Convective Outlook Valid for Today

Regional Impacts

NB.. A few isolated showers this afternoon will bring a very slight risk  of thunderstorms with a few lightning strikes.

NS..A non zero chance of a thunderstorm, with a slight chance of a shower, no impacts.

Elsewhere.. No thunderstorms expected.

Convective Discussion.. Today marks the first day of the summer severe weather desk at the ASPC and it seems we will be off to a slow start. As is often the case this time of the year low moisture in boundary layer will be a limiting factor with surface Dewpoint Temperatures remaining in the single digits through the day. However there will be some instability as an upper trough tracks across New Brunswick with most unstable CAPE values likely below 250 J/kg. The upper trough will move through rather quickly so the potential will be short lived as we settle into calm weather for the next couple of days. No significant hazards are expected today but a few lightning strikes are possible with the showers as they move through the Maritimes.

Thunderstorm Outlook for Today..

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Isolated thundershowers over a portion of the southern GB today.

 

Tonight and Tuesday offers the potential for waterspouts for a good portion of the Gulf of St. Lawrence and into southern Gulf-Port au Port.

 

Convective Discussion

A weak frontal wave will give isolated thunderstorms today over a portion of the southern Grand Banks today. A fairly cold upper trough will be moving down from Quebec and Labrador tonight and Tuesday that will create favourable conditions for non-tornadic waterspouts for a good chunk of the GLFSTLAWR and into the Port au Port Peninsula area.

 

OTWZ nil sig wx xpctd.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Risk of a thunderstorm in western LAB, NW NB and SW NS later today.

 

Risk of thundershowers tonight along most of the ATL coast of NS.

 

Risk of thundershowers later today and tonight over the SRN GB.

 

Convective Discussion

3 separate features evident in SAT imagery: one being a weak surface low southeast of MRTM waters that will move up and over the southern GB later today and tonight giving the risk of thundershowers. The second feature will be an approaching cold frontal trough that is currently in Quebec. This will likely produce isolated thunderstorms upstream today, with the chance that one or 2 cells survive and make it to far western LAB and NW NB. Gusty winds and brief downpours are possible. The 3^rd feature will be a surface trough that is currently sliding towards NS. There is a chance of some late day and overnight thundershowers associated with it near Atlantic coastal NS. However there is no history with this so confidence on that happening is on the low side. Locally heavy downpours would be the only concern.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Slight risk of a thundershower tonight for NB.

 

Risk of a late day thunderstorm for W/NW NB Sunday giving gusty winds and heavy downpours. Slight risk of a thundershower Sunday evening for far southwestern NS.

 

Convective Discussion

Quiet today right across the board as the MRTMS and NL are under the influence of a ridge of high pressure. A frontal trough will give showers to most of Labrador but no lightning is expected. The same frontal trough will slide down over NB tonight giving just the slight risk of a thundershower overnight and early Sunday with the aid of cloud top cooling. Sunday will give the risk of a late day thunderstorm to W/NW NB as a secondary frontal trough rapidly swings in upstream from Quebec. This front could give some strong wind gusts and locally brief heavy downpours. The aforementioned trough impacting NB tonight will give some showers and risk of thundershowers to NS Sunday night.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

 

Today

Labrador: Chance of isolated thundershowers.

NB/NS/PEI/NL: None.

 

Tonight

NB/NS/PEI/NL/LAB: None.

 

Tomorrow

NB/NS/PEI/NL/LAB: None.

 

Convective Discussion

 

A cold front will sweep across Labrador today from Quebec and continue through the Maritimes and Newfoundland on Wednesday. There is a slight risk of convection over western and northern Labrador today, but the air mass is expected to be too stable with warming 500mb temperatures as the font continues tonight and Wednesday across the Maritimes. Nonetheless, there could still be some heavier pockets of rain in TCUs with precipitable water increasing to 40 mm over the Maritimes, but the front is forecast to move through quickly, which will limit rainfall amounts.

 

This cold front ushers in a cooler, drier air mass under a strong high pressure system that will suppress any convection in the region until at least the end of the week.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

 

 

Roberta McArthur