Convective Outlook Valid for June 26, 2019

Convective discussion

Basically there is a risk of non-severe thundershowers for the western Maritimes. Currently there is a nearly stationary low near James Bay with a frontal trough extending from it southeast over Maine. This trough is nearly stationary with little dynamic upper support. There is also very little moisture west of the main feature. There is some weak detstabilisation in the mid levels, with a 500 mb thermal trough well east of the 700 mb trough thisch continues down to 850 mb. There is also some moisture near and below 850, with a moist tongue over northern Maine extending toward  Northwest New Brunswick, and mid level clouds are moving away to the east. If and when the stratus breaks up there may be enough heating to produce some thundershowers.

In the Gulf of Maine a nearly stationary broad weak low is triggering some  embedded which  moving towards southwestern  Nova Scotia. There cellc should not go much east of the tri-county area.

For Thursday, indications are for a slow progression into Labrador and across the western Maritimes.

Regional Impacts

Nova Scotia: Slight risk for this afternoon into this evening and overnight for non-severe thundershowers.

New Brunswick: Slight risk for evening and overnight for non-severe thundershowers.

Newfoundland, Labrador, and Prince Edward Island: None for today and tonight. Overnight into early Thursday morning there is a slight risk for western Labrador.

Doug Mercer

Convective Outlook Valid for June 25th, 2019

Convective Discussion

A quasi-stationary low pressure system just off the coast of Labrador will continue to weaken today. Clouds and scattered showers will persist over Newfoundland/Labrador. Very low dew points in the wake of this system will continue to suppress any possible convection.

Regional Impacts

Maritimes…

None.

Newfoundland and Labrador…

None.

Andy Firth

Convective Outlook Valid for June 24th, 2019

Convective Discussion

A quasi-stationary low pressure system just off the coast of Labrador will gradually weaken over the next two days. Clouds and showers are expected over Newfoundland/Labrador. Very low dew points in the wake of this system will suppress any possible convection.

Regional Impacts

Maritimes…

None.

Newfoundland and Labrador…

None.

Andy Firth

Convective Outlook for Atlantic Canada Valid for June 23rd, 2019

Convective Discussion

 

The Atlantic Region is still under the influence of what is now a nearly vertically stacked low pressure system over Northern Newfoundland. In terms of the thunderstorm activity there is still a chance of embedded thunderstorms near the main band of heavier rain wrapping around the low. These are will be more pronounced in the trough ahead of this system, which will be near the Labrador coast today. Any thunderstorms triggered here will initiate well aloft and could generate some locally heavier downpours.

 

Across the Maritimes dry air and weak dynamics greatly reduce the potential for any severe weather. However, there is a very slight chance that weak thundershowers could develop over central and northern Nova Scotia as a weak trough passes through picking up a bit of moisture from the Northumberland Strait. No significant impacts are expected although there is a chance of a heavier shower likely with 10-15mm of rain with pea sized hail.

 

 

 

Convective Outlook for Atlantic Canada Valid for Saturday June 22nd 2019

Convective Discussion

 

There is a low probability that thunderstorms could develop over three main areas today, which are  extreme western Labrador, southwestern New Brunswick and Newfoundland.

Over Newfoundland the heaviest area of Total Precipitable Water (TPW) has swung past the Island and weakened somewhat. With TPW values in the mid 30mm range heavier rainfall in embedded convection is possible but the heaviest rainfall will likely be just north of the Island or possible over the Northern Peninsula.

 

For extreme western Labrador a band of showers could impact the area this evening as a weak through moves through. Updrafts with this feature will be very weak, however there may be just enough depth to these storms to produce some lightning.

 

Finally across western New Brunswick we are looking at TCU’s and CB’s forming early this afternoon, the  more intense  cells will likely remain over Maine.  However,  some could impact SW New Brunswick as well. CAPE values will generally be as high as 500 J/kg and locally heavier downpours are possible in the 15mm to 20mm range should they affect NB. Some stronger gusty winds and small hail could be generated as well.  However,  warning level criteria are not expected.

 

 

 

 

Mel Lemmon