Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Today:

NS: Isolated non-severe thunderstorms possible in Cumberland county dependent on partial clearing. Better dynamics remain offshore of NS.

 

Tonight:

None over land.

 

Thursday:

NFLD: Thunderstorms are possible across portions of Newfoundland – non-severe in nature.

NS/NB: Isolated non-severe thunderstorms are possible, again in partial clearing.

 

Friday:

NB/NS: Daytime heating can contribute to convection developing across inland areas of the Maritimes. Dynamics are not overly strong, but shear is building.

 

 

Convective Discussion

 

The weather pattern is dominated by a stubborn upper level low centred over NB. This feature has a large cloud shield, and is funneling smoke from QUE back down and around its western side. Isolated thundershowers are possible on Wednesday where a cloud hole may occur allowing for enough daytime heating to cause enhanced lift. The dynamics at play are very weak, but we are cool aloft with a ton of boundary layer moisture. The 12z balloon from Shearwater is saturated up to 550mb. 0-6k shear is very low. However, this is the type of weather feature that tends to form funnel clouds in the fall months. Something to consider in coming days as we gain surface based thermodynamics. Nfld has better ingredients tomorrow. Shear will be 25-30kTs with a weak trigger. CAPE values of 100-200J/kg will be enough to generate excited TCUs. Friday will likely see a greater abundance of cells fire-up across the spine of NS and central NB – instability continues to increase as we remain cold aloft. Smoke activing as CIN in the mid levels will need to be re-assessed with future shifts.

 

 

Thunderstorm Outlook for TODAY

 

Thunderstorm Outlook for TONIGHT

 

Thunderstorm Outlook for THURSDAY

 

Preliminary Thunderstorm Outlook for FRIDAY

 

Forecaster: J. TIRONE

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Today:

NS: A slight risk of an embedded thundershower for some regions of Nova Scotia.

 

Tonight:

None.

 

Tuesday:

None.

 

Convective Discussion

 

There is a slight risk of an elevated, embedded thundershower for a portion of NS today in the divergent flow aloft, ahead of an approaching upper level low pressure system. There has been some history of convection with the upper low, but very little lightning has been observed the past 6-10 hours or so. The only threat would be very heavy rainfall amounts in a short period of time. Elsewhere an approaching frontal trough over central Quebec will likely give some afternoon thunderstorms that are expected to remain southwest of the Wabush/Lab City area. OTWZ nil sig wx to talk about.

 

Thunderstorm Outlook for today

 

Thunderstorm Outlook for tonight

 

Thunderstorm Outlook for Tuesday

 

Jeremy

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Today: none.

 

Tonight: none.

 

Monday: isolated embedded thundershowers possible for a portion of mainland Nova Scotia.

 

Convective Discussion

 

An upper level low pressure system will continue to churn southwest of NS today, and will gradually shift northeastward on Monday. There have been some isolated embedded and elevated thundershowers in the plume of moisture associated with the thermal thickness ridge ahead of the upper low which will likely continue today and tonight over marine waters south and west of NS. This same feature will give just a slight risk of a thundershower over portions of mainland Nova Scotia on Monday as the upper low gets closer to the province. With or without the thunder there will be localized heavy rainfall amounts for some regions of western mainland NS. OTWZ nil sig wx is expected in the region.

 

Thunderstorm Outlook for Sunday

 

Thunderstorm Outlook for Sunday night

 

Thunderstorm Outlook for Monday

 

Jeremy

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Today

 

None.

 

Tonight and Sunday

 

Isolated elevated thundershowers for waters south of NS.

 

Convective Discussion

 

Isolated embedded thundershowers are possible for some waters south of NS tonight and most of Sunday in vicinity of an upper level low pressure system spinning southwest of the marine district. OTWZ nil sig wx expected.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for tonight

 

Thunderstorm Outlook for Sunday

 

Jeremy

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Today

NB: Isolated non-severe thundershowers possible

NS: Isolated thunderstorms possible over southwestern sections of province – biggest hazard is wind gusts 60-75 km/h near a storm cell

 

Tonight

Atlantic Canada: None forecast

 

Saturday

Atlantic Canada: None expected

 

 

Convective Discussion

 

Embedded thundershowers are on the go this morning/early aft on the Bay of Chaleur coastline. Additionally, as the frontal feature leaves the St Lawrence river valley, a few cells are firing up outside of the greater cloud shield near the Maine border. These cells lack formal dynamics necessary for any significant development. 5-15mm of rain can be expected, locally. NS is a bit more interesting as a few more factors are at play this afternoon. Firstly, there is a lot of wildfire smoke in the mid-levels of the atmosphere. If this can be overcome, there is 300 J/kg of well mixed CAPE available from the Sackville area down to Yarmouth. Nothing will last very long near the coasts as water is still very cold this time of year. Storms today will be very high based, as the boundary layer remains unseasonably dry – albeit dew points are climbing since yesterday (now near 12-14). Shear is another limiting factor. There is very little shear. Anything triggered from this backdoor cold front will only transit along the front, and not for very long. Biggest hazards today are gusty winds (sub-warning) near a storm, small hail(less than 1cm) and lightning. Synoptic rain is on the way for the Maritimes this weekend and shuts of any further TS risk. Newfoundland’s weather remains dominated by a large re-circulating cloud shield.

 

 

Thunderstorm Outlook for TODAY

 

Thunderstorm Outlook for TONIGHT

 

Thunderstorm Outlook for SATURDAY

 

Forecaster: TIRONE