Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

Isolated thunderstorms are possible for NB, western and northern NS – some of these storms could approach severe limits,

Scattered thunderstorms western NF, central and eastern Labrador – some of these storms could approach severe limits over the lower Churchill valley.

 

Convective Discussion

The main feature this morning is a surface low pressure system over the Smallwood reservoir with a trough extending southward to the Gulf of St. Lawrence. Both Stephenville and Goose Bay soundings support energy in the order of about 500 J/kg off the surface, and there is plenty of energy in the hail growth zone for small hail withing some of the stronger clusters. A weak zonal upper jet from Maine to the east coast of NF will provide some extra support for stronger cells , the caribou soundings hints at deep layer shear values in excess of 35kt and the possibility of longer-lasting cells with cape values in excess of 1000 J/kg which could produce 2+cm hail and damaging wind gusts. Over NS the upper winds are somewhat lighter but the airmass is much more buoyant with CB tops to 8-9 km. The airmass is becoming more rich with moisture content with CB cloud top possibly exploding to 12-14 km.

 

 

 

Thunderstorm Outlook for Monday

Increasingly humid airmass advancing from New England late in the day.

Convective Outlook valid for Today, and Tomorrow

ECCC Thunderstorm Outlook valid for July 16^th, 2022.

 

Regional Impacts

Isolated non-severe thundershowers are possible in northern NB, and western Labrador as a disturbance in Quebec affects the region.

 

Convective Discussion

With a warm frontal approach, a few showers may spark lightning across the northern tier of New Brunswick and western Labrador this afternoon. Moisture in this airmass is far less than yesterday across the Maritimes, and ML CAPE at best is only near 300 J/kg. Storms do not have good upper dynamics so they are expected to be short lived in nature. With the return of the Maniwaki sounding, confidence in model initialization has increased.

 

Thunderstorm Outlook for Day 1 - SATURDAY

 

Thunderstorm Outlook for Day 2 - SUNDAY

*broad risk of thunderstorms across most areas as an upper trof can trigger convection in a growingly humid airmass. If heat warning criteria is reached, a few cells in the Annapolis valley could push severe limits briefly.  

 

Forecaster: TIRONE

Convective Outlook valid for Today, and Tomorrow

ECCC Thunderstorm Outlook valid for July 15^th, 2022.

 

Regional Impacts

Broadly, scattered non-severe thunderstorms are possible over many regions of Atlantic Canada this afternoon and evening. Additionally, isolated severe thunderstorms are possible in areas of Nova Scotia and eastern portions of New Brunswick.

 

Convective Discussion

As sticky humidity continues across the Maritimes today, the risk for thunderstorms follows suit. With dew points expected to remain near 17C, and some good pockets of direct solar heating, things should fire off this afternoon. Upper features are in place to sustain storms today especially near Truro and Bathurst to severe limits. Hail, gusty winds, and heavy rainfall can all be expected under a strong cell. Lapse rates of 500-700mb are similar to yesterday across Maine and NB (16-18). ML CAPE values are a bit better than yesterday near 1200J/kg, and 0-6k shear is 35-40Kts. Development of storms will be monitored closely and watches may be required. Storm motion today is expected to be E-ly at 15kts. A supercell will head SE at similar speeds should it develop. Additionally, the sweeping cold trof from the decaying Labrador low will spark a few thundershowers in marine waters and some areas of Newfoundland. The dynamics at play in these regions are much weaker.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 2

*slight risk of thundershowers across northern tier of NB, and extreme western Labrador as upper trof continues to affect central Quebec.

 

Forecaster: TIRONE

Convective Outlook valid for Today, and Tomorrow

Thunderstorm Outlook valid for July 14^th, 2022.

 

Regional Impacts

Isolated non-severe thunderstorms are forecast today for areas in Labrador, western New Brunswick, and offshore over the slope waters.

 

Convective Discussion

Thundershowers are possible near the low centre in the Labrador sea and over the Big Land. In NB, thundershowers are also possible north of Fredericton this afternoon in an area of clearing already apparent on satellite. Dew points are moist enough to trigger surface convection, with CAPE values 500-700J/kg. The second part of the story is tonight as a shortwave trof swings into the humid airmass from the west near midnight. This is the dynamic feature that will cause nocturnal thunderstorms over the province, and parts of PEI. Pwats are near 30mm, and 0-6k shear values near 30kTs. The biggest hazard is pockets of heavy rain and lightning.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Night 1

 

Thunderstorm Outlook for Day 2

*Thundershowers still possible along broad frontal feature stemming from Labrador low.

 

Forecaster: TIRONE

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

For Nova Scotia… there is a low likelihood that thunderstorms will occur however thunderstorms that do develop have the potential to produce small hail, heavy downpours and strong wind gusts. Primarily over central and eastern parts of the province.

For Labrador… some embedded thunderstorms are possible.

 

Convective Discussion

 

Once again the favourable dynamics will be the primary driver of organised thunderstorm activity today. Overall Cape will be modest with values between 500 and 1000 j/kg but wind shear values are fairly significant with over 50 knots of deep shear. The initiation of thunderstorms will depend largely on the timing of the cooling at 850 and depth of the moisture available near the surface. Thunderstorms are most likely to develop along the spine of NS and track northeastward, affecting areas of central through to eastern and possibly northern NS. These storms, should they develop are likely produce small to moderate hail and heavy downpours. Given the dry mid levels and significant DCAPES there is a good chance for strong surface wind gusts with these thunderstorms. Watches may be issued if some convective initiation triggers deep convection.

 

ML

 

Thunderstorm Outlook for Day 1