Pages

Friday, August 19, 2022

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:

Thursday, August 18, 2022

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:

 

Wednesday, August 17, 2022

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

 

 

Tuesday, August 16, 2022

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

 

Monday, August 15, 2022

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

None

 

Tonight

None

 

Tuesday:

NB: isolated lightning over northern areas.

Marine: isolated lightning, except scattered lightning with gusts of 70-90 km/h over southern West Scotian Slope and Georges Bank (not shown on outlook).

 

Convective Discussion:

MLCAPE of 200-300 J/Kg over northern NB is anticipated but no real triggering mechanism exists beyond daytime insolation. Dry air entrainment above 700 mb will also limit lift today making lightning unlikely.

Tomorrow a very similar environment will be in place, however a weak cold front moving southward into northern NB may provide enough lift to cause the odd strike. There is the potential for severe storms in the Southwestern slope waters with MLCAPEs locally exceeding 2000 J/Kg and effective shears of 30-40 knots. Storms will be forced by a shortwave currently located to the east of New Jersey that is anticipated to move near the slope waters by Tuesday evening. The primary hazard with these storms will be strong wind gusts and reduced visibilities in downpours.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight:

 

 

Thunderstorm outlook for Tuesday: