Convective Outlook Valid for Today and Tomorrow

Regional Impacts

For Nova Scotia… there is a low likelihood that thunderstorms will occur however thunderstorms that do develop have the potential to produce small hail, heavy downpours and strong wind gusts. Primarily over central and eastern parts of the province.

For Labrador… some embedded thunderstorms are possible.

 

Convective Discussion

 

Once again the favourable dynamics will be the primary driver of organised thunderstorm activity today. Overall Cape will be modest with values between 500 and 1000 j/kg but wind shear values are fairly significant with over 50 knots of deep shear. The initiation of thunderstorms will depend largely on the timing of the cooling at 850 and depth of the moisture available near the surface. Thunderstorms are most likely to develop along the spine of NS and track northeastward, affecting areas of central through to eastern and possibly northern NS. These storms, should they develop are likely produce small to moderate hail and heavy downpours. Given the dry mid levels and significant DCAPES there is a good chance for strong surface wind gusts with these thunderstorms. Watches may be issued if some convective initiation triggers deep convection.

 

ML

 

Thunderstorm Outlook for Day 1

 

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

For Labrador… some embedded thunderstorms could lead to locally heavier rainfall this evening.

For New Brunswick… potentially severe thunderstorms could affect northern New Brunswick late this afternoon. Small hail with strong wind gusts and potentially heavy downpours can be expected.

 

Convective Discussion

We are looking at very favourable dynamics for the development of severe thunderstorms later this afternoon. Aloft the 250 mb jet will be in a good position for enhanced vertical motion later today with the exit region over northern New Brunswick. The windshear through to mid-levels is favourable for the development of supercells or possibly bow echoes, but it is still possible that a QLCS( Quasi Linear Convective System) could form west and move over New Brunswick later today. One remaining concern if the amount of available low level moisture and CAPE, but with the approaching upper trough the atmosphere will destabilize at some point today. Needless to say a large variety of possible outcomes, but in all likelihood severe winds will be the main concern should thunderstorms develop. Watches may be issued a little later today once we have some stronger indication of the clouds dissipating and more insolation occurring upstream of our area of concern.

 

ML

 

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Day 2

Convective Outlook for the Maritimes valid for tomorrow July 12th

This is an update to the previous forecast for tomorrow July 12^th.

 

With a higher level of confidence I have updated the outlook for tomorrow to include a increased area of severe weather for northwestern New Brunswick. Most of the outlook remains the same with a chance of organised convection late in the afternoon, overall updrafts are not particularly strong but favourable dynamics may be enough to produce severe storms, with heavy rain and potentially strong wind gusts.

 

ML

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow and Wednesday

Regional Impacts

For Today... Minimal impacts expected with only a slight chance of thunderstorms expected parts of New Brunswick and Labrador.

For Tomorrow... Organized convection possible late tomorrow afternoon and evening for northern New Brunswick, locally heavy downpours can be expected.

Convective Discussion

No significant convection is expected today with little potential energy and no significant forcings. Tomorrow the dynamics will begin to organize with an approaching upper trough and increasing mid level shear. There is still some uncertainty with the amount of CAPE with expected values around 500 J/kg, but with high Precipitable Water values approaching 50mm some locally heavy downpours could occur. In addition there is a slight risk that organized convection in the form of a squall line or QLCS (quasi linear convective system) may form further west and move over NB late in the afternoon. As the system develops we will have a better understanding of the potential, please look for the updated outlook tomorrow.

Mel Lemmon

Outlook for Today

Outlook For Tomorrow

Outlook for Wednesday

Convective Outlook Valid for Today and Tomorrow

Regional Impacts:

 

Today

Labrador: scattered lightning over southern and eastern areas with 0-1 cm hail, 20 mm rainfall, isolated lightning elsewhere.

Northern Newfoundland and Gulf waters: isolated lightning and locally heavy downpours.

 

Tonight

Labrador: isolated lightning over southeastern areas.

 

Sunday

Labrador: Isolated lightning over western area and southeastern areas.

Newfoundland: isolated lightning over northern and northeastern areas.

 

Convective Discussion:

A stacked centre of low pressure remains nearly stationary over southern Labrador today with an upper trough moving eastward through Newfoundland today with scattered showers. This low will continue to weaken then slowly drift southeastward on Sunday. Instability near the low centre and within the trough will allow the possibility of isolated to scattered convection today that is already gotten going over the lower North Shore Quebec. In the area near and east of the low centre, with bulk shears of 25-30 kts, MLCAPES of 500-750 J/kg, and precipitable water near 20 mm, storms are expected to remain sub-severe criteria. Small hail near 1cm is also possible given low freezing levels. There is also a risk of cold core funnels with low LCLs and weak vertical shear. Elsewhere across Labrador and northern Newfoundland, isolated lightning is possible.

 

For tonight, storms will weaken in the evening and become elevated as the low slowly moves eastward.

 

For Sunday, some lingering convection is possible over southeastern Labrador and northeastern Newfoundland as the low centre continues to drift southeastward. Meanwhile, another upper low will move into western Labrador from central Quebec in the afternoon,  providing some instability with isolated thunderstorms.

 

Thunderstorm outlook for today:

 

 

Thunderstorm outlook for tonight:

 

 

Thunderstorm outlook for tomorrow: