Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NB: Scattered thunderstorms developing, some becoming strong with potential for damaging wind gusts and 1-2 cm hail. Severe weather watch for western portions of the province for the afternoon into the evening.

NS/PEI: risk of non-severe thunderstorms

NF: A slight chance of thunderstorms south coast

Labrador: None

 

Tonight

NS and NF: A chance of embedded thunderstorms

NB/PEI/Labrador: None

 

Monday

NS and NF: A chance of embedded thunderstorms

NB/PEI/Labrador: None

 

Convective Discussion…

Low pressure near Sept-Iles with an attached frontal wave system is slowly moving eastward. In the warm sector, a 50-60kt SWly low-level-jet has been pushing very moist air northward and a large area of area of moderate-heavy rain has spread across NS earlier this morning which resulted in amounts of 10-30mm. This activity will advancing towards NF during the day.

 

To the west, an upper  trough over western Quebec will be advancing towards the Maritimes today and will be the focus severe weather (the main threat is the potential for damaging wind gusts WINDEX gusts estimates 50kt). There is not much convective inhibition ahead of this feature, and towering clouds are already noticeable north and south of the St. Lawrence valley. The main forcing will be a sharp area of convergence at the surface, emerging 30kt Wly low-level-jet, right entrance of a slightly cyclonic upper level jet, and 500mb PVA. Temperature and Dewpoint combination of 23,18 are sufficient to produce surface-based CAPE values of 1,000 J/Kg (MU 1,500) with Lifted index of -3 to -5, and deep-layer shear of 40-60kt. Under this very strong flow, hodograph is indicating straight/linear winds with storm motion of 260/35kt. Some of the storms could be long-lived especially over central Maine later this afternoon. This could produce bowing lines which could advance east of the international border.  

 

 

Thunderstorm Outlook for Today

 

 

Thunderstorm Outlook for Tonight

 

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

Labrador: A chance of thunderstorms north coast.

NB/NS/PEI/NL: None.

 

Tonight

NB/NS: A chance of embedded thunderstorms.

PEI/NL/Labrador: None.

 

Sunday

NB/NS/PEI/NL: A chance of embedded thunderstorms. Over New Brunswick, surface based storms will likely give severe weather in the afternoon.

Labrador: None.

 

Convective Discussion…

A low pressure system tracking across northern Labrador may give a few elevated thundershowers to that area this afternoon.  Tonight an approaching low pressure system will give rain across the Maritimes starting overnight. On Sunday, embedded/elevated thundershowers are expected across the region. Sunday afternoon with some clearing ahead of the low’s associated cold front, surface based thundershowers are expected over portions of New Brunswick and they will likely become severe. CAPE values of 500-1000 J/kg, shear of 40-50 knots and strong low level winds below 6000 feet will likely produce multicell and bow echo elements.  Wind is the main threat (possible 90 km/h +) but 2 cm hail and torrential downpours (PWAT values 30-40 mm) are also likely. Because of some uncertainty with clearing in the afternoon and daytime high temperatures, the Sunday (day 2) chart below is likely a bit on the conservative side but will be updated again Sunday morning.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NB: A chance of thunderstorms east.

NS/PEI/NL/Labrador: None.

 

Tonight

NB/NS/PEI/NL/Labrador: None.

 

Saturday

NB/NS/PEI/NL/Labrador: None.

 

Convective Discussion…

A low pressure system will track northeastward across Newfoundland today. Unstable air in the wake of the low will give a chance of non-severe (CAPE values of 200 J/kg or less) thundershowers over eastern New Brunswick this afternoon.  There is a slight chance of thundershowers in areas of prolonged sunshine (if there are any) in central Newfoundland this afternoon.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NB/NS/PEI/NL: Scattered thunderstorms giving possible giving rainfall rates of 10 to 20 mm/h.

Labrador: None.

 

Tonight

NL: Scattered thunderstorms giving possible giving rainfall rates of 10 to 20 mm/h.

NS/NB/PEI/Labrador: None.

