Why Are Waves Developing So Far South?

[adelphi_sky]

Why ware waves developing so far south? Or is it just me? I can't recall so many coming off the coast so close to the equator. Has something major shifted?

[PurdueWx80]

The subtropical ridge is further south this year. That pushes the ITCZ further south as well. It is starting to hamper the development of these African waves because they are moving quickly, and end up either being hampered by, or plowing into South America.

[The_Cycloman_PR]

The subtropical ridge is further south this year. That pushes the ITCZ further south as well. It is starting to hamper the development of these African waves because they are moving quickly, and end up either being hampered by, or plowing into South America.

Do you have a link for graphic map showing the Azores High and the whole atlantic? If so please provide it for me please! Also a question...The azoress high is placed too far south at this time and is making the tropicale waves to travel the Atlantic at very low latitudes. Is the Azores high too strong at this moment also to make the waves travel as fast as they are now to stop them from development or are the tradewinds guilty for that to happen? I have read in the NHC tropical weather discussion that the waves are enbeded in stron easterly flow. This strong flow is caused by the Azores high or the Tradewinds? Or it's a conbination of both phenomena? Finally... Can you provide links for the Azores high current status and the tradewinds current status also...!

Anyone help about this questions will be very welcome!!!

Thanks in advance everyone!!

Cycloman.

[PurdueWx80]

00Z 12 hr (valid 8 a.m. EDT) 500 mb GFS forecast:
http://weather.unisys.com/hurricane/5av_12.gif

While this is a model forecast, it's close enough. See the big high in the eastern Atlantic between 20 and 30 N? There is very strong flow on the south side of it (subtropical easterlies) which is helping keep these waves on a fast pace towards the west. If you substitute 48 for 12 in the URL, you'll see the 48 hour forecast has the high expanding towards the west. The flow becomes ENE, which would stear the waves towards the WSW if it can verify. That big strong high will have weak flow near it, but very strong flow around it, especially on the north side where the temperature gradient is stronger. Someone else will have to help out with tropical/subtropical synoptic flow as I am not too educated on the matter. Hope this helps for now.

Also see http://weather.unisys.com/hurricane/slp_12.gif for the 12 hour surface forecast. There is very strong flow out of the NE in the far east Atlantic between the surface high over the mid-Atlantic and the ITCZ.

[The_Cycloman_PR]

Thanks for the links!!

[CaluWxBill]

The subtropical ridge is further south this year. That pushes the ITCZ further south as well. It is starting to hamper the development of these African waves because they are moving quickly, and end up either being hampered by, or plowing into South America.

Do you have a link for graphic map showing the Azores High and the whole atlantic? If so please provide it for me please! Also a question...The azoress high is placed too far south at this time and is making the tropicale waves to travel the Atlantic at very low latitudes. Is the Azores high too strong at this moment also to make the waves travel as fast as they are now to stop them from development or are the tradewinds guilty for that to happen? I have read in the NHC tropical weather discussion that the waves are enbeded in stron easterly flow. This strong flow is caused by the Azores high or the Tradewinds? Or it's a conbination of both phenomena? Finally... Can you provide links for the Azores high current status and the tradewinds current status also...!

Anyone help about this questions will be very welcome!!!

Thanks in advance everyone!!

Cycloman.

The subtropical Highs in conjuction with the ITCZ are responsible for the trade winds. So a stronger Azores High will almost assuredly mean a stronger tradewinds, or atleast a strong push of the ITCZ south, I guess if the High in the S. Atlantic is very weak then the ITCZ may be forced very far south, and the tradewinds may not increase much even with a strong Azores high. But, just keep in mind the tradewinds are a result of the subtropical highs.

[B-Bear]

I have a question:

Doesn't the fact that they are starting further south give them a better chance of getting across the Atlantic, and, providing they slow down once they hit the island area, increase the chances of more hurricanes actually getting into the Gulf of Mexico?

[PurdueWx80]

I have a question:

Doesn't the fact that they are starting further south give them a better chance of getting across the Atlantic, and, providing they slow down once they hit the island area, increase the chances of more hurricanes actually getting into the Gulf of Mexico?

Yes...sorta. Right now it is too far south since the waves are heading towards South America (e.g. Earl). Their fate doesn't just depend on that ridge though, it also depends on smaller upper lows and ridges. Once they get to the west Atlantic, there has been no trough along the Eastern Seaboard to recurve them..which is why Bonnie and Charley made it to the Gulf.

[CaluWxBill]

I have a question:

Doesn't the fact that they are starting further south give them a better chance of getting across the Atlantic, and, providing they slow down once they hit the island area, increase the chances of more hurricanes actually getting into the Gulf of Mexico?

Yes absolutely, if most waves end up in the carribean, rather than turning North then yes. However most tropical waves that do develop usually start farther north off the African coast and will turn away, whether like Danielle, or like Fabian. but more waves making it through the carribean should enhance the likelihood of Gulf of Mexico hurricanes.

[B-Bear]

Thanks! That's kind of what I thought. Granted, I realize that once these depressions get across the Atlantic there are other factors which must be in place to steer the storms north, but getting across the Atlantic seems to be the first major hurdle these storms must overcome. If this trend of storms coming off Africa further south continues, it seems that, sooner or later, those other factors will be in place to put one in the Gulf. It's early in the year yet. I have a gut feeling (yes, I know, completely unscientific) that it may be a nervous year for Gulf coast residents.

[PurdueWx80]

Thanks! That's kind of what I thought. Granted, I realize that once these depressions get across the Atlantic there are other factors which must be in place to steer the storms north, but getting across the Atlantic seems to be the first major hurdle these storms must overcome. If this trend of storms coming off Africa further south continues, it seems that, sooner or later, those other factors will be in place to put one in the Gulf. It's early in the year yet. I have a gut feeling (yes, I know, completely unscientific) that it may be a nervous year for Gulf coast residents.

Even though I'm a scientist-in-training, I share those gut feelings. I think it's some weird sixth sense that some of us have, whether it's founded or not. What happened to Charley (very rapid intensification) is a very good indicator of what can happen in the gulf this year with the steambath waters and such.

[B-Bear]

Well, it has been a very temperate summer. Much cooler than usual in many parts of the nation. If I understand it correctly, the high pressure systems that are bringing this cooler air down from the north can act as magnets to the tropical systems if the cold air gets far enough south--and it is making it farther south earlier than usual. So we've got cooler than normal air plunging further south than usual plus storms coming off of Africa further south than usual, so more of them are likely to get across the Atlantic and work their way up into the Gulf. That's what leads me to my unscientific gut feeling that at least one of them, if not more, is going to yet clobber the Gulf coast somewhere this year.