Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today: Organized thunderstorms today across the SErn marine district, approaching the Nfld coastline early this afternoon. Lightning is the main hazard. An isolated cell or 2 may also pop up this evening in western Labrador and the Edmundston valley area of NWrn NB. A quick 5-10mm of rain could fall.

Tonight: No thunderstorms forecast in ATL Canada.

Tuesday: Late-day thunderstorms are forecast, with the progression of a destabilizing trof out of the Great Lakes region of Ontario. The timing of this trof is quite slow. The main hazards would be gusty winds ahead of the system and pockets of moderate rain. Rainfall rates are forecast to exceed 40 mm/h in the tri-counties area of NS *if* the system develops as models suggest.

Wednesday: Atmospheric conditions remain unstable, so afternoon storms are possible across Labrador, NB, NS, and portions of PEI with daytime heating, and relatively high humidity.

Convective Discussion

The first forcing at play is pulling out of the eastern marine region this afternoon. Mid-levels behind this feature on this morning’s soundings are prohibitively dry. However, Caribou is expected to moisten at 700 throughout the afternoon and as such could produce enough lift late day to spark a cell or 2. They will remain non-severe in nature. The regime tomorrow is somewhat more complex. Another trof is cutting across the Great Lakes and will de-stabilize the now moistened (and near heat warning) Maritimes environment. This will lead to both a wind gust hazard and moderate rainfall hazard on Day 2. If the total energy can be realized before sunset, some cells could approach severe limits. This is being closely monitored as many factors have to line up just right. The Day 3 outlook remains unstable across much of the Maritimes and Labrador with humid sfc conditions and cool air aloft from a developing upper low. This will create pockets of moderate shear with organized convection developing in the afternoon.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Canada Day

Thunderstorm Outlook for Wednesday

Forecaster: Tirone.

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today: No thunderstorms forecast over land regions of the Maritimes. Not enough lift available with an advancing warm nose between 850 and 700 mb.

Tonight: No thunderstorms forecast.

Monday: Non-severe thundershowers are possible in extreme NWrn NB late in the day, as well as in extreme western Labrador. The main hazard with these cells would be lightning.

Tuesday (Canada Day): A broader area of convection is possible across a large portion of the Maritimes and forecasters will be updating hazards in next 24hrs.

 

Convective Discussion

Warm air advection is advancing into the Maritimes and as such, there is a cap in place. Dominant showers and drizzle lack the colder mid levels and cloud tops to produce charge separation and lightning. There is an area of organized convection across the southern marine district which will slowly drift SE today, enhanced by warmer sfc waters of the gulf stream. Humidity is forecast to increase early this week and an advancing trof late in the day on Tuesday may be enough to destabilize and trigger organized convection. However, there remains uncertainty about the timing of this slow-moving feature. Details will be honed in coming forecasts, as the feature is timed across the Great Lakes region. (The Grey hazard area on day3 may be upgraded.)

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Thunderstorm Outlook for Tuesday

Forecaster: Tirone.

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today: risk of non-severe thunderstorms across the interior of NF and southeastern LAB. Risk of embedded thundershowers for some southwestern areas of the MRTMs this evening.

 

Tonight: continuing with that risk for embedded thundershowers across far southwestern NS.

 

Sunday: nil.

 

Convective Discussion

There will likely be some isolated cells this afternoon form over the traditional area of inland southwestern NF then advect E/NEward during the afternoon hours, in association with a weak short wave trough moving through the area. The 12Z sounding out of YJT supports some small hail and gusty winds to about 70 km/h. Pwats are super low so rainfall is not a concern at all. Expect isolated cells for inland areas of southeastern LAB as well but are not anticipated to impact any of the coastal communities. Lastly a frontal zone will remain over the western MRTMs today and tonight so there will be a risk of embedded, elevated thundershowers for some counties tonight that will give intense rainfall at times, as model Pwats will be running up around 40 mm. Sunday looks rather quiet across the entire region.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today:

NL/Lab: Risk of thundershowers with small hail and strong wind gusts.

Maritimes/NL: None

Tonight:

Lab: Risk of thundershowers with small hail and strong wind gusts early this evening.

Maritimes/NL: None

Tomorrow:

NL/Lab: Risk of thundershowers with small hail and strong wind gusts.

Maritimes: None

Convective Discussion

A weak trough over eastern Newfoundland and associated cold pool aloft has triggered a few thunderstorms producing small hail this morning over the Avalon Peninsula and this may continue into the early afternoon as the trough moves eastward. Another weak trough and destabilization from surface based heating will aid in the triggering of non-severe thundershowers across western Labrador this afternoon. This feature will then move southeastward on Saturday. Daytime heating and this trough will help trigger non-severe thundershowers over southeastern Labrador and across Newfoundland tomorrow afternoon. Overall, precipitable water is low to moderate and the CAPE in realized could reach 300 J/kg and effective shear are low to moderate, but freezing levels area low, thus some stronger showers may have small hail and with somewhat inverted V profiles, locally strong wind gusts are also possible.

Thunderstorm Outlook for TODAY

 

Thunderstorm Outlook for TONIGHT

Thunderstorm Outlook for TOMORROW

 

Roberta McArthur

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NL/Labrador: A chance of non-severe thunderstorms with small hail.

NB/NS/PEI:  None.

 

Tonight

NB/NS/PEI/NL/Labrador: None

 

Friday

NL/Labrador: A chance of non-severe thunderstorms with small hail.

NB/NS/PEI: None

 

Convective Discussion

A cold pool is descending across Newfoundland and Labrador today. A few non-severe lightning strikes are possible. Additionally with the low freezing levels (3000-5000 feet) there is a chance of small hail. CAPE values are very low (300-500 J/kg) so that will limit any hail growth. Friday morning the cold pool may kick off a couple thunderstorms across the Avalon and extreme eastern Newfoundland. Friday afternoon a weak trough in associated with continued cold air across Labrador may trigger some non-severe thundershowers across western areas.  Continued low freezing levels but limited CAPE will provide the opportunity for small hail.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow