Why is south wind always followed by low pressure?

[oem7110]

Referring to following article, I would like to know on why south wind is always followed by low pressure.

Does anyone have any suggestions?
Thanks in advance for any suggestions


"Low pressure is often accompanied by wind and waves from the south, which push north with the Gulf Stream. The southbound sailfish are now prone to more resistance at the surface. There are no northerly swells or winds for them to use to their advantage when swimming against the Stream. During this stage, I believe the fish stay deep to conserve energy. When this occurs, my flat and deep lines get the most bites. A good example occurred recently when my co-captain, Alex Castellanos, caught five sails in calm conditions. The next day, the barometric pressure increased and the wind shifted around from the north. Alex caught and released 15 out of 16 sailfish in less than four hours!"

 

Ref :

http://www.weather.com/sports-rec/outdoor-fishing-reports/fishing-barometer-20120328

[Mallow]

Fortunately this is a relatively easy one to explain.

 

First and foremost, the word "always" is not exactly accurate, but in the Northern Hemisphere outside the tropics, it is usually true that southerly winds are followed by a low pressure reading. The simple explanation is that weather systems in the mid-latitudes tend to move from west to east (for reasons that we need not address here, though if you're curious, we can get into that point as well). Importantly, low pressure areas in the Northern Hemisphere are characterized by counterclockwise wind circulations, as viewed from above, and vice-versa for regions of high pressure (again, for reasons that need not be addressed here, but that we can discuss as well if you're curious). Therefore, southerly winds in the Northern Hemisphere are found in areas with high pressures to the east and low pressures to the west. Since these pressure systems tend to move from west to east, the explanation is now complete.

 

[oem7110]

First and foremost, the word "always" is not exactly accurate, but in the Northern Hemisphere outside the tropics, it is usually true that southerly winds are followed by a low pressure reading. The simple explanation is that weather systems in the mid-latitudes tend to move from west to east (for reasons that we need not address here, though if you're curious, we can get into that point as well). Importantly, low pressure areas in the Northern Hemisphere are characterized by counterclockwise wind circulations, as viewed from above, and vice-versa for regions of high pressure (again, for reasons that need not be addressed here, but that we can discuss as well if you're curious). Therefore, southerly winds in the Northern Hemisphere are found in areas with high pressures to the east and low pressures to the west. Since these pressure systems tend to move from west to east, the explanation is now complete.

 

Referring to following image, the weather systems on westerlies region between 30N and 60N are move from south-west to northeast, such as New York (40°42'51"N/74°0'23"W). If southerly winds in New York is found, do you have any suggestions on whether New York tends to have lower pressure or higher pressure?

 

Furthermore, the weather systems on NE Trade Winds region between 0N and 23.5N are move from northeast to south-west, such as Mexico (23°0'0"N/102°0'0"W). If southerly winds in Mexico is found, do you have any suggestions on whether Mexico tends to have lower pressure or higher pressure?

 

Do you have any suggestions?

Thank you very much for any suggestions :>

 

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