Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Southern Grand Banks may see some elevated thundershowers today and overnight. No other regional impacts are expected.

 

Convective Discussion

 

An upper-level low is slowly tracking over the southern marine district and will stall over the Grand Banks today and tomorrow. Most convection associated with the low is now south of the Maritimes marine waters, however, a strong southerly push over the eastern Grand Banks and upper level jet over the area will help lift. The highest risk for embedded convection will be in the overnight hours into Friday morning, when cloud top cooling will also help to enhance the destabilisation aloft.

 

Thunderstorm Outlook for Day 1

 

 

 

Thunderstorm Outlook for Day 2

 

A large trough will approach Atlantic Canada from central/northern Quebec on Friday and a secondary trough further south over southern Quebec. At this time, the dynamics appear more favourable further west over Quebec as the air aloft over New Brunswick remains too warm and would need a good amount of surface based heating in order to break the cap. Showers are expected to move into western New Brunswick in the mid afternoon so cloudiness out ahead in the morning could be key factor for anything getting going other than showers. Low risk has been added for now.

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Eastern Nova Scotia, southeastern Newfoundland, and the southern marine district will see locally high rainfall amounts with embedded thunderstorms possible mainly over the southern marine waters as an upper level features slowly moves eastward south of Nova Scotia today.

 

Convective Discussion

 

An upper-level low south of Nova Scotia will move eastward toward the Grand Banks today and stall over the area into Friday. For today, the primary threats for embedded convection will remain offshore near and ahead of the low centre, but there could be some enhancement this afternoon over eastern parts of Nova Scotia including Cape Breton as the low drifts further east. This system had a history of dropping high rainfall amounts over parts of southwestern Nova Scotia with precipitable water values of near 40 mm were and this may be the case today over eastern portions.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

The upper-level low will stall over the southeastern Grand Banks where some embedded convection may develop in the overnight hours into Friday morning.

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Nova Scotia.. A stationary area of thunderstorm development over southwest Nova Scotia could produce locally heavy rainfall amounts of 20 to 30mm.

 

New Brunswick.. A low probability of isolated thundershowers late this afternoon or this evening.

 

Convective Discussion

 

Thunderstorm development is expected to continue ahead of and near an upper low that is slowly progressing towards the Maritimes. Most of the convection will be triggered aloft but daytime heating could contribute to increased updraft strength this afternoon. There is some indication that a quasi-stationary feature could set up possible giving heavy rainfall amounts to some parts of southwest Nova Scotia.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Isolated Thunderstorms could develop over New Brunswick. No Severe weather expected.

 

Convective Discussion

 

There is a slight potential for thunderstorms to develop over New Brunswick today. Overall cape values are low at less than generally 500 j/kg but with high dew point temperatures. The approaching trough moving from the north may provide a sufficient trigger for storms to initiate. However with weaker updrafts severe storms are unlikely.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

For New Brunswick.. Heavy Downpours and winds gusting to 70km/hr are possible in thunderstorms.

 

For Labrador.. In addition to the heavy rain, downpours in thunderstorms and gusts to 50 km/hr are possible in thunderstorms.

 

Convective Discussion

The amount of available moisture available today is very high with precipitable water values between 40 and 50mm for most of the region. The main synoptic feature is the trough of low pressure that is moving through Labrador and eastern Quebec today. The trough should be sufficient to trigger some thunderstorms over Labrador but updrafts should remain weak enough that severe thunderstorms are unlikely, however there is still a slight possibility of severe storms and the situation should be monitored. Over New Brunswick slightly stronger updrafts will increase the potential for severe thunderstorms with mean layer capes between 1000 – 1500 j/kg. Thunderstorms are likely to move into the area this afternoon, and with low level shear values exceeding 30 knots there is some potential for organized convection. Watches may be required.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2