Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today: risk of an embedded thundershower for eastern NS giving torrential downpours. Isolated thunderstorms possible for northwestern NB and parts of Labrador giving heavy downpours and gusty winds.

Tonight: continuing with the risk of an embedded thundershower for eastern NS and a portion of NL giving torrential downpours.

Tuesday: once again a risk of an embedded thundershower across southeastern NL giving heavy downpours. Scattered thunderstorms likely for most of Labrador and northern areas of NB giving heavy downpours, gusty winds and small hail.

Convective Discussion

A couple areas to watch today through to Tuesday. The first is an approaching frontal trough and associated thickness ridge moving up south of Nova Scotia that will move eastward into NL tonight and Tuesday. The PWATs with this feature could be in excess of 50 mm so torrential rainfall is a definite concern. But there looks to be a very limited chance in seeing lightning due to the warming aloft creating a stable, nimbostratus-type profile. The instability seems to get good just in behind the thermal trough, basically when the precipitation is ending from west to east. But no doubt some embedded deep layer TCUs capable of dropping copious amounts of rain over a short period of time.

The second feature is an upper-level trough that will give bouts of non-severe thunderstorms to north/northwestern NB today and Tuesday as well as a good chunk of Labrador, as short wave troughs move up along the base of the long wave trough.  As freezing levels lower on Tuesday, some small hail is possible in some of the stronger cells.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Jeremy

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today:

LAB: Risk of isolated thunderstorms over west LAB: Risk of isolated thunderstorms over southern Labrador.ern Labrador giving locally heavy downpours, strong wind gust and small hail.

NB: Risk of an isolated thunderstorm over extreme northwestern NB.

NS/PEI/NL: No thunderstorms forecast.

Tonight:

LAB: Risk of isolated thunderstorms over southwestern Labrador.

NB: Risk of an isolated thunderstorm over extreme northwestern NB.

NS/PEI/NL: No thunderstorms forecast.

Tomorrow:

NB: Risk of isolated thunderstorms giving locally heavy downpours and strong wind gusts.

NS: Risk of embedded thunderstorms giving locally heavy downpours.

LAB: Risk of isolated thunderstorms over southern Labrador.

NL:PEI: No thunderstorms forecast.

Convective Discussion

As a low pressure system over James Bay remains stationary, a warm front is moving across southern Labrador this morning with a cold front extending from western Labrador southwest towards the St. Lawrence River. The cold front this afternoon will trigger some thunderstorms across central Quebec and towards western Labrador by late afternoon or early evening. With CAPE values reaching 500 J/kg and increasing effective shear of 30kt, some thunderstorms may organize into multicells or lines prior to reaching. With freezing levels at around 10,000 ft and sufficient lift, small hail is also possible. Convection is expected to remain mainly west of New Brunswick today but may graze parts of western Madawaska and Restigouche counties.

Tomorrow, the front stalls over western New Brunswick while a low pressure system is expected to form off Cape Hatteras later today and move northeast towards Nova Scotia tomorrow. High rainfall amounts and embedded thunderstorms are possible mainly over coastal Nova Scotia and southern marine waters leading to potential locally heavy rainfall as precipitable water increases to more than 50 mm. The cold front will continue to spark thunderstorms for the afternoon in northwestern New Brunswick. CAPE values may only reach 250 but there is moderate bulk shear and increasing precipitable water so strong winds and heavy downpours are possible. A trough line may also spark a few embedded thunderstorms across southern Labrador as that tracks slowly northward.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Roberta McArthur

 

 

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today: No thunderstorms forecast in Atlantic Canada.

Tonight: No thunderstorms.

Tomorrow: Non-severe thundershowers possible over extreme western Labrador.

Friday: Organized thunderstorms are forecast in the right quadrant of Erin over the southern-most marine regions.

Convective Discussion

Nil sig weather convection wise across the Atlantic domain until tomorrow late day. An advancing trof in central and northern Quebec may bring a lightning strike or 2 embedded in some shower activity late day tomorrow in parts of western Labrador. The bigger weather system to watch in next 3 days in Erin. Detailed hurricane forecast information can be found on weather.gc.ca/hurricane. Thunderstorms associated with this system will creep into the marine domain on Friday (into Saturday). They may push orange limits for rain and wind gusts near the southern border of our Canadian domain.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Thunderstorm Outlook for FRIDAY

 

 

Forecaster: TIRONE.

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today:

NL: Risk of isolated embedded thundershowers over the eastern Avalon Peninsula and east coast.

NB/NS/PEI/LAB: No thunderstorms forecast.

Tonight:

No thunderstorms forecast.

Tomorrow:

No thunderstorms forecast.

Convective Discussion

Isolated embedded thundershowers affected parts of the Avalon and the northeast and east coasts of Newfoundland overnight and this morning as an upper low continues to slowly move east into the northern Grand Banks today. Showers and drizzle are expected to continue for most of Newfoundland in a strong northerly flow today with an odd thunderstorm still possible today mainly east of the Avalon. Otherwise, a ridge of high pressure will remain over the Maritimes this week limiting potential for convection. A weak trough over central Quebec will bring some isolated showers to parts of northern Labrador tomorrow, but are not expected to produce any thunderstorms at this time.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Roberta McArthur

 

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today: risk of an embedded thundershower over southeastern NL.

Tonight: risk of an embedded thundershower over eastern NL.

Tuesday: risk of an embedded thundershower over the Avalon Peninsula.

Convective Discussion

A developing upper low will be the only weather to talk about this week. There has been very little in the way of lightning up until now, but the instability does get better later today, through tonight and into early Tuesday. So, there should be some isolated elevated thundershowers as the upper low spins around eastern/southeastern NL. The PWATs are relatively low however, areas of convection will be very slow to move so locally heavy rainfall amounts are a concern with this feature.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Jeremy