Atlantic hurricane season 07

[Gray-Wolf]

NOAA have confimed La Nina forming quite rapidly so maybe a busy season in the offing?

[kold weather]

Quite likely, I do think this is developing a look of a active hurricane season, mind you how strong i still wouldn't like to say till i see how much dust is coming off Africa, there was a huge outbreak last week and its something to balance with.

Worth noting that La Nina tends to favor Atlantic storms rather then GOM storms but any that do get in could well end up being quite strong given recent years trends.

Odds are stacked however against a season like 2005, because they are super rare, and require so many things to fall in place, probably a noce in 50-100 year season that one...not to say we can't have very active seasons mind you, I'll say we have a good 40-50% chanc eof this being in the top 10 mowst active seasons in terms of ACE ever, at least right now.

[tinybill]

Quite likely, I do think this is developing a look of a active hurricane season, mind you how strong i still wouldn't like to say till i see how much dust is coming off Africa, there was a huge outbreak last week and its something to balance with.

Worth noting that La Nina tends to favor Atlantic storms rather then GOM storms but any that do get in could well end up being quite strong given recent years trends.

Odds are stacked however against a season like 2005, because they are super rare, and require so many things to fall in place, probably a noce in 50-100 year season that one...not to say we can't have very active seasons mind you, I'll say we have a good 40-50% chanc eof this being in the top 10 mowst active seasons in terms of ACE ever, at least right now.

as for the 07season being the uk and the alantic with all the lows which seems to be there at the momemt i am thinking this season could be a lot more in a way of storms as last year was a non avent , ,and this year uk summer could be a lot wetter if the hurrican season is more liverly ,

Edited March 3, 2007 by tinybill

[tinybill]

as for the 07season being the uk and the alantic with all the lows which seems to be there at the momemt i am thinking this season could be a lot more in a way of storms as last year was a non avent , ,and this year uk summer could be a lot wetter if the hurrican season is more liverly ,

here a link

http://www.hurricanealley.net/swp.htm

[kold weather]

Couple of days late but here is the latest for the Pacific situation right now...and its one where La Nina is rapidly forming, quite a bit faster as well it appear then the world organisations predicted:

Summary: Pacific Ocean continues to cool

The eastern equatorial Pacific Ocean has continued to cool rapidly following the demise of the El Niño event. While current conditions are neutral, the cooling has increased the likelihood of, though not guaranteed, a switch to La Niña conditions over the coming months. The Trade Winds have mostly been close to or somewhat stronger than normal since December, the SOI has been neutral for three of the past four months and is now close to zero and cloudiness has shifted to the western Pacific. There would now appear to be little chance of a return to El Niño conditions in 2007, with a continuation of neutral, or a switch to La Niña conditions, the more likely scenarios.

In Brief

Equatorial Pacific SSTs have further cooled and anomalies are below zero in the eastern equatorial Pacific.

Negative subsurface anomalies have strengthened and reached the surface in the eastern Pacific.

The SOI has a current (5th March) 30-day value of zero.

Trade Winds have generally been close to or somewhat stronger than average in the western Pacific during February.

Cloudiness near the date-line has recently been close to or slightly below average.

Most computer models predict further cooling of the Pacific during the first half of 2007.

As for the Atlantic, temps warming up quite neatly out there right now, the gulf is still cooler then average but as its shallow water compared to the Atlantic that will likely warm-up quite rapidly under a more favorable pattern. Temps are warmer then 2006 at the same time, not seen a comprasion to other years mind you. heat content is also incresing quite sharply in the eastern Caribbean and west Atlantic which isn't good if it continues in a La nina set-up, IF La nina comes along.

Edited March 9, 2007 by kold weather

[summer blizzard]

http://jisao.washington.edu/pdo/PDO.latest

Sorry, i was wrong, February recorded a neutral to positive PDO, anologues for years in which both January and February recorded a neutral to positive PDO are:

2005

2004

2001

1997

1996

1993

1992

1982

1960

1958

http://www.cdc.noaa.gov/Correlation/mei.data

February recorded a weak El Nino figure of 0.5, the anologues for a moderate El Nino January followed by a weak El Nino February are:

2003

1995

1988

http://www.cdc.noaa.gov/Correlation/qbo.data

February recorded a neutral to weak westerly QBO, as did January, anologues for this are:

2000

1979

1962

1960

http://www.cpc.noaa.gov/products/precip/CW...ent.ascii.table

No value has been given for Januarys AO value however it was deinitely positive to very positive, February recorded a negative AO value, the anologues for this pattern are:

1983

1957

These are the current two month anologues for January and February, as you can see, the current ENSO signals strongly supposrt a very active hurricane season.

[kold weather]

Intresting one of the years that you mention in the AO section was the least active ever!

In other words tohugh SB there is no one year that really stands out as a match, at least out of the variables.

Hard to call this summer still at this stage though i think we'll get a better idea a month from now how the ENSO signal is and the temps in he tropical part of the Atlantic.

