Convective Outlook Valid for Today and Tomorrow

Regional Impacts

A risk of isolated thundershowers over southeastern Labrador today.

A risk of some embedded thundershowers Saturday night across portions of western Nova Scotia.

 

Convective Discussion

A risk of thundershowers over SE LAB today associated with the upper low sitting over the area. SAT PIX does show some partial clearing which would help with some shallow CBs this afternoon. Highly doubt if anything will be observed near the coastal communities. Locally heavy downpours possible in some cells…if they develop.

 

A warm frontal trough will give the risk of embedded thundershowers Saturday night across portions of WRN NS. Heavy downpours would be the only threat.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 2

 

Jeremy

Convective Outlook Valid for Today and Tomorrow

Regional Impacts: Thundershowers, rain and possible gusty winds up to 80 km/h are expected later today for the northern Gulf of St. Lawrence and the Northern Peninsula of Newfoundland. Small hail is possible as well.

 

Convective Discussion: Freezing levels are expected to be around 6500 feet and the equilibrium point is expected to be around 20,000 feet. So, low topped CB’s expected near the upper low. The low is vertically stacked from the sfc right up to 250 mb. So, not a lot of dynamics leading to severe weather. Just quite unstable due to cold air aloft and the water still quite warm. Cool air CB’s. In general, the winds are expected to be too strong for waterspouts since gales are expected.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Isolated t-shwrs are expected in Labrador tomorrow as the upper low pulls to the north. Convection is not expected to be severe since the upper low will starting to fill and the instability is no longer over the warm water.

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1

 

Regional Impacts

Newfoundland: embedded TCus and Isolated thunderstorms giving mainly high rainfall amounts, exceeding 50 mm, combined with synoptic rainfall.

Southern Labrador: isolated to scattered thundershowers

Marine for southern Gulf of St. Lawrence, Cabot Strait and southern Gulf – Port au Port: Slight chance of waterspouts late this afternoon into this evening with gusts to gales possible.

 

Convective Discussion

A low over southern Labrador has a frontal trough extending southeast  to western Newfoundland. Ahead of the trough a strong southerly  jet extending from near the surface to midlevels is advecting significant moisture. While the tephi profiles are marginal at best, with low level capping,  lower level lift and moderate PVA, combined with some orographic forcing along the southern coast of the island, will give some enhance embedded TCus  and isolated CBs to enhance rainfall amounts. Winds will be brisk just with the synoptic forcing, and freezing levels are probably too high for anything significant.  For Labrador the situation is similar, but without the moisture feed. Almost moist adiabatic profiles with drying above 700 mb, with PWAT between `15-25 mm and southerly shear around 25 kts, argues  for isolated to scattered thundershowers with some gusty winds. With freezing levels near 5000 feet, small hail is definitely possible.

 

 

Thunderstorm Outlook for Day 2

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

NB and PEI: for this afternoon numerous clusters of strong thunderstorms producing heavy downpours 25+mm, hail 1cm, and gusts between 60-90 km/h.

Newfoundland&Labrador: Very moist airmass with isolated embedded thunderstorms spreading throughout the province - producing rainfall amounts in excess of 50 mm.

 

Convective Discussion

Surface Low pressure over Lower Quebec North Shore with cold front extending southwestwards along the St. Lawrence Valley. A southerly low level jet is spreading moisture from the Gulf of Maine across NB to Western Labrador. While steady rain is expected over northern regions, multi-cellular thunderstorms will continue to develop ahead of the advancing cold front. The threat of these storms becoming severe is reduced over areas where showers and thunderstorms have already developed during the morning. The focus will now be over southernmost NB and PEI for the most robust storms, and the main threat will remain the possibility of EF0-1 wind damage.

 

Thunderstorm Outlook for Day 1

 

 

 

Thunderstorm Outlook for Day 2

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

This afternoon until early evening: Isolated thundershowers over southern Labrador and central and eastern Newfoundland. Brief moderate showers with wind gusts between 50-70 km/h are possible.

Tonight: A few thundershowers over western and southern New Brunswick and western Nova Scotia. Brief heavier showers.

 

Convective Discussion

A number of weather features stand out this morning. The 500mb upper trough extends from the Labrador Sea to Northeastern Gulf of St. Lawrence, and a weakly cyclonic upper jet stretches from the Quebec North Shore to Southeastern Newfoundland. The cold air aloft more than makes up the limited surface heating and so a few cumulonimbus will develop this afternoon despite CAPE values between 250-500 J/kg. The airmass is drying nicely as open cellular pattern forming over the region. Weak downdraft could produce wind gusts between 30-40 kt.

 

A warm front will advance over the Maritimes tonight, but it will be quickly followed by a cold front advancing from Quebec Tuesday. Along the warm front some embedded non-severe thundershowers may touch westernmost areas.

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 2