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

 

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:

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

Today: isolated thunderstorms over southern marine waters.

Tonight: Isolated thunderstorms possible over western NS and southern NB. Isolated thunderstorms once again for southern marine waters.

Sunday: Isolated thunderstorms for most of NL and some marine waters.

 

Convective Discussion

Some ongoing morning thunderstorms for southern waters today through to Sunday in association with a persistent trough of low pressure. Will likely continue to see the diurnal tendencies for these cells with CTC being favourable (overnight and morning). Some gusty winds are possible especially over the warmer waters.

 

An upper low will approach the MRTMS today bringing some showers, with a risk of a thunderstorm tonight as an area of PVA moves in promoting upper level divergence. The guidance will likely miss this potential in conventional indices. Heavy downpours would be the threat and given the slow movement, localized heavy amounts are also a possibility.

 

The trough that has been south of the region will move northward towards NL on Sunday with the risk for isolated thunderstorms giving heavy downpours.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 1 night

 

Thunderstorm Outlook for Day 2

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

Labrador.. Isolated thunderstorms potentially producing heavy showers with rainfall rates of 10-20 mm/h, gusts to 70 km/h and small hail.

Central New Brunswick.. slight risk of a thunderstorm

 

Convective Discussion

The Upper air analysis this morning shows a 500mb low near Lab City and a 130kt southwesterly jet stretching from New England to SE Lab. Lowest temperatures in the 500mb cold pool range from -18 over Lab west to -20 over Ungava Bay. At the surface a frontal boundary extends from NE NB to Anticosti Island to SE Lab. Light shower activity is detected along the frontal boundary at the current time, but latest Satellite imagery is showing cold cloud tops and some heavier radar echoes over the south side of MT Carleton. There are a couple of moisture plumes over the region, one from NS to SE Lab and another from Laurentian Fan to SE NF. Precipitable water drop quickly below 20 mm west of the upper low. Instability will be prevailing over much of Labrador especially along the Churchill valley and around Lake Melville, a second area of instability is evolving over central NB. Initiation will be favored by surface convergence near the front, but also by the cold pool and the presence of positive vorticity over Labrador. Once again today MLCAPE values of 500-750 J/kg.. shear values of 30-40 kt will prolong the life of individual cells that form over Labrador, and with strong upper dynamics some of these storms could become organized in lines which could possibly be bowing. Also, Predicted DCAPE in excess of 600 J/kg around Lake Melville indicates the possibility of strong gusts. The thunderstorms over NB will be pulse type and are not likely to be significant.

A second frontal feature currently east of Sable Island will advance over Banquereau and Laurentian Fan this afternoon, the plume of moisture will propagate towards SE NF tonight bringing a risk of embedded thunderstorm.  

 

 

Thunderstorm Outlook for tonight

 

 

 

Thunderstorm Outlook for Saturday