Gulf of Maine quarterly climate impacts and outlook: September 2017

Gulf of Maine region

September 2017

Gulf of Maine significant events – June - August 2017

Summer was characterized by high variability in temperature, rainfall, and weather events. Moderate drought developed in portions of Maine and the Maritimes, while parts of Massachusetts and New Hampshire had several heavy rain events.

There were multiple severe thunderstorm and flash flooding events during summer.

  • June 27: In New Brunswick, golf ball-sized hail and wind gusts near 100 km/h occurred in the Plaster Rock area. A tornado warning was issued for the Doaktown to Blackville area. Some stations saw more than 25 mm (1 in.) of rain in an hour.
  •  July 1: In Maine, a state that averages only two tornadoes a year, the Gray National Weather Service office issued seven tornado warnings, their greatest number in recorded history. Five weak (EF-0 or EF-1) tornadoes touched down, the most Maine has had in a single day. The tornadoes snapped or uprooted dozens of trees, damaging buildings, vehicles, and other structures. In New Hampshire, straight-line winds of up to 137 km/h (85 mph), a funnel cloud, and golf-ball-sized hail were reported. Flash flooding damaged dozens of roads in the two states, with damage in New Hampshire exceeding $4 million.
  • July 7, July 12, August 2: Heavy rain caused significant street flooding in parts of eastern Massachusetts. The downpours left some roads impassable and numerous vehicles stuck, with several having water up to their windows or hoods.
  • July 20–21: A strong cold front produced severe thunderstorms in the region. Hail damaged crops, including over 200 acres of corn in Maine and around 100 acres of potatoes in P.E.I. In Aroostook County, ME, wind gusts of up to 97 km/h (60 mph) downed trees and damaged a few outbuildings. In P.E.I., heavy rain caused localized flooding, and 20,000 homes and business were left without power. Charlottetown received 45.2 mm (1.78 in.) of rain, a daily record. Behind the system, from July 22–26, temperatures dropped as low as -0.6°C (31°F), with several sites setting record lows. Edmundston, NB, had a low of 1.3°C (34°F) on the 23rd, which was its all-time coldest July temperature since 1918.
  •  August 5: Two tornadoes damaged more than 1,000 trees and several structures in northern Maine.
  • August 19: Up to 209.6 mm (8.25 in.) of rain led to numerous flooded basements and roads in Cape Cod, MA. A car fell into a sinkhole after a dune eroded beneath it.

In mid-August, Hurricane Gert caused high waves, rough surf, and rip currents along several coastlines in the region

Cold temperatures and frequent storms in May reduced lobster landings in the Maritimes. Due to weather conditions and high demand, Canadian lobster prices were at an all-time high for late May and early June. 

Long description

Map of the Gulf of Maine Region, which comprises the eastern half of Massachusetts, New Hampshire, Maine, New Brunswick, Nova Scotia, Prince Edward Island, and the nearby marine areas, highlighting key significant events that occurred in the summer of 2017 (June to August 2017). The highlights are as follows:

  • Moderate drought developed in Maine and parts of the Maritimes.
  • During summer, temperatures varied greatly, setting both record lows and record highs.
  • Severe thunderstorms struck the region repeatedly during summer. Maine had a record number of tornadoes on July 1.
  • Portions of Massachusetts and New Hampshire experienced flash flooding.

Regional climate overview – June - August 2017


Departure from normal

Long description

Map of the Gulf of Maine Region showing the mean temperature departure from normal, averaged over June to August 2017. The scale to the right shows positive anomalies (above normal) in shades of red, to plus 5 degrees Celsius, negative anomalies (below normal) in shades of blue, to negative 5 degrees Celsius, and near normal (plus 0.5 Celsius to minus 0.5 Celsius) in white. Much of the region had generally near-normal mean temperatures. Parts of central New Brunswick, northern New Brunswick, Prince Edward Island, and Cape Breton were warmer than normal, with the departure from normal ranging from plus 0.5 to 1 degree Celsius. Parts of central New Hampshire were cooler than normal, with the departure from normal ranging from minus 0.5 to minus 1 degree Celsius.

Summer temperatures (averaged over June, July, and August) ranged from 1°C (2°F) below normal in central New Hampshire to 1°C (2°F) above normal in parts of New Brunswick and P.E.I. June temperatures ranged from normal to 2°C (4°F) above normal. On June 6, highs near 10°C (50°F) ranked among the top five coldest for summer at Concord, NH, and Boston, MA. On June 8 and June 11–13, high temperatures ranging from 27° to 36°C (81° to 97°F) set records at several sites across the region. On June 19, Caribou, ME, tied its all-time warmest low temperature for June with a low of 21°C (69°F). July temperatures ranged from 1°C (2°F) below normal to near normal in the region. August temperatures ranged from 2°C (4°F) below normal in parts of Maine and New Hampshire to 1°C (2°F) above normal in parts of the Maritimes.


Percent of normal

Long description

Map of the Gulf of Maine region showing the total precipitation as a percentage of normal precipitation, accumulated over June to August 2017. Above normal (110% of normal and above) is shown in shades of green, below normal (90% of normal and less) in shades of brown, and near normal (90% to 110% of normal) in white. New Brunswick, Prince Edward Island, and northern and eastern Nova Scotia, as well as much of Maine and parts of the other New England states were drier than normal, ranging as low as 25% of normal in central New Brunswick and parts of coastal Maine. Most of the rest of Nova Scotia was near normal with some areas in southwestern Nova Scotia up to 125% of normal.

Summer precipitation (accumulated from June to August) ranged from 25% of normal in central New Brunswick and coastal Maine to 150% of normal in western Maine and Cape Cod, MA. At four sites in New Brunswick, the summer was one of the top three driest on record. June precipitation ranged from 25% of normal in Cape Breton, N.S., to 150% of normal in western Nova Scotia and parts of New England. In July, many areas received 25%–110% of normal precipitation, with central New Brunswick seeing less than 25% of normal. July ranked among the top 10 driest on record for more than a dozen sites. The wetter-than-normal areas in July included central Nova Scotia, western Maine, and central New Hampshire. August precipitation was 25%–110% of normal for much of the region. However, Cape Cod, MA, and parts of Nova Scotia, were wetter than normal.

Temperature and precipitation normals based on 1981–2010 data.

Sea surface temperature

Departure from normal

Long description

Map of the Gulf of Maine Region marine areas showing the sea surface temperature departure from normal, averaged over June to August 2017. Positive anomalies (above normal) are shown in shades of red, to plus 3 degrees Celsius. Negative anomalies (below normal) are shown in shades of blue, to negative 3 degrees Celsius. Anomalies near 0 degrees Celsius (near-normal temperatures) are shown in white. The areas of above-normal and below-normal sea surface temperatures are described in the main text.

Summer sea surface temperature anomalies were highly location-dependent in the Gulf of Maine. Over most near-coastal regions in shallower water, temperatures were about 0.5°C (1°F) cooler than normal. These cool anomalies were also present over parts of the central Gulf of Maine south of Penobscot Bay, north of Georges Bank, and in the Northeast Channel region. Temperatures were 0.5°–1°C (1°–2°F) warmer than normal over the deeper basins of the Gulf of Maine, over Georges Bank, in the Bay of Fundy, and the southern Nova Scotia shelf.

Sea surface temperature anomalies based on 1985–2017. Mean SST anomalies from NOAA AVHRR data. Credit: University of Maine School of Marine Sciences and NERACOOS

Regional impacts – June - August 2017

Summer dryness

The August 2017 North American Drought Monitor

Long description

North American Drought Monitor map for August 2017 over New England and the Maritimes. The map shows the intensity of abnormally dry or drought conditions in five categories: D0 - abnormally dry, D1 drought - moderate, D2 drought - severe, D3 drought - extreme, and D4 drought - exceptional.

The map shows moderate drought conditions over south central New Brunswick, adjacent parts of Maine, and parts of northern Nova Scotia. It shows abnormally dry conditions over the rest of New Brunswick, Prince Edward Island, and parts of eastern Nova Scotia, and parts of Massachusetts, New Hampshire, and Maine. It shows no drought over remaining areas.  The letter S over the area with moderate drought indicates short-term impacts, typically less than 6 months (e.g. to agriculture).

Logos of contributing agencies are shown below the map, including from left to right, top: USDA (U.S. Department of Agriculture), US National Drought Mitigation Center, CONAGUA (Comisión Nacional Del Agua), and from left to right, bottom: USA Department of Commerce, NOAA (National Oceanographic Administration), Agriculture and Agri-Food Canada, and Environment and Climate Change Canada.

Much of the Gulf of Maine region was drier than normal during summer, with moderate drought developing in parts of coastal Maine, central P.E.I., northern Nova Scotia, and the southern half of New Brunswick. Drought conditions eased in P.E.I. in August due to increased precipitation. Some farmers in New Brunswick and Maine had to increase their reliance on irrigation. The Maine Potato Board expected reduced potato yields compared to previous years due to the dry conditions, a concern shared by P.E.I. potato growers. Pastures and hay fields were dry, brittle, and slow-growing in parts of Maine and P.E.I., with some farmers giving their cattle supplemental feed. Below-normal rainfall reduced crop yields of berries. Growers in New Brunswick and P.E.I. reported fewer and smaller raspberries, strawberries, and blueberries, and Maine blueberry growers reported some shriveled berries. Grapes were also smaller in size, giving them a higher sugar concentration, which could result in better wine according to winemakers. Southwestern Nova Scotia was one of the few places in the Maritimes that was wetter than normal in June, which boosted the strawberry crop; however, a dry July combined with long-term precipitation deficits contributed to some wells going dry. Residents of Cornwall, P.E.I., were asked to reduce their water usage. New Brunswick officials expect this tourist season to be one of the best in years due in part to the dry, sunny weather.

Sep. 5 streamflow compared to historical values. Credit: USGS.

