Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

NL… Some strong thunderstorms possible in parts of northern and central Newfoundland today. Main hazards are torrential downpours of 20 to 30 mm/h and strong wind gusts of 50 to 80 km/h.

NB… Some isolated thunderstorms possible over extreme northern New Brunswick this afternoon. Heavy rainfall of 10 to 20 mm/h possible.

NS/PEI… None

 

Convective Discussion

Two areas of interest exist today, the first being triggered by a weakening shortwave currently near the Strait of Belle Isle, the second being triggered by a broad upper trough over central Quebec, extending down into New England. The shortwave moving into western Newfoundland already has a history of lightning activity, with this expected to continue as it moves across northern Newfoundland today. MLCAPE is expected to build today in central Newfoundland as clear skies will allow surface temperatures to climb ahead of the approaching feature. In addition, decent dynamics (30 to 40 kts of bulk shear) will aid in sustaining some organized convection today across this region. This shortwave is forecast to weaken slightly as it traverses east across northern Newfoundland, however PWAT values of 40 to 45 mm may produce some torrential downpours of 20 to 30 mm per hour. Some strong wind gusts of 50 to 80 km/h are also possible in convection here today.

The second feature being monitored will approach western Labrador and parts of northern New Brunswick later this afternoon. Although MLCAPE values are forecast to climb above 500 J/kg, weaker bulk shear (15 to 25 kts) keeps the risk for any organized thunderstorms low. Low level cloud cover this morning is also expected to limit the available CAPE in northern New Brunswick, as such the risk for thunderstorms is lower here than in western Labrador, where clear skies are allowing CAPE to better build. The broad nature of this upper trough should keep the risk for any severe weather near nil due to the lack of shear and cold air advection. Nonetheless, some brief heavy downpours of 10 to 20 mm/h are possible in any thunderstorms here today.

Tomorrow, this upper trough will move into central New Brunswick. Again, bulk shear values remain quite low (10 to 20 kts), however PWAT values are expected to climb upwards of 45 mm by tomorrow afternoon over the southwestern Maritimes. Torrential rainfall rates of 15 to 25 mm/h will be the main hazard here in any thunderstorms that do develop here.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Copp

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today.

Scattered thunderstorms expected for central and western LAB as well as most of NB. There is a chance that a couple of the storms will become severe across northwestern NB giving strong wind gusts, small hail and torrential downpours.

 

Tonight.

Scattered thunderstorms are possible across most of LAB. Isolated thunderstorms possible for NE NB and most of NL.

 

Wednesday.

Scattered thunderstorms likely again for a portion of LAB, central and NE NL and northern NB. Some of these storms could approach severe limits.

 

Convective Discussion

A couple features today will be responsible for some thunderstorm activity – the first one being an upper level low/trough currently over ME that will drift northeastward and the second a frontal trough ahead of the upper low that is currently just south of NS. The upper trough could give a severe thunderstorm or 2 to northwestern NB this afternoon and into this evening. Adjusting upstream TEP over New England gives 700-1000 MLCAPE. Wind shear is in the 30-35 knot range with PWAT values of 35-40 mm. The only thing that could limit the growth of the cells would be the available sunshine and associated instability. If things clear sufficiently it will allow for a fairly buoyant atmosphere to exist which would give way to some strong to severe cells. Also of note is some storms will be fairly slow-moving owing to a threat for locally heavy rainfall amounts. Right now things are pretty overcast so time will tell. Slightly falling atmospheric heights and a surface trough should be enough to trigger some non-severe thunderstorms across central and western LAB this afternoon and evening. Locally heavy downpours seem to be the main threat.

 

Isolated thunderstorms are expected for northeastern NB and a portion of NL tonight as that frontal trough ahead of the upper low/trough moves through the region. High PWATs will give way to locally intense rainfall rates. There is a little history of lightning south of NS associated with this feature. Scattered thunderstorms could persist into tonight across LAB associated with the surface trough.

