Quarterly Climate Impacts 

and Outlook

Great Lakes Region

December 2017

#regionalclimateoutlooks

Great Lakes Region 

Quarterly Climate Impacts and Outlook

 - December 2017 - 

http://mrcc.isws.illinois.edu/pubs/pubsGreatLakes.jsp

www.ec.gc.ca/eau-water/default.asp?lang=En&n=F5329B03-1

Across the Great Lakes basin, conditions were generally 

unseasonably warm. Several instances of record-breaking 

temperatures occurred. Chicago experienced seven 

consecutive days (September 20-26) with record-breaking 

warm temperatures up to 35°C (95°F). At the same time, 

several locations in southern Ontario reported heat-wave 

conditions with some locations experiencing humidex 

values reaching 40°C (104°F). These events marked 

the latest recorded heat wave for the season of this 

magnitude. Conversely, record cold temperatures were set 

from November 10-11 in many parts of southern Ontario, 

New York, and Pennsylvania. Most locations broke their 

previous record by several degrees.

Precipitation overall for autumn was near-normal 

across the Great Lakes basin; however, it varied greatly 

depending on the month and location. Michigan went 

from its fifth driest September on record to its wettest 

October on record for the state. Watertown, NY had its 

wettest October on record, breaking the previous record 

by 9.1 cm (3.6 in). A storm system on November 5 produced 7.2 cm (2.85 in) of precipitation in Erie, PA, a record for daily November precipitation 

for the location. This event flooded roads and buildings, and resulted in two fatalities.

A strong wind event on October 24 led to straight-line-wind damage and high waves along the southern coastline of Lake Superior. Wind gusts of 

up to 97 kph (60 mph) resulted in downed trees and power lines leading to road closures and widespread power outages. Waves up to 9.1 m (30 ft) 

in height were also reported.

 Great Lakes Significant Events - for September - November 2017

Precipitation

Regional Climate Overview - for September - November 2017

Water level statistics based on 1918-2016.

Temperature

All lake basins saw near- or above-average autumn precipitation, with the Great 

Lakes basin receiving 103% of average. In September, all basins were drier than 

average except Superior. The overall basin received 71% of average. All basins were 

wetter than average in October, with the overall basin seeing 144% of average. 

November precipitation was below average in the Michigan-Huron basin, near 

average in the Superior and Ontario basins, and above average in the Erie basin. 

The overall basin received 97% of average in November. 

Precipitation normals 

based on 1981-2010.

Sep. and Oct. graphics are 

shown to highlight large 

precipitation range this 

autumn.

September (A) and October (B) 2017 Precipitation: Percent of Normal (%)

Great Lakes Water Levels

Air temperature normals based on 1981-2010. Water temperature LTA from 1995-2016.

Lake

End of November 2017 

Compared to:

Change since 

Sept 1st

Average Last Year 2017 Average

Superior +28 cm 

(+11 in)

+14 cm 

(+5.5 in)

-7 cm 

(-2.8 in)

-10 cm 

(-3.9 in)

MichiganHuron+47 cm 

(+18.5 in)

+26 cm 

(+10.2 in)

-14 cm 

(-5.5 in)

-17 cm 

(-6.7 in)

Erie +49 cm 

(+19.3 in)

+29 cm 

(+11.4 in)

-22 cm 

(-8.7 in)

-23 cm 

(-9.1 in)

Ontario +31 cm 

(+12.2 in)

+38 cm 

(+15 in)

-39 cm 

(-15.4 in)

-29 cm 

(-11.4 in)

Autumn 2017 Air Temperature:

Departure from Normal

Air Temperature: Autumn was up to 3°C (5°F) warmer than normal. 

September temperatures ranged from 1°C (2°F) to 3°C (5°F) above normal. 

October temperatures ranged from 1°C (2°F) above normal in the western 

Superior basin to 5°C (9°F) above normal in the Huron and Ontario basins. 

November temperatures ranged from 2°C (4°F) below to near normal.

Water Temperature: The average lake water temperatures for the autumn 

months were consistently above the long-term average (LTA). Several lakes 

exceeded the LTA by as much as two degrees Celsius. This was especially 

the case in November (left)

A B

November Lake Surface Temperature 

(LST) Anomaly

Anomaly calculated with average Nov. 2017 LST 

compared to LTA Nov. LST (1995-2016).
Regional Impacts - for September - November 2017

Regional Outlook - for January - March 2018 Great Lakes Region Partners

Environment and Climate Change Canada (ECCC)

www.ec.gc.ca

Agriculture and Agri-Food Canada

www.agr.gc.ca 

Midwestern Regional Climate Center

mrcc.isws.illinois.edu

Northeast Regional Climate Center

www.nrcc.cornell.edu

Great Lakes Region State Climatologists

www.stateclimate.org

National Oceanic and Atmospheric Administration

www.noaa.gov

National Centers for Environmental Information

www.ncei.noaa.gov

Great Lakes Environmental Research Laboratory

www.glerl.noaa.gov

NOAA Great Lakes Sea Grant Network 

www.seagrant.noaa.gov

North Central River Forecast Center

www.crh.noaa.gov/ncrfc

Ohio River Forecast Center

www.weather.gov/ohrfc 

Climate Prediction Center

www.cpc.noaa.gov

Office for Coastal Management

http://coast.noaa.gov/

Great Lakes Integrated Sciences & Assessments

www.glisa.umich.edu

US Army Corps of Engineers, Detroit District

www.lre.usace.army.mil

National Integrated Drought Information System 

www.drought.gov

USDA Midwest Climate Hub

https://www.climatehubs.oce.usda.gov/midwest

Contact for NOAA: 