Long description

Dot map of streamflow compared to historical values over the Gulf of Maine region, for September 5, 2017. The dots mark the locations of streamflow measurements. The colour of the dot shows the recent (September 5) streamflow compared to the historical distribution in one of 8 percentile classes: low, much-below normal (< 10th percentile), below normal (10th to 24th percentile), normal  (25th to 75th percentile), above normal (76th to 90th percentile), much-above normal (> 90th percentile), high, and not ranked.

Streamflows were much-below normal or below normal at several sites in the western and southeastern sections of New Brunswick and parts of Maine. In Nova Scotia the streamflows at most sites were near normal, with only one in the Annapolis Valley below normal. Elsewhere in the region streamflows were generally near normal or below normal.

Drought conditions in Fredericton, NB, on August 12, 2017. Credit: Rick Fleetwood.

Long description

The photograph shows a large expanse of parched dry grass and a few small shrubs in the foreground with the Saint John River in the background.

A forest fire on Miscou Island, NB, in late July forced residents of 25 homes to evacuate. According to the fire chief, the fire grew due to dry conditions and trees downed by the January ice storm. In early August, the fire danger in New Brunswick was the highest it has been in more than 20 years, leading the province to restrict forestry operations during the day. Fire danger was also high in Nova Scotia and P.E.I., with the latter province limiting burning in some parks. Sporadic rainfall from late July through mid-August helped keep drought conditions from worsening. With the fire hazard reduced, restrictions on forestry operations in New Brunswick were lifted in mid-August.

Localized heavy precipitation

In contrast, fields were soggy and rutted in parts of New Hampshire. Farmers had difficulty harvesting hay and were concerned about declining quality. There was also an increase in diseases in fruit. However, the conditions were good for berry crops and boosted grass growth in the state. Runoff from the heavy rain likely contributed to high bacteria levels in the water at 12 Massachusetts beaches, with some beaches closed for a few days.

Regional outlook – autumn 2017

Temperature and precipitation

ECCC temperature map (left) produced on August 31.
CPC temperature map (right) produced on August 17.

Long description

(Left) The map shows the forecast probability of above-normal temperatures, averaged over September to November 2017, over the Maritime Provinces. It shows that the probability of above-normal temperatures is 40% to 50% over New Brunswick and southwestern Nova Scotia. It shows higher probabilities toward the east with probabilities of 50% to 60% over Prince Edward Island and central Nova Scotia, and 60% to 70% over the eastern mainland of Nova Scotia and over Cape Breton.

(Right) The map shows the forecast probability of above-normal temperatures, averaged over September to November 2017, over the New England states. It shows a probability of at least 50% of above-normal temperatures over the whole area.

As of mid- to late August, Environment and Climate Change Canada (ECCC) and NOAA’s Climate Prediction Center (CPC) were calling for an increased chance of above-normal September–November temperatures for the entire region. ECCC was predicting an increased chance of above-normal September–November precipitation for P.E.I. and parts of New Brunswick and Nova Scotia, while CPC was forecasting equal chances of below-, near-, or above-normal precipitation for New England.

While ENSO-neutral conditions were in place as of mid-September, CPC indicated there is an increasing chance (55–60%) of La Niña during autumn and winter 2017–18.

According to the U.S. Seasonal Drought Outlook, drought conditions are expected to ease in Maine.

Atlantic hurricane season

NOAA’s 2017 Atlantic hurricane season outlook called for an active season. Already by mid- September, there have been 13 named storms, close to the season average. The outlook updated on August 9 called for 14–19 named storms, including 2–5 major hurricanes, slightly more than the May outlook. Factors contributing to the updated forecast include storm activity through early August, the decreased likelihood of El Niño, warmer-than-normal waters in the tropical Atlantic Ocean, and computer model forecasts. The Atlantic hurricane season runs from June 1 to November 30, with the peak of the season from mid-August to late October.

In mid-August, Hurricane Gert caused high waves, rough surf, and rip currents along the Northeast coastline. Two of the major hurricanes, Harvey and Irma, were record-setting. Based on preliminary data, Hurricane Harvey dumped up to 1317.8 mm (51.88 in.) of rain on southeastern Texas in late August, which could become the all-time greatest rain total from a single storm in the continental United States. In early September, Hurricane Irma maintained max winds of 298 km/h (185 mph) for 37 hours, longer than any other cyclone across the globe according to a report from Colorado State University. These two storms did not significantly impact the Gulf of Maine region.

Gulf of Maine region partners

Environment and Climate Change Canada

Northeast Regional Climate Center

National Oceanic and Atmospheric Administration

National Centers for Environmental Information

National Operational Hydrologic Remote Sensing Center

NOAA Sea Grant Network

Northeast River Forecast Center

Climate Prediction Center

Regional Climate Services

Gulf of Maine Research Institute

State Climatologists

National Integrated Drought Information System

Cooperative Institute for the North Atlantic Region

Gulf of Maine Council on the Marine Environment, Climate Network

Northeastern Regional Association of Coastal and Ocean Systems

University of Maine, School of Marine Sciences



Ellen Mecray (
Samantha Borisoff (

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