Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1 - Saturday

 

Regional Impacts

There is a slight risk of non-severe thunderstorms for northeastern NB, northern PEI, Iles-de-la-Madeleine, and northern Cape Breton.

Isolated thunderstorms are likely over central NF and southeastern Lab.

 

Convective Discussion

Extensive cloud cover over southern Labrador and much of the Gulf of St. Lawrence due to the presence of a mature surface low pressure system near Blanc Sablon. A couple of cold fronts trailing behind could provide enough lift for convective cloud growth over the Atlantic provinces. For the Maritimes, the convective temperature for this afternoon is about 22 degrees which might be reached in areas of eastern NB where solar insolation will be greater. T/Td of 22/10 will yield CAPE values slightly above 200 J/kg. Similar conditions are expected over central NF with the advancing airmass. While the surface temperature required for initiation is similar, the moisture content of the airmass is higher over NF – this will contribute to somewhat higher energy from the surface and mixed-layer CAPE above 300 J/kg. Brief heavier showers is the main threat.

 

 

Thunderstorm Outlook for Day 2 – Sunday

 

Some lingering daytime instability over parts of NF giving a slight risk of thunderstorm.

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1

 

Regional Impacts

Isolated thunderstorms with heavier showers throughout NS, PEI, and Les Iles-de-la-Madeleine this afternoon and this evening. This activity will continue into the night for areas adjacent to the Gulf of St. Lawrence.

 

Some daytime convection might develop over southern Lab during the afternoon – an isolated/non-severe thunderstorm.

 

There is a slight chance of a thunderstorm along with brief heavier showers over southern areas of NF tonight.

 

Convective Discussion

Frontal wave at the surface approaching Yarmouth county at 12z. The associated low will travel northeasterward and reach the Northern Peninsula of NF Saturday. The airmass around this system is fairly moist with overcast layers of cloud extending from the low levels to 7-8 km, and embedded CB’s to about 9 km. Precipitable water from the area soundings are showing values of 30-25mm. Deterministic models are suggesting synoptic rainfall of 15 to 30 mm over the region, with the EU is hinting at areas of 40-50mm. Rainfall rates of 10mm/hr reported along the Atlantic coast west of Halifax this morning would support the idea of locally higher amounts.

 

 

 

Thunderstorm Outlook for Day 2 – Saturday

 

Late day thunderstorms with heavy showers are possible especially for areas adjacent to the Gulf of St. Lawrence.

 

ATL Thunderstorm Outlook for Today and Tomorrow

Convective Outlook for Today – THURS July 29^th

 

Regional Impacts

Non-severe thundershowers are possible over offshore waters from a frontal passage. Isolated, non-severe thundershowers are also possible over eastern Labrador.

 

Convective Discussion

The main forcing for today’s weather is a sweeping trough that is well east of the Maritimes. The rest of the region is dominated by a ridge of high pressure and strongly capped at 700mb. Nova Scotia in particular is quite dry at the surface. If a cell does manage to bubble up in Labrador, it will be short lived and single cell pulse in nature.

 

 

Convective Outlook for Tomorrow – FRI July 30^th

 

Regional Impacts

Embedded non-severe thunderstorms are possible in parts of the Maritimes with a developing low pressure system. Heavy synoptic rain is the main hazard, in New Brunswick.

 

Convective Discussion

The limiting factor for any storms to develop will simply be the battle with cloud cover. If the low does not have clear slots to facilitate daytime heating, it will be difficult to create strong lift and cloud tops cold enough to cause any lightning. Nevertheless, a rainy/windy day in store for many parts of Atlantic Canada.

 

 

Convective Outlook for Day 3 – SAT July 31^st

 

Regional Impacts

The start of the long weekend does not look to be very stormy in regards to thunderstorms. No deep shear or strong CAPE is being resolved by the models at this time. No forcing of concern is expected on Saturday specifically.

 

Convective Discussion

There does not appear to be a signal for severe convective weather for PEI at this time. Check future forecasts from Environment Canada for updates.

