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

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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

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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

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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

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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

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Thunderstorm Outlook for Tomorrow