 

Friday

NB/NL: Scattered thunderstorms giving possible giving rainfall rates of 10 to 20 mm/h.

NS/PEI/Labrador: None.

 

Convective Discussion…

A trough of low pressure stretching from New Brunswick to Newfoundland will slowly track eastward today and Friday.  Embedded thunderstorms are occurring near and ahead of the trough and are giving downpours of 10-20 mm/hr. Some pop-up thundershowers are possible this afternoon over New Brunswick. Cape values are 200-300 J/kg with shear of 40-60 kts. The shear will be too much to assist with the thunderstorm development so these should remain non-severe.  More pop-up thundershowers are possible Friday afternoon over New Brunswick but again the Cape values are quite low.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts…

NB… Scattered thunderstorms possible over northwestern New Brunswick early this afternoon. Rainfall rates of 10 to 20 mm/h and wind gusts up to 70 km/h.

NL… Isolated thunderstorms possible over southwest Labrador this afternoon. Rainfall rates of 10 to 20 mm/h and wind gusts up to 70 km/h.

NS/PEI… Embedded thundershowers possible tomorrow morning and afternoon. Rainfall rates of 10 to 20 mm/h.

 

Convective Discussion…

A trough entering New Brunswick today brings the risk for some scattered thunderstorms early this afternoon. The biggest threat for severe weather exists in northern New Brunswick, where better thermodynamics and forcing are present. However, dense cloud cover northern New Brunswick is preventing CAPE values from rising too much, though some brief clearing behind this is expected. The risk remains low due to this, in addition to a stalling thermal trough this afternoon. The thermal ridge sitting over southern New Brunswick should remain intact and inhibit much thunderstorm activity here today, as the frontal boundary slows down and stalls over northern New Brunswick later this afternoon. Bulk shear values of 40 to 50 kts are present (though quite linear), as well as PWAT values in the range of 30 to 35 mm. As such, the main threats with any storms today will be strong wind gusts up to 70 km/h and heavy downpours of 10 to 20 mm/h.

A second system, that is expected to bring severe weather to parts of the northeast US today, will approach the Maritimes over the Gulf of Maine tonight, reaching southwest Nova Scotia early tomorrow morning. Strong dynamics and adequate instability in the mid-levels will aid in sustaining convection overnight and into tomorrow morning as the trough passes over the Gulf of Maine. With PWAT values expected around 40 to 50 mm, heavy downpours up to 20 mm/h are possible tomorrow morning across southern Nova Scotia and potentially into the Bay of Fundy.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Copp

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

NS/NB/PEI… Isolated thundershowers today producing locally heavy downpours of 10 to 20 mm/h.

NL… None.

 

Convective Discussion…

A low passing south of Nova Scotia today brings a slight chance for some isolated thundershowers over portions of the central and eastern Maritimes. Meager MLCAPE values of less than 500 J/kg, and weak bulk shear might be enough to squeeze out a few lightning strikes, but no organized convection is expected. Nonetheless, a steady stream of moisture around the northern side of the low will provide PWAT values in the range of 25 to 30 mm, so locally heavy downpours of 10 to 20 mm/h will be possible this afternoon. The risk will quickly diminish this evening as the low approaches Newfoundland.

Tomorrow, a trough will approach western Newfoundland and northern New Brunswick, bringing the risk for some isolated thunderstorms in the afternoon. A slightly better environment for severe weather is in place in northern New Brunswick, with higher CAPE and bulk shear values present tomorrow. The limiting factor is the timing of the thermal trough, as current guidance doesn’t have it moving through until 21Z, thus the risk currently remains low for organized thudnerstorms.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Copp

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

 

NS and PEI

Today… Isolated thunderstorms giving amounts of 15 to 25 mm.

Tuesday… Isolated thunderstorms.

 

NB

Today… Isolated thunderstorms likely, especially over southern sections giving amounts of 15 to 25 mm.

Tuesday… Isolated thunderstorms likely, especially over southeastern sections.

