Convective Outlook Valid for June 6th, 2019

Convective Discussion

A weak low pressure system with an associated tropical moisture feed will move across Nova Scotia today. Rain at times heavy is occurring ahead of this feature. Cloudiness will limit daytime and any severe weather threat.

 

Regional Impacts

Maritimes…

A risk of non-severe thunderstorms over southwestern sections. Synoptic rainfall warnings of 50 mm in 24 hours are in place for parts of Nova Scotia. Severe rainfall warning criteria of 25 mm in 1 hour is not expected to be met.

 

Newfoundland and Labrador…

Significant rainfall but no warnings currently in place.

 

 

 

Andy Firth

Lead Meteorologist

Atlantic Storm Prediction Centre, MSC
Environment Canada / Government of Canada

3rd Floor, 45 Alderney Drive

Dartmouth NS B2Y 2N6

andrew.firth@canada.ca / Tel: 902-426-7779 / Fax: 902-426-4873

 

Andy Firth

Premier Météorologue

Le Centre de prévision des intempéries de l'Atlantique, SMC
Environnement Canada / Gouvernement du Canada
3e étage, 45 Alderney Drive

Dartmouth NS B2Y 2N6

andrew.firth@canada.ca / Tél: 902-426-7779 / Télécopieur: 902-426-4873

 

Convective Outlook Valid for June 5th, 2019

Convective Discussion

Satellite images are showing multiple bands of convective clouds ahead of an advancing upper low located just west of Labrador. The instability is limited to the low and mid levels for the time being. A cyclonic southwesterly upper level jet over western Newfoundland is supporting isolated TCU/CB’s east of Stephenville, and with the advancing cold air aloft the mid-level lapse rates are expected to favorable for continued development of isolated cells over central and eastern NF. The moisture available in this airmass is limited so rainfall amounts should remain low.

 

 

Regional Impacts

Newfoundland and Labrador…

Isolated non-severe thunderstorms are expected this afternoon over much of Newfoundland and Southeastern Labrador

The main threat ahead of these isolated clusters would be gusts of around 70 km/h.

 

Maritimes…

No thunderstorms expected

 

 

Jean-Marc Couturier

 

Forecaster / Meteorological Service of Canada

Environment and Climate Change Canada / Government of Canada

Jeanmarc.couturier@canada.ca

 

Prévisionniste / Service météorologique du Canada

Environnement et Changement climatique Canada / Gouvernement du Canada

Jeanmarc.couturier@canada.ca

 

Convective Outlook Valid for June 4th, 2019

 

Convective Discussion

 

Not much on the go today. A weakening frontal trough affecting some offshore waters and NL will give rise to a slight risk of an embedded TSRA today. OTWZ a weak upper trough will give some ISOL TCU to NB this afternoon. KCAR has a freezing level of 4,300 ft…so would not be surprised if there are some IP mixed in with some of the heavier showers.

 

Regional Impacts

 

Newfoundland: slight risk of an embedded TSRA across the SE.

Elsewhere: nil

 

Jeremy

Convective Outlook Valid for June 3 2019

 

 

 

Convective Discussion

A cold front associated with a deep low over southern Quebec will move into New Brunswick this afternoon, and an associated trough moving into  Nova Scotia will cross the province by overnight tonight. As the associated  trough approaches Newfoundland, it  may re-initiate convection over southwestern Newfoundland later today into tonight. Meanwhile a warm front moving north over Newfoundland today has triggered a few thundershowers along the South Coast, which should end this afternoon.

