Water levels ease on Ottawa River rise on Saint Lawrence

Lake Ontario and the Saint Lawrence River are expected to crest over the next few weeks above the record flood of 2017. The image above is from the Thousand Islands near Gananoque, Ontario in 2017. (CBC)

Tuesday was the 16th consecutive day with some form of precipitation in Montreal, a new record for the month of May, dating back to the late 1800s. It has rained at Trudeau Airport in Montreal on 24 of 29 days so far in May, totalling 95mm. The normal is 81.2mm for the month. Wet and cool weather is forecast to persist into early June as we remain trapped in this annoying cycle.

Cool moist air is dominating Ontario and Quebec, while very warm air remains trapped across the southeastern US. The battleground in between has featured several weeks of strong thunderstorms, devastating tornadoes and record flooding from the southern plains into the Ohio Valley.

In Montreal, the flood warning has been lifted and the long clean-up is underway. Hundreds of volunteers spent last weekend removing sandbags for homes in Pierrefonds and Vaudreuil-Dorion. Just this week, the barriers were removed that had been in place along Saint-Charles Avenue in Vaudreuil-Dorion for the last six weeks. They worked, the municipality managed to save the road as well as homes and businesses along it. The threat appears to have passed as water levels continue to lower. The level of Lake of Two Mountains at Sainte-Anne-de-Bellevue was 23.89 metres on Tuesday, finally dropping below the major flood stage of 23.90 metres.

Concern is now shifting to Lake Ontario and the Saint Lawrence River which continues to rise to record levels. Flooding is occurring along both the Canadian and American shorelines. Lake Ontario is at 75.87 metres, a notch below the record set in 2017 of 75.88 metres. Water levels remain high in all of the Great Lakes. The International Lake Ontario-Saint Lawrence River Board is monitoring the levels and adjusting the outflow of the Moses-Saunders Dam near Massena, New York. This is in an attempt to balance the flooding on both sides of the dam, including here in the Montreal region. However for shoreline residents experiencing flooding for the second time in two years, it seems like little is being done. The lake is expected to crest over the next two weeks, but water levels are forecast to remain high well into the summer.

Crazy May weather from coast to coast

Flood waters are slowly receding in Vaudreuil-Dorion this week. (Valley Weather Photo)

April is typically a month of sharp transitions in the weather. This past April was just plain cold, so as a result May has become the battleground month between winter and summer. The weather is angry all over North America.

In southern Quebec, another 15mm of rain fell over the weekend, much of that coming in the first thunderstorms to rattle across the metro Montreal region. The nocturnal storms crossed the city shortly after midnight early Monday morning. Monday started off with a blanket of thick fog across southern Quebec, followed by strong southwest winds up to 70km/h and the warmest day of 2019 to date, reaching 24C (76F) at my home on Île Perrot.

The rain has little impact on water levels along the Lake of Two Mountains. On Monday, the lake was at 24.15 metres in Sainte-Anne-de-Bellevue, forecast to drop to 24.02 metres by Wednesday. Major flood stage starts at 23.90 metres, with a little luck the lake will continue to drop over the coming days. Meanwhile both Lake Ontario and the Saint Lawrence River continue to rise into major flood stage. Typically the Saint Lawrence River in Montreal does a good job of handling the excess water, but many municipalities remain on high alert. The word is, leave all your sandbags and dikes in place until told otherwise by your town.

A tornado forms over Oklahoma Monday afternoon.

The warm air and storms were part of a larger weather system that produced widespread severe weather over the southern plains and into the Midwest, parts of Ontario and the Eastern Seaboard. There were dozens of reports of tornadoes, wind and hail damage, as well as flash flooding. On the backside of this low pressure system, cold air is pouring into the Rockies and western US plains, with snow falling in several locations including Denver. Widespread winter storm warnings for heavy snow stretch from Colorado to Montana.

A friend sent me this photo of a May snowstorm in suburban Denver on Tuesday morning. This is part of the same low pressure system producing severe thunderstorms across Oklahoma and Texas. (Photo courtesy Amanda Comeau)

Meanwhile, very warm temperatures and strong winds are fuelling wildfires across northern Alberta. The region is very dry, with High Level, Alberta recording a paltry 4 percent of normal rainfall in March and April. According to Alberta Wildfire, the Chuckegg Creek fire has already consumed 69,000 hectares and remains out of control. The fire is only 3 km south of High Level, as a result a full evacuation in the town of 4000 was ordered Monday afternoon at 4pm.

If all this wild weather was not enough for you, the first tropical system of the Atlantic hurricane season formed on Monday. Sub-tropical storm Andrea, located 280 miles west of Bermuda on Tuesday morning, is already weakening with 35mph winds. The storm is forecast to dissipate later today.

A wall of smoke and flames generated from the massive Chuckegg Creek wildfire, looms just south of High Level, Alberta on Monday afternoon. (Alberta Wildfire)

Unsettled weather to continue in Montreal through May

Snow covers spring flowers in Northern Vermont on Tuesday morning. Rare May snow fell across portions of southern Quebec and northern New England on Tuesday, as a late season Nor'easter moved along the Atlantic coast circulating cold, moist air into the region. Below normal temperatures are expected to persist this week in Montreal. (AccuWeather)

Low pressure moving along the Atlantic coast continues to circulate cold, moist air down the Saint Lawrence Valley. Overnight, another 14mm of rain fell in Montreal, bringing our monthly total up over 60mm. The Ottawa River and Lake of Two Mountains remain well above flood stage. The lake level at Sainte-Anne-de-Bellevue was 24.36 metres on Tuesday. The lake should remain stable this week, however major flooding continues to occur along the Ottawa River.

The cold and dreary weather pattern across Ontario and southern Quebec is expected to continue this week, with near or below normal temperatures expected for the foreseeable future. The forecast high on Tuesday in Montreal was expected to be just shy of 10C (50F), this is well below the normal of 19C (66F) for the date. Several locations in northern New England, New Brunswick and southeastern Quebec even had measurable snow overnight. Killington, Vermont reported 15 to 20cm of new snow on the summit. The cold weather is even impacting the northeastern US, New York's Central Park recorded its coldest May 13 ever on Monday, with a high of only 48F. The previous record was 49F set in 1914.

The weather is actually warmer in northern Quebec today, with Eastmain on James Bay the warmest location in the province at 2pm Tuesday, at 20C (68F). Moosonee in northern Ontario is the warmest location in the country at 22C (72F).

Snow along State Route 112 at Kancamagus Pass in northern New Hampshire on May 14. (Photo by Chris Whiton)

Unfortunately the unsettled weather is expected to continue well into next week, with perhaps a decent day or two somewhere in between. An active weather pattern will produce plenty of opportunities for additional rainfall through the end of the month.