 

NF

Today… Isolated thunderstorms likely, especially over southern sections giving amounts of 15 to 25 mm.

Tuesday… None.

 

Labrador

Today… Risk of thunderstorms south of the Churchill river – East to Eagle river – and then Cartwright area with a risk of small hail and brief wind gusts.

Tuesday… None

 

 

Convective Discussion

 

An area of low pressure currently centred over Maine will slowly track eastward today to lie over Nova Scotia by Tuesday morning then should track towards the northeast over Newfoundland by Wednesday morning. There has been ongoing elevated embedded convection ahead of this low, from off Cape Hatteras stretching northeast towards southern Newfoundland, aided by a strong upper jet and very warm air near 850mb. Some rainfall amounts of upwards of 50 mm have already fallen since yesterday over parts of the Maritimes and southern Newfoundland. Embedded convection is expected to continue today and into Tuesday and the low moves eastward. 12Z soundings from YQI and YAW indicate precipitable water near 45 mm, but with a strong mean flow ahead of the low centre from the southwest (50KT at 700mb), convection is moving through quickly. However, closer to the centre of the low in southern Maine and southwestern New Brunswick, convection is also expected this afternoon but will be slower to move so there is the risk of locally heavy downpours.

 

Meanwhile, a trough over southern central Labrador along with some clear skies this morning will aid in increased instability and surface convection for this afternoon for areas of southern and southeastern Labrador. MUCAPE may reach 500 J/kg but 0-6km shear above 50kt may prohibit much convection from maintaining for long but there is the risk of small hail and brief strong wind gusts.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Labrador

Today…Isolated non-severe thunderstorms over southern sections

Monday…Risk of non-severe thunderstorms south of the Churchill river – East to Eagle river – and then Cartwright area

 

NF

Today…Slight Risk of a non-severe thunderstorm over northeastern sections

Monday…Rain and Isolated embedded thunderstorms over southern sections giving some heavier rain (15-30 mm)

 

NB

Today…Rain spreading throughout the province with embedded thunderstorms giving higher amounts (30-60 mm through tonight)

Monday…Isolated thunderstorms likely, especially over southern sections

 

NS and PEI

Today…Rain spreading from west to east and with a few embedded thunderstorms likely giving amounts of 20-40 mm

Monday…Rain with Isolated embedded thunderstorms giving amounts of 10 to 15mm

 

 

Convective Discussion

Some weak surface-based instability is expected over southern Labrador today the main forcing is a convergence line between the mid-coast and the southwest corner. The main limiting factor is the lack of moisture near the surface, however Td of 9 or 10 deg and temperatures of 20 to 25 were sufficient to trigger isolated CB’s. Using this combination on the 12z Goose sounding yielded MLCAPE values in excess of 500 J/kg, LI of 0 or -1, and equilibrium levels to almost 20,000 ft

The main threat of severe weather lies west of the region today, between southern QC and NE where a number of upper air soundings revealed curved hodographs this morning. Atlantic provinces will be under the influence of a low pressure system which will travel from the Ottawa valley through the Gulf of St. Lawrence then NF tonight and Monday. Some of the forecast guidance is suggesting rainfall amounts enhanced significantly by embedded convection, generally along the track of the low, amounts of 50 to 75 mm can be expected with hints of 100+ west of the region.

 

Thunderstorm Outlook for Today

 

 

Thunderstorm Outlook for Tonight

 

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

 

Labrador

Today…Risk of a non-severe thunderstorm over southeastern sections during the afternoon, and late in the day in the west

Sunday…Risk of a non-severe thunderstorm over southernmost sections

 

NF

Today…Isolated non-severe thunderstorms over central and northeast sections

Sunday…Risk of a non-severe thunderstorm especially over northeast sections

 

NB

Today…Risk of a non-severe thunderstorm over northern regions, especially the Chaleur region

Sunday…Heavy rain likely from embedded thunderstorms

 

NS and PEI

Today…none

Sunday…Rain with Isolated embedded thunderstorms

 