I'll be really intrested to see what years had a negative NAO between March-May, this IMO has a more important role then the AO. A strong Azores/Bermuda high usually supresses hurricanes a little, though in recent years the high pressure belt has been so far north its not quite had such an effect as it did in the past though last year the Bermuda high did make an impact of sorts along with the el nino.

[Thunder Snow]

Atlantic Hurricanes 2007 Names

Andrea

Barry

Chantal

Dean

Erin

Felix

Gabrielle

Humberto

Ingrid

Jerry

Karen

Lorenzo

Melissa

Noel

Olga

Pablo

Rebekah

Sebastien

Tanya

Van

Wendy

I wonder where we will get to.

[summer blizzard]

Intresting one of the years that you mention in the AO section was the least active ever!

In other words tohugh SB there is no one year that really stands out as a match, at least out of the variables.

Hard to call this summer still at this stage though i think we'll get a better idea a month from now how the ENSO signal is and the temps in he tropical part of the Atlantic.

I'll be really intrested to see what years had a negative NAO between March-May, this IMO has a more important role then the AO. A strong Azores/Bermuda high usually supresses hurricanes a little, though in recent years the high pressure belt has been so far north its not quite had such an effect as it did in the past though last year the Bermuda high did make an impact of sorts along with the el nino.

That is all true, though i would say the state of the PNA is more important than the NAO, a positive PNA will favour recurviture in the Atlantic, while a negatve PNA favours the Gulf Of Mexico, obviously the NAO does have some effect, though i suspect that it meerly backs up the PNA state.

Taking each teleconnection, i thought i would post the average number of storms from the current anologues...

AO: 6

Both AO anologues favour a below average hurricane season.

QBO: 9

There is an even split between anologues favouring a below and above average hurricane season.

PDO: 12

A more or less even balance.

MEI: 16

Strongly favours a above average hurricane season.

Averaged: 11

[kold weather]

Well here is the latest offical forecast, suggesting a very active season:

http://hurricane.atmos.colostate.edu/Forec...2007/april2007/

I have to say I'm still happy with the forecast of a season akin to 1995. The differences that there are between 1995 and 2007 maybe enough to make it a slightly lower number then was the case in 1995, however in return I think we could see more hits then that year.

Offical start of the season now less then 2 months away but now we ar ein April its not impossible for sub-tropical storms to get going so we increasingly need to be wary of such systems devloping.

Anyway just watch the media hype get going now that forecast has been pusblished!

My numbers right now---16/10/6

Slightly lower then expected in terms of named storms but higher for hurricanes and Major hurricanes, because i expect a fair few long range trackers.

Edited April 3, 2007 by kold weather

[summer blizzard]

I will make a preliminary forecast once the March data is available, but needless to say, i expect an above average huricane season, and contrary to Kold Weather, i expect a Gulf Of Mexico season.

At the current moment in time, i may actually go for something between 1995 and 2005, this is because in my opinion, an easterly QBO is better than a westerly QBO for an above average hurricane season, this means that aside from the QBO, all other teleconnection must have been set up so perfectly, that it was enougth to overpower the westerly QBO.

Conditions this year, seem to be very close to 2005 aside from a greater La Nina and a less easterly QBO, so i will not be forecasting a record breaking season.

Edited April 3, 2007 by summer blizzard

[Gray-Wolf]

Some new research from NOAA et al suggests that increased wind shear (caused by global warming) will make 'bigger Hurricanes/more frequent Hurricanes" less sustainable in the future. Hmmmm.....

[Mondy]

Y'know... it's kinda annoying to watch these scientists do their studies, come out and tell us global warming causes more hurricanes... then come back in a while and say it causes fewer...

Or that it causes more this, or... wait... it really causes less this...

The fact of the matter is.. they don't know. Nobody does.

Roll on June 1st and let nature take its course with regards hurricanes, not "climate specialists".

[summer blizzard]

The March data is available, so i will make a preliminary forecast within the next week.

[kold weather]

As for that study, its an intresting one however it is also only based on models, and over the past 15 years the trend has been for decreasing shear so at the moment the actual trend isn't following that model, though I suppose it could occur I've got no real reason to say why it can't.

Saying that though if we follow logic that the pressure belts are moving northwawrds then surely that leaves more 'space' so to speak for waves to traverse across the Atlantic so there surely would be a greater chance of storms developing, and then you've also got the increase in SSt's which is really helping to cause more intense storms.

[summer blizzard]

I think they mean that more frequant El Ninos will cause this.

[Gray-Wolf]

I get the feeling that our 'understanding' of what changes to expect are in flux.

We know the warming is set to continue so SST's will rise and isotherms will continue to move north. You could be right about the El-Nino frequencies increasing leading to more sheer over the Atlantic (but that would mean less disruption over the Pacific) but if the last little El-Nino is anything to go by changing oceanic currents/oceanic mixing could help limit their impact.

I think I'd go for more severe storms reaching the northern extremities of the 'hurricane belt' and more 'Hybrids' making N.African/SW European landfall.