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

Scattered thundershowers are expected across portions of NL today. Some embedded TSRA possible for the far eastern Avalon associated with the frontal trough. Some surface-based cells are likely this afternoon and evening for central regions of the island if given enough solar insolation. An isolated TSRA is also possible for SERN LAB.

 

Convective Discussion

There is a chance for an isolated strong storm or 2 for central regions of Newfoundland today giving torrential downpours and gusty winds (to about 70 km/h). PWATs are in the low to mid 30’s and shear is decent at about 40 knots or so. The instability is modest at best, but CAPE of about 500 j/kg or so is possible once the sun breaks through the clouds. The likelihood of any cell becoming severe is really low.

 

Thunderstorm Outlook for Day 1

 

Jeremy

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

There is a risk of isolated severe thunderstorms for across extreme SE NB, PEI and a good chunk of NS today giving strong winds, torrential rainfall and small hail. There will also be scattered thundershowers/storms for SE LAB and NL giving heavy downpours and gusty winds.

 

Convective Discussion

There will not be a lot of time to delve into the gory details in this section today due to the current strong storms and watches in place for those resulting in an obvious time contraint. Long story short: The CAPE is high (in excess of 1000 j/kg), shear up around 40 knots, PWAT 30-40 mm, a fairly active surface trough (with history to boot for strong storms) and a moist, unstable atmosphere. Given the fact strong storms developed overnight and into this morning shows the already good dynamics at play…and add the thermodynamics could exasperate things. Currently watches are in effect for Kent County and Moncton and Southeast New Brunswick County, as well as Cumberland County-Minas Shore and Cumberland County North and Cobequid Pass of Nova Scotia. Watches will be extended further to the south and east across NS in the next half an hour or so.

 

Thunderstorm Outlook for July 27^th, 2021

 

Thunderstorm Outlook for July 28^th, 2021

 

Jeremy

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1

 

Regional Impacts

 

Scattered thunderstorms are likely to develop this afternoon and into the evening across southern NB and portions of NS  as skies partially clear. There is a slight risk for a strong thunderstorm or 2.

 

Convective Discussion

 

A frontal trough is currently giving some non-severe thundershower activity to parts of NB and southern marine waters. This will likely weaken soon. Skies are beginning to clear in New England and that trend will progress eastward this afternoon. The dynamics are marginally favourable for isolated strong thunderstorms for portions of NB and NS, with the main threat being strong winds. 12Z tephi analysis supports 500-1000 CAPE with shear approaching 40 knots. While low level moisture is decent there is not an abundant amount of instability in the atmosphere. PWATs are roughly 30 mm from KCAR, YCX and YQI. It is also difficult to pinpoint an upstream surface trough at this point in time. Lastly, there is a large amount of smoke aloft from the ongoing forest fires to the west that could inhibit thunderstorm development. All that being said there will be scattered storms develop this afternoon with a couple of them approaching severe criteria (gusts close to 90 km/h and hail near 2 cm – owing to the somewhat lower freezing levels). Locally heavy downpours are also likely in some cells.

 

 

Thunderstorm Outlook for Day 2

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1 – July 25^th, 2021

 

Regional Impacts

 

None during the day. Showers are moving into western New Brunswick early this afternoon. There is a slight risk for a thundershower this evening over northwestern New Brunswick and western Nova Scotia early Monday morning.

 

Convective Discussion

 

A trough over central Quebec extending southward into New England will progress eastward today while a ridge of high pressure lies over Newfoundland and Labrador today. Showers associated with the warm front will move into western New Brunswick this afternoon. Upper dynamics remain west of the Maritimes today. However, behind this area of showers, there is the possibility of convection in the warm air mass this afternoon over southern Quebec and Maine. A weak low-level jet over Maine may help to maintain convection into northwestern New Brunswick this evening. Some elevated convection is also possible overnight over the Maritimes western marine district.