 

Convective Discussion

The main area of focus this afternoon is over central NF. The convective temperature should be reached fairly early in the period but low level moisture is low and the deep layer shears are too high to produce more widespread / deeper convection. Regardless, conditions will likely produce moderate TCU’s (and even one or two CB’s) with local 5-10 mm and gusts around 50 km/h. For Lab west, there is an approaching surface trough with a large area of cloud is associated with it. Satellite imagery is indicating the presence of embedded convections west of Schefferville (however there is no lightning activity detected). The moisture in the low levels is clearly lacking over YKL-ZUM-YWK but Td’s should increase during the afternoon.. this combined with the long period of early summer surface heating, and the emergence of a low and upper level jet – should provide some support for the development of deeper (moderate) convection ahead of this feature. Having formed in a low moisture environment, rainfall rate potential is 5 mm/h at the most.  

A frontal band over New England will shift north on Sunday and spread rain across the Maritimes. Rainfall rates will be enhanced by embedded thunderstorms, especially over NB

 

 

Thunderstorm Outlook for Today

 

 

Thunderstorm Outlook for Tonight

 

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Isolated non-severe thunderstorms are possible this morning along portions of South Shore NS and offshore across marine areas – slope waters, and Sable Island. Elsewhere across Maritimes the atmosphere is stabilizing.

 

Convective Discussion

Soundings behind the frontal feature are drying out nicely at 700mb as forecast. This is stabilizing the mid levels of the atmosphere with the noticeable change in air mass. No thunderstorms are forecast overnight tonight across the AOR. Pockets of instability are possible in parts of central Newfoundland tomorrow, along parts of the Lab coast, and across extreme northern NB. No dynamics suggest anything near severe limits. Cells will be embedded in shower activity. Sunday late in the day has the potential to be more organized in NB and NS as a frontal feature amps up dew points and lift indices again. This risk will be honed in on in coming shifts, with a particularly watchful eye on shear.

 

Thunderstorm Outlook for TODAY

 

Thunderstorm Outlook for TONIGHT

 

Thunderstorm Outlook for SATURDAY

 

Thunderstorm Outlook for SUNDAY

 

Forecaster: Tirone

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

NS/NB/PEI… Scattered thunderstorms possible across the central Maritimes this afternoon, main risks are heavy downpours, strong wind gusts, and small hail.

NLFD… Isolated thunderstorms possible in central Newfoundland this afternoon, main risks are strong wind gusts and heavy downpours.

 

Convective Discussion…

As very warm temperatures continue across the Maritimes today, a cold front will begin to move south across the region. Surface based CAPE values are forecast to soar upwards of 2000 J/kg in southern New Brunswick and mainland Nova Scotia ahead of the front in addition to decent bulk shear values of 30 to 35 kts. Due to the strength of the ridge south of Nova Scotia, the front is expected to slow down and weaken as it moves across New Brunswick, and stall over southern Nova Scotia tonight. This will cause some issues in the erosion of the thermal ridge, especially over southern Nova Scotia. In addition, the location of the 500 mb jet over central Quebec is not ideal. As such, the main focus for severe thunderstorms will be in southeastern New Brunswick and central Nova Scotia today. PWAT values on the Yarmouth tephigram this morning indicate 45 to 50 mm, which is consistent with what models have been forecasting ahead of the front. With these high PWAT values, heavy downpours of 25 to 50 mm/h are expected to be the main hazard with any thunderstorms that develop, in addition to strong wind gusts of 70 to 90 km/h and small hail up to dime size.

A second round of convection may move through southern Nova Scotia from the west overnight tonight, as a weak shortwave rides the thermal ridge across the region. Heavy downpours may company these storms if they persist over the Gulf of Maine.

