Gulf of Maine region quarterly climate impacts and outlook: September 2018

Gulf of Maine region, September 2018

Gulf of Maine region significant events – June to August 2018

Long description

Map of the Gulf of Maine region with text listing the following significant event highlights:

  • Widespread frost in early June caused crop damage
  • Several severe thunderstorms impacted the region over the summer
  • Heat waves affected the region throughout July and August

In early June a significant frost event impacted the Maritimes and northern Maine.

A June 14 rain event brought up to 40 mm (1.57 in.) to the Maritimes and associated thunderstorms caused over 7,000 customers in New Brunswick to lose power due to lightning strikes.

A slow-moving, low pressure system brought up to 100 mm (3.94 in.) of rain to southern parts of the Maritimes on June 28 to 29. Lightning strikes during this event caused one death and a house fire in New Brunswick.

From July 1 to 5, high humidity along with unusually warm temperatures throughout the region resulted in heat indices/humidex values over 43°C (110°F) in some areas, prompting heat warnings to be issued.

On July 10, strong thunderstorms crossed the region, bringing damaging high winds, power outages, hail, and localized heavy rain. Up to 100 mm (3.94 in.) fell in northern New Brunswick. Large hail which damaged cars, buildings, and crops was reported in Maine and northern New Brunswick.

A heat event affected the Maritimes on July 22-25, as temperatures reached as high as 32°C (90°F) and humidex values reached as high as 39°C (102°F). The heat forced some businesses to close and extra caution to be taken during outside activities. Locations in New Brunswick reported 13 days with temperatures greater than 30°C (86°F), much more than the normal 3.5 days. Heat waves throughout August led to heat advisories being issued and record warm overnight lows in New England. The Maritimes also experienced heat events and many days with high humidex and heat warnings. During the first week of August, St. Stephen, N.B. had a humidex value of 41°C (106°F) and Maritime Electric (P.E.I.) reported that use of air conditioning this summer had resulted in higher-than-normal electricity loads. The extreme heat over the summer caused additional hardship for the homeless in Nova Scotia, and one confirmed death in New Brunswick.

Strong storms on August 6 to 7 brought high winds and intense lightning that knocked down trees and impacted power distribution in parts of southern New Brunswick with more than 50,000 customers losing power.

Severe storms in the Maritimes on August 9 to 10 brought flooding rain, including 89 mm (3.50 in) reported in Harvey Bank, N.B., golf-ball-size hail, and power outages.

On August 11 to 12, heavy rains flooded streets and homes in Massachusetts; the town of Lynn had 207 mm (8.14 in.).

During a rain event on August 17 to 18, Sussex, N.B. received 129 mm (5.08 in.) of rain, which surpassed the August daily extreme of 95 mm (3.74 in.). The heavy rain caused localized flooding and road closures in Charlottetown, P.E.I.

Regional climate overview – June to August 2018


Summer departure from normal

Long description

Map of the Gulf of Maine region showing the mean temperature departure from normal, averaged over June July and August 2018. 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.

The map shows that averaged over the three months much of the region, including New Brunswick, Prince Edward Island, and southwestern Nova Scotia, was warmer than normal, with the average temperature departure from normal in the +1 to 2°C range. The temperature anomaly in eastern Nova Scotia was less strong, in the range -0.5 to +1°C.

Summer temperatures (averaged over June, July, and August) were near normal to 2°C (4°F) above normal. Caribou, ME, had its warmest summer on record. June temperatures ranged from 4°C (7°F) below normal to 1°C (2°F) above normal. July temperatures ranged from near normal to 4°C (7°F) above normal. August temperatures ranged from 1°C (2°F) to 4°C (7°F) above normal. While several locations had their warmest July and/or August on record, June was much colder than average.


Summer 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 2018. Above normal (110% of normal and above, up to 200% of normal) 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.

