El Niño Impacts 

and Outlook

Missouri River Basin

October 2018

Typical El Niño Winter Pattern

Highlights for the Basin

An El Niño develops when sea surface 

temperatures are warmer than average 

in the equatorial Pacific for an extended 

time. This is important to North America 

because El Niño can impact our weather 

patterns, especially in the winter. 

Although each El Niño is different, 

there are some general patterns that 

are predictable. For instance, the polar 

jet stream is typically farther north 

than usual, while the Pacific jet stream 

remains across the southern U.S. 

This pattern brings above-normal 

temperatures to much of the Missouri 

River Basin region, particularly across 

the north. But, this does not mean cold 

weather will not happen this winter. 

Extreme cold weather may be milder 

and less frequent, however.

The image above shows the typical pattern in the winter during El Niño events. The 

polar jet stream tends to stay to the north of the Missouri Basin region, while the 

Pacific jet stream remains across the southern U.S. With the Missouri Basin isolated 

between the storm tracks, warmer and possibly drier conditions can develop during 

El Niño events.

Image courtesy of the National Oceanic and Atmospheric Administration.

El Niño Outlook

Winter Temperature and Precipitation Outlooks

Valid for December 2018 - February 2019

As of October, the winter outlooks for the region show that below-normal 

precipitation is favored for the headwaters of the Missouri River, while 

above-normal precipitation is favored for areas of the southern Rockies. This 

could have implications for many sectors, in both positive ways (increased 

snowpack to the south could be welcomed by ski resorts) and negative ways 

(reduced snowpack to the north could impact spring runoff). Meanwhile, the 

temperature outlook indicates that above-normal temperatures are favored 

across the majority of the region, with the exception of portions of Missouri, 

where equal chances for above, near, or below normal temperatures exist. 

El Niño Strength

Winter 2018-19

According to the Climate Prediction 

Center, ENSO-neutral conditions 

are present. Outlooks favor the 

development of a weak to moderate 

El Niño event, which could continue 

through the winter (70-75% chance). 

An El Niño Watch is in effect. The chart 

above shows the potential intensity of 

this winter's El Niño, with data from 

the International Research Institute 

for Climate and Society. 

Missouri Basin Region El Niño Impacts and Outlook | October 2018 

https://www.drought.gov/drought/dews/missouri-river-basin

Contact: Natalie Umphlett (numphlett2@unl.edu)

Doug Kluck (doug.kluck@noaa.gov)

Temperature Precipitation

EC: Equal chances of above, near, or below normal 

A: Above normal, B: Below normal
Potential Winter and Spring Impacts

Comparisons and Limitations

Winter Conditions During Past El Niños 

Maps courtesy of the High Plains Regional Climate Center.

The maps above illustrate the winter conditions of the last weak El Niño,

which occurred in 2014-15. Much of the Basin was warmer than average, 

but precipitation signals varied. Please note that each El Niño is different and 

other factors can be considered, such as antecedent conditions or the Arctic 

Oscillation, which trumped the El Niño during the winter of 2009-10. 

While past El Niño events can help inform forecasters about certain 

conditions, there are some limitations. For instance, in the Missouri Basin, El 

Niño is not known to impact: 1) potential for ice storms or blizzards, 2) track 

or intensity of any single weather system, 3) first freeze in the fall (early or 

late), or 4) last freeze in the spring (early or late).

MO River Basin Partners

Missouri Basin Region El Niño Impacts and Outlook | October 2018 

https://www.drought.gov/drought/dews/missouri-river-basin

High Plains Regional Climate Center 

www.hprcc.unl.edu

National Drought Mitigation Center 

http://drought.unl.edu/

National Oceanic and Atmospheric 

Administration 

https://www.noaa.gov/

 National Integrated Drought Information 

 System 

 https://www.drought.gov/

 NOAA NCEI 

 www.ncdc.noaa.gov

 NOAA NWS - Central Region 

 www.crh.noaa.gov/crh

 NOAA NWS Climate Prediction Center

 www.cpc.ncep.noaa.gov

 NOAA NWS Missouri Basin River Forecast 

 Center 

 www.crh.noaa.gov/mbrfc

American Association of State 

Climatologists 

https://www.stateclimate.org/

U.S. Army Corps of Engineers 

www.usace.army.mil

USDA Northern Plains Climate Hub 

www.climatehubs.oce.usda.gov

Missouri River Agriculture Ecosystems

In the northern tier of the Basin, 

where warmer and drier conditions 

are possible, increased fire danger 

could be an issue this winter and 

spring, especially in areas where 

forage has accumulated. If a lower 

snowpack occurs as a result of the 

drier conditions, reduced runoff could 

occur in the spring, which may impact 

wildlife later in the season. Warmer 

conditions could also accelerate the 

growth of non-native cool-season 

plants, such as cheatgrass.

Platte River, a tributary of the Missouri 

River, photo courtesy Bill Sorensen.

Getting ready for spring planting, photo 

courtesy Ken Dewey.

Sandhill cranes in central Nebraska, photo 

courtesy Ken Dewey.

With the potential for above-normal 

temperatures across the Basin this 

winter, a variety of impacts could 

occur. For livestock producers, 

reduced needs for extra forage and 

hay could be beneficial as hay stocks 

are near historic lows. For winter 

wheat producers, a warmer winter 

could signal less risk to the crop. 

Looking ahead to spring, planting 

issues could be a concern across parts 

of the Basin, where autumn rains have 

produced ample soil moisture.

This year, the combination of an 

above-normal snowpack and heavy 

rains has led to one of the highest 

runoffs for the Upper Missouri River 

Basin on record. According to the U.S. 

Army Corps of Engineers, 2018 runoff 

above Sioux City, Iowa is forecast at 

40.6 million acre feet, which is 160 

percent of average. Above-average 

releases will continue through the 

fall in order to evacuate all stored 

floodwaters. Snowpack will be 

monitored through the spring.

Contact: Natalie Umphlett (numphlett2@unl.edu)

Doug Kluck (doug.kluck@noaa.gov)

Departure from Normal Temperature (°F) (left) and

Percent of Normal Precipitation (right) for Winter 2014-15