Quarterly Climate Impacts 

and Outlook

Great Lakes Region

June 2018

Great Lakes Significant Events – for March - May 2018 

Several strong low pressure systems in 

March and April brought with them near-torecord-breaking cold temperatures as well as 

late season winter precipitation events. By 

contrast, May saw above-normal conditions 

for the majority of the basin.

In mid-April, a strong low pressure system 

created a mixture of hazardous weather 

conditions to southern Ontario. Multiple 

hours of freezing rain and ice pellets were 

reported leading to hazardous traveling 

conditions. Other locations saw more than 

40 cm (16 in) of snowfall. Gusts of up to 90 

km/h (56 mi/h) left more than 120,000 homes 

without power.

Several strong nor'easters brought late season snow and damaging winds to much of the eastern portion of the basin. 

Erie, PA experienced 91 cm (36 in) of snow for the month of March, breaking the previous record. Across the basin, 

anomalously cold conditions in April broke both daily and monthly records including the record for the coldest April on 

record for both Wisconsin and Michigan. In southern Ontario, most locations were in their top 5 coldest Aprils on record 

over the past 100 years. The below-normal April temperatures gave way to above-normal temperatures in May that 

broke records across the basin including Buffalo, NY which saw its warmest May on record.

Regional Climate Overview – for March - May 2018

Precipitation and Temperature April 2018 Temperature

Departure from Normal March temperatures ranged from 3°C 

(5°F) below normal to 2°C (4°F) above 

normal. April was much below normal, 

ranging from 7 to 2°C (13 to 4°F) below 

normal. May was warmer, ranging from 

2°C (4°F) below normal to 6°C (11°F) 

above normal. This led to a temporary 

surge in Great Lakes water surface

temperatures. The contrasting months 

balanced out the average spring temperatures, which ranged from 2°C 

(4°F) below normal to 1°C (2°F) above 

normal.

In March, all lake basins except Erie 

received less than 25% of their normal 

precipitation. April precipitation ranged 

from only 45% of normal in the Lake 

Superior basin to 138% of normal in the 

Lake Huron basin. May precipitation 

ranged from near to below-normal. 

Overall, spring precipitation was below 

to near normal over all basins.

Great Lakes Water Levels

All of the Great Lakes ended May with 

above normal levels for this time of 

year. After starting at near-record-high 

values, Lake Superior had relatively 

low water supplies over the past 

three months, ending May only 13 cm 

above normal. Lakes Michigan-Huron 

and Erie saw closer-to-normal waterlevel changes, leaving both lakes wellabove-normal for the time of year. 

Lake Ontario saw a below-normal 

water-level rise since the beginning of 

March, leaving levels above average.

Great Lakes Region Quarterly Climate Impacts and Outlook| June 2018

https://www.drought.gov/drought/resources/reports

Contact: Jonathan Weaver (jw1067@illinois.edu)

Normals based on 1981-2010.

Spring 2018 Precipitation

Percent of Normal

Lake

End of May 2018 

Compared to:

Change since 

March 1st

Average 2017 2018 Average

Sup. +13 cm 

+5.1 in

-9 cm 

-3.5 in

-4 cm 

-1.6 in

+17 cm 

+6.7 in

Mich.-

Huron

+46 cm 

+18.1 in

+12 cm 

+4.7 in

+19 cm 

+7.5 in

+24 cm 

+9.4 in

Erie +57 cm 

+22.4 in

+4 cm 

+1.6 in

+30 cm 

+11.8 in

+32 cm 

+12.6 in

Ont. +20 cm 

+7.9 in

-61 cm 

-24.0 in

+30 cm 

+11.8 in

+43 cm 

+16.9 in
Regional Impacts – for March - May 2018

Seeding and emergence of many crops were delayed due to prolonged cold periods in March and April. This was a 

common theme across the agricultural industry as growing degree days stayed well behind normal conditions through 

April for most locations. Fortunately, above-normal temperatures in May allowed crop producers to make up for the 

delayed start.

Sporting events across the basin were affected by several large winter weather events in the early season. The Chicago 

Cubs were forced to postpone several early season games by up to three weeks due to snowcover. This tied a record

for the most weather-related postponements through April. The Toronto Blue Jays home game against the Kansas City 

Royals was also postponed on April 16 due to ice accumulation causing damage to the roof of the stadium.

High water levels in Lake Erie broke seawalls just southwest of Detroit and flooded several neighborhoods. Grand 

Haven's South Pier construction project was delayed once again as a result of high water levels in Lake Michigan. On 

April 13, several strong thunderstorms pushed across Lake Michigan and created a pair of meteotsunamis. The large 

surge of water impacted large sections of the eastern coastline of Lake Michigan. One gauge in Ludington reported a 

water level rise of 46 cm (1.51 ft). Several docks were damaged along the coast near Manistee, Michigan as a result.

Meteotsunami on April 13 (red=above 

normal, blue=below normal water levels) 

Regional Outlook – for July - September 2018

Temperature and Precipitation

Great Lakes Water Levels

Both American and Canadian forecasters predict above-normal temperatures 

for most of the Great Lakes basin in the July through September timeframe. 

At the same time, precipitation has been predicted to have an equal chance of 

being above, near, or below normal for the entire basin.

The harmful algal bloom (HAB) season 

in the Great Lakes typically peaks in 

the late summer. NOAA issues a Lake 

Erie HAB seasonal forecast in early 

July. Because conditions in the lake 

can change quickly, a HAB Bulletin is 

posted and distributed twice weekly 

from July to October.

Partners

Contact: Jonathan Weaver (jw1067@illinois.edu) Great Lakes Region Quarterly Climate Impacts and Outlook| June 2018 

https://www.drought.gov/drought/resources/reports

Midwestern Regional Climate Center

Environment and Climate Change Canada

Agriculture and Agri-Food Canada

Northeast Regional Climate Center

Great Lakes Region State Climatologists

NOAA

 NCEI

 GLERL Great Lakes Sea Grant Network

 North Central River Forecast Center

 Ohio River Forecast Center

 CPC Office for Coastal Management

GLISA

US Army Corps of Engineers, Detroit District

NIDIS

USDA Midwest Climate Hub

Lakes Superior and Michigan-Huron levels are expected to rise over the 

beginning of the third quarter but by the end of September all lake levels are 

entering their seasonal fall decline with normal water supply conditions. Lakes 

Michigan-Huron and Erie levels are likely to stay well above average, even if 

very dry conditions are encountered. Lakes Superior and Ontario levels could 

drop below average if drier-than-normal conditions occur, but are expected to 

stay above average levels with normal water supplies.

Harmful Algal Bloom

Buds on an apple tree Rogers Centre, Toronto, ON. Roof was 

damaged in April due to Ice Accumulation.