In central Newfoundland, similar conditions to central Nova Scotia are expected, however bulk shear values are likely to be slightly lower here (20 to 25 kts), which may prevent more organized thunderstorm activity. Another limiting factor is a layer of warmer air evident in the mid levels persisting over central Newfoundland today. Any thunderstorms that do develop may struggle to get organized, but may produce strong wind gusts of 70 to 90 km/h and heavy downpours up to 25 mm/h, in addition to the small chance of some pea sized hail.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Copp

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

NB

Today…Risk of severe thunderstorms late in the day - heavy rain and strong wind gusts (and some hail)

Thursday… Scattered thunderstorms - heavy rain, strong wind gusts (and some hail)

 

NS

Today…risk of a non-severe thunderstorm late this afternoon

Thursday… Scattered thunderstorms - heavy rain, strong wind gusts (and some hail)

 

PEI

Today…risk of non-severe thunderstorms, except for northern Prince county where strong wind gusts are possible late in the day

Thursday… Scattered thunderstorms - heavy rain, strong wind gusts (and some hail)

 

Labrador

Today…Numerous strong thunderstorms with strong wind gusts, heavy rain (and some hail)

Thursday…Isolated thunderstorms - heavy rain, strong wind gusts

 

NF

Today…isolated non-severe thunderstorms along portions of the west coast

Thursday…Scattered thunderstorms - heavy rain, strong wind gusts (and some hail)

 

Convective Discussion

 

The 500mm heights continue to rise over the region, the highest value reported this morning is Washington and Long Island with 598 dam. The moisture content is also slowly increasing at the surface dewpoint temperatures are ranging from 18 to 24 and derived precipitable water from this morning soundings are ranging from 40 to 50 mm.

Most of the convective action will be occurring over Labrador today and a Watch message has been issued. In terms of forcing the surface cold front extends from Ungava to James bay and is already triggering some thunderstorm activity. This feature will be advancing gradually throughout the day, as the airmass ahead it becomes more unstable with falling 500mb heights. Surface dewpoints of 20 deg., Surface CAPE values between 1000-1500 J/Kg, and deep-layer shears of 40 kt will contribute to the development of hefty thunderstorms capable of producing straight-line 50kt gusts, rain rates of 25-50 mm/h, and to a lesser extent 1-3 cm hail.

Conditions will become more favorable for severe weather over NB-NS-NF on Thursday.

 

 

Thunderstorm Outlook for Today

 

 

Thunderstorm Outlook for Tonight

 

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

NB

Today…slight chance of severe thunderstorms late this afternoon and evening with heavy rain and strong wind gusts

Tomorrow… Occasional thunderstorms bring heavy downpours and some strong winds

 

Labrador

Tomorrow… Thunderstorms wind strong winds and some small to moderate hail, heavy rain possible.

 

Convective Discussion

With the very high moisture making its way over the region and the slowly approaching low pressure system we are in for a multi-day event for convective weather, beginning late today in northwest NB and slowly spreading eastward tomorrow and finally into Thursday. Quebec is expected to see severe thunderstorms today with the edge of the severe thunderstorm risk just coming into NB later today. There is some indication that some thunderstorms could organise into supercell/bow echo cells but with a significant area on convective inhibition around 700 mb it may be a challenge to get thunderstorms going. However the potential for strong surface will be a concern as the day unfolds.

 

Tomorrow things shift a bit becoming more favourable for a multicell situation with the potential for heavy rain, should storms become organised (ie training thunderstorms) some areas of New Brunswick could receive more than the highlighted amounts in the forecast for day 2. For Labrador tomorrow the environment will move to a supercell/bow echo situation so strong wind gust to warning level a certainly possible. Paying close attention to overshooting tops and lightning will be helpful in the absence of radar data.

 

As we move into Thursday the dynamics will become more favourable for severe thunderstorms for the remaining areas of the Atlantic provinces please stay tuned as the situation develops over the next couple of days.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Mel Lemmon

 

 

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Slight risk of a thundershower this afternoon over southeastern Labrador.

Risk of a thunderstorm for NW New Brunswick Tuesday late afternoon and evening.

