Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

Central-western Labrador: Isolated thundershowers

 

Tonight

None

 

Saturday

Labrador/NB: Isolated to scattered thunderstorms

 

Convective Discussion:

 

A ridge of high pressure moves through the region today while the tail end of a trough of low pressure moves southeastward over Newfoundland today. Isolated showers with the slight risk of a thunderstorm is expected over central Labrador this afternoon. Convective temperatures near 25C are expected to be reached. With CAPE values of 500 J/kg but little moisture in the low levels and weak effective shear, the main threat would be some gusty winds. Some robust TCUs are expected over central to southeastern Newfoundland this afternoon but will be fighting a thermal ridge between 700 and 500 mb. Some locally heavy downpours are possible.

 

For Sunday, a trough of low pressure will slowly track eastward over Hudson Bay toward central Quebec. Ahead of the trough, an increasingly unstable air mass will aid in the formation of scattered showers and thunderstorms over western and central Labrador and into northern and western New Brunswick. Although there is an increase in precipitable water and CAPE, shear will remain weak so pulse type storms with locally heavy downpours and strong wind gusts are possible.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight:

 

 

Thunderstorm outlook for Sunday:

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

NB/NL: Isolated thunderstorms.

NS/PEI/Labrador: None

 

Tonight

None

 

Saturday

None

 

Convective Discussion:

 

An upper low pressure system is slowly tracking northeastward over the northern Gulf of St. Lawrence and northern Newfoundland by Saturday morning. Scattered TCUs and isolated CBs were present along the frontal axis extending from the Great northern Peninsula and south over the Grand Banks earlier this morning. Some convection is possible along the northern Newfoundland coasts this afternoon if a cap at 850 mb can be broken. With precipitable water values of 30 to 40 mm, weak to moderate unidirectional wind shear, locally heavy downpours and strong wind gusts are possible. Isolated convection is also possible along the cold front which is tracking through the Grand Banks.

 

There is the possibility of isolated thunderstorms over New Brunswick today, however a capping inversion at 700mb with be the main inhibitor along with current cloud cover. KCARs 12Z sounding indicates that the RDPS is slightly overdoing this cap and with sufficient surface based heating, this cap may be able to break by this afternoon. Any showers that do develop will be slow to move given little upper flow around the upper low and with precipitable water near 30 mm, some locally heavy downpours are possible. Given more dry air in the mid level, some strong wind gusts are also possible.

 

For Saturday, a ridge of high pressure moves into the region, keeping most areas hot and dry. Some isolated TCUs are likely for Newfoundland as they remain under the influence of a trough and western Labrador as a low pressure system approaches central Quebec.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight:

 

Thunderstorm outlook for Friday:

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

NL: Isolated/embedded thunderstorms.

NB: Chance of afternoon thunderstorms.

PEI/NS/Labrador: None

 

Tonight

NL: Isolated/embedded thunderstorms.

NS/NB/PEI/Labrador: None

 

Thursday:

NB/NL: Isolated thunderstorms.

NS/PEI/Labrador: None

 

Convective Discussion:

Isolated/embedded thunderstorms are possible over Newfoundland this afternoon. Over northern New Brunswick, surface based convection may develop this afternoon and Friday afternoon. It is also possible for Newfoundland Friday afternoon. MLCAPE near 500 J/Kg is anticipated. For both days there is a cap near 700 mb so it may inhibit initiation. Not much of a trigger other than diurnal heating and a supportive upper low. The shear is very low so if thunderstorms do develop they will be pulse type and very slow moving. Pwat values near 30 mm exist so good downpours are likely with this slow moving system. Small hail and gusty winds are also possible.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight:

 

 

Thunderstorm outlook for Friday:

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

NS: Isolated/embedded thunderstorms.

NB/PEI/NL/Labrador: None

 

Tonight

NS/NB/PEI/NL: Isolated/embedded thunderstorms.

Labrador: None

 

Thursday:

NB/NL: Isolated thunderstorms.

NS/PEI/Labrador: None

 

Convective Discussion:

Isolated/embedded thunderstorms are occurring associated with a warm front extending from a low southwest of Nova Scotia. As the low occludes tonight, the thunderstorm potential will move eastward to include Newfoundland.  On Thursday, elevated thundershower potential will continue for Newfoundland. Over central and northern New Brunswick, surface based convection may develop Thursday afternoon. MLCAPE of 500 -750 J/Kg is anticipated with a favourable diffluent 500 mb environment ahead of an approaching upper low. The shear is very low so if thunderstorms do develop they will be pulse type and very slow moving. Pwat values near 30 mm exist so good downpours are likely with this slow moving system. Small hail and gusty winds are also possible.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight

 

 

Thunderstorm outlook for Thursday

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

NB: Isolated thunderstorms central and north.

NS/PEI/NL/Labrador: None

 

Tonight

NS: Isolated thunderstorms.

NB/PEI/NL/Labrador: None

 

Wednesday:

NS/NB/PEI/NL: Isolated thunderstorms.

Labrador: None

 

Convective Discussion:

MLCAPE near 500 J/Kg over central and northern NB is anticipated but no real triggering mechanism exists beyond daytime insolation. The shear is very low so if thunderstorms do develop they will be pulse type and very slow moving. Pwat values near 25 mm exist with this airmass. Dry mid layers would allow wind gusts to 60-70 km/h. For tonight and Wednesday embedded thunderstorms are expected associated with a low approaching from the southwest. Pwat values near 45 mm are expected so good downpours are likely with this system. Conditions have been quite dry in many areas of Atlantic Canada this summer so any rain will likely be welcome.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight

 

 

Thunderstorm outlook for Wednesday