Regional Impacts
Today
Risk of a severe thunderstorm this afternoon for central and northeastern NL as well as eastern NS and parts of PEI giving locally torrential downpours. Risk of non severe thunderstorms for central and eastern LAB.
Tonight/Tuesday morning
Scattered embedded thunderstorms likely across a good portion of the Maritimes, southwestern NL and southeastern LAB giving locally heavy downpours.
Tuesday afternoon/evening
Scattered thunderstorms possible for a good portion of NL as well as southeastern LAB.
Convective Discussion
The air mass responsible for several rain-producing severe thunderstorms in NS yesterday is now in place over NL, with a surface trough now entering the island portion of the province to act as the trigger after lunch. PWATs are in the low to mid 40’s (observed at 12Z in YJT), and adjusting for high temps of about 26 gives plenty of mixed-layer CAPE. Expect to see a couple strong to severe thunderstorms giving locally torrential rainfall. Some gusty winds also possible but nothing drastic. At first glance one would expect the same potential across eastern NS and eastern PEI, and it does exist. The only caveat today is lack of a trigger as the MRTMS are in between short wave troughs. It might be tough to get enough forcing to generate good storms today. There is certainly plenty of moisture and decent instability so if there is local areas of surface convergence we could see an isolated severe storm giving intense rainfall. Lastly scattered thunderstorms look likely for a chunk of LAB today as a short wave trough passes through. Gusty winds and locally heavy downpours look likely, as well as small hail owing to the fairly steep low level lapse rates observed out of YYR.
A fairly large scale cold front will sweep across the MRTMS tonight and then NL Tuesday bringing some scattered thunderstorms to the region. Locally heavy rainfall seems to be the only concern at this time.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Jeremy