The map shows that the driest conditions were over northern New Brunswick, northern Maine, and southwestern sections and the Atlantic coast of Nova Scotia. In these locations the precipitation was half or less than half the normal amount (50 to 75% of normal). Southeastern New Brunswick and north-western sections of mainland Nova Scotia were wetter than normal, generally in the range of 110 to 150% of normal. Some southwestern sections of New England received up to 200% of the normal amount of precipitation. Elsewhere the pattern was more varied with some locations averaging near normal.

Summer precipitation (accumulated from June to August) ranged from 50% to 150% of normal. June precipitation ranged from 50% to over 200% of normal. July precipitation ranged from less than 25% in the Maritimes to over 150% of normal in parts of New England. August precipitation ranged from less than 25% of normal in parts of Nova Scotia to 200% of normal in parts of New England

Sea surface temperature

Departure from normal

Long description

Map of sea surface temperature departure from normal in the Gulf of Maine Region, averaged over June to August 2018. 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 map shows higher than normal sea surface temperatures over nearly the entire area. Over most of the Gulf of Maine the temperature anomaly was +1 to 2°C. Some areas over the central basin parts of the Gulf of Maine and off the continental shelf, south of Nova Scotia, were up to 3°C above normal.

Summer sea surface temperature anomalies were 1°C (2°F) to 3°C (5°F) above the 30- year average over the region. These positive anomalies were strongest over the deeper central basin portions of the Gulf of Maine and off the shelf, south of Nova Scotia where temperatures approached 3°C (5°F) above normal. Ocean heat waves are becoming more common in the Gulf of Maine. On August 8, the sea surface temperatures measured were the second warmest ever observed there.

Regional impacts – June to August 2018


The increasingly dry conditions in June prompted over 75 public water suppliers in Massachusetts to enforce varying degrees of water bans. Abnormally dry conditions in June and early July across parts of New Brunswick contributed to much lower-than-normal river levels. During July many farmers in parts of northern New England had reduced harvests and heat stressed crops. Across the Maritimes, the Fire Weather Index was high to extreme at times, but despite dry, hot conditions across Nova Scotia, the number of forest fires and hectares burned was not unusual, possibly due to the high humidity. The lack of rain in P.E.I for the second year in a row caused concerns about low potato yields, but late-season rains may save the crop. Over the summer, moderate drought persisted or developed over portions of Nova Scotia and coastal Maine.

Long description

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

The map shows that southwestern Nova Scotia was experiencing moderate drought or abnormally dry conditions, with short and long term impacts expected. It shows that conditions were abnormally dry over extreme northwestern New Brunswick, over northern and southern Maine, and over New Hampshire. No drought conditions were noted elsewhere in the Gulf of Maine region.

Logos of contributing agencies are shown with the map, including from left to right, top: USDA (US 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 Oceanic and Atmospheric Administration), Agriculture and Agri-Food Canada, and Environment and Climate Change Canada.

August 31, 2018 North American Drought Monitor


Blue-green algae were reported in some rivers and lakes in New Brunswick and in Lake Banook in N.S. in late July and early August, creating a concern for human and animal health and prompting a warning for residents to not swim or allow pets into the water. The algae is linked to the hotter than normal weather this summer. Two ocean beaches in southwest Nova Scotia were closed for the first time ever due to high bacteria levels which were linked to the abnormally high temperatures and humidity and relatively light winds observed this summer.

Harmful Algal Bloom. Credit: NOAA (US National Oceanic Atmospheric Administration)
Long description
Photograph of harmful algal bloom. The photograph shows water covered in green algae near a dock and a boat ramp.

Forestry and agriculture

Colder than normal conditions in early June resulted in widespread frost in the Maritimes and northern Maine, which heavily damaged berry, grape, and apple crops, and slowed down corn. The hard frost also affected Christmas tree crops in Nova Scotia and P.E.I., damaging new growth and affecting the quality of the trees. An unusually warm July brought an early end to the berry picking season, already challenged due to the June frost. Southern pine beetles, which caused over one billion dollars in losses to the timber industry in the southeastern U.S., have been found as far north as New England. Research showed these beetles could reach Nova Scotia by 2020 due to a warming climate. Hot and dry conditions forced some farmers in Nova Scotia to change their harvesting practices this year.

