Tuesday, July 28, 2015

Massive Manitoba tornado - heat advisory for Montreal

A spectacular shot of Greg Johnson's team tracking a large tornado near Tilston, Manitoba Monday evening. 
(Tornado Hunters)
It was a wild weather night across southern Manitoba on Monday as a strong low pressure area lifted north from the Dakotas into Saskatchewan. The ingredients were perfect for supercell thunderstorms and mother nature did not disappoint. A large wedge shaped tornado with multiple vortices was on the ground for nearly 3 hours according to Environment Canada. The tornado, up to 4km wide at times, was largely in rural areas of southwest Manitoba near Tilston. Storm chasers in the area recorded winds in excess of 120mph (200km/h). They were likely stronger closer to the tornado with pavement being scoured from highways. At first light we will see if more damage has occurred. Hail the size of baseballs also fell in the region along the North Dakota border. Heavy rain on the backside of the storm produced flooding in Saskatchewan including Regina, where more rain fell yesterday (78.2 mm), than in the last three months. Flooding was also reported in my old home town of Gravelbourg, Saskatchewan. More storms are forecast today in Manitoba, with strong winds in Saskatchewan.

Lightning illuminates the sky on L'Ile Perrot last night. (ValleyWeather)
 Meanwhile southern Quebec had a warm and humid day Monday followed by strong thunderstorms last evening. The storms rolled across the Island of Montreal and L'Ile Perrot after 8pm. Heavy rain and frequent lightning occurred, putting on quite a show. I measured 16 mm of rain at my home in less than 30 minutes along with vivid lightning, lasting over one hour. Lightning is extremely dangerous, and this was highlighted last night as a cyclist was struck in the Rosemont district of Montreal. He was listed in critical condition this morning after going into cardiac arrest. The storms also knocked out power to thousands in Quebec. A fire in Brossard was blamed on a lightning strike and there were reports of hail in St Hubert. Numerous trees were knocked down across the Beauce along with flooding. Between 50-100mm of rain fell near the New York State border in Huntingdon.

The warm and humid weather will persist through Thursday with more storms likely each day. A heat advisory is in effect stretching from southern Ontario into southern Quebec. High temperatures at or above 30C along with high humidity, will make it feel more like 40C. Stay hydrated and keep an eye on the sky for late afternoon and evening storms.

Street flooding from Gravelbourg, Saskatchewan after more than 75mm of rainfall Monday. 
(Gravelbourg Fire Department)

Monday, July 27, 2015

Active weather week - warm & humid with thunderstorms

More widespread severe weather is forecast for the southern Prairies today and tonight. There is an elevated risk of dangerous storms in southern Saskatchewan and Manitoba today. Above: Strong thunderstorms produced this funnel cloud near Calgary late last week. (CBC News)
An unseasonably strong area of low pressure will move from the northern US plain states into southern Manitoba over the next 48 hours. This storm will push a surge of warm and humid air from eastern Saskatchewan across the Great Lakes and into Quebec this week. Along the path of the storm very strong thunderstorms are likely, with heavy rain, up to 30mm behind the system. There is an elevated risk of large hail and tornadoes across eastern Saskatchewan and southern Manitoba today into tonight. Already this morning watches and warnings are on place across the southern Prairies. Temperatures will soar into the low 30's (low to middle 90's) from Manitoba across southern Ontario and into southwest Quebec this week. Humidex readings will approach 40C (104F) in many locations including Toronto and Montreal.

For the specifics, we are looking at hazy sunshine in Montreal through Thursday with daytime highs near 30C (86F) and overnight lows near 21C (70F). Areas of fog are reported this morning in the region, and may form each morning this week. Each afternoon into the early evening there is a 40 per cent change of scattered thunderstorms, some may be strong. A cold front will bring more widespread showers and thunderstorms by Thursday. Cooler and dryer weather will return to southern Quebec by next weekend.