On Wednesday that same upper trough impacting NB today will cross central/northeastern NL giving some scattered thunderstorms with some approaching severe limits. Of course this is based on model information and what happens today in NB will be a better gauge on what could happen tomorrow. Lastly another upper trough will approach NB and LAB on Wednesday giving some scattered afternoon/evening thunderstorms.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

 

Labrador… A risk of severe thunderstorms over western areas with some potential for significant wind gusts and heavy downpours.

Maritimes… Some embedded thunderstorms tomorrow in showers and rain moving in from the south during the day.

 

 

Convective Discussion

 

The potential for severe thunderstorms edging into western Labrador still persists for today. It is possible that the most severe storms will remain in Quebec, but should storms track into Labrador there is a reasonable chance that some will produce very strong wind gusts. Lightning and satellite should be monitored closely.  Weak upper ridging could be sufficient to limit convection early in the day, however wind shear is favourable for the development of some discrete supercells, with strong shear to 3 km it is likely that strong rear flank downdraft could develop on some of these storms.

 

For the remainder of the Atlantic provinces today there is little to know risk of thunderstorms, however there is a risk of some embedded thunderstorms in the moisture plume moving into the region tomorrow. At this point the instability isn’t looking high enough for torrential downpours but with PWAT values near 50mm there is still some potential for heavy rainfall rates should thunderstorms develop.

 

 

Thunderstorm Outlook for Today

 

 

Thunderstorm Outlook for Tonight

 

 

Thunderstorm Outlook for Tomorrow

 

 

Mel Lemmon

 

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

 

Labrador.. chance of a few isolated thunderstorms later today and this evening. For tomorrow a low risk of severe thunderstorms over western areas with some potential for significant wind gusts.

 

Convective Discussion

 

After the passage of the cold front yesterday, most of the Atlantic Provinces will remain relatively quiet with respect to thunderstorm activity today and tomorrow. Most of the preferable dynamics are well north across northern Quebec, moving into western Labrador later today. Low level moisture will be the biggest limiting factor but dewpoint temperatures are expected to increase into the mid-teens tomorrow. With ample shear over 50 knots to 6 km and decent moisture it will largely be a question of timing, if daytime heating is sufficient and the weak upper ridge breaks down early enough there is some potential for severe thunderstorms later in the day. Most of the shear is straight line but there is some potential for supercells to develop, looking for long lived cells on Satellite will be helpful, should they develop.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Mel Lemmon

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NB/NS/PEI/NL:  Chance of afternoon thunderstorms.

Labrador:  None.

 

Tonight

NB/NS/PEI/NL/Labrador:  None.

 

Saturday

NB/NS/PEI/NL/Labrador:  None.

Convective Discussion…

A weak trough of low pressure will track across the southern Maritimes and Newfoundland this afternoon. Embedded thunderstorms are possible over western Newfoundland this afternoon and evening. Over the Maritimes, non-severe surface based thunderstorms are possible this afternoon in the vicinity of the trough. CAPE values are 500-1000 J/kg, shear is near 20 kts and PWAT is 20-25 mm. If thunderstorms do develop, then brief downpours and gusty winds are a possibility.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

Labrador:  Chance of afternoon thunderstorms southeast.

NB/NS/PEI/NL:  None.

 

Tonight

NB/NS/PEI/NL/ Labrador:  None.

 

Thursday

NB/PEI/Labrador:  A chance of afternoon/evening thunderstorms.

NS/NL: None.

 

Convective Discussion…

A weak trough of low pressure tracking across Labrador will give a chance of non-severe afternoon thundershowers over sections of southeast Labrador today. On Thursday, some embedded thundershowers are possible across portions of New Brunswick and Prince Edward Island. If clearing occurs late in the day over extreme northwest New Brunswick then some surface based activity is possible. Another trough of low pressure tracking across northern Labrador will give a chance of non-severe afternoon thundershowers over sections of central and northern Labrador Thursday afternoon.

 

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

 

Today

Labrador: 70-90 km/h gusts, 2-3 cm hail, risk of cold core funnels.

