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Aloha from Beautiful Honolulu,

Greetings all. Here goes my first post of the new season.

Well, I've been watching since Mid-May. No doubt about it. Things are starting to get very interesting!

Since mid-May, I've watched as the 'crucial' 26-degree isotherm has steadily tongued it's way westward from Mexico and Central America out into the vast expanse of the Tropical Eastern and Central Pacific Oceans.

It's quite remarkable to see just how closely correlated the extent and intensity of the ITCZ depends on the underlying sea surface temps (SST's).

In short, the ITCZ in the EastPac has *dramatically* expanded in extent and intensity compared to a month or so ago. Of course, all this is quite normal, as we enter the Summer Season and the oceans begin to warm in earnest.

And other seasonal factors appear to be shaping up, as well, including a generally and increasingly favorable upper-level environment and stronger cross-equatorial flow from the southern hemisphere; hence the recent flare-up and westward propagation of a now rather active ITCZ, now extending all the way out into the Central Pacific over the past few days.

My, what a difference a month makes!

For all you 'Met Techies', here's a little something regarding the so-called Madden-Julian Oscillation, which I gleaned from the Tropical Weather Discussion for the EastPac, from a few weeks ago: (Remember, this is from about 2 weeks ago!)

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FINALLY...REAL-TIME NCEP RE-ANALYSIS DATA INDICATE ANOMALOUS CYCLONIC CIRCULATIONS AT UPPER-LEVELS EITHER SIDE OF THE DATE-LINE AROUND 20N AND 20S.

A STREAM OF ANOMALOUS WESTERLY FLOW ASSOCIATED WITH THESE FEATURES...WITH ANOMALIES OF 20 TO 60 KT ABOVE CLIMATOLOGY...EXTENDS FROM THE DATELINE TO FAR E AS 120W. THE STRONG WESTERLY FLOW PRECEDES A MODERATELY STRONG MADDEN-JULIAN OSCILLATION /MJO/ CURRENTLY ORGANIZING OVER THE INDIAN OCEAN...WHICH IS SLOWLY HEADING EAST.

ALTHOUGH THE EXACT DETAILS ARE ELUSIVE AT THIS TIME...THE CURRENT MJO SHOULD SPREAD ACROSS THE REMAINDER OF THE INDIAN OCEAN AND WESTERN PACIFIC IN THE NEXT WEEK OR TWO...LIKELY RESULTING IN AN INCREASE IN THE CHANCE OF TROPICAL CYCLONE ACTIVITY.

THE EXPECTATION IS THAT A SIMILAR INCREASE IN THE CHANCE OF TROPICAL CYCLONE ACTIVITY SHOULD EVENTUALLY REACH THE TROPICAL EASTERN PACIFIC TOWARD THE VERY END OF JUNE OR THE FIRST WEEK OF JULY.



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And, as Hurricane29 pointed out here this past Sunday:

Quote:

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"Interesting to note if the current SOI trend continues it could be a sign that the atlantic basin may not be to far away from coming to life. With an MJO pulse set to move in about 2 weeks time frame, things might get interesting."

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Quote:

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"I am giving some consideration to recent FSUMM5 runs, which have suggested that an Eastern Pacific system forms and runs NNWD, which might make one think it could follow the same route that Alma took before her remnants helped jump over into the Caribbean to help form Arthur. Indeed a new low pressure center appears now to be forming in the vicinity of 90W 7.5N, (now near 99W) ( ... with most models ... ) driving it decidedly west, of course. ... Should the disturbance in the far eastern pacific develop further, and I suspect that it very well might, it would be the next named system out there."

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The latest discussion continues to hint at the likely possibility of TC formation, as the amplitude of this wave is sharpening and effecting the ITCZ:

"TROPICAL WAVE ALONG 99W S OF 14N MOVING W 10 KT. LOW-LEVEL FLOW
AROUND THE WAVE APPEARS TO BE STRENGTHENING AS THE ITCZ IS
BECOMING MORE INFLECTED."

It appears to be organizing by the hour, now that we have a good daylight visual on it, and if trends continue, I suspect there may be a TCFA issued for this disturbance within a day or two.

Another wave is now seen between 120W and 125W, and, although smaller, has some very deep convection also, and apparent increasing organization over the past few hours.

Systems that form 120W, or farther west, are of greater interest to Hawaii than storms forming closer to Mexico. All storms that form here usually head "in the general direction" of the Hawaiian Islands, although very few arrive with much punch left in them after crossing over slightly cooler waters and, more importantly, SW shear that usually protects these Islands from incursions of marauding cyclones from the EastPac.

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Finally, I'll wrap up here with a "late-breaking" note regarding the Madden-Julian Oscillation, from the Climate Prediction Center.

Although the MJO reasoning presented above appears to have correlated well with first Typhoon Fengshen forming a week or so ago, and now the increased activity in the EastPac basin, implying a steady eastward propagation of the MJO pulse, this MAY NOT be the case, after all. Read on!

From the latest "Expert Discussion" (June 23rd) from the good folks at the Climate Prediction Center:

( http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf )


- The MJO has become incoherent during the past week.

- Most MJO forecast tools indicate a generally incoherent MJO signal and combined with the most recent observations it is most likely the MJO will remain incoherent during the next 1-2 weeks.

- The MJO is expected to contribute little to the patterns of tropical convection during the next 1-2 weeks.


(Attachment Provided)

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So it looks like we may have to 'temper' that previous discussion of a few weeks ago, and may not be able to attribute, after all, EastPac cyclogenesis (if any) directly to a (now non-existant) MJO pulse propagating through the basin.

The MJO pulse event predicted two weeks ago appears to have "fizzled" ??

What are your thoughts on this? Is the MJO "pulse" still propagating eastward, but simply 'incoherent'? Does anyone have a better understanding of the MJO? And what are the implications of an 'incoherent' MJO on tropical storm formation in the EastPac and the Western Atlantic/Caribbean over the next few weeks? Would it be a "Non-Factor"? Thanks for your input and insights.

( Former Coconut Grove, Florida Resident from 1977-1980 )


Edited by CoconutCandy (Thu Jun 26 2008 02:16 AM)

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