Thunderstorm Outlook for SATURDAY:
Regional Impacts
Isolated non-severe thunderstorms possible this afternoon in many different areas of the Atlantic provinces, due to various weak forcing features. An approaching trof in northern Quebec may produce a marginally severe thunderstorm this afternoon in extreme western Labrador – greatest hazards being heavy rain and lightning.
Convective Discussion
Various features will create weak and short-lived thunderstorms today. A decaying trof over northern Nfld, a weakening low centre with associated occluded fronts near James Bay, and a weak sea breeze convergence zone over interior NS are the easiest to pick out from this morning’s air mass analysis. The ongoing heat wave across the Maritimes is keeping mid levels quite dry. Surface dew points are over 19 already, bringing Humidex values near 40 in Cape Breton this morning. Across NS/NB/PEI the expected weak thermal trof-ing at 850 to 500 is also occurring. Hence a shower that struggles to build will do just that, struggle.
Thunderstorm Outlook for Day 1 - JULY 23, 2022
Thunderstorm Outlook for SUNDAY:
Regional Impacts
Scattered non-severe thunderstorms possible tomorrow afternoon in parts of New Brunswick and Labrador. Isolated severe thunderstorms are possible in central Newfoundland including Gander and vicinity. Main hazards will be gusty winds, small hail, and frequent lightning. Rainfall rates could exceed 30mm/h in local pockets of heaviest downpours.
Convective Discussion
The focus of this discussion will be central Newfoundland. A strong short wave setup will destabilize a very hot and humid air mass currently established over the interior mid-day Sunday. As such, MU CAPE values are very high at over 2000J/kg, and ML CAPE is near 1300. ML CAPE is the most important here as we need the dew points to remain over 16 to have heights climb to severe levels. 0-6k shear is at 40kts. Storm type will be Supercell in this environment, and storm motion will be Bunkers RM. This has the potential to become a complex weather situation if the ingredients all line up at the right time of day. A funnel cloud or short lived tornado cannot be completely ruled out, however the probability of that remains very low at this time. Hail and strong winds have been included on the Day2 graphic in Area B to express the severe weather risk to the public. This weather threat may be upgraded to HIGH in future forecast issues. Storms will weaken in the evening as they head out over much cooler ocean waters and become de-coupled from the surface. Elevated lightning (from 700mb and above) could continue along the coast late into the evening.
Thunderstorm Outlook for Day 2 - JULY 24, 2022
Forecaster: TIRONE.