NS: 70-90 km/h gusts, 15-25 mm/h rainfall rates, ~1cm hail

NL/PEI : isolated to scattered thunderstorms

NB/Magdalen- QC:  None

Tonight

Labrador:  A chance of thunderstorms.

NB/NS/NL/Magdalen- QC: None.

Monday

Labrador:  chance of thunderstorms.

NB/NS/NL/Magdalen- QC: None.

 

Convective Discussion

A 3-4 SD vertically stacked cold upper low continues to slowly move east across Labrador. Near the centre of the upper low, an area of minimal vertical wind shear will yield the potential for widespread cold core funnel clouds across western Labrador with plenty of vertically slacked low level vorticity. Southeastern sections of Labrador will benefit from strong potential vorticity advection from the upstream deep upper low. This in combination with steeper lapse rates, lower freezing levels, linear shear profiles of 35-45 kts and daytime instability up to 1500 J/kg of SBCAPE will yield the primary hazard of significant hail in organized convection. The steeper low level lapse rates and cooler environment also presents a strong wind gust secondary hazard. Small hail is also possible across western NL, but weaker instability through the HGZ should keep this smaller in nature despite lower freezing levels.

 

On going clearing ahead of a weakening cold front across NS may also result in severe weather later this afternoon. Initiation is expected to be aided by coastal convergence at the surface with a sea breeze front in addition to the weakening cold front. Higher freezing levels and instability through the hail growth zone should keep any hail small in nature, however strong wind gusts may occur with significantly developed convection. PWATs appear to be slightly higher as well across NS near 35 mm, which would also present a near severe rainfall rate threat with organized convection.  

 

Tonight a chance of thunderstorms will be limited to the stronger dynamics near the upper low tonight as day time instability abates. Tomorrow a similar situation is expected

across south central Labrador, with any storms being dynamically driven given limited expected thermodynamics (MLCAPEs ~300-400 J/kg).

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Brennan

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

 

Today

NB/Labrador: Isolated of  thunderstorm.

NL/NS/PEI/Magdalen- QC:  None

Tonight

Labrador:  A chance of thunderstorms.

NB/NS/PEI/:  None.

Sunday

NB/NS/NL/Labrador:  isolated to scattered thunderstorms, 10-15 mm/h rainfall rates, small hail, wind gusts ~70 km/h.

Magdalen- QC: None.

 

Convective Discussion

Focus of thunderstorms today will be mainly across Labrador with potential vorticity advection ahead of a slow moving upper low centered over western QC.

Surface instability - MLCAPE is rather meager for the 30-40kts of bulk shear, but strong dynamic forcing and higher MUCAPE will likely produce elevated storms and lightning among showers.

South of this feature a cold front will gradually cross the St. Lawrence valley and move into northwestern NB later this evening giving a chance of thunderstorms.

Tonight dynamics will remain more or less status quo across Labrador, but the focus of lightning will be more confined to the upper low with less surface instability overnight.

 

Tomorrow convection will again be focused near the upper low across much of Labrador (to be centred near Churchill Falls), with some stacked low level voracity cold core funnel clouds are possible across western Labrador…

although unlike to be observed given the population density.

Further east instability will have a better opportunity to build during the day ahead of the cold front across southeast most NB, most of PEI, NS and western NL. MLCAPEs up to 750 J/kg will be sufficient in places with 35-45 kts of bulk shear to yield organized convection.

Lower PWATs (25-30mm) than what has been observed most of the summer to date on significant convective days should limit the rainfall rate hazard. On the other hand lower freezing levels and the drier air could yield small hail and gusty winds.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Brennan

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

NL… Slight risk for some isolated thundershowers in parts of Labrador today and tomorrow. Heavy downpours possible.

NS/NB/PEI… None.

 

Convective Discussion…

As a ridge of high pressure builds into the Maritimes today, any lightning activity will be isolated to parts of Labrador, under the upper trough. Meager MLCAPE and weak bulk shear values lead to a low risk for any thunderstorm development today, however brief heavy downpours are possible with any storms that do develop.

