Thursday, July 14, 2016

Where's La Niña?

Earlier this year before the start of hurricane season, most outlooks were taking into account the death of El Niño and the birth of La Niña. This would mean more favorable conditions for tropical systems to grow.  But with a steady plume of Saharan Dust dominating the Atlantic Ocean, systems have been scarce, and that's fine with us.

So where are we now?
The color enhanced satellite image shows that most of the Equator across the Pacific is white to blue.

This suggests that water temps are near typical values or just slightly cooler.

Waters to the north and south of the Equator are running a little warmer but this is normal as well.

In June NOAA reported:
"After dominating the tropical Pacific for more than a year, El Niño ended in May 2016. Near- or below-average temperatures existed in 3 out of 4  (El Niño Southern Oscillation or ENSO for short) monitoring regions of the tropical Pacific. And for the first time in 2016, wind and air pressure patterns were consistent with neutral conditions. There's a 75% chance that La Niña will develop by winter."

What's the latest on La Niña?
As of July 14th, NOAA seems to think if it does develop it may be a weaker event. They add:

"Compared to last month, models have slightly backed off their confidence—from 75% to 55-60%—that La Niña will occur this fall and winter. While tropical Pacific waters have cooled, the trade winds have not showed the La-Niña-like strengthening needed to amplify cold-water upwelling. The current outlook favors a weak event, but remember: impacts aren't always tied to event strength."
What does this mean for the rest of hurricane season?
If indeed we get a weak La Niña, then we may not see increased activity. Add to that, so much Saharan Dust in the atmosphere, and storms may not be as frequent for the rest of the season. The fly in the ointment to all this will be the arrival of Cape Verde season which typically kicks off in August. Here we keep our eyes on the West Coast of Africa as more tropical waves tend to start their cross Atlantic voyage and aim for the Caribbean and US East Coast.

Also, the peak of hurricane season is mid September, when we usually see the most tropical activity. We may still get a few storms and a hurricane or two in the Atlantic basin, but with a weaker La Niña expected, this should NOT provide any additional fuel for more storms to develop. Lets hope this is the case.

Here's a little background on El Niño and La Niña.

What is El Niño?
This is a WARMING of the Equatorial waters of the Pacific. It not only impacts marine currents but atmospheric ones as well. It kind of shakes up the planet turning mostly dry areas into soggy ones and wet ones into drier ones. It also keeps hurricane formation at bay.

What is La Niña?
This is a COOLING of the Equatorial waters of the Pacific. Here too, it impacts both marine and atmospheric currents. In this case, it makes wind patterns in the Atlantic more favorable for storm formation.

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