Regional Impacts
Today
NS: There is a risk of a severe thunderstorm this afternoon and evening for a portion of the Valley, with torrential rainfall in the order of 25-50 mm/h the main threat. Elsewhere for NB and most of the rest of mainland NS, some isolated non-severe thunderstorms are possible.
Tonight
NW NB: Some isolated thunderstorms possible giving mainly heavy downpours.
SW NL: A slight risk of an embedded thundershower giving locally heavy downpours.
Friday
NB: Isolated thunderstorms likely for a good portion of NB giving possible small hail, strong winds and heavy downpours.
SW NL/WRN LAB: A slight risk of a thundershower giving locally heavy downpours.
Convective Discussion
The main area of threat today will be the Valley of NS, with a lesser threat for areas of NB and most of the rest of the mainland of NS. The 12Z tep out of YQI looks decent for possible torrential rainfall and small hail. Adjusting for a surface temperature of 31 gives over 1000 j/kg of MUCAPE, with fairly fat CAPE below 500 mb owing to some decent updrafts. Tds are in the lower 20’s, so surface moisture if plentiful…as well at 850 mb. The instability is modest with LI’s of around -4 or so. The concern will be for training convection and hence locally very high rainfall rates in a relatively short period of time. The shear is very weak so wind gusts won’t be a big deal. Will have to see how things unfold this afternoon.
Some isolated thunderstorms are possible later tonight across NW NB as some development in ME might drift across the border. Also a slight risk of an elevated, embedded thundershower for SW NL associated with a very slow moving trough of low pressure.
More thunderstorms are likely for a good portion of NB and western LAB Friday afternoon and evening. Dynamically speaking, tomorrow is a better day for convection as the large scale trough to the west makes its way into our region. That aforementioned trough over NL will continue to give a slight risk of an embedded thundershower as well across SRN NL.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Friday
Jeremy