Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NL: Chance of non-severe thunderstorms.

NB/NS/PEI/Labrador: None.

 

Tonight

NB/NS/PEI/NL/Labrador:  None.

 

Wednesday

NB: Chance of non-severe thunderstorms.

Labrador: Chance of embedded thunderstorms.

NS/PEI/NL: None.

 

Convective Discussion

A trough will track across Newfoundland later today. Isolated thundershowers are possible ahead and near the trough over northeast Newfoundland this afternoon. Limited CAPE will keep anything from getting too organized. On Wednesday, a low pressure system will move into Labrador, with a frontal boundary extending from the low back into the St. Lawrence River Valley. Isolated thundershowers will be possible along this boundary Wednesday afternoon over extreme northwestern New Brunswick. Limited CAPE should keep anything from getting too organized. Over Labrador some embedded thundershowers are expected on Wednesday.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today, Tonight and Tomorrow

For June 15^th, 2025

 

Regional Impacts

 

Today: Some scattered thunderstorms possible in southeast Labrador today, main threat is strong wind gusts. Isolated chance of a thundershower over north-central Newfoundland and west-central New Brunswick this afternoon.

 

Tonight: No thunderstorms expected.

 

Tomorrow: No thunderstorms expected.

 

Tuesday: Slight risk of a thundershower over north-central Newfoundland on Monday afternoon.

 

Convective Discussion...

 

A few areas of interest are at play today, with the most prominent being southeast Labrador. Here, scattered thunderstorms are expected to develop in the warm sector this afternoon ahead of an approaching cold front moving through the region. Modest mixed-layer CAPE and effective shear will aid in the organization of some of these thunderstorms, however a lack of surface moisture and very dry low-levels will likely keep storms fairly elevated. Strong dynamics over the region may be enough to support an isolated supercell given enough CAPE, though this risk is low. As such, strong winds are the main hazard with these storms, with gusts of 70 to 80 km/h possible. Small hail and some locally heavy downpours are also possible.

 

In addition, a few isolated thundershowers are possible in west-central New Brunswick and north-central Labrador this afternoon under a diverging 500 mb jet with some embedded pockets of weak vorticity. Low CAPE and minimal shear will keep these storms from becoming organized and are not likely to be very long-lived, however some locally heavy downpours will be possible.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Thunderstorm Outlook for Tuesday

 

Forecaster: Copp

 

Convective Outlook Valid for Today, Tonight and Tomorrow

Today: Isolated non-severe thundershowers possible over central Nova Scotia and south-central Labrador this afternoon. Main threat is brief heavy downpours, with no significant accumulations.

Tonight: No thunderstorms expected.

Tomorrow: Isolated risk of a thundershower along a cold front extending from Labrador to New Brunswick tomorrow afternoon.

Monday: No thunderstorms expected.

Convective Discussion...

A fairly quiet day is expected today, with a few areas that may see a couple lightning strikes this afternoon. First, a weak shortwave moving across New Brunswick this morning will pass over PEI this afternoon, triggering some showers along the Cobequids in central Nova Scotia. Higher dewpoints and a slight upslope enhancement are expected to aid in convection here today. These showers will have a slight chance to produce a lightning strike or two as they move east, however very little shear and minimal CAPE will likely inhibit the lifespan of these cells.

A second weak shortwave moving southeast along the Labrador coast is producing some scattered showers today across south-central Labrador. Some stronger low and mid-level jets over this region highlight the risk for some of these showers to produce some lightning strikes early this afternoon, though this risk remains low.

Tomorrow, a weakening cold front moving across Atlantic Canada may trigger some thundershowers in parts of New Brunswick and Labrador, but at this time the risk is low.

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Thunderstorm Outlook for Monday

 

Forecaster: Copp

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today: No thunderstorms expected with a trailing cold front departing, smoke aloft, and general building ridge conditions.

Tonight: No convective activity. Pockets of frost.

Tomorrow: Non-severe thundershowers/showers are forecast across portions of eastern and northern mainland NS in the afternoon from daytime heating. Labrador could see a few ridge-rider cells move from the NW to the SE in the day. Airmass is fairly dry and only a few mm of rain would be expected.

Sunday: Weak trof line across northern tier of NB and SE Labrador. No hazards expected other than a lightning strike or 2.

Convective Discussion

Much quieter day than yesterday expected. Cold front and Jet dynamics have pulled out of the Maritimes. Mid-levels are drying out significantly on this morning’s soundings. Sfc dewpoints in NB are struggling to reach 5 in places. Haze and smoke aloft are also further adding to stability. Saturday has low and skinny CAPE, and minimal shear (effective is only 10kts) across parts of NS – could see a spark or 2 with the tallest TCU. Single cell is the expected storm mode with not much motion. Sunday, this setup is established in northern NB and across eastern Labrador. Risk of -TS is now in the public bulletins.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Thunderstorm Outlook for Sunday (Day 3)

 

 

Forecaster: Tirone.

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today: 1. Thundershowers are possible along an advancing trof line in eastern Labrador. 2. Additionally thunderstorms are possible in central Nfld (vicinity Gander). Only hazards here are 5-10mm of rain. 3. The weather with the greater dynamics at play is over the Maritimes, with thunderstorms approaching severe limits later today across parts of SE NB, central PEI and northern and central mainland Nova Scotia. Please see the detailed yellow area on the graphic for all counties included. Hazards here include wind risk, hail, and near 25mm of rainfall in the most organized cells.

Tonight: Remnants of storms expected to advect across CB and nearby waters. Should not be surface based convection after sunset.

Tomorrow: No thunderstorms forecast. Not enough lift, no defined trigger.

Saturday: Weak non-severe cells are possible to pop up on a weak trof line across the northern tier of NB. Elsewhere, no activity forecast.

 

Convective Discussion

Today is a High Shear day. The upper dynamics across the Maritimes include a 110 kt WSW-ly jet at 250, with a strong jet core of 140 positioned over northern Ontario. Effective shear values are over 40kts, with 0-6k values over 60 in places. This may prove to be too much shear for the small amount of sfc based CAPE at play, however – if it isn’t overwhelmed, it is the correct recipe and orientation for supporting supercell development. The main hazards if this can develop would be 2cm hail and downdrafts near 90 km/h. Dewpoints this morning are holding strong under mainly clear skies still at 13 to 14C. Upstream Pwats are in the 22 to 30 range off morning soundings. A quieter Friday is forecast, and a weak trof line is the only possible trigger for a few unorganized single cells on Saturday.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Thunderstorm Outlook for Saturday (Day 3)

 

 

Forecaster: Tirone.