 

For the Maritimes the moisture is low, with surface dewpoints in the 5-10 C range, and a strong dry intrusion is approaching from the southwest along the front towards New Brunswick. The 0-6 km shear near the frontal jet is about 90 kt, and the 0-3 km shear is near 50 kts, which given the low moisture may shear off any convection. Over Nova Scotia the moisture is a little better, and CAPE’s may approach 300 J/kg if the inversion breaks, but the fast upper flow is moving things along fast enough to reduce local rainfall rates. For Newfoundland moisture is higher, with precipitable  water amounts near 30 mm, which may go higher later today. 0-6 km shear is in the 40-50 kt range, but will diminish from west to east as a southerly jet moves east along the south coast. As the trough moving across Nova Scotia approaches, there may be a second bout, again with high shear, but with a bit more moisture than for the Maritimes. In general, rainfall amounts should remain below warning levels unless there is training, and wind gusts should stay below warning levels due to relatively low CAPEs.

 

Regional Impacts

 

Newfoundland: A few non-severe thundershowers in the east tapering off this afternoon. In the west a second batch of thundershowers beginning late this afternoon into this evening and persisting into the overnight period.

Labrador: no impacts expected.

New Brunswick: Non-severe thunderstorms this afternoon into this evening.

Nova Scotia: Non-severe thunderstorms mainly along the Atlantic coast. These thunderstorms will move east across the province, and will pass east of the mainland this evening and for Cape Breton by Wednesday morning.

Prince Edward Island: Nothing severe expected.

 

Doug Mercer

Lead Meteorologist

Atlantic Storm Prediction Centre

Meteorological Service of Canada

45 Alderney Drive, Dartmouth

Nova Scotia, B2Y 2N6

Doug.mercer@canada.ca

Office: (902) 426-9200

 

Premier Météorologue
Centre de prévision des intempéries de la région de l'atlantique

Service météorologique du Canada

45 promenade Alderney, Dartmouth

Nouvelle-Écosse, B2Y 2N6

Doug.mercer@canada.ca

Bureau: (902) 426-9200

Cell: (902) 403-7951

 

Convective Outlook Valid for June 2nd 2019

Convective discussion

The general picture is for little no impacts for most of the forecast region. Impacts are expected mainly along the Atlantic coast of Nova Scotia today and tonight, and southern coastal regions of Newfoundland. There is also a risk for Northwest New Brunswick.

There are two main feature. A slow moving low south of Nova Scotia has a warm front extending well  to the east as a triggering feature, along with good moisture advection, precipitable water amounts in the 40 mm range, CAPES probably in the 500-1000 J/kg range, and above the marine inversion winds in the 55 kt range. While there is veering with height in the inversion, this should have little or no effect. The main impacts are rainfall, especially enhanced by topography near landfall, and gusty winds. With freezing levels in the 8000-10000 foot range, there is also a slight possibility for small hail.

For new Brunswick there is a line of weak convection across central main as an organising feature and a trigger. Mositure is relatively low, and the Caribou 12Z tephigram has zero CAPE. However, the  trigger temperature is near today’s daytime high, and CAPES of 300-500 J/kg are possible this afternoon, with shear near 38 kts. Again, the main impacts would be rain followed by gusty winds. With freezing levels in the 8000-10000 foot range, there is also a slight possibility for small hail.

Regional Impacts

Newfoundland: Rain and some gusty winds late today into tonight. A slight chance of hail. Topographic enhancement may give 25 mm/hr especially in the southwest.

Labrador: none

Nova Scotia: Rain and some gusty winds today into tonight. A slight chance of hail. Topographic enhancement may give 25 mm/hr especially in the east.

Prince Edward Island: none.

New Brunswick: Rain and some gusty winds, and a slight chance of hail.

Doug Mercer

Lead Meteorologist

Atlantic Storm Prediction Centre

Meteorological Service of Canada

45 Alderney Drive, Dartmouth

Nova Scotia, B2Y 2N6

Doug.mercer@canada.ca

Office: (902) 426-9200

Premier Météorologue
Centre de prévision des intempéries de la région de l'atlantique

Service météorologique du Canada

45 promenade Alderney, Dartmouth

Nouvelle-Écosse, B2Y 2N6

Doug.mercer@canada.ca

Bureau: (902) 426-9200

Cell: (902) 403-7951