 

 

 

 

Thunderstorm Outlook for Day 2 – July 26^th, 2021

 

As the warm front pushes through overnight into Monday morning, moisture is expected to increase in the warm sector. A short-wave trough is expected to track over Maine and into New Brunswick on Monday. With increasing instability and 0-6km shear near 35KT over southern New Brunswick and parts central/northern Nova Scotia, there is the possibility storms to develops with strong wind gusts along with localized heavy rain.

 

 

 

 

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1- July 24^th, 2021

 

Regional Impacts

 

New Brunswick…Isolated thundershowers are possible this afternoon with locally heavy showers and small hail.

 

Convective Discussion

 

A slow moving low pressure system over Newfoundland will slowly drift eastward today while a ridge of high pressure builds into the western Maritimes. There is little in the way of dynamics today, but with solar insolation along with some coastal convergence and cooler air aloft, there may be enough instability to kick up some isolated showers with the risk of a thundershower this afternoon mainly over eastern New Brunswick today. PWAT of 20-25 mm with freezing levels around 9500ft mean that some brief heavy downpours and very small hail are possible.

 

There will also be some showers and Newfoundland and isolated showers in Nova Scotia today.

 

 

Thunderstorm Outlook for Day 2- July 25^th, 2021

 

No thunderstorms are expected during the day tomorrow. A trough will be approaching from the west Sunday night and there is the possibility of overnight convection into the early morning hours on Monday.

Convective Outlook Valid for Today

Thunderstorm Outlook for Today

 

Regional Impacts

Scattered thunderstorms today across the Maritime provinces.  Locally heavy showers, small hail and gusty winds are likely.

 

Convective Discussion

There is very little shear but cape values of 500-1000 J/kg are expected. This will lead to short lived pulse storms giving brief downpours (PWAT 20-25 mm), small hail (freezing levels near 8000 feet) and gusty winds. 

 

Convective Outlook Valid for Today

Thunderstorm Outlook for Today

 

Regional Impacts

Isolated thunderstorms today over NB and western Labrador. Over eastern NS and southwestern NFLD, locally heavy showers are possible.  20 mm/hr or more is not out of the question.

 

Convective Discussion

A favourable left exit of a jet over weak surface troughing supported heavy rain over portions of Nova Scotia and PEI this morning. 25 mm or more in an hour was reported in the Bridgewater area. The embedded line of convection has moved east and watches are in place in areas of most concern this afternoon. The PWAT values of 35-40 mm persist in this area and that is the same airmass that gave flooding to areas of King County Nova Scotia yesterday. Southwestern Newfoundland will need to be monitored for potential significant rainfall this afternoon. Over NB and western Labrador, surface heating this afternoon will give isolated thundershowers and low freezing levels which will support small hail formation. Cape values of less than 500 J/kg and shear less than 20 knots are expected in these areas.

 

Convective Outlook Valid for Today

Thunderstorm Outlook for Today

 

Regional Impacts

Isolated thunderstorms today over NS and southern NB with locally heavy showers possible.  20 mm or more is not out of the question.

 

Convective Discussion

Dynamics are not great today for severe thunderstorms, however the risk is still there but likely low.  There is not much support in the upper level dynamics with no significant jet stream over the area and a lot of moisture at 700 mb.  A lot of cloud over most of the area will inhibit solar insolation.  Wind shear values between 20 to 30 kts will likely not be enough to help maintain long lived cells.  However, there is a lot of low level moisture over the area and a marginally unstable atmosphere (500 J/kg ) associated with a broad and nearly stationary trough over the region. Any storms have a low chance of becoming severe however they could still bring quite significant rain due to the abundance of moisture (PWAT near 35 mm) and the fact that the cells will likely be slow moving. 

 

 

Convective Outlook Valid for July 20th and July 21st

Thunderstorm Outlook for Day 1 – July 20^th, 2021

 

Regional Impacts

Scattered thunderstorms today over NFLD, PEI, NS and southeastern NB with locally heavy showers possible especially over southeastern NB.  10 to 20 mm but higher not out of the question.

