Second
Monster Kelvin Wave Forming? West Wind Back Bursts North of New
Guinea Rival Intensities Last Seen in January.
1
July, 2014
This
January, a powerful period of west wind bursts tapped a very hot,
deep pool of Pacific Ocean water and shoved it eastward along the
equator. The hot water was driven downward by Eckman pumping forces
even as it began to propagate across the Pacific. The resulting
Kelvin Wave was, by March, among the most intense sub-sea warming
events ever seen for the Equatorial Pacific during this time of year.
By
late May and through June, this heat had transferred to surface
waters and the Equatorial Pacific, overall, had greatly warmed.
This
initial warming prepped the ocean surface for continued atmospheric
feedbacks and the emergence of an El Nino by sometime during the
summer and fall of 2014. A monster event that, should it form on top
of human-caused warming, could push both global temperature and
weather extremes to record levels never before seen. But for El Nino
to continue to emerge, more strong west wind back bursts are required
to keep shoving the hot pool of Pacific Ocean water eastward,
spreading it out across the Pacific and dumping its warmth into the
atmosphere.
Now,
during early July, just that appears to be happening.
(Strong west wind back burst visible in the Western Pacific north of New Guinea and the Solomon Islands and just north of the Equator. Image source: Earth Nullschool. Data Source: Numerous Including NOAA GFS.)
For
along a synoptic band ranging from the Philippines to north of New
Guinea and the Solomon Islands a powerful zone of west winds has
emerged between two double-barrel low pressure systems. The first set
of lows form a broad counter-clockwise circulation along the 10
degree North Latitude line.
The
second set hovers just south of the equator, forming a clockwise wind
flow. These two wind patterns merge in a significant back-burst
pushing against the traditional flow of the east-to-west trades.
Wind
speeds in the anomaly zone are in the range of 30-40 kilometers per
hour with higher gusts, or currently just shy of the wind strength
observed during the very strong January west wind back burst.
Strong
West Winds Tapping Pool of Very Hot Water
It
is worth noting that winds in this region have been slowly
intensifying over the past few days. So any further increase in
strength would make this event easily comparable to the January event
that spawned such a powerful Kelvin Wave.
Surface
waters in this west wind zone range from 86 to upwards of 90 degrees
Fahrenheit over a broad zone along the equator and northward to a
very hot pool just east of the Philippines. Eastward and downward
propagation of such intensely hot water, driven by these strong west
winds has the potential to generate a second strong Kelvin Wave. The
back-burst winds we are seeing now are strong enough to generate such
a wave and the sea surface temperatures in the region are at very
high positive anomalies, especially in the region east of the
Philippines. Propagation of a second strong Kelvin Wave would spike
0-300 meter temperatures again and would lock in the formation of the
expected El Nino later this year.
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