World Grain - November 2020 - 66

US Drought Monitor
Oct 20,2020
None
D0 Abnormally dry
D1 Moderate drought
D2 Severe drought
D3 Extreme drought

The Drought Monitor focuses on broad-scale
conditions. Local conditions may vary. For more
information on the Drought Monitor, go to
https://droughtmonitor.unl.edu/about.aspx

In addition to concern about dryness remaining over
the winter this year, there is La Niña. Many of the more
significant La Niña events that last longest and are most
intense tend to occur between the solar minimum and the
solar maximum. The solar minimum was reached earlier this year and the maximum is expected in 2025. The
longer La Niña events last the more they drain moisture
from the atmosphere in the middle latitudes. If the current La Niña event lingers into spring and temporarily
goes away only to return again later next summer, the
environment would be similar to those La Niña events
of the 1950s and 1970s and possibly the 1930s, although
there is not much reliable data from back then.
La Niña events also tend to be associated with more
heat and cold because as moisture is removed from the
mid-latitudes, the air will heat and cool much faster.
Notice the temperature extremes in the dry areas of the
Plains and Canada this late summer and autumn. The
gyrations have been very impressive.
PACIFIC DECADAL OSCILLATION
Then there is the Pacific Decadal Oscillation (PDO).
Ocean temperatures in the central Pacific Ocean determine the phase of PDO. Basically, in an overly simplified definition, cooler-than-usual ocean water off the
West Coast of North America can lead to negative PDO,
and negative PDO events during the summer promote
stronger high-pressure ridges aloft over central North
America. PDO has a tendency to be in one phase or
the other (warm or cold) over many decades at a time
before changing its phase. The last short-term bout of
negative PDO occurred in the 2010-12 period, which
helped contribute to the mega drought of 2012, which,
by the way, also occurred after La Niña prevailed over
a two-year period. World Weather, Inc. believes this
setup may return again in the next couple of years and
a close monitoring of the situation is warranted.
66

WG_Nov20.indb 66

Credit

D4 Exceptional drought

Quite often the drier bias that occurs in the United
States because of a multi-year La Niña event is mirrored with dryness in a part of Russia. There were some
hints of that in 2020 and there are some areas in southern Russia and Ukraine that are still quite dry like that
of western North America today, raising more concern
that a period of more significant dryness may be lurking in the next couple of years.
In the meantime, there is South America, which also is
feeling the effects of La Niña today with recent dryness
in Argentina and talk about possible dryness in southern
Brazil. These trends often are associated with La Niña
events, and even though there has been significant rain
recently in Argentina, that does not mean that La Niña
will not deprive a part of that nation from extremely important rainfall later this year. The threat of dryness in
South America is greatest for southern Brazil, Uruguay,
southern Paraguay and extreme eastern Argentina.
Dryness in those areas during their summer and a possible more challenging weather pattern in North America
in 2021 and/or 2022 might lead to more rising futures
prices and general costs for many food companies.
That makes now an excellent opportunity for the
smarter businesses to begin making strategic investment decisions to protect their bottom lines just in case
we are heading for more trying times from an agricultural perspective.
Drew Lerner is senior agricultural meteorologist with World
Weather, Inc. He may be reached at worldweather@bizkc.
rr.com. World Weather, Inc. forecasts and comments pertaining
to present, past and future weather conditions included in this
report constitute the corporation's judgment as of the date of this
report and are subject to change without notice.
We want to hear from you - Send comments and inquiries
to worldgrain@sosland.com. For reprints of WG articles,
e-mail reprints@sosland.com.

November 2020 / World Grain / www.World-Grain.com

11/2/2020 4:16:05 PM

https://droughtmonitor.unl.edu/about.aspx http://www.rr.com http://www.World-Grain.com

World Grain - November 2020

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