 

Convective Discussion

Dynamics are not great today for severe thunderstorms, however the risk is still there but likely low.  There is not much support in the upper level dynamics with no significant jet stream over the area and a lot of moisture at the 700.  A lot of smoke and cloud over the area will inhibit solar insolation.  Wind shear values of between 20 to 30 kts will likely not be enough to help maintain long lived cells.  However, there is a lot of low level moisture over the area and marginally unstable atmosphere ahead of a trough currently located over NB.  This trough will track southeastward through the day and will likely kick off some tstorms.  These storms have a low chance of becoming severe due to all the inhibiting ingredients mentioned above, however they could still bring down quite a bit of rain due to the abundance of moisture and the fact that the cells will likely be slow moving.  10 to 20 mm expected with higher possible.

 

 

 

 

 

Thunderstorm Outlook for Day 2 – July 21^st, 2021

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1- July 19^th, 2021

 

 

Regional Impacts

 

Nova Scotia and Prince Edward Island…Isolated risk today and this evening. Locally heavy downpours and gusty winds are possible.

 

New Brunswick…Isolated risk mainly for central regions with heavy downpours possible today and this evening.

 

Labrador…Isolated risk for southern regions near this afternoon and evening.

 

Maritime waters…Isolated thunderstorms continue today and overnight, possibly reaching southern Newfoundland early tomorrow morning.

 

Convective Discussion

 

A surface trough lies to the west extending from southern Labrador toward southern Quebec and into the New England. The main threat of organized convection remains closer to the trough north of the St. Lawrence River and extended northeast towards extreme southern Labrador today where heavy downpours and small hail is possible. The Maritimes remain in a moist southwesterly flow today ahead of this trough. Precipitation moved through the region yesterday evening and is now moving into southern Newfoundland today. Isolated thundershowers continue this morning south of Nova Scotia and may make their way inland along the Atlantic coast of Nova Scotia today bringing heavy downpours. Although most of the Maritimes remains cloudy this morning, some scattering of the cloud mainly over the Annapolis Valley and northern Nova Scotia could help the area reach their convective temperature. Dew points this morning are near 20C. There is also the aid of an 850mb low-level jet, weak 0-6km shear of near 20 kts, some cooling in the upper levels, and precipitable water values near 40 mm. Thunderstorms should be short-lived but would likely produce heavy downpours that will drift to the northeast into eastern Prince Edward Island or western Cape Breton this evening.

 

 

Thunderstorm Outlook for Day 2- July 20^th, 2021

 

This trough today will continue to slide further east tomorrow. Some enhanced risk is possible over much of New Brunswick, Nova Scotia and Prince Edward Island.

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

Labrador… Today isolated non-severe thunderstorms possible. Tomorrow an increased potential for more intense thunderstorms with

gusty winds.

 

Nova Scotia… Today a chance of thunderstorms with locally heavy amounts for southwest areas late this afternoon and this evening. Tomorrow an enhanced chance of thunderstorms with locally heavy downpours and gusty  winds expected.

 

New Brunswick and PEI… Tomorrow a chance of thunderstorms with locally heavy downpours.

 

Convective Discussion

 

Overall moisture will remain high for the next couple days in a general southwest flow over the region. Surface troughing will act to enhance the chance of thunderstorms tomorrow for most of the Atlantic region. Moderate wind shear will remain as well over Nova Scotia and Labrador giving a slightly higher chance of organised convection tomorrow.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

For today limited impacts are expected with only a chance of embedded thunderstorms possible in highlighted areas.

 

For tomorrow embedded thunderstorms in a broader area of precipitation could produce locally heavy downpours across southwest Nova Scotia.

 

Convective Discussion

 

Overall today should not be overly active with a weak surface ridge building. Most of the enhanced convection is expected to remain south of the region but some remnant convection could persist over Newfoundland chance should pass though fairly early today.

 

For tomorrow surface convergence and very high precipitable water (PWAT) contents over 50mm for some areas could lead to potentially heavy downpours across western Nova Scotia.

