Regional Impacts
Newfoundland and Labrador… Embedded thunderstorms giving 5 to 10mm with a possibility of showery ice pellets today
Maritimes… none today
Convective Discussion
An upper cold low currently sits over western NF and soundings are indicating temperatures below -20 at the 500mb level. Surface reports are showing a weak cyclonic circulation over the Island with a few rain bands rotating around it. Forecast guidance is suggesting the possibility of isolated weak/low-top CB’s within the cold pool. The main indicator is surface-based CAPE values in excess of 200 J/kg and LI between 0 to -2 over central regions. Brief moderate showers (with showery ice pellets) can be expected
A frontal trough currently over the Scotian Slope will intensify into a closed low pressure system as it moves towards the Grand Banks tonight. This very dynamic feature will be supported by a 50kt southerly low-level jet which will provide a good supply of moisture (precipitable water of 30+mm) and instability (MUCAPE of 500 J/kg and Showalter Index of -2 or less). Moderate to heavy rain (rainfall rates of 10-20mm) are expected offshore / Grand Banks but isolated thundershowers could brush the Avalon.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