Right whales

Right whale sightings in June and July caused fishing areas to close. Sightings in the Gulf of St. Lawrence are thought to be linked to warming ocean temperatures and migration of their food sources into cooler waters farther north. In late August a dead right whale was spotted off the coast of Massachusetts.

Regional outlook – Autumn 2018

Temperature and precipitation

For September–November, the Environment and Climate Change Canada (ECCC) and NOAA's Climate Prediction Center (CPC) outlooks favor above-normal temperatures and call for equal chances of below-, near-, or above-normal precipitation.

Long description

The maps show the probability of above-normal temperatures averaged over the months of September to November.

The map issued by ECCC (left) covers the Maritimes and the Gaspé peninsula of Quebec.  It shows that chances of above-normal temperatures increase from from west to east, with chances of 60 to 70% over northwestern New Brunswick to 80% or more over Nova Scotia and Prince Edward Island.

The map issued by NOAA’s Climate Prediction Center (right) covers the New England states. It shows probabilities of 50 to 60% for above-normal temperatures for the entire area.

Probability (%) of  above-normal (A) temperature. Environment and Climate Change Canada (ECCC) temperature map (left) produced August 31. U.S. Climate Prediction Center (CPC) temperature map (right) produced August 16.
Atlantic Hurricane Season
# Through Sep. 20 Aug. 9 Outlook Average Season
# of Named Storms 10 9 to 13 12
# of Hurricanes 5 4 to 7 6
# of Major Hurricanes 1 0 to 2 3

By September 20 there had been 10 named storms of which 5 were hurricanes, including Florence which made landfall in North Carolina September 14 causing catastrophic flooding. NOAA's 2018 Atlantic hurricane outlook, updated August 9, had indicated a less active hurricane season than initially predicted in May, due to the forecast development of El Niño in the fall, cooler-than-average sea surface temperatures in the tropical Atlantic Ocean, and strong wind shear.

El Niño Southern Oscillation (EÑSO)

According to the U.S. Climate Prediction Center, the chance of El Niño is 50-55% during fall, increasing to 65 to 70% during winter.

Long description

Time series graph of the official probabilistic El Niño Southern Oscillation (ENSO) forecast, issued in early September by the US Climate Prediction Center (CPC) and the International Research Institute (IRI) for Climate and Society.

EÑSO state based on NINO3.4 Sea surface temperature (SST) Anomaly

Neutral ENSO: -0.5 °C to 0.5 °C

Vertical bars show the probability, covering 3-month intervals, of each EÑSO condition (La Niña, neutral, and El Niño) with bars in blue, grey, and red, respectively. The 3-month intervals overlap by two months. The time period extends from the summer/autumn months of August, September, and October to spring the following year (April, May, and June).

Lines of the equivalent colours show the climatological probability of each condition over the 3-month intervals. These show that the neutral condition is the most probable in from early spring through summer to fall. El Nino or La Nina conditions are somewhat more probable than neutral in the late fall/early winter months (November to February).

The bar graph shows that the neutral condition is the most probable (at over 60%) for the late summer and early fall (August, September, and October), with El Nino the next most probable condition. The chance of an El Nino increases to become greater than the neutral condition in the fall (in the 3-month interval of September, October, and November).

The chance of El Nino is over 60%, much higher than the chance for neutral conditions, for most of the fall and winter (from the October, November, and December interval through to the January, February, and March interval). El Nino remains the most probable condition into the spring. The probability of La Nina conditions is negligible for the entire period.

Early-September CPC/IRI (Climate Prediction Center/International Research Institute for Climate and Society) Probabilistic El Niño Southern Oscillation (EÑSO) Forecasts

Gulf of Maine partners

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