 

Thunderstorm Outlook for Day 1

 

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1

 

A cold front will sweep through New Brunswick this afternoon, with a fair chance for severe weather.

 

Regional Impacts

 

New Brunswick and parts of Western Nova Scotia: heavy rain, high winds, and possible hail. For the rest of the Maritimes, local heavy rain and some gusty winds.

Labrador: local heavy rain and gusty winds.

Newfoundland: nothing significant.

 

Convective Discussion

 

A deep low over western Labrador with a surface manifestation north of Gaspe has a cold front extending southwest, roughly along the St. Lawrence River. Shear near and ahead of the front is healthy at about 40-50 diminishing to 24 kts in the south of NB and NS. There is a corridor of moisture ahead of the front being advected ENE, with surface dew points near 20 C and PWATs near 30-50 mm. Finally, there’s some clearing of low level clouds out ahead, mainly southern Maine, southern New Brunswick,  and PEI and Nova Scotia. There’s little evidence for strong SRH, so straight line winds and bow echoes should be mainly the order of the day. With the PWATs higher rainfall amounts are likely, especially id there is some training. Surface CAPEs in excess of 1000 and possibly 2000 J/kg are possible, and despite freezing levels of 14,000 feet, hail is also possible with isolated supercells. Conditions should decrease late this afternoon into this evening as the main action moves into Nova scotia.

 

 

 

Thunderstorm Outlook for Day 2

 

The remnant of the system with give a chance of local heavy showers and gusty winds.

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1

A frontal trough with an associated vort max from WV near Yarmouth maintained a line of thunderstorms this morning, with pcpn amounts up to 30 mm observed. This feature will continue into the afternoon for Nova Scotia with gradual weakening. There may be some thundershowers later this afternoon in northwestern New Brunswick. Nothing significant is expected for Labrador nor Newfoundland.

 

Regional Impacts

Maritimes: Local heavy showers ending later today for Nova Scotia and possibly for northwestern New Brunswick, who might also see some gusty winds.

Newfoundland and Labrador: nothing significant. A strike ot two south of forecasts areas are possible.

 

Convective Discussion:

For Newfoundland and Labrador there are significant inversions, preventing any significant convection in their forecast areas.

 

There is currently a deep ridge over eastern Newfoundland and a deep low slanting down from 250 mb over Hudson Bay to near Ungava Bay at the surface.  There is also a trough over the Gulf with a couple of vort maxes, with the one near Yarmouth this morning giving some extra support for convection. Things should weaken a bit this afternoon along the trough. For New Brunswick there’s some moisture and low stratus trapped under an inversion that should erode with daytime heating this afternoon, especially in the northwest, where the shear should reach or exceed 30 kts. PWATs are healthy and around 30 mm. Impacts there are local heavy downpours and gusty winds.

 

 

 

Thunderstorm Outlook for Day 2

On Friday a deep trough extending southwest to the Great Lakes will move into our region with a healthy jet and a fair amount of moisture. Unadjusted ML CAPEs are near 500 J/kg, and with some extra heating things could get interesting.

 

 

Convective Outlook Valid for Today and Tomorrow

 

Thunderstorm Outlook for Today

 

Regional Impacts

Slight risk of a thunderstorm over southwestern NB late in the day, and later in the evening in the northwest. Main threat is heavy downpours

from storms that would advance over NB from Maine and the St. Lawrence valley.

Convective Discussion

The Upper ridge has continued to build over eastern Atlantic Canada in the past day or so. A moderate southwesterly flow in behind is advecting

warmer temperatures and higher humidity values across southern Ontario/Quebec/Maine. The environment will remain stable over NB, however

over western Maine the airmass will likely destabilize during the afternoon. Using a combination of Maniwaki and Albany for this morning's sounding -

MCAPE values of 600-1100 J/kg will likely produce deep convection to the west, which will result in scattered thunderstorms capable of producing

very heavy downpours in this moist environment. All sounding in the area of interest are showing precipitable water of 40+mm, with a maximum

of 44 for Maniwaki. Early this evening, some of the storms will try to enter the stable environment over western NB.

