Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Today

NB: isolated thunderstorms.. potential for small hail and gusty winds

NS/PEI/NL&Lab: None

 

Tonight

NB#NS/PEI/NL&Lab: None

 

Friday

NB/PEI/NL&Lab: None

NS: slight risk of a thunderstorm westernmost regions  

 

Convective Discussion

The heat continues to build this morning, and as of this hour several stations in NB are reporting temperatures above 30 degrees. The ridge of high pressure over the region will begin to weaken signaling a threat for thunderstorm activity. The environment is charged with large amounts of CAPE in the mid and upper levels, mean layer CAPE in excess of 1000 J/kg. Convective trigger temperature runs between 32 to 35 degrees, and the upper range makes a significant difference on the outcome of the instability. The missing ingredient is moisture, however Td’s have been slowly increasing and current values range from 12 to 16 in NB, 10 to 12 in NS, and below 10 in NF. Given the amount of instability and lifting convective initiation will likely occur over the hills of northern and central NB, and then further south during the late afternoon. The towering clouds could evolve into CB’s with tops almost reaching the tropopause with sits at about 12km this morning. Deep layer shear values are 10-15kt limiting the possibility of any storm that forms of becoming severe. The main threat with these storms will be small hair and strong wind gusts.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Friday

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

Labrador: an isolated thunderstorm (brief heavy shower and gust 60km/h) in the Churchill Valley-Goose Bay-Eagle River areas

NB/NS/PEI/NL: None

 

Tonight

Labrador: convection slowly dissipating

NS/NB/PEI/NL: None

 

Wednesday

NS/PEI/NL: None

NB: slight risk of a thunderstorm  

 

Convective Discussion

A surface frontal band extends from the north Labrador coast to James Bay and then northern Ontario this morning. Mid-level convection embedded in the cloud produced some lightning activity last night. This feature will be advancing over the Atlantic provinces during the next couple of days producing a slight risk of thunderstorm over the region.

The main threat today lies across central Labrador.. upper air sounding from Goose Bay indicates plenty of instability and the surface moisture has been increasing since sunrise. Surface T/Td combination of 28/14 (MLCAPE 400 LI -3) is enough to trigger the odd high base pulse thunderstorm which could give a brief heavier shower and gust to 60 km/h. Upper support for this activity is not very good so any storm that forms will not last very long.

 

 

Thunderstorm Outlook for today

 

 

Thunderstorm outlook for tonight:

 

 

Thunderstorm Outlook for Thursday

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

NB/NS/PEI/NL/Labrador: None

 

Tonight

NS/NB/PEI/NL/Labrador: None

 

Wednesday

NB/NS/PEI/NL: None

Labrador: A chance of thundershowers  

 

Convective Discussion:

 

A ridge of high pressure will continue to move south of Nova Scotia today and Wednesday. For Labrador on Wednesday, a frontal trough will move across the region giving a risk of non-severe convective showers.

 

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight:

 

Thunderstorm outlook for Wednesday:

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

NB/NS/PEI/NL/Labrador: None

 

Tonight

NS/NB/PEI/NL/Labrador: None

 

Tuesday

NB/NS/PEI/NL/Labrador: None

 

Convective Discussion:

 

A ridge of high pressure will move into the region as a weakening low departs Newfoundland.  Stable and dry artic air associated with the ridge will inhibit any potential convection. Non convective showers are expected over Labrador on Tuesday associated with a warm front.

Thunderstorm outlook for today:

 

Thunderstorm outlook for tonight:

 

 

Thunderstorm outlook for Tuesday:

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

None.

 

Convective Discussion

 

An upper low northeast of Newfoundland will weaken and slowly pull east today. Warming between 850-700 mb will prevent any convection today.

 

Meanwhile, a warm front and surface low pressure centre will move across central Quebec and into western Labrador tonight. The low will track southeastward across southern Labrador early Sunday morning and over Newfoundland by Sunday evening. Showers will move into Labrador tonight but are not expected to produce any convection given warming at 700 mb. A trailing cold front on Sunday will track across the Gulf of St. Lawrence in the afternoon and over the eastern Maritimes in the evening. Although there will be some surface-based instability given strong daytime heating over the Maritimes, the area remains quite dry, with strong upper-level subsidence and a warm nose at 500 mb which should prevent any convection beyond isolated TCUs in showers. There may be a slight risk of an isolated thundershower near the centre of the low over the lower North Shore Quebec Sunday afternoon behind the 500 mb thermal ridge but 0-6km shear will be quite strong (70kts) which may inhibit development.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2