Tomorrow, a cut-off low will swing into western Labrador, bringing a slightly greater chance for thunderstorms. More favourable dynamics are in place, but once again meager instability may hinder more organized storms from developing. Some isolated torrential downpours are possible in thunderstorms tomorrow, however this risk remains low.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Copp

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

NS… Scattered thunderstorms today across southern Nova Scotia, with torrential downpours of 30 to 50 mm/h.

NB… Isolated thunderstorms possible this afternoon across northwestern New Brunswick with strong wind gusts and heavy downpours of 15 to 25 mm/h.

PEI… Isolated thunderstorm possible early this afternoon with heavy downpours of 15 to 25 mm/h.

NL… Isolated thunderstorms possible this afternoon across southern Labrador with heavy downpours of 15 to 25 mm/h.

 

Convective Discussion…

A cold front sweeping across the Maritimes is triggering thunderstorms across the region this morning, with this expected to continue into tonight as the front moves east. PWATs of 52 mm from the 12Z Yarmouth sounding indicate an extremely moist atmosphere ahead of the main front. An area of tropical moisture sitting off Cape Hatteras is being pumped north into the Gulf of Maine by a strong ridge over the southern Atlantic. A line of thunderstorms has developed along this stream of moisture this morning, and have already begun moving onshore into southwestern Nova Scotia. These storms will likely continue to move north and east as the day progresses, reaching the eastern shores of Nova Scotia tonight. Current guidance suggest the heaviest convection will remain along the Atlantic coast, however it is possible for some thunderstorms to continue further inland. Due to the high amount of moisture available today, the main threats with these storms will be torrential downpours of 25 to 50 mm/h, which will continue overnight along the Eastern Shore. Localized flooding will be possible with heavy showers and thunderstorms today.

In addition, some isolated thunderstorms are also possible over parts of New Brunswick and southern Labrador this afternoon closer to the upper low. Clearing skies here will allow SBCAPE to build up over 1000 J/kg by this afternoon and bulk shear is forecast to be extremely high but linear; upwards of 60 kts. Due to the high shear, it is possible that storms may struggle to get organized, however strong wind gusts and heavy rain are possible with any storms that do fire.

 

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Copp

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Newfoundland… some thunderstorms giving locally 15 to 25mm possible.

NB… slight chance of thunderstorms today with low possibility of 15-25 mm rain and some strong winds. Overnight and tomorrow morning an enhance risk of heavy nocturnal rainfall for southern areas.

NS and PEI… Slight chance of TS today. Overnight and tomorrow morning an enhance risk of heavy nocturnal rainfall in vicinity of Bay of Fundy into central PEI. Could impact northern NS and the Annapolis Valley.

Convective Discussion

The subtleties of nailing down these convective outlooks continues to be a challenge as we move into the next couple of days. The high moisture content and unstable airmass will continue to linger until Friday when things begin to dry out somewhat. Most of the significant weather events over eastern Canada have been largely linked to the series of short-wave troughs that have been moving through, the system that impacted southern Ontario yesterday fortunately weakened as it approached the Maritimes overnight.  However, we are looking at a potential event overnight and early tomorrow as the large-scale upper trough begins to push east. We should be able to watch how the convection develops today over northeastern US, this should give us a clue to weather we are impacted by a nocturnal MCS or not however any messaging in term of alerts would likely be a very short notice if anything is warranted at all. It should be noted that high-res models like the HRRR have been somewhat useful in forecasting these nocturnal events, perhaps not in the sense that the locations are completely accurate, but the general occurrences have been pretty good.  The Day 1 night Outlook covers a large area yellow and represents the most probable location for intense storms but there is still some uncertainty in the exact location

For today newfoundland and Labrador will continue with there relatively active thunderstorm activity with some isolated and possibly more organized cells in NFLD, updrafts aren’t very strong but the moderate shear and high moisture content bring some concern for heavier rainfall amounts than individual cells might suggest. Keeping a close eye on radar rainfall estimates is likely the best approach. 