 

 

Thunderstorm Outlook for Thursday

 Warm and humid airmass, slight risk of thunderstorms over parts of the region.

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

No thundertorms expected

 

Convective Discussion

Upper and surface ridge dominating over Atlantic Canada.

 

 

Thunderstorm Outlook for Wednesday

 

Warm front approaching from the Great Lakes, warm and humid airmass may destabilize late in the day. Isolated

thunderstorms are possible with fairly high precipitable water values.

 

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Today

 

Regional Impacts

Isolated thunderstorms over central and southeastern NF, brief heavier showers and gusty winds to 75 km/h. Some of these

Storms could advance in the Northern Avalon.

 

Convective Discussion

Trough moving across eastern part of NF today while an Upper low remains anchored off Labrador with a cold pool aloft.

There is enough energy (300-500 J/Kg) to push CB tops up to 6-7km. Westerly deep layer shear is quite strong so vertical

Development is limited. The main threat will be gusty winds in the outflow ahead of the storms.

 

 

 

Thunderstorm Outlook for Day 2

Convective Outlook Valid for Today and Tomorrow

Thunderstorm Outlook for Day 1 – July 11th

 

Regional Impacts

Isolated thunderstorms across New Brunswick expected late this afternoon or early evening with the possibility of a severe thunderstorm over northernmost NB.  Local heavy downpour and strong gusts are the main threats.

Convective Discussion

Thunderstorm development later this afternoon or early evening over New Brunswick is possible.  Current conditions are not favourable for tstorm development as a capping inversion generally around the 700mb level will inhibit any convective activity.  However, this cap may begin to erode later in the day as cooling in the mid levels will help destabilize the column.  An upper level jet also begins to descend from the north which could help enhance vertical lift.  If the capping inversion does erode, 500 – 750 J/kg of CAPE may be realized and wind shear around 35 kts will help to tilt the updraft and may help realize longer lived cells.  A trough moving in later today will help kick off any convective activity.  Low level moisture is not impressive as Td’s sit around the 15C mark so this could inhibit stronger cells.  Overall, it’s a marginal situation for severe tstorm development with the uncertainty of the capping inversion and dry lower levels so I will not be issuing watches and will see how things develop this afternoon.

 

 

Thunderstorm Outlook for Day 2 – July 12^th

Convective Outlook valid for Today and Tomorrow

Thunderstorm Outlook for Day 1 – JULY 10th

 

Regional Impacts

Slight risk of non severe thunderstorms over southwestern NS late this afternoon or evening.

 

Convective Discussion

Severe thunderstorms not expected today.  Drying conditions behind the remnants of Elsa will not be favourable for tstorm development over the Maritimes today.  No tstorms expected over Nfld and Labrador today. A few thundershowers over the Gulf of Maine may move over southwestern NS late this afternoon or tonight.

 

 

Thunderstorm Outlook for Day 2 – JULY 11th

 

Regional Impacts

Thunderstorms possible over areas of New Brunswick tomorrow as a trough tracks in over the area late in the day.  There is a slight possibility for some of these thunderstorms to become severe.

 

 

Convective Outlook valid for Today and Tomorrow

Thunderstorm Outlook for Day 1 – JULY 9th

 

Regional Impacts

Non-severe thunderstorms are forecast for Nova Scotia, PEI, Cape Breton, and parts of New Brunswick as Elsa approaches the Maritimes and passes over this evening.

 

Convective Discussion

With today’s storms, heavy rainfall and lightning will be the main threats. Convection is possible on Elsa’s eastern side as a warm tropical airmass gets pumped into the region and the circulation brings decent midlevel shear. Freezing levels are very high so hail is not expected. Any discrete cells over the marine district could be marginally severe this afternoon and evening with gusts above 70km/h.

 

 

 

Thunderstorm Outlook for Day 2 – JULY 10th

 

Regional Impacts

Non-severe thunderstorms are possible for areas of southwestern Nova Scotia and SE New Brunswick, in clearing behind Elsa.

