EPAC has been unusually quiet in 2004

[cycloneye]

Tropical Storm AGATHA
Tropical Depression TWO-E
Tropical Storm BLAS
Hurricane CELIA
Hurricane DARBY
Tropical Depression SIX-E

For a basin that on average has 16 named systems to have only four that had formed is very unusual.At this date august 16 the EPAC has to be in the H name.



This kind of image is very unusual to see how the basin is very quiet.

[PurdueWx80]

El Nino is starting up soon, maybe that has something to do with it.

[Stormsfury]

Boils down to the ATL signals overwhelming the EPAC signals even with Nino WEST/Nina EAST type pattern (overall, neutral) ...

SF

[OtherHD]

El Nino would typically enhance EPAC activity but that cold pool off of SA has been very persistent, so it's not exactly a textbook Hell Nino that we'll be talking about.

[Aquawind]

Sure has been..I wonder why?

[cycloneye]

A combination of factors Neutral ENSO,the trade winds strong,pressure more higher than normal,the PDO,the NAO etc.Any of those factors or more may haved contributed to a quiet EPAC.

[Aquawind]

A combination of factors Neutral ENSO,the trade winds strong,pressure more higher than normal,the PDO,the NAO etc.Any of those factors or more may haved contributed to a quiet EPAC.

Well sure..It's something we know of..or not?..lol

[USAwx1]

No, HD, we wont be talking about a "Hell Nino" anytime soon (which i can only imagine would be along the lines of something such as 1982-83 or 1997-98). A weak or close to Moderate EL Nino for the coming fall and winter? most likely, yes.



The cold pool has been VERY persistent in the EPAC and equatorial thermocline closer to the surface. But that alone does not explain it. We have been seeing this quite frequently regardless of ENSO phase since 1995 --- which leads me to believe that the effects of the ATC cycles on pacific basin TC activity is Inversely proportional to the Atlantic. Or in other words these periods which bring about decadal upturns in Atlantic activity are also correlated with downturns in pacific activity.

lets use 1969 as an example here, since it had an El Nino event ongoing during the Tropical season and was in the Atlantic and pacific long-term cold phases

Atlantic activity:


Little description needed here...we all know very well what type of a season 1969 was in the Atlantic.

Pacific:


Not very impressive at all for an El Nino hurricane season in the Pacific basin. Now compare that with 1982 (Strong EL Nino year in the warm PDO phase):



WOW !! What a difference a PDO cycle makes.

lets look at 1969 SSTA info (by month --- listed below):

1969 6 24.30 1.28 27.09 0.72 28.98 0.34 28.09 0.60
1969 7 22.24 0.39 25.80 0.22 28.75 0.18 27.28 0.20
1969 8 21.01 0.19 25.50 0.55 28.86 0.41 27.33 0.63
1969 9 20.68 0.21 25.44 0.61 29.05 0.56 27.27 0.63
1969 10 21.80 0.88 25.66 0.77 29.19 0.78 27.44 0.85
1969 11 22.33 0.65 25.73 0.78 28.89 0.53 27.24 0.73

Basically warmer than average across the board INCLUDING the 1+2 region. the NINO 3.4 criteria for statistical El Nino conditions was met in 5/6 months of the season.

the QBO was also west

1969 -8.58 -4.43 -1.50 3.98 8.18 9.35 9.08 9.78 9.74 9.75 7.34 5.00

The west QBO may also have a suppressant effect on on Pacific activity so that could be playing a role here as well (Gray 1988).

the QBO is also west this year, not to mention the long term ocean cycles which are favorable for enhanced Atlantic activity. El Nino (or the slight existence of which right now) is having virtually NO effect on helping to mitigate Atlantic activity and similarly doing little to bolster the EPAC season.

[USAwx1]

http://www.weather.unisys.com/hurricane ... /track.gif

1982 in the Atlantic was also disinteresting. Only one major cane (Debby) and 6 NS

So what does this all prove?

We may be able to make the assumption that the long-term cycles in the Atlantic and pacific will have a stronger governing force over short term (seasonal) fluctuations in activity. The QBO phase MAY also play a role with the East phase being favorable for EPAC activity, and the west phase favorable for Atlantic activity.

[weatherfan]

The NAO the last week or so went moderatey negative and there has been some studeys that doing negative NAO periolds there seems to be an increase in tropica activetey something like we just saw this past week with 5 systems that ended up forming.For a Nurtrul year the Epac has been unusaly calm as you said.One could argure the Alantic or other singels might be a factor.But the true fact is that one might not really have an good anwer on why right now on why the Epac has not had a active season. It just condtions have it faverd formation there this year.

[cycloneye]

Thank you USAwx1 for bringing that interesting data and explain in some detail why the EPAC has been quiet for the most part in 2004.Yes the QBO I forgot to mention it in my other post but it is one of the most importat factors being a west QBO enhancing atlantic hurricane activity and supressing EPAC.That is why the atlantic so far in 2004 has 3 hurricanes and from those 2 majors.

[weatherfan]

Agreed 100 percent with you and USA

[weatherlover427]

You are stealing all of our storms! No wonder our monsoon has sucked major (censor) this year! Give them back!

[cswitwer]

I know I saw a link to the abbreviations here on Storm2k the other day, but can't find it. Could someone point me in the right direction? (Looking for things like ENSO, EPAC, ULL, etc)

Thanks!

[USAwx1]

I know I saw a link to the abbreviations here on Storm2k the other day, but can't find it. Could someone point me in the right direction? (Looking for things like ENSO, EPAC, ULL, etc)

Thanks!

ENSO = EL Nino / Southern OScillation
EPAC = East Pacific
ULL = Upper level low.


let me know which others you would like to know.

[USAwx1]

The NAO the last week or so went moderatey negative and there has been some studeys that doing negative NAO periolds there seems to be an increase in tropica activetey something like we just saw this past week with 5 systems that ended up forming.For a Nurtrul year the Epac has been unusaly calm as you said.One could argure the Alantic or other singels might be a factor.But the true fact is that one might not really have an good anwer on why right now on why the Epac has not had a active season. It just condtions have it faverd formation there this year.

the QBO and long term ocean cycles are the best i can come up with right now. Well have to see what happens between now and the end of the season but that is at least IMO 75% of the reason. others may be short term influences such as the MJO cycles etc...

I do agree with you about the NAO and development spurts in the atlantic though.

[cswitwer]

Thanks a lot, USAwx1. I figured out wx on my own (I'm very bright). I'm sure I'll pick up the rest as I go along. I'm pretty new here. But if anything stumps me, I'll ask again. Thanks!

[USAwx1]

Thank you USAwx1 for bringing that interesting data and explain in some detail why the EPAC has been quiet for the most part in 2004.Yes the QBO I forgot to mention it in my other post but it is one of the most importat factors being a west QBO enhancing atlantic hurricane activity and supressing EPAC.That is why the atlantic so far in 2004 has 3 hurricanes and from those 2 majors.

Furthermore, All of our activity this year has developed and been active during the MJO dry phase in the ATL which is unusual.

[USAwx1]

Thanks a lot, USAwx1. I figured out wx on my own (I'm very bright). I'm sure I'll pick up the rest as I go along. I'm pretty new here. But if anything stumps me, I'll ask again. Thanks!

Not a problem, and by the way...welcome aboard!

[frankthetank]

can the sea of cortez (i think thats right) support hurricanes the scale of Charley??? CHarley seemed to do fine in CHarlotte bay (harbor).....