Milling & Baking News - January 28, 2020 - 30

Weather Outlook

Changing temperatures bring
rainfall across Indonesia
BY DREW LERNER

Scientists continue to learn more and
more about our oceans and atmosphere and how they interact with
each other. Back in the infancy of this
meteorologist's career in the late 1970s
we had little to no clue just how much
the ocean influences weather. Research
over the decades has proven over and
over again that the atmosphere's engine largely is fueled by the sun and
by the oceans.
At first it was all about ENSO (El
Niño Southern Oscillation - including El Niño and La Niña). Now it is
becoming evident that other large
anomalies in ocean temperatures can
radically change weather.
The past few years have driven
this point home with huge regions
of anomalous ocean temperature in
various places in the world resulting
in unusual weather. One such region

was in the Gulf of Alaska in 2017 and
2018, when a super large region of cool
ocean water similar to that which occurred in 1988 evolved, and suddenly
Canada's Prairies stopped seeing rainfall just like in the past. Drought that
began in 2017 became quite severe in
2018 and lingered through early 2019,
but that unusually cold ocean water
anomaly in the Gulf of Alaska translated into a huge region of warmer ocean
water in 2019. It remains there today.
The drought across Canada's prairies began diminishing in the summer of 2019, and it is predicted to fall
away completely in 2020 because of the
warm water bias.
Why has the water temperature had
such an influence? Well, it is all about
water vapor. Anytime you heat up a
body of water - no matter how slight
the warming is - water vapor is released into the air. This is most evident

Average 7-day topsoil moisture
ended Dec. 27, 2019

Average 7-day topsoil moisture
ended Nov. 1, 2019

30 / January 28, 2020

Milling & Baking News

in your kitchen when you start to boil
water. As the pot of water warms, water vapor is released. But you cannot
see it until the pot of water becomes
exceptionally warm, and you start to
see steam rising from the water. Long
before you can see the steam there is a
steadily increasing amount of moisture
reaching the air above the pot of water as the water warms. The air above
the pot of water then warms as the
water vapor is released into the atmosphere. Air that becomes warmer than
its surrounding air will rise because it
becomes less dense. As that air rises it
carries the water vapor up into the atmosphere along with the warming.
The rising air above the pot of water
creates a region of low pressure because
the air is moving away from the body
of water, thereby reducing the weight of
air pressing downward on the surface
of the water. That is all that a low-pressure center is - just rising air. If you
take the same principle out to the ocean
and warm a super large area of ocean
water, you release water vapor into the
atmosphere, and under ideal conditions
you create a low-pressure center.
Today's warm ocean water in the
Gulf of Alaska has created a large region of low pressure with abundant
moisture in the atmosphere. As storm
systems move across the warm body
of water they tend to intensify by getting more lift by the rising air over the
Gulf of Alaska, and the added moisture rising in the atmosphere sets the
stage for greater storminess once the
warm, moist air reaches a certain altitude when it meets colder air aloft.
The dynamics in the atmosphere then
become quite impressive as the warm,
moist air meets the cooler air aloft
and substantial rain falls downstream
from where the storm center moved
across the warmer-than-usual ocean
body. Hence, the warm Gulf of Alaska this year has helped create more
rain in Canada's prairies and brought
drought conditions down in many
areas. The longer the warm water remains in place the higher the potential
for additional precipitation.
A few years ago when the Gulf of
Alaska was colder than usual, storm
systems were not gaining moisture or
lift from the ocean because the cool
water was suppressing rising motions
in the atmosphere. This in turn suppressed rainfall downstream across
Canada's Prairies, resulting in drought.
In 2019, western Indian Ocean water
temperatures soared well above average while the water off the southwest
coast of Sumatra, Indonesia, was colder
bakingbusiness.com / world-grain.com

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Milling & Baking News - January 28, 2020

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