Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today:

NL: Risk of isolated embedded thundershowers over the eastern Avalon Peninsula and east coast.

NB/NS/PEI/LAB: No thunderstorms forecast.

Tonight:

No thunderstorms forecast.

Tomorrow:

No thunderstorms forecast.

Convective Discussion

Isolated embedded thundershowers affected parts of the Avalon and the northeast and east coasts of Newfoundland overnight and this morning as an upper low continues to slowly move east into the northern Grand Banks today. Showers and drizzle are expected to continue for most of Newfoundland in a strong northerly flow today with an odd thunderstorm still possible today mainly east of the Avalon. Otherwise, a ridge of high pressure will remain over the Maritimes this week limiting potential for convection. A weak trough over central Quebec will bring some isolated showers to parts of northern Labrador tomorrow, but are not expected to produce any thunderstorms at this time.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Roberta McArthur

 

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today: risk of an embedded thundershower over southeastern NL.

Tonight: risk of an embedded thundershower over eastern NL.

Tuesday: risk of an embedded thundershower over the Avalon Peninsula.

Convective Discussion

A developing upper low will be the only weather to talk about this week. There has been very little in the way of lightning up until now, but the instability does get better later today, through tonight and into early Tuesday. So, there should be some isolated elevated thundershowers as the upper low spins around eastern/southeastern NL. The PWATs are relatively low however, areas of convection will be very slow to move so locally heavy rainfall amounts are a concern with this feature.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Jeremy

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today: slight risk of an afternoon or evening thunderstorm across south/southwestern NB.

Tonight: slight risk of an embedded thundershower along the South Shore of NS.

Convective Discussion

A weakening cold front currently lying across northern NB will slide southeastward today and tonight giving just a slight risk of a thunderstorm across southern areas of the province. The better instability along with the low-level moisture will remain in southern New England but an isolated cell or 2 could advect into the southwest this afternoon giving locally gusty winds. Aside from that there will also be a slight risk of an elevated, embedded thundershower over southwestern NS tonight as the front passes through. There have been some isolated wind gusts close to 40 knots just in the wake of the front in northern ME so cannot rule out the same for some areas of northern NB today.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Jeremy

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today and tonight: nil.

Sunday: risk of an afternoon or evening thunderstorm across southern areas of NB.

Convective Discussion

A cold frontal trough will cross NB during the day Sunday but will be weakening quite a bit. So just the slightest risk of a thunderstorm across the south in the afternoon and evening.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Newfoundland and Labrador…. Scattered thunderstorms giving locally heavy downpours for central and eastern Newfoundland.

PEI… No impacts.

NS… No impacts.

NB… No impacts.

Convective Discussion

Thunderstorms will continue to develop ahead of the cold front moving across Newfoundland today. The same airmass that brought localized rainfall amounts exceeding 50 mm to parts of the Maritimes has now shifted over Newfoundland. The timing of the front will likely limit deeper convection due to reduced daytime heating.

With precipitable water (PW) values near 35 mm and most unstable CAPE between 500 and 1000 J/kg, there remains some potential for locally heavy downpours. Given the front’s forward speed, back-building thunderstorms are not expected; however, there is a slight risk of this occurring across central and northeastern Newfoundland.

Following the passage of the front, most of the region will see much drier conditions over the next couple of days, with little in the way of active weather until Sunday or Monday, when another system is expected to bring some precipitation. This next front is unlikely to produce as much active convection as the current one.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Mel Lemmon

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NB/NS/PEI: Scattered severe thundershowers.

Labrador/Newfoundland: Scattered non-severe thundershowers.

 

Tonight

NS/PEI/Newfoundland: Scattered non-severe thundershowers.

NB/Labrador: None.

 

Friday

Newfoundland: Scattered non-severe thundershowers.

NB/NS/PEI/Labrador: None.

 

Convective Discussion

A cold front stretching from Labrador to central New Brunswick will slowly continue eastward today. Over southern New Brunswick, Prince Edward Island and portions of Nova Scotia severe weather is possible near and ahead of the front this afternoon and evening.  CAPE values of 1000-1500 J/kg are expected and effective shear will be 20-30 knots. Additionally, a supportive right entrance region of the upper jet will move over southern New Brunswick this afternoon and support convection. The airmass ahead of the cold front remains very moist with PWAT values of 40-50 mm. Due to some cloud cover, the thunderstorms will be a combination of embedded and surface based. Over western Newfoundland and eastern Labrador, non-severe thundershowers are likely today. CAPE values of 500-750 J/kg are expected with effective shear of 20-30 knots. There is a fair amount of cloud cover so that should mitigate severe weather there. On Friday,  non-severe thundershowers are expected over eastern Newfoundland associated with the same cold front.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

 Regional Impacts…

 

Today

Labrador: Scattered severe thundershowers.

NB/NS: Scattered non-severe thundershowers.

PEI/Newfoundland: None.

 

Tonight

NB/NS/PEI/Labrador: Scattered non-severe thundershowers.

Newfoundland: None.

 

Thursday

NB/NS/PEI/Newfoundland/Labrador: Scattered non-severe thundershowers.

 

Convective Discussion

A slow moving cold front will drift across Labrador today and Thursday. The same front will move across New Brunswick on Thursday. Over Labrador, severe weather is possible ahead of the front this afternoon and evening.  CAPE values near 1500 J/kg are expected and effective shear will be 30-40 knots. Additionally, a supportive right entrance region of the upper jet will move over western Labrador this afternoon. Over New Brunswick and western Nova Scotia today non-severe thundershowers are possible. CAPE values near 2000 J/kg are expected but effective shear will only be 10-20 knots and only weak forcing mechanisms are anticipated. On Thursday, the convection should become more embedded in nature but  some surface based convection is still possible. CAPE values of 500-1000 J/kg are expected. Effective shear near 20 knots is anticipated over the Maritimes and closer to 30 knots over Labrador. Cells could become near severe with rain and wind but should stay below warning conditions.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow