Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

NB/NS/PEI/Labrador:  No significant impacts expected.

 

Newfoundland: Slight risk of short lived thunderstorms over central and eastern Newfoundland.  Main threat is local heavier showers and gusty winds. 

 

Convective Discussion

 

An area of PVA is currently bringing some showers and thundershowers just southwest of Newfoundland.  This area of PVA along with cooler upper atmosphere temperatures and high insolation will bring some thundershower activity to parts of Newfoundland today.  Wind shear is low so long lived severe thunderstorms is not expected.  Precipitable water is low as well so torrential downpours are not expected.  Still, there is a low potential for short lived severe storms bringing localised heavy rainfall and gusty winds mainly over eastern Newfoundland.  Prog tephis over eastern Newfoundland showing between 500 to 1000 J/kg with low shear and low precipitatble water.

 

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 2

 

 

Barrie MacKinnon

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

For Labrador.. Small hail and gusty winds in thunderstorms this afternoon and this evening. Heavy downpours may occur.

 

For New Brunswick.. Isolated thunderstorms possible over norther New Brunswick this afternoon. No Severe Weather expected. Small Hail possible.

 

Convective Discussion

 

Labrador continues to be a main threat area today with an upper trough progressing eastward through northern Quebec. Aloft at 250 there isn’t strong support but the dynamics are somewhat more favourable as you move down through the atmosphere. Good low level shear below 500 mb could favour the development of organised thunderstorms this afternoon, possible affecting western Labrador late this afternoon and early in the evening.

 

Not much is expected southward in New Brunswick with somewhat dry, relatively speaking,  lower levels and upper lapse rate that are not overly conducive to deep convection. However an upper trough may act to destabilize the atmosphere allowing for daytime heating and surface convergence near the northern coastlines to trigger some convection.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

NS/NB/PEI/NFLD/Labrador: None

 

Convective Discussion

 

Lower dew points and a stable airmass has moved into the area. There is a thundershower risk for southern Maritime marine areas today.  On Saturday there is a thundershower risk for NW New Brunswick and parts of Labrador as separate surface troughs move across those regions.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

NS/NB/PEI/NFLD: None

Labrador:  A risk for most regions and a chance of gusty winds and hail southeast.

 

Convective Discussion

 

A low pressure system will track across Labrador today. Ahead of the low, daytime heating will allow temperatures to reach 27 degrees. Modifying the upstream sounding at Sept-Iles yields precipital water of 25- 30 mm, cape of 1000 J/kg and unidirectional shear of 30 kts. Additionally the freezing level is fairly low at 9,000 feet.  An upper level jet will approach this afternoon and southeastern Labrador will be in a favourable area of enhanced lift (left exit). The low freezing levels and decent cape above -10 C will support hail growth. The dry mid levels will support possible wind gusts.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

Risk of  thunderstorms over Northern and Western NB this afternoon, main threat is gusty winds and brief downpours.

Some thunderstorm activity is expected over central Quebec this afternoon and evening, some of these storms may propagate to western Labrador late evening and after midnight

Convective Discussion

This morning, an upper ridge with stable dry conditions prevails over NF, while a cold trough extends from an upper low south of James Bay to southern Quebec. The area with the highest potential for convection is central and southern Quebec and northern Maine. Convective initiation should be fairly easy to attain given the buoyancy of this airmass. Using the most recent Maniwaki sounding, mean layer energy should easily reach 750-1000 J/kg - and with deep layer shear values of about 25kt – this will be adequate to sustain more robust isolated storm cells. Behind the remnants of Isaias, there is a marked drop in moisture content, so the main threat with these storms would be moderate to strong wind gusts.

Thunderstorm Outlook for Day 1

 

Thunderstorm Outlook for Day 2