Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

Isolated non-severe thunderstorms are expected today in parts of northern New Brunswick.

 

Convective Discussion

In a moderate southwest flow, and dew points building throughout today, there will be a few isolated non-severe thunderstorms. Pockets of heavy rain would be the biggest threat with any cell that develops. Storms will be short lived however with not much shear at play in the atmosphere.

 

 

Thunderstorm Outlook for Tuesday

 

Regional Impacts

Isolated non-severe thunderstorms are possible in Western Labrador and parts of New Brunswick.

 

Convective Discussion

Surface based CAPE (500-1000J/kg) and shear (30+kTs) are more favourable for single cell/multi cell storms to develop on Tuesday under the passage of a cold front. With PWATs of 30+mm, heavy rain is again the risk under a cell that may develop.

 

 

 

 

 

 

 

 

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts:

 

Over extreme southeastern Labrador and Newfoundland (except for the southwest and southeast), there is a risk of a popup thundershower today. Small hail is possible due to the low freezing levels even though the thundershowers are expected to be weak.

 

Convective Discussion

 

A deep layer trough from the surface to 250 mb extends from eastern Labrador to western Newfoundland. The upper and mid levels are very cold (freezing levels are 4500 – 5000 feet). With daytime heating, there may be isolated popup thundershowers near and east of the trough. Shear values are low (less than 30 knots). West of the trough, the environment is strongly capped near 700 mb and the low levels are dry. Thundershowers are very unlikely west of the trough. A strong upper level jet over 100 knots exists to the south of Newfoundland. This jet is too far south to affect convection over land areas.

 

This deep layer trough is expected to move to the east of Newfoundland and Labrador tonight and Monday. No thundershowers are expected tonight and Monday over Atlantic Canada.

 

Thunderstorm Outlook for Today:

 

 

 

Thunderstorm Outlook for Monday: None expected.

 

 

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts:

 

Over southeastern Labrador and northern and central Newfoundland, there is a slight risk of a popup thundershower this afternoon and Sunday afternoon.

 

Convective Discussion

 

A slow moving deep layer trough from the surface to 250 mb extends from an upper low over Labrador to the Gulf of St. Lawrence. As this trough moves very slowly eastward, upper level temperatures will drop east of it over southern Labrador and northern and central Newfoundland. With daytime heating, there is a slight possibility of CBs topped at 30,000 to 35,000 feet in a low shear environment. West of the trough, over the Maritimes, the environment is strongly capped near 700 mb, inhibiting thunderstorm activity.

 

Similar conditions are forecast for Sunday afternoon except that the trough will be slightly farther east making the risk area slightly farther east.

 

Thunderstorm Outlook for Today:

 

 

Thunderstorm Outlook for Sunday:

 

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

No thunderstorms forecast.

 

Convective Discussion

Cool northwesterly flow continues across the region under a 100+kt NWly upper Jet extending from James Bay to NS. Generally over the Atlantic provinces, Instability is limited to the lower levels with most morning soundings over the region showing two inversions, at 700mb and 550mb. Moisture is more prevalent over NF and Lab where multiple layers of cloud are analysed. Freezing levels have risen somewhat and are between above 2,000ft.

 

 

 

Thunderstorm Outlook for Saturday

An upper low will slide over central Labrador, and the cold air aloft will destabilize the airmass further. A sligh risk of thunderstorms is suggested by some of the forecast guidance.

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for today

 

Regional Impacts

Isolated Non-severe thunderstorms are expected today with sporadic downpours over southwestern NF and the Burin.

 

Slight risk of a thunderstorm over the Cape Breton Highland.

 

Convective Discussion

A cool and dry northwesterly flow prevails over the Maritimes this morning. Over the Gulf of St. Lawrence, a cold low is triggering widespread showers mainly over southwestern NF and the Burin. The airmass is unstable enough (CAPE values of 200-300 J/kg) to support thunderstorm activity. One such cluster is currently detected by CLDN at the intersection of Cabot strait, southwest coast and Banquereau regions. A few lightning flashes were also detected along the coast east of Port-aux-Basques. The instability will be maintained ahead of the cold pool aloft. Some of the forecast guidance is suggesting a slight risk of thunderstorm over the Cape Breton Highlands in response the approach of the cold pool and some extra orographic lift.

 

 

Thunderstorm Outlook for Friday

 

Some of the global guidance is suggesting the possibility of some shower activity associated with a weak surface feature

over central NB.