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

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

Thunderstorms likely in western Labrador giving heavy downpours of rain and possible small hail. Gusty winds up to 40 knots are possible.

Non-severe thundershowers possible in western New Brunswick.

 

Convective Discussion

There is lots of low-level heat and moisture to give energy for convection in Atlantic Canada. However, cloud cover and low CAPEs are limiting factors in the Maritimes.

 

The best chance for significant convection today is in western Labrador. There is upper level dynamics with a 50-60 knot jet at the 250 level. The 0-6 km shear if about 40 knots. If there is sufficient sunshine as a trigger, the CAPE is between 1000 and 1500 J/kg in the extreme west and about 500 J/kg east of Churchill Falls.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

Western Labrador: risk of afternoon and evening thundershowers.

Northern New Brunswick: Risk of afternoon and evening thundershowers.

 

Convective Discussion

Isolated thundershowers are expected to form over western Labrador this afternoon in association with a trough of low pressure moving into the region from Quebec. La Grande tephi shows decent shear but somewhat of a cap in the mid-upper levels. PWAT is around 36 mm. Expected non-severe cells to develop with locally heavy rainfall and gusty winds.

 

There is also the risk of a thundershower this afternoon and evening across northern New Brunswick. KCAR tephi shows 500+ CAPE but very little shear. There is also the lack of a trigger so if cells do develop they will be slow moving. PWAT is around 35 mm so heavy downpours would be the main concern. Looking at both the YQI and YAW soundings it will be quite difficult to generate CBs in NS. However local areas of convergence could generate an isolated cell.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 2