Friday, July 24, 2015

More showers and storms for southern Quebec

Numerous showers and thunderstorms developed in southern Quebec on Wednesday and Thursday including this one near Vaudreuil. The trend will continue today. (ValleyWX)
An upper level low spinning over southern Quebec has maintained a pool of cool and unstable air over the region. Montreal has had very unsettled weather the last 48 hours, with numerous showers and thunderstorms. The trend will continue today with showers and thunderstorms scattered about all day. The clouds and precipitation will help to keep temperatures cooler than normal in the low to perhaps middle 20's. Additional rainfall may be significant is some of the storms, adding to the impressive totals so far this month. Small hail is also possible. I have measured 104.5mm (over 4 inches) of rain here at my home on L'Ile Perrot, 105.9mm has fallen at Sainte-Anne-de-Bellevue with 87.2mm at Trudeau Airport. The clouds and frequent rain has meant a cooler than normal July for the city.

Warmer air will nudge the upper level low northeast and out of Quebec this weekend. (AccuWeather)
Looking ahead, high pressure will briefly clear the skies over Montreal and southern Quebec tonight into Saturday with sunshine forecast, lows of 16C (60F) and highs up to 26C (79F) Saturday. By Sunday the heat and humidity will be on the rise with temperatures climbing into the upper 20's and even low 30's by Tuesday. Numerous showers and thunderstorms will be around Sunday and next week in the warmer more humid air mass.

El Nino
The much talked about El Nino, that ribbon of warmer than normal water in the Pacific Ocean off the South American coast, continues to upset weather patterns across the globe. The current El Nino is showing no signs of leaving anytime soon and may be strengthening. It has led to a very unsettled and at times destructive weather pattern across North America from heavy rain and flooding in California to intense wildfires in northern Saskatchewan. El Nino has also been responsible for an increase in severe weather across central portions of the continent as well as cool weather for Atlantic Canada and Quebec.

Tuesday, July 21, 2015

More thunderstorms today - then cooler & less humid

It was hot at the New Hampshire Motor Speedway for the NASCAR race on Sunday. Thankfully the heavy thunderstorms shown above remained just north of the venue until after the race ended. (Valley Weather Photo)
Another round of showers and thunderstorms is likely today for Montreal along a cold front slipping into Quebec and Ontario. The storms may have some brief heavy rain but should not be as strong as the severe weather outbreak that occured over the weekend. High temperatures will be warm again today near 28C (83F) before a cooling trend to end the week.

Over the weekend strong thunderstorms developed in the very humid air mass locked in place over the region. Tropical dew points and a strong jet stream allowed some of the storms to be quite strong including several funnel clouds and hail. A tornado warning was even issued from Kemptville, Ontario east towards the Quebec border. The Sunday morning storms brought very heavy rain to southern Quebec including 65mm measured at my home on L'Ile Perrot, half of that in a 20 minute period around 6:20AM. Sainte-Anne-de-Bellevue recorded 58mm, while Trudeau Airport had 35mm.

Major flooding from thunderstorms occurred in Barre, Vermont late Sunday night. The photo above is the clean up Monday morning. (VPR Photo)
The other story over the weekend was the elevated heat and humidity levels making it very uncomfortable. Montreal had a temperature close to 30C (86F) on Sunday with humidex readings near 40C (104F). I was at the NASCAR race in Loudon, New Hampshire where the temperature soared to 32C (90F) with heat index values well over 100F. Several of the drivers had to be treated for heat related issues, and the venue actually ran out of bottled water! Elsewhere the thunderstorms produced major flooding across portions of northern Vermont and New Hampshire. In Barre, Vermont mud and water flowed into several neighborhoods after torrential rain from severe storms. Nearly 80 homes were flooded and some have been left uninhabitable.

Friday, July 17, 2015

Warm and humid weekend ahead for Montreal

Heat and humidity will surge into southern Ontario and Quebec this weekend. (AccuWeather)
After a couple of cooler days with lower humidity levels in southern Quebec, the heat will begin to build once again today heading into the weekend. We are starting what is typically the biggest holiday period in Quebec as many take summer vacations. The weather will also be typical for middle July as warm and very humid air invades southern Quebec and Ontario. Today will be sunny but with increasing clouds as a warm front moves east from the Great Lakes, the high should be from 25 to 28C (77 to 82F). Showers and even an isolated thunderstorm will develop overnight and Saturday across eastern Ontario into Quebec and New York as temperatures remain mild overnight at 19C (66F). Saturday will be muggy and warm with showers and thunderstorms and a high near 27C (81F). Sunday and Monday look similar with more scattered storms, warm and humid with highs in the upper 20's.

