Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for today

 

Regional Impacts

Isolated Non-severe thunderstorms are expected today with sporadic downpours over southwestern NF and the Burin.

 

Slight risk of a thunderstorm over the Cape Breton Highland.

 

Convective Discussion

A cool and dry northwesterly flow prevails over the Maritimes this morning. Over the Gulf of St. Lawrence, a cold low is triggering widespread showers mainly over southwestern NF and the Burin. The airmass is unstable enough (CAPE values of 200-300 J/kg) to support thunderstorm activity. One such cluster is currently detected by CLDN at the intersection of Cabot strait, southwest coast and Banquereau regions. A few lightning flashes were also detected along the coast east of Port-aux-Basques. The instability will be maintained ahead of the cold pool aloft. Some of the forecast guidance is suggesting a slight risk of thunderstorm over the Cape Breton Highlands in response the approach of the cold pool and some extra orographic lift.

 

 

Thunderstorm Outlook for Friday

 

Some of the global guidance is suggesting the possibility of some shower activity associated with a weak surface feature

over central NB.

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

No thunderstorms forecast.

 

Convective Discussion

The hot and humid airmass is slowly exiting the region to the south this morning. The axis of moisture (linked to precitable water of 40+ mm) is now extending from southern New England and then offshore to the Scotian Slope. This where convective activity persists at this hour. Otherwise, no thunderstorms are forecast over land today.

 

Convective Outlook Valid for Today

Regional Impacts

 

New Brunswick:  Isolated to scattered thundershowers this afternoon and evening.  Potential severe thundershowers giving downpours, gusty winds and hail.

NS/PEI: A risk of thundershowers this afternoon and evening.

NFLD/Labrador: Nil.

 

Convective Discussion

 

A cold front will cross New Brunswick afternoon and Nova Scotia this evening. ML cape values of 1000-1500 J/kg are expected and straight line wind shear near 30 kts.  Freezing levels are high but decent cape exists in the hail growth zone. Dry mid layers will allow for gusty conditions this afternoon. Precipitable water values will be near 40 mm so rainfall is a concern. The upper support/dynamics are not strong so this event will be mostly driven by the surface trigger of the cold front and general instability caused by daytime heating.

 

Thunderstorm Outlook for Day 1

 

Convective Outlook Valid for the Maritimes Tomorrow

Regional Impacts

 

NS/PEI: A risk of thundershowers Tuesday.

NFLD/Labrador: Nil.

New Brunswick:  Isolated to scattered thundershowers tomorrow afternoon.  Potential for downpours and gusty winds.

 

Convective Discussion

 

In New Brunswick a cold front will be crossing the region Tuesday afternoon. ML cape of 500-1000 J/kg is expected and straight line wind shear of 20 to 30 kts.  Dry mid layers will allow for gusty conditions in the afternoon. Precipitable water values will be near 30 mm so rainfall maybe a concern.

 

Thunderstorm Outlook for Day 1

 

Convective Outlook for Atlantic Canada Valid for Today

Regional Impacts

 

NS/NB/PEI/NFLD: Nil.

Labrador: Isolated to scattered thundershowers this afternoon and evening.  Potential for downpours and gusty winds west.

 

Convective Discussion

 

In Labrador, ML cape is generally low (300-500 J/kg) and the shear is 40 to 50 kts so any storms that develop will be mostly pulse in variety. The low level jet is quite high (50 knots plus) so gusty winds are likely even without any thunderstorms. Dry mid layers will also help with gustiness this afternoon. Precipitable water values are near 35 mm so rainfall maybe a concern but the cells will be moving very fast.

 

Thunderstorm Outlook for Day 1