 

Convective Discussion

Storms will be short lived and very isolated. Highly dependent on back-side clearing of synoptic driven clouds.

 

FW: Convective Outlook Valid for Today and Tomorrow

 

 

From: AD CPIA / ASPC DS (EC) <adcpia-aspcds@ec.gc.ca>
Sent: Thursday, July 08, 2021 2:26 PM
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Subject: Convective Outlook Valid for Today and Tomorrow

 

Thunderstorm Outlook for Day 1 – JULY 8th

 

Regional Impacts

Non-severe thunderstorms are forecast for areas of southwestern Nova Scotia and the valley this afternoon and evening.

 

Convective Discussion

Storms will be elevated in nature, with lightning being the main hazard. Heaviest rainfall will be over the southern marine district, where up to 45mm could fall in a strong pulse cell.

 

 

 

Thunderstorm Outlook for Day 2 – JULY 9th

 

Regional Impacts

Embedded non-severe convection is possible in isolated pockets associated with the passage of post-tropical storm Elsa.

 

Convective Discussion

Main hazards from any cell that does develop would be locally heavy downpours and lightning. Storms will be moving quite quickly along the 500mb steering flow. Additionally, plentiful cloud cover will keep discrete storm development to a minimum.

 

Convective Outlook Valid for Today and Tomorrow

Convective Outlook for Day 1 – JULY 7th

 

Regional Impacts

Non-severe thundershowers are forecast for offshore waters and coastal areas of Labrador with the passage of a weak cold front.

 

Convective Discussion

Most areas in the Maritimes are strongly capped at 700mb with a building ridge off to our west. Any cells that do develop over the marine district will be non-severe with lightning and pockets of heavy showers as the main hazard.

 

 

Convective Outlook for Day 2 – JULY 8th

 

Regional Impacts

Non-severe elevated convection is possible late in the day with an advancing tropical airmass over extreme southwestern Nova Scotia and the Bay of Fundy.

 

Convective Discussion

Main hazards from this would be locally heavy downpours and lightning. Storms will be moving quite quickly along the sub-tropical jet.

 

 

Thunderstorm Outlook for Day 1

 

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts

 

For Labrador…

Isolated Thunderstorms producing locally 20mm of rain and potentially gusting winds to 60 km/hr.

 

For New Brunswick…

Scattered thunderstorms potentially in the late afternoon or evening. Possibly winds gusting to 70km/hr and locally 25mm for northwestern areas.

 

For PEI…

Isolated Thunderstorms possible this evening.

 

Convective Discussion

Thunderstorm development today will depend on the weakening upper ridge and the timing of the approaching cold front. There is the expectation that low level moisture will continue to build today leading to an increase in thunderstorm potential with some organised storms possibly developing. Most of the initiation will be in Quebec with storms eventually moving into the Atlantic region late this afternoon. The overall threat of severe weather is low but that outlook may change if a linear feature forms along the cold front and moves over the area.

 

Thunderstorm Outlook for Day 1

 

 

Thunderstorm Outlook for Day 2

 

Convective Outlook Valid for Today and Tomorrow

Regional Impacts…

No thunderstorms are expected today.

 

For tomorrow…

New Brunswick… Thunderstorms are expected late tomorrow for western parts of the province with locally heavy downpours of 25mm and wind gusts to 60km/hr.

 

Convective Discussion…

 

For the most part convection will be fairly settled today as an upper ridge builds across the region. Shallow convection is possible but strong updrafts are not expected to develop into thunderstorms.

Tomorrow  as the upper ridge gradually breaks down and low level moisture begins to increase the likelihood of deep convection will increase. Overall Cape values will not be high at ~ 500j/kg, precipitable water values will be above 40mm and low lever shear values will likely be around 30 knots. This could lead to some organised convection with locally heavy downpours possibly exceeding 25mm and strong wind gusts.

 

Thunderstorm Outlook for Day 1 *No Thunderstorms Expected

 

 

Thunderstorm Outlook for Day 2