Regional Impacts
Today
NS: Chance for elevated thunderstorms spanning Southwestern Nova Scotia through Central Nova Scotia. Risk for gusts of 60 to 70 km/h and rainfall of 20mm.
PEI: Chance for elevated thunderstorms spanning the province. Risk for gusts of 60 to 70 km/h and rainfall of 20mm.
NB: Chance for elevated thunderstorms in the Southeast sections of the province. Risk for gusts of 60 to 70 km/h and rainfall of 20mm. Slight chance of an Isolated thundershower over extreme Northwestern New Brunswick.
NFLD/LAB: Nil.
Tonight
NS: Chance for elevated thundershowers spanning Southwestern Nova Scotia through Central Nova Scotia. Risk for gusts of 60 to 70 km/h and rainfall of 20mm.
PEI: Chance for elevated thundershowers spanning the province. Risk for gusts of 60 to 70 km/h and rainfall of 20mm.
NB: Chance for elevated thundershowers in the Southeast sections of the province. Risk for gusts of 60 to 70 km/h and rainfall of 20mm. Slight chance of an isolated thundershower over extreme Northwestern New Brunswick.
NFLD/LAB: Nil.
Tomorrow
NS: Chance for elevated thundershowers spanning Central Nova Scotia through Cape Breton.
PEI: Chance for elevated thundershowers spanning the province in the morning.
NB: Chance for elevated thundershowers over the majority of the province.
NFLD: Chance for elevated thundershowers over the extreme Southwest and South-central regions of the province.
Lab: Nil
Wednesday
NS: Chance for isolated thunderstorms predominantly over the Central regions of the province.
PEI: Chance for isolated thunderstorms over the province.
NB: Chance for isolated thunderstorms over the interior of the province. Risks include gusts of 70-80km/h and hail near 2cm.
NFLD: Chance for elevated thundershowers over the Southern and Central regions of the province.
LAB: Nil.
Convective Discussion…
An approaching frontal system is progressing through the Atlantic Canada today is eroding the previously placed high pressure system throughout today and tomorrow.
Today, the main threat area will be in the Southeastern sections of New Brunswick and over most of mainland Nova Scotia where elevated thunderstorms could produce heavy downpours with rainfall possibly exceeding 20mm of rain and wind gusts of 60 to 70km/h. From ship observations there was reports of winds in excess of 60km/h. Current satellite imagery shows the approaching frontal system with embedded thunderstorms over the marine regions from overnight approaching the Nova Scotia coast. This should allow the continuation of MUCAPE to near 600 J/Kg, along with PWAT’s to remain near 30-40mm by this afternoon and progress eastward.
Tonight, as the frontal system progresses eastward bringing the elevated thunderstorms into Cape Breton and begin approaching Southern Newfoundland. Additionally, behind the frontal system there is expected to be a clearing in behind the system allowing for instability to approach New Brunswick allowing for further convection to occur. Thunderstorms in the clearing are expected to start off as surface based showers and becoming elevated overnight. This instability mixed with cloud-top cooling is expected to give rise to elevated thunderstorms.
Tomorrow, the frontal system from overnight will continue to progress eastward and begin to slow down over Cape Breton and Southern Newfoundland. In behind the frontal system tomorrow there is likely to be a narrow corridor of MUCAPE nearing 700 J/Kg with shear of 20 to 30Kt giving rise to the possibility of thundershowers from Southeast New Brunswick into Central Nova Scotia.
Wednesday, as the frontal system has departed and began to diminish over Newfoundland the previous couple of days rainfall is expected to give rise to excess moisture that align with Jet streak approaching from the West to act as a trigger for more severe thunderstorms over the interior of NB. There remains some uncertainty with this setup as it does rely on how must moisture gets injected into the interior of New Brunswick from these next couple of days. Current computer guidance is indicating that within the interior of New Brunswick there could be a risk of thunderstorm with gusts in excess of 80 km/h and hail nearing 2 cm. This come from MUCAPE nearing 2,000 J/Kg and MLCAPE nearing 1,000 J/Kg along with relatively good shear throughout the profile.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Thunderstorm Outlook for Wednesday
Forecaster: McArthur/Lambert