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The
Neverending Deluge: Pacific Heat + Fixed Jet Stream Parks Anomalous
January Cyclone Lingling Over Philippines For Two Weeks
24
January, 2014
The
vulnerable island chain that is the Philippines already sits on the
firing line of tropical storm devastation. During a typical year,
about 20 tropical cyclones roar ashore, wrecking all sorts of havoc.
In a typical year, this amazing parade of such cyclones begins in
June.
But
now it appears that weather in the Philippines, which was already
rather extreme, has gotten much worse. For so far, this island nation
has been treated to a tropical storm season that hasn’t ended for
at least 20 months. The storm season didn’t end in 2013, when
January 1rst saw the formation of that year’s first tropical
cyclone. And the season didn’t end with the winter of 2014 when the
devastating rainmaker that was Tropical Storm Lingling formed on
January 10th.
(Lingling
Track. Image source: Commons)
Lingling
developed to the east of the Philippines over a
pool of abnormally hot and deep warm water.
Temperature anomalies for this region ranged up to 2.5 C above
average. Perhaps more importantly and more ominously, the depth of
this abnormally warm water extended far below the surface.
In
a Deepening Pool of Hot Water
Such
strange and anomalous conditions are expected under a regime of
intensifying human-caused warming. In the hottest regions of the
ocean, evaporation is expected to intensify as warmth increases.
Eventually, the surface water becomes saltier as it becomes hotter,
causing it to sink. This mechanism transfers heat deeper and deeper
into the world’s tropical oceans. This
process is the start of a dangerous ocean turnover. One related to
hypoxia, ocean current changes, and stratification.
And it appears that just such a perilous heat transfer is beginning
in a region of the Pacific east of the Philippines.
We
won’t go too far into detail about the initial signs of tropical
ocean warming and turnover or its other hazards and implications
here. However, suffice it to say that a deepening hot water pool in
this region of the world appears to, at this time, be having a
profound impact on storm formation and strength. Namely, it has
spawned the almost constant progression of storms mentioned above. A
hurricane season without end for two years. It is also the mechanism
that, according
to NOAA fueled the extraordinarily powerful Typhoon Haiyan, one of
the strongest storms on record, which devastated the Philippines in
November of 2013.
Now
the same zone has spawned the epic rainmaker that is Lingling to
again harry the Philippines just two months later.
The
Storm that Wouldn’t End Forces More Than a Million to Flee
Lingling
formed over this anomalously deep, hot water then marched in through
the southern reaches of the Philippines where it has been dumping
copious amounts of rain over the islands ever since. You can note the
almost zero movement of the cyclone from January 11 to January 23 in
the MODIS image sequence below:
By
January 22nd, over the course of 11 days of near-biblical flooding,
the
storm had inundated some parts of the Philippines with an astonishing
52 inches of rainfall,
more than the amount New York receives in an entire year. By
today, the never-ending deluge had resulted in 1.14 million
evacuated, 63 missing, and over 54 lost lives.
Numerous bridges and dams were also destroyed by the flooding, along
with hundreds of homes. This, just two months after the strongest
tropical cyclone ever to make landfall struck the northern part of
this vulnerable island chain.
And
with the anomalous January formation of a devastatingly persistent
Lingling, there is simply no respite.
Jet
Stream Lag, Stalled Fronts, and Hot, Deep Water
Lingling’s
persistence over the Philippines for so long can be attributed to
numerous factors. First, the storm was caught up in a stalled frontal
boundary whose tail end had snagged over the Philippines for about 15
days running. The front itself was caught up in a Jet Stream trough
shoved south by a disrupted and collapsing polar vortex (one
that currently appears to be in the process of getting ripped in
half).
So Lingling became indirectly linked with polar amplification related
events further north.
The
stalled frontal boundary and related Jet Stream lag also resulted in
Lingling remaining parked over hot Pacific waters of great depth.
Normally, the cyclonic action of the storm would pump cooler, deeper
waters to the surface and result in the storm’s weakening.
Unfortunately, the deeper waters were also quite warm, so Lingling
maintained enough strength to continue dumping epic amounts of rain
over the Philippines for two weeks straight.
(Lingling,
lower left, entangled in frontal system stretching all the way across
the western Pacific on January 20, 2014. Front entanglement in a
fixed Jet Stream pattern and related stalled frontal boundary helped
result in Lingling’s 2 week persistence. Image source:
Lance-Modis.)
This
combination of conditions: hot, deep water, exceedingly early
tropical storm formation (such that there is essentially no end to
the Pacific cyclone season) and a lagging, persistent Jet Stream
pattern resulting in an entirely abnormal storm event are unlikely to
have occurred without the added weather forcing of human caused
warming.
Unfortunately,
the Philippines, at least for this year as in 2013, are likely to
expect storm formation and impact to continue on throughout the year.
Water conditions are certainly warm enough. So we will likely see the
current 20 month storm season continue for another 11. A shift in
winds, blowing the warmer waters east with an El Nino might bring
some brief respite. But with human caused climate change pushing
temperatures ever higher, we are likely to see the waters continue to
warm, eventually over-riding such variability. In the end, the
Philippines is indeed likely to see a never ending storm season.
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