It seems likely that most of NB will have slight capping aloft which should initially make deeper cells unlikely until later today. Givin the decent shear, likely above 40 knots of bulk shear (0-6 km) and dry mid-levels some isolated severe storms are possible should things initiate sooner than expected.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

 

Mel Lemmon

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

NB.. Heavy downpours possible in thunderstorm, slight chance of significant wind gusts.

NS and PEI... Potential for thunderstorms to develop this afternoon with heavy downpours.

NFLD and Labrador... Isolated thunderstorms could produce local downpours.

Discussion

This will be short discussion as thunderstorms are already moving through some areas. This line below may serve as the trigger for severe weather later this afternoon for NB. There is some potential for a weak mesoscale system to develop which could lead to heavy rain and some stronger wind gusts. As of right now a lack of solar insolation could also somewhat limit this potential, therefor the worst areas for severe weather treat will likely be further east.

In Nova Scotia and into PEI where surface temperatures are going to be slightly warmer and the total precipitable water values are around 50mm there will be better chance for local flooding should thunderstorms develop.

NFLD will likely continue to get similar thunderstorms to what they have had over the last few days with isolated or somewhat loosely organized areas giving up to 25mm or so of rain.

Today

Tonight

Tomorrow

Mel Lemmon

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Newfoundland… Some isolated thunderstorms today and nocturnal thunderstorms tonight. Up to 25mm in thunderstorms possible.

 

Labrador… Isolated thunderstorms today and tomorrow, locally heavy downpours possible.

 

New Brunswick… Slight risk of isolated thunderstorms today. Some thunderstorms tomorrow with amounts possibly reaching 50mm/hr rainfall rates for southeastern areas. Northwestern areas 25mm possible in thunderstorms.

 

PEI… Possible thunderstorms tomorrow with rainfall rates possibly reaching 50mm/hr.

 

Nova Scotia.. Possible thunderstorms tomorrow with rainfall rates possibly reaching 50mm/hr most likely for central and northern areas.

 

Convective Discussion

A few interesting features will contribute to the convective potential over the next couple of days, first and foremost the high moisture content covering much of the region, which will aid in heavy downpours in even weaker thunderstorms. For today the shear isn’t conducive to organised convection and severe weather with a predominately zonal flow, in general any thunderstorms that do develop should be fairly isolated. However a trough/weak frontal zone currently over Anticosti will impact Newfoundland tonight possibly causing Thunderstorm activity to linger overnight.

 

A shortwave tough approaching from southern Ontario has the potential to trigger heavy downpours tomorrow. The total precipitable water (TPW) values are likely to be near 50mm and the airmass will be quite unstable ahead of the shortwave trough. If thunderstorms develop heavy rainfall can be expected, and alerts may be required, although not all models agree with this assessment. However unlike some of the recent convective rainfall events this feature should progress through more quickly, but multiple cells could still impact some areas.

 

The dynamics will continue to improve into the middle of the week as the upper trough gradually approaches from the west, but the low level moisture may be somewhat depleted leading to potentially weaker updraft potential.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Mel Lemmon

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today.. Isolated Thunderstorms giving some locally heavy downpours up to 25 mm, some stronger gusts possible.

 

Convective Discussion

The most favourable dynamics have shifted to lie just of the coast of Nova Scotia, in terms of upper support for prolonged and organized convection that will continue to diminish through the day. However there is still a decent amount of moisture in the atmosphere and surface dew point temperature will be in the high teens or even 20 C in some areas. Thunderstorms started early over eastern areas where a week trough was able to help trigger some smaller thunderstorms. As daytime heating continues there will be a slight chance of thunderstorms developing over areas including SW Newfoundland and NW New Brunswick. Moderate Cape could potentially lead to some heavier downpours and gusty winds. Wind gusts are not expected to be at warning level but if deeper thunderstorms develop it there may be a slight risk.

 

Dynamics will become more significant over the next couple days with a chance of organised convection on Tuesday. More details can be expected as we move into the shorter range.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Mel Lemmon

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

Today.

