La nina trying to dominate the pacific

[cycloneye]

http://www.pmel.noaa.gov/tao/jsdisplay/ ... y_ps32.gif

http://152.80.49.210/products/OTIS/US05 ... nomaly.gif

http://www.bom.gov.au/climate/ahead/ENSO-summary.shtml


No question that the recent data shows by the numbers that la nina is already taking over in the equatorial pacific.The only area that has + readings is the el nino 4 one where +0.5 temps are found but the rest of el nino areas1-2 off southamerica and el nino 3 in the central pacific are cool so my question is when NOAA will declare officially that la nina is out there.The models are too conservative on their data but I guess that some of them will go for cool conditions or la nina in the next few months as they update every month.

Folks a busy season ahead as my outlook said but steve said something important in another thread and that is this season may be more active than all the forecasters are predicting and he may be right and that is a scary thought. :o

[ColdFront77]

Sounds interesting. This season and the next few have been forecast to be around average and at least slightly above. I wouldn't be too surprised if we have a very active season. Last season could of been a lot "calmer."

[Anonymous]

I have to disagree. El Nino may be gone, but La Nina is no where near present. ENSO is currently neutral, and I expect it to remain so for a few more months at least. If you look at the subsurface temp anomaly data, you'll notice how the cool tongue has deteriorated quite a bit, delaying the La Nina development even more, as it now has some reviving to do.

I'm not saying we won't see La Nina at all this year, just saying that it won't arrive until much later. Now will it come in time to enhance hurricane activity this season? That, I will not say until our 2003 season forecast comes out at the end of the month. I will say this...it's gonna be CLOSE.

[cycloneye]

Rob those are fluctuations that happen as the temps go up and down in occasions but the general trend has been for the past few months moving from el nino phase to neutral-weak la nina and that is where we are now.

[Anonymous]

Rob those are fluctuations that happen as the temps go up and down in occasions but the general trend has been for the past few months moving from el nino phase to neutral-weak la nina and that is where we are now.

Exactly. I didn't say the weakening of the subsurface cool tongue was a trend, but still, it will take a few months to regain intensity. Thus, the development of La Nina will likely be delayed to later in the summer or fall (as opposed to very soon).

[Kevin_Wx]

FWIW, if you look back in history, some of the worst hurricane seasons have actually come in years with neutral ENSO conditions. But many of the other factors *may* be favorable this year. Rob, TWW, and I will give more details about this when the seasonal comes out.

[Derek Ortt]

We are still in an el nino, though its days are numbered. We may be in a very weak nino at the start of the season, but it should go to neutral based upon the current trends. As long as 3.4 and 4 remain above normal, that is a nino

[WidreMann]

As of the 30th, 3.4 has just gone below normal. Every new map on OTIS has the cold water further and further west and it remains cold in the east with some fluctuation. The SOI is finally beginning to be more consistently positive, though it looks like it might go negative for a little bit over the next few days.

Supercane, I don't see the weaking of the subsurface cold tongue. Can you post a link since the CPC hasn't updated that since the 16th (when it was actually strengthening).

[Anonymous]

April
http://www.bom.gov.au/bmrc/ocean/result ... 03/Apr.gif

May (so far)
http://www.bom.gov.au/bmrc/ocean/result ... 03/Apr.gif

Notice how the cool tongue has weakened some since last month. Fluctuation? Probably. But will it slow the La Nina development process? Again, probably.

[Kevin_Wx]

Ya, SC, this Nina is kind of like the one in 1995. That year had a strong subsurface SSTA cooling that backed off in May. But in August, it came on bigtime. I think that is something we can watch for this season.

[WidreMann]

I see. However, the warm anomalies are also decreasing. So it shouldn't really come back as such, it just may slow down the current rapid cooling trend.

So, what effect does a neutral ENSO have on the hurricane season?

[cycloneye]

With el nino now almost gone and by the time the season is in a full pace by august neutral conditions that means that el nino not present wont have the inhibitor effect for the season as it had when october came last year to shut that season early.

In other words more active than 2002 because no el nino means no sutting down but on the contrary more positive for developments when it is neutral.