Jonathan Weaver: jw1067@illinois.edu

Samantha Borisoff: samantha.borisoff@cornell.edu

Contact for ECCC: ec.enviroinfo.ec@canada.ca

Archive: goo.gl/3WA5QZ 

Contact Information

#regionalclimateoutlooks

Great Lakes Region 

Quarterly Climate Impacts and Outlook

 - December 2017 - 

http://mrcc.isws.illinois.edu/pubs/pubsGreatLakes.jsp

www.ec.gc.ca/eau-water/default.asp?lang=En&n=F5329B03-1

The Climate Prediction Center (CPC) and Environment and Climate Change Canada (ECCC) are 

forecasting a greater chance for below-normal temperatures for much of the west and central 

portions of the basin and a greater chance for above-normal precipitation across the entire Great 

Lakes basin for January-March. Similarly, NOAA now says there is an increasing chance (>80%) of 

La Niña continuing through winter 2017-18. While not always the most reliable predictor, La Niña 

can often create wetter and cooler conditions in the winter months. Current outlooks can be 

found through CPC and ECCC.

Agriculture While early autumn saw promising 

harvest conditions, the rapid transition 

to above normal precipitation in 

October increased harvest difficulties. 

For Michigan, this led to the harvesting 

of both corn and soybean transitioning 

from being ahead of schedule in midOctober to being behind schedule by late 

November. In Wisconsin and Minnesota, 

the rapid onset of cold conditions in 

conjunction with wetter weather also led to a delayed harvest. This 

pattern was largely representative of the conditions across the basin.

Water Quality

A heavy precipitation event on October 

14 led to more than 12.7 cm (5 in) of rain 

falling in a 24-hour period. Such rapid 

inundation led to the flooding of the 

Chicago River. For the first time since June 

2015, the locks were opened allowing the 

Chicago River to flow into Lake Michigan. 

This reversal polluted the waters of Lake 

Michigan by forcing storm runoff and 

sewage into the lake. The 2017 Lake Erie 

harmful algal bloom has extended into 

autumn and covered over 2500 km2 (1000 

mi2). This ties it with 2013 as the third worst bloom this century.

Coastal Damage and Erosion

The shoreline of Lake Superior was 

heavily impacted by the storms present 

in late October. These storms were able 

to generate winds of 97 kph (60 mph) 

which, when combined with already 

high lake levels, produced record 

breaking waves as high as 9.1 m (30 ft). 

Such extreme conditions led to damage 

along the northern and southern 

coastlines of Lake Superior. Many 

locations experienced lakeshore flooding 

while others saw coastal erosion that 

was able to uproot trees and destroy structures. The impacted coastline 

was declared a disaster area, and damages were estimated to exceed 3.5 

million US dollars.

Societal

On November 5, an outbreak of tornadoes 

impacted many parts of northern Ohio 

and western Pennsylvania. As many as 14 

tornadoes were documented and ranged 

in intensity from EF0-EF2 in magnitude. 

The tornadoes caused damage to several 

structures and injured many locals. Many 

rural areas reported large livestock fatalities 

and lost crops.

Water Levels

Temperature & Precipitation

Potential range for water levels for Jan-Mar 2018 

compared to the long-term average (1918-2016). 

Corn harvest

(Photo: USDA)

Great Lakes water levels typically decline to 

seasonal lows during winter largely due to reduced 

runoff and streamflow combined with higher lake 

evaporation rate. Nonetheless, levels of Lakes 

Superior, Michigan-Huron and Erie are likely to 

remain well above average even with very dry 

conditions. Lake Ontario’s levels will approach 

average levels if typical conditions occur over the 

next few months.

Damage due to coastal erosion in 

Marquette, MI

(Photo: NWS Marquette, MI)

Ice Cover

On January 3, 2018, NOAA’s Great Lakes 

Environmental Research Laboratory updated 

the maximum 2018 Great Lakes ice cover 

projection to 60%. The long-term average is 

55%. The updated forecast reflects changes in 

teleconnection patterns since early December 

2017—movement from a strong to a weak La 

Nina, a negative to a positive Pacific Decadal 

Oscillation, and a positive to a negative North 

Atlantic Oscillation. These patterns combine to 

create colder than average conditions for the 

Great Lakes.

Damaged home in Williamsfield, 

OH due to EF2 tornado on Nov. 5

(Photo: NWS Cleveland, OH)

Harmful Algal Bloom - Western Lake 

Erie - September 2017

(Photo: NOAA GLERL)