Scattered thunderstorms for western NB and portions of NS this afternoon and evening. Main threat is torrential downpours, but strong wind gusts are also possible in the stronger cells. There is a chance of a strong to severe thunderstorm for the eastern mainland. Storms should be non-severe for western NB.

 

Tonight.

Isolated thunderstorms possible for NS, PEI and portions of NB. Main threat is torrential downpours.

 

Sunday.

Isolated thunderstorms possible for Cape Breton. Main threat is torrential downpours.

 

Convective Discussion

There are a couple features that will impact the region today – a weak trough that’s currently stretching from the Cape Cod area into southwestern NB and an upstream short wave trough currently over southern Quebec. The aforementioned trough could be the catalyst for an isolated strong to severe thunderstorm this afternoon/evening for a portion of eastern NS. The 12Z tephi out of YQI looks decent and adjusting the surface temp and dewpoint results in a mixed CAPE close to 1000 J/KG. There is also decent shear of around 35 knots. Of course there is PLENTY of low level moisture as we continue to be plagued with very high humidity near the surface (PWAT just shy of 50 mm at YQI). The instability is modest as well so we just need some sunshine to fire off a storm or 2. Upstream SAT PIX does show some openings in the overcast ST/SC deck but also some fairly fast approaching mid-level cloud in the gulf of ME. Given the recent flooding in areas of NS there is somewhat heightened awareness today in the event we see cells develop. The one saving grace would be the forward motion of the convection as the mean flow would have it moving eastward at 60-70 km/h. Rainfall rates of up to 50 mm/h look possible. The issue would be if we see any training/back-building of cells. We shall see…

 

The second feature mentioned above is already producing some storms upstream. As the short wave approaches ME and western NB we expect to see some scattered thunderstorms this afternoon and into this evening. Locally torrential downpours seem to be the main concern.

 

There could be some isolated convection tonight and into Sunday morning for eastern NB, NS and PEI as that same short wave moves across the MRTMS. And given what we are seeing at this hour in southern QB there is a chance that Cape Breton sees a isolated cells Sunday afternoon as the short wave just exits the region.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Jeremy

Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Scattered thunderstorms are forecast over extreme SW-ern NS late today, as well as the potential for isolated marginally severe thunderstorms from Windsor through to Collegeville area today. More organized thunderstorms are forecast over western NB where partial clearing is forecast to occur. The main hazard for the day is heavy rain.

 

Convective Discussion

Complex “tropical-like” dynamics at play today for 3 main forcings for convection each with individual hazards associated. A front in Labrador may spark a few lightning strikes as it transits through over the next 24-hrs.

1. Western NB: MUCAPE values near 1000 could (with a strong enough forcing) even overcome the cap that exists at 500mb, leading to gusty winds and heavy rain. PWATS in this area with actual dew points near 20 at 45mm today.

2. An area of potential instability exists from Kings county through to Guysborough county late this afternoon. The forcing here would be a sea breeze type front. If this materializes, dew points are near 22 and PWATS close to 50 so rain is the main hazard.

3. A frontal feature streaming up from the U.S. eastern seaboard is feeding in moisture and buoyancy causing non-severe thundershowers – Shelburne area likely to be in this moisture feed this evening. Saturday morning the rain hazard exists again in central NS marked in yellow on the overnight graphic. Models are not in perfect agreement on placement, but there is a consistent signal again for decent rain rates (greater than 30mm/hr). These local areas have a high vulnerability/sensitivity based on rainfall that has fallen in the last week.

The rest of Saturday sees generally improving conditions for NS, with pop-up showers across much of NB, PEI and in eastern areas of Nfld. Sunday’s dynamics as humidity builds back into the Maritimes is not a clear picture at this point.

 

Thunderstorm Outlook for Today

 

Thunderstorm Outlook for Tonight

 

Thunderstorm Outlook for Tomorrow

 

Thunderstorm Outlook for Sunday

 

Forecaster: TIRONE