As K.W. points out ,with more 'Hurricane nursery' available you'd tend to expect more Hurricanes.

[kold weather]

SB-No I've seen another copy of this and its not El nino, its the Walker circulation shift that is progged to change the jet stream axis and cause more shear in the tropical paret of the Atlantic as the pressure belt also strengthens, causing a pressure graident to grow I'd guess. What they did say is the effect is rather similar to El nino.

Gw-Logical thinking would suggest your right about the chances of more northern hurricanes because the SST's that can support are seemingly getting bit by bit further north and also the upper part sof the Atmosphere do seem to be cooling just a touch which leads to greater lapse rates, maybe only by 1-2C but in the right condtions thats as much as 50-60mph difference in max strength.

[Calrissian]

I look forward to more of those hybrid storms. October 2007 will mark 2 decades since the Biscay bomb hit the UK, maybe we'll get lucky this year?

--

Anyway, am looking forward to the new storm season, I can't wait for this new season of entertainment. Endless TV feeds of doom and destruction, it doesn't get much better

Calrissian: Awaiting Andrea

[summer blizzard]

http://jisao.washington.edu/pdo/PDO.latest

Sorry, i was wrong, February recorded a neutral to positive PDO, anologues for years in which both January and February recorded a neutral to positive PDO are:

2005

2004

2001

1997

1996

1993

1992

1982

1960

1958

http://www.cdc.noaa.gov/Correlation/mei.data

February recorded a weak El Nino figure of 0.5, the anologues for a moderate El Nino January followed by a weak El Nino February are:

2003

1995

1988

http://www.cdc.noaa.gov/Correlation/qbo.data

February recorded a neutral to weak westerly QBO, as did January, anologues for this are:

2000

1979

1962

1960

http://www.cpc.noaa.gov/products/precip/CW...ent.ascii.table

No value has been given for Januarys AO value however it was deinitely positive to very positive, February recorded a negative AO value, the anologues for this pattern are:

1983

1957

These are the current two month anologues for January and February, as you can see, the current ENSO signals strongly supposrt a very active hurricane season.

The March data is in....

1960 is the only PDO match, 1960 observed a neutral to negative PDO during the hurricane season, this strongly corelates with a negative PNA and slightly negative AO, this will have the effect of encouraging a suppressed storm track (Gulf Of Mexico season).

The MEI data is in, and all three previous anologues are no longer valid, the new anologues are:

1994

1991

1986

1984

1982

1981

1979

1977

1970

1969

1959

1957

1954

1953

1952

The March QBO data is in and still has a neutral to weak westerly value, the 1979 anologue is still valid, and observed a strong easterly QBO the following hurricane season, this indicates weakened trade winds and encourages an active hurricane season.

The AO data is in and as with the MEI, no anologues are valid any more, indicating a big change, the new anologues are:

1997

1994

1989

1986

1982

1968

1967

1959

1953

Having had a look through:

PDO: 7

QBO: 9

MEI: 10

AO: 8

Rather suprising developments in that conditions are actually becoming more unfavourable for a above average hurricane season.

Also, i'm not convinced that La Nina will dip as low as is being forecast, one solution i have calculated is May, June and July observing weak La Nina values but neautral to weak La Nina values afterward.

[kold weather]

Intresting post SB, though I do note only one of your years fall in the active phase of the Atlantic so I think you can't read too much into those other years. 1997 is the only one but lest us forget the 2nd strongest El nino ever was developing as well which is a little different.

[summer blizzard]

Intresting post SB, though I do note only one of your years fall in the active phase of the Atlantic so I think you can't read too much into those other years. 1997 is the only one but lest us forget the 2nd strongest El nino ever was developing as well which is a little different.

Yes, i was very suprised when i computed the results, though i do anticipate large chances in the PDO and QBO anologues for next month, my 2007 hurricane season forecast should be released around the 20th May all being well.

[summer blizzard]

The April QBO data is available, and 1979 and 2005 are the anologues i will be including in my 2007 hurricane season forecast.

[summer blizzard]

The April AO data is available, 1997, 1994, 1986, 1968 and 1959 are the anologues i will be including in my 2007 hurricane forecast.

[tinybill]

The latest forecast which was issued on the 3rd of April 2007 by Philip J Klotzbach, William M Gray and assistance from William Thorson of the Colorado State University, brings some significant concern.

Below is the current forecast with the numbers in brackets being the averages and the second set of numbers signaling what is currently being forecast.

Number of;

Named Storms (9.6) - 17

Hurricanes (5.9) - 9

Hurricane Days (24.5) - 40

Intense Hurricanes (2.3) - 5

There is also a 74% probability for at least one major hurricane (category 3 or higher) to make landfall anywhere on the US coastline.

The above information is just a general guide and it is very difficult to specifically say how active the hurricane season will be. Overall however it does make for worrying times, because with the recent reduction in the intensity of El Nino, the signs are there for quite an active season!.