 

Convective Discussion

As an upper trough moves into western Labrador this afternoon, daytime heating (inland temperatures into the mid 20s) and convergence ahead of the trough could help trigger an isolated CB over southeastern Labrador this afternoon. Some strong convective gusts are possible, however, increasing shear above 50kt may shear off any developing TCUs. Moisture is also only low to moderate with precipitable water less than 20 mm.  

 

A ridge of high pressure dominates south of the Maritimes today while an upper warm front weakens as it tracks into the southwestern Maritimes this afternoon and tonight.

 

A trough approaches New Brunswick tomorrow and there is a risk of a thunderstorm reaching northwestern areas by the late afternoon or early evening. Although there is good thermodynamic potential with daytime highs reaching 30C, there is increasing warmth in the lower to mid layers may cap convection.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

 

Roberta McArthur

 

 

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Slight risk of a thunderstorm this afternoon across central NL.

Slight risk of a afternoon thunderstorm for SE LAB Monday afternoon.

 

Convective Discussion

An upper trough will cross NL today giving the chance for an isolated thunderstorm. The 12Z tephi out of YJT has a pretty good warm nose at 700 mb, but steep lapse rates below that layer so, if there is ample surface heating, the cap could be breached and an isolated CB could develop this afternoon. There is a fairly strong jet of 30-35 knots in the lower levels so gusty surface winds are possible (even in areas of TCU). PWATs are low so rainfall is not a concern.

 

There will be a slight chance of an afternoon thunderstorm in SE LAB on Monday in association with a short wave trough.

 

OTWZ nil sig wx is xpctd.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

 

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts:

 

Today

NB/NS/PEI/NL/Labrador: None.

 

Tonight

NS/NB/PEI/NL/Labrador: None.

 

Tuesday

NB/NS/PEI/NL/Labrador: None.

 

Convective Discussion:

A trough moving across the region will usher in a cooler and drier airmass today. No thundershowers are expected today or tomorrow over land although according to the ECMWF, there is a very slight risk over interior Newfoundland on Sunday.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

NB … Strong thunderstorms possible this afternoon and into this evening with 70 to 90 km/h wind gusts, rainfall rates of 20 to 40 mm/h, and pea sized hail.

NL … Risk of some scattered thunderstorms this afternoon in western Labrador with rainfall rates of 20 to 30 mm/h and wind gusts of 60 to 80 km/h.

NS/PEI … Risk of an isolated thundershower later this evening with rainfall rates of up to 15 mm/h.

 

Convective Discussion …

An upper trough moving into the Maritimes brings the threat for strong thunderstorms across New Brunswick this afternoon. Good moisture advection at the surface will increase dewpoints to near 20 degrees in western New Brunswick, as such MUCAPE values are expected to climb to 1000 to 1500 J/kg this afternoon in this region. Remnant cloud from yesterdays convection over Ontario and Quebec moving through New Brunswick this morning will keep surface temperatures in the low to mid twenties, nonetheless an approaching cold front should provide ample surface lift to break any capping inversion that remains this afternoon. High shear values upwards of 50 knots will allow these storms to remain fairly organized throughout their lifespan, with a few supercells even possible. The main hazards with these storms will be strong wind gusts of up to 90 km/h, and heavy downpours of 20 to 40 mm/h. There is also a chance for some pea sized hail in some of the stronger cells. These storms are expected to die off as they approach the cooler waters of the Bay of Fundy and the Gulf of St. Lawrence later this evening, though a few lightning strikes are possible over southern Nova Scotia overnight.

In Labrador, some scattered thunderstorms are possible from Labrador City to Churchill Falls as the aforementioned upper trough approaches from the west. Thunderstorms may become organized this afternoon, as bulk shear values of 40 to 50 knots move through the region. Cape values are expected to reach 1000 J/kg this afternoon, however cloudy skies this morning may inhibit CAPE from getting this high. Thus the threat for any strong thunderstorms remains low. Any storms that do become organized may bring locally heavy rainfall of 20 to 30 mm/h and strong wind gusts of 60 to 80 km/h.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Copp