Where is the El Niño?

August SST anomalies in the tropical Pacific

August SST anomalies in the tropical Pacific

Earlier in the year, it seemed almost a certainty that El Niño would develop in the tropical Pacific. As we moved through the spring and summer, the tropical Pacific began to warm and it looked like we were well on our way to seeing an El Niño develop. Then, it just stopped.

In recent weeks, the tropical Pacific has actually cooled significantly, especially in the

October SST anomalies in the tropical Pacific. Notice the cooling along the Equator

October SST anomalies in the tropical Pacific. Notice the cooling along the Equator

central Pacific. Just compare the two SST anomaly maps from August and now. You can clearly see a substantial decrease in SST anomalies across the tropical Pacific.

So what happened? It’s hard to say. The latest report from Australia’s Bureau of Meteorology site addresses the retreat in SST values across the region that was warming up until recent weeks. It seems that the pressure pattern across the Pacific changed and the abnormally weak trade winds picked up, cooling the sea surface rather quickly.

Sub-surface temperatures in the tropical Pacific. Notice the distinct cooling in recent weeks

Sub-surface temperatures in the tropical Pacific. Notice the distinct cooling in recent weeks

It is also very interesting to note that the sub-surface temperatures also have declined in dramatic fashion since the late summer. While there was a growing pool of warm water since the spring, it suddenly cooled and now we have a noticeable large area of cooler than normal sub-surface water across a large section of the Pacific. This means that the chances of seeing a true El Niño are getting quite slim.

Why is El Niño even an issue? Well, aside from the weather patterns that El Niño tends to have an influence on globally, if we look at the Atlantic hurricane season specifically, there tends to be a suppression of overall activity. This is mainly due to the increase in tropical convection over the Pacific which is due to the increase in sea surface temperatures because of the El Niño. Persistent tropical convection over the Pacific will usually mean stronger upper level winds and sinking air across the tropical Atlantic. These two negative factors limit the amount of development typically seen in the Atlantic main development region. It’s interesting that the end result seems to have been present this season. In other words, we have seen a limit to the numbers of hurricanes that have developed in the deep tropics. In fact, the ONLY major hurricane to form did so well outside of the typical breeding grounds and was very short-lived.

I do not understand why we had the effects of El Niño without the El Niño itself. Perhaps the atmosphere was responding as if there was an El Niño coming on even though the tropical Pacific was not quite there yet. Who knows? It’s all so complex and there are many interactions between the ocean and atmosphere that it’s difficult at best to know the real reasons behind some of this.

The bottom line is that El Niño has been put on hold, or so it would seem. It may be that it never fully takes root and this could have an effect on the upcoming winter season and most certainly the 2013 Atlantic hurricane season. None of the reliable climate models indicate an El Niño for the early part of 2013 and one could reasonably assume that there won’t be an El Niño during the peak of next year’s season in August-September-October. And yet, even with the near-El Niño observed this season, the Atlantic still has managed to produce eight hurricanes total. This is above the 100 year average. And, on the topic of abnormal sea surface temps, the tropical Atlantic was thought to have been cooler than normal this season. It wasn’t and still isn’t. In fact, a good deal of the tropical Atlantic is running nearly 1 degree C above normal right now. I guess there is a lot we still do not understand about our oceans and the atmosphere.

I’ll have another post here later this afternoon to address the current goings on in the tropics and what we might expect with 98L.

 

Share

Favorable MJO pulse could lead to more development but not where we would expect

ECMWF indicating a more favorable MJO pulse coming for the Western Hemisphere

ECMWF indicating a more favorable MJO pulse coming for the Western Hemisphere

It’s October and climatology would suggest that we would be looking in the western Caribbean or Gulf of Mexico for the best chance of development right now. While this may be the favored region, the tropical Atlantic is not quite ready to shut down just yet and we may actually see something develop out that way over the next several days.

Right now, the MJO pulse for enhanced upward motion and tropical convection is still weak and centered over the west Pacific. However, it looks as though the MJO will strengthen and begin to shift eastward around the tropics, heading in to the Western Hemisphere soon.

Add to this an existing area of low pressure associated with a tropical wave over the deep tropical Atlantic and we may yet see another named storm before all is said and done. The arrival of the favorable MJO pattern could be the spark needed to get this disturbance, actually labeled as 98L, to spin up and be some thing to track.

Looking at the various global models, the GFS seems to be the most ambitious with development though it does not take place until about a week out. I am leery about putting too much faith in any model that indicates development that far out in time. However, considering the favorable conditions that look to be present, I would not rule out the possibility that we will in fact see 98L slowly come together over the next several days.

In addition, it looks like the steering pattern will more typical of summer than fall and as such, 98L may track fairly far to the west over time and not turn out to the open Atlantic like Nadine and Oscar did. I suggest that interests in the Lesser Antilles pay close attention to 98L over the next week. It is possible that some impacts will be felt in the islands but to what extent, it’s hard to say.

Elsewhere, 97L remains off the coast of the Southeast U.S. and is bringing showers and some thunderstorms to the Bahamas but that’s going to be the limit of the impact from this system. Upper level winds will preclude any significant additional development.

In the east Pacific, TS Olivia will track south of west in the coming days and fizzle over the cooler Pacific waters. In fact, the Pacific is quite a bit cooler than the major climate models were predicting for this time of year, a sign that the much talked about El Nino has not come to pass. This may have an impact on the remaining weeks of the Atlantic hurricane season since El Nino conditions typically thwart late season Atlantic/Caribbean development. There are no other areas of interest in the east Pacific to monitor right now.

For those who have our iPhone app, be sure to catch today’s Hurricane Outlook video which will be posted within the hour. I’ll go over in extensive detail all of the topics in the blog post plus take a look at the state of the ENSO and how much the Pacific has cooled in recent weeks. I’ll have more here tomorrow.

Share

MJO heading to more favorable status but will it lead to more development?

ECMWF MJO Forecast

ECMWF MJO Forecast

The hurricane season continues to move right along with tropical storm Oscar on the maps this morning. In fact, the NHC has been writing advisories continuously on something in the Atlantic Basin since Ernesto back on August 1. Fortunately, things have been relatively tame with no major hurricanes impacting land areas.

Oscar will soon be gone and we might actually have a period of time where there is nothing to track. Imagine that.

How long will that last if indeed it does happen? One clue is to look at the upcoming MJO or Madden-Julian Oscillation pattern. Both the GFS and the ECMWF forecast it to move out of the western Pacific and in to the east Pacific and perhaps in to the western Caribbean area. This will take a couple of weeks but I believe that once we see the wet phase of the MJO move in to the region that is normally favored for development anyway, that we’ll see at least one more hurricane. Odds are it would form somewhere in the western Caribbean and while it is certainly not a guarantee, the ocean heat content in that region is very high and almost completely undisturbed this season. It will be interesting to see if the projected MJO pattern comes to pass and what enhancing effect it might have on development chances later in the month.

Otherwise, the tropics are quiet though the global models are developing a weak low pressure area out of a disturbance that is currently dropping southwest between Bermuda and Puerto Rico. It does not seem likely that it will have much chance to develop in to anything significant but it could bring some squally weather to the southeast Bahamas over the next few days.

I’ll be covering all of these topics in the daily hurricane outlook video blog for our iPhone app, so if you have it, be sure to refresh the video page later this morning for the most current video discussion.

 

Share

New depression forming in the open tropical Atlantic as we prepare to say goodbye to Nadine

96L and TS Nadine

96L and TS Nadine

It looks like invest 96L will be our next tropical depression at anytime. It’s situated over warm sea surface temps and upper level winds are somewhat favorable for continued growth. I suspect it will become tropical storm Oscar before all is said and done.

The track is likely to be a quick turn north and then northeast as the lack of deep layer high pressure in the eastern Atlantic means that nothing can get very far to the west right now. After this system passes, we should be done with the Cape Verde season.

Meanwhile, Nadine is weakening and is about to turn north and head out in to the colder waters of the Atlantic. This will mean the end of the long-lived storm that twice became a hurricane. I wonder if the staff of the NHC will miss writing advisories for Nadine? Probably not.

Looking down the road in to the longer term, the global computer models do not show much of anything developing in the western Caribbean which is where we typically watch for tropical cyclone formation this time of year. The MJO pulse is currently not favorable for the Atlantic Basin and unless that changes, I think it will be tough to get development. However, once we get past the mid part of the month, I have a feeling, based on past experience, that we will see at least one more storm or hurricane get going somewhere in the Caribbean Sea. So far, nothing has managed to do so since Ernesto back in early August.

I am still on the road shooting interviews for the documentary that I am producing. I have interviewed nearly a dozen people so far and have some great real life stories of how they deal with hurricanes. I will add several more of those stories today and tomorrow before finally returning home to begin working on even more interviews in North Carolina. It’s amazing to see the areas affected by such hurricanes as Charley, Ivan, Katrina, Rita and Ike (and of course most recently Isaac) this many years later. In some areas much progress has been made while in others, just overgrown empty lots stand as reminders of the powerful forces of Nature that overwhelmed the region several years ago. I hope to convey this sense of living with hurricanes in the documentary. The people are what makes it so special and their sense of pride in their communities is touching and can be a lesson for other parts of the country that have to deal with adversity on many levels.

I’ll have more here tomorrow.

Share

Nadine has a ticket out of town as we await the possible arrival of Oscar

Nadine and 96L

Nadine and 96L

As of 5am ET, the NHC had written 75 advisories on Nadine. They began almost a month ago and have just a few more days to go until it looks like the long-lived system will finally hitch a ride in to the North Atlantic and fade away.

So what happens next? Well, we do have a new invest area, 96L, to monitor as we begin October. The NHC gives it a 30% of developing in to a tropical depression over the next couple of days. Several of the global computer models also develop it which is fairly rare for this time of year. The seedling is a tropical wave that emerged from Africa recently. We normally don’t look for development that far east this time of year but it does happen every once in a while.

Even if 96L does go on to develop, it won’t last too long nor will it be a threat to the Caribbean or elsewhere. Upper level winds are just too strong to allow for significant strengthening and the steering pattern remains favorable for avoiding interaction with land.

Beyond this week, I see nothing in the long range model guidance to even remotely suggest we will see anything else develop. This can change, sure, but so far, the outlook is good as we begin the month.

I am currently in Louisiana as I continue my work gathering interviews for the documentary that I am producing. Today, I will head over to Texas and the Bolivar Peninsula which was heavily damaged by hurricane Ike four years ago. I’ll end up in Houston before heading back east tomorrow afternoon to pick up more interviews along the way home. I’ll post updates here each day throughout the week.

Share