There is a risk of some severe weather late Sunday and Monday. I understand that I have mentioned this often this summer and seemingly the storms have avoided metro Montreal. They have however affected other portions of southern Quebec, eastern Ontario and northern New England/NY. It is important to remember that thunderstorm activity can be very isolated. That does not diminish the dangers from lightning, hail  and winds. If storms are forecast, or a weather watch or warning is in effect, and you have any outdoor activity planned, be aware of the sky. Also when the thunder roars go indoors. Lightning injuries and fatalities have been on the rise across North America this year.

Tuesday, July 14, 2015

Gusty thunderstorms to break the humidity in Quebec

NOAA image of Tropical Storm Claudette located well east of Delaware, over the Atlantic Ocean, late Monday.
 Monday was the warmest day of 2015 across southern Quebec and featured finally our third 30C high for the city  this year, 30.1C at Trudeau Airport. Other reporting stations across the region had highs well into the 30's including 32.6C on L'Ile Perrot, 31.2C in Cornwall and St Anicet and 30.6C in Ottawa. Downtown Montreal was scorching with several locations showing mid-afternoon highs greater than 32C (90F) and humidex values close to 40C. Temperatures remained very warm overnight with lows from 21 to 23C (70 to 73F) across metro Montreal. Scattered thunderstorms Monday afternoon affected mainly the area from Valleyfield east to Granby and south to the US border. A much more widespread shower and thunderstorm event will develop later today as a cold front slices into the warm and humid air. High temperatures will reach 30C (86F) again today before the front arrives after sunset. Thunderstorms this afternoon and tonight have the potential to produce very heavy rain in a short period of time. Overnight storms have already produced flash flooding across western New York. By Wednesday expect a break in the high humidity with clearing skies and pleasant highs of 24C (76F) in Montreal. The fair weather will hold into Friday.

Environment Canada forecast track of Tropical Storm Claudette into Newfoundland on Wednesday. (Canadian Hurricane Centre)

Tropical Storm Claudette
The third tropical system of the 2015 season formed well east of the Carolina's late Sunday. Claudette developed over the warm waters of the Gulf Stream. This morning the system is located approximately 500km south of Halifax, Nova Scotia, and moving northeast at 20mph. Claudette is expected to slowly weaken and become a post tropical cyclone later today as she heads towards the colder waters around Newfoundland on Wednesday. Gusty winds, a period of steady rain and rough seas will affect the south and east coast of Newfoundland with just some wave action expected elsewhere in eastern Atlantic Canada.

Monday, July 13, 2015

Warm & humid start to the week for Quebec & Ontario

The annual Valleyfield Regatta hydroplane races in southern Quebec had perfect weather over the weekend. (Photo Regates Valleyfield).
It is a grab bag of weather across North America as this El Nino driven summer continues to unfold. Some of the warmest air this summer has streamed into southern Quebec and Ontario over the last few days with daily highs over the weekend in the upper 20's and low 30's. I recorded 31C (88F) on L'Ile Perrot on Sunday, while the typically cooler Trudeau Airport had 29.5C (85F). So officially we are still stuck at two 30C days for summer 2015 in Montreal. It was a dry weekend in Montreal but some rather decent thunderstorms with hail and gusty winds did affect the Gatineau region into southeastern Ontario late Sunday afternoon.

Today will be another warm and humid day with scattered afternoon thunderstorms and a high near 30C (86F). Tonight will be warm and humid with lows in the low 20's (70F). On Tuesday more sunshine and warm highs will fade behind afternoon clouds as a cold front arrives and cools us down for Wednesday. More showers and some thunder are possible along that front Tuesday evening. The high on Tuesday will be 30C (86F) for Montreal, lowering to 25C (77F) for Wednesday with clearing skies.

July snow stunned travelers along the higher elevations of the eastern Sierra Nevada mountains in Northern California on Friday, including those at Tioga Pass shown above. (CalTrans Photo.)
Weather features over the weekend included big thunderstorms across the southern Prairies with large hail, strong winds and even a few isolated tornadoes. Most of the country remained rather warm on Sunday with more heat forecast to start the week. It remains dangerously dry across portions of western Canada. Despite the fact it is July, an upper level low over northern California, produced some July snow across the eastern Eastern Sierra Nevada Mountains. Look for more bizarre weather across North America as the El Nino off the South American Pacific coast continues to strengthen into the fall.