think of it like a map and contour lines; it doesn’t matter where sea level is, a peak is the highest point on that particular hill.

But above 1013 mb it's going to be a very feeble cyclone!

Coincidentally, there's 1013mB Low east of Hudson's Bay on Saturday 12th, 16:00, which appears to be carrying some bad weather

https://www.windy.com/-Rain-thunder-rain?rain,2019-10-12-18,61.565,-34.805,...