Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Nova Scotia/New Brunswick/PEI/Newfoundland:  A risk of embedded thundershowers from the tropical moisture left over from Ida. Heavy downpours giving 30 mm in an hour are possible today and tonight.

Labrador: Nil.

 

Convective Discussion

 

A risk of embedded thundershowers as the remnants of Ida move across the region. PWAT values are near 50 mm so rainfall is a concern but we have rainfall warnings out for a broad area of Atlantic Canada. Heavy downpours giving 30 mm in an hour are possible today.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Newfoundland:  Isolated thundershowers this afternoon and evening.  Potential severe thundershowers giving downpours, gusty winds and hail in the southwest early this afternoon.

Nova Scotia: Slight risk over Cape Breton

New Brunswick/PEI/Labrador: Nil.

 

Convective Discussion

 

A weak low pressure system will approach western Newfoundland this afternoon. ML cape values near 500 J/kg are expected and wind shear near 25 kts.  This morning, convection developed over the Gulf of St. Lawrence near the Magdalen Island and then advected eastward. The earlier convection was mainly driven by upper level dynamics which weaken somewhat this afternoon as the jet slips south of Newfoundland.  Dry mid layers will allow for gusty conditions. PWAT values will be near 25 mm so rainfall is a concern. Just a risk of embedded non-severe thunderstorms over the Maritimes on Thursday.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

For Labrador today… Isolated thunderstorms giving 15-20mm locally.

NB, PEI and NS today… Low probability of near severe thunderstorms.

 

Convective Discussion

 

There is a low probability that severe or near severe thunderstorms could develop today over the gulf waters and Northumberland Straight. The dynamics are good with plenty of deep shear and weak convergence along a surface trough. It may be a struggle to break through a stable layer above 700mb until later today when it weakens however daytime heating will also be weakening. For now no severe thunderstorm alerts are expected however should longer lived cells develop they may be issued. The warmer waters this time of year may also help to feed the thunderstorms and should they develop could pose a risk to marine waters.

 

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

 

Mel Lemmon

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

New Brunswick…Isolated thunderstorms giving locally heavy downpours.

PEI… Chance of isolated thunderstorms late today.

Nova Scotia… A few thunderstorms are expected tonight with locally heavy downpours.

 

Convective Discussion

Despite the cloudiness, favourable dynamics and high moisture are expected to keep thunderstorms progressing though the day in NB and into NS and PEI this evening and tonight. Locally heavy downpours, exceeding 25mm are possible for some areas today and tonight.

 

Tomorrow the upper level jet and increasing wind shear may offset the weaker instability especially over the warmer Gulf and Northumberland Straight waters where there is a chance of thunderstorms.

 

Thunderstorm Outlook for Day 1

 

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

Today.. No thunderstorms expected

Tomorrow.. Isolated thunderstorms with locally heavy downpours.

 

Convective Discussion

 

Not much expected today however the dynamics will improve tomorrow as the upper ridge moves away ahead of the approaching cold front. With respect to the moisture we are looking at high precipitable water values and high surface moisture. Vertical velocity could be somewhat limited but most unstable capes could be in the 500-1000 J/kg range, with low level shear above 30 knots some longer lived cells could be a concern, possible producing gusty winds and heavy downpours with local amounts exceeding 25mm/hr.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2