Saharan Air Layer - MASSIVE dust storm flooding the Atlantic with dry air

hatrickpatrick

This is quite incredible. One of the factors every August which can hamper the earlier part of the Atlantic Hurricane Season is dry air advected from the Sahara desert in North Afrcia. As tropical cyclones rely on warm sea temperatures and moist air, the dust can slow their development both through drying out the air and by slightly cooling the sea below through sunlight blocking. Such dust storms are standard for this time of year, but the scale of the current one is mind boggling:

https://www.youtube.com/watch?v=F3Q8Sh2AjPo

This is pretty fascinating. What happens when this storm reaches Central and South America? What would conditions be like on the ground, in a non-desert country unaccustomed to such dust storms?

weisses

I thought the rainforest was depending on the dust from the Sahara because it contains loads of minerals as well that are beneficial for the soil there

Red Nissan

weisses wrote: »

I thought the rainforest was depending on the dust from the Sahara because it contains loads of minerals as well that are beneficial for the soil there

Could well have validity, in Ireland we complain about having to wash our cars!!

Ahorseofaman

weisses wrote: »

I thought the rainforest was depending on the dust from the Sahara because it contains loads of minerals as well that are beneficial for the soil there

Exactly,I was only watching them say the very same thing on one of the sky docu channnels during the week.

Mr Cumulonimbus

hatrickpatrick wrote: »

This is quite incredible. One of the factors every August which can hamper the earlier part of the Atlantic Hurricane Season is dry air advected from the Sahara desert in North Afrcia. As tropical cyclones rely on warm sea temperatures and moist air, the dust can slow their development both through drying out the air and by slightly cooling the sea below through sunlight blocking. Such dust storms are standard for this time of year, but the scale of the current one is mind boggling:

Mentioned during the week by Evelyn Cusack during one of the weather forecasts as to why the Atlantic hurricane season has been so quiet up to now. Conditions will improve for cyclone formation I'm guessing?

rickdangerouss

Mr Cumulonimbus wrote: »

Mentioned during the week by Evelyn Cusack during one of the weather forecasts as to why the Atlantic hurricane season has been so quiet up to now. Conditions will improve for cyclone formation I'm guessing?

http://www.bbc.co.uk/weather/features/23903253

Ben Rich explains how the recent rainfall in Mali could lead to increased Tropical storm activity across North America and the Caribbean.

One is getting created in the next few days.

hatrickpatrick

Mr Cumulonimbus wrote: »

Mentioned during the week by Evelyn Cusack during one of the weather forecasts as to why the Atlantic hurricane season has been so quiet up to now. Conditions will improve for cyclone formation I'm guessing?

I'm not so sure. It's an unbelievably hostile environment this year, as evidenced by the number of times the NHC has classified invests with a more than 50% chance of developing only to later roll back and say they've been killed by either wind shear, dry air, or moving too quickly across the tropics to have time to develop.

If you look at the most active hurricane season, 2005, wind shear seems to be the number one factor in terms of activity - sea temperatures are unusually warm now as they were back then but the difference is that upper winds are ripping any potential disturbances apart before they have time to close their circulation.

Apparently this is linked to the Pacific ENSO phase. If you look at late 2005, there was a strong La Nina in the Pacific, which is known to lower wind shear across the Atlantic - I doubt it's a coincidence that this same year, the hurricane season continued for a month and a half longer than it usually would.

martin.covan

Yes and in turn it follows we are not getting any returning ex hurricanes in our neck of the woods,so our summer this year has been allowed to continue to be warmer and dryer as a consequence of less active disturbances routing our way.

hatrickpatrick

I would appear to have spoken too soon

maquiladora

Thanks SAL....

Mr Cumulonimbus

Just checking back in here to ask has there ever been a quieter Atlantic hurricane season I wonder?

Red Nissan

Seems likely to be one of the quieter ones. But it's not unprecedented.