Subtropical System Nears Landfall In Nova Scotia

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FXUS61 KCAR 070114

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

914 PM EDT Fri Sep 6 2024

.SYNOPSIS...

An ocean low will lift toward Nova Scotia overnight through

Saturday. A front will cross the region Saturday night into

Sunday then exit across the Maritimes Monday. High pressure will

build toward the region Tuesday into Wednesday.

&&

.NEAR TERM /THROUGH SATURDAY/...

9:14 PM Update: Satellite pictures show low pressure a couple

hundred miles east/southeast of Cape Cod. The low is expected to

track toward Halifax, Nova Scotia by this time Saturday

evening. Rain associated with the low will likely get into

portions of coastal Washington County around daybreak Saturday

morning. Elsewhere, there is a frontal boundary off to the west

of the region. This front will move slowly east as an occluded

front through Saturday, but the fronts progress will be slowed

by the ocean low. Minor tweaks for the remainder of the night,

but overall the forecast is in great shape.

Previous discussion:

An ocean low will lift toward Nova Scotia tonight through

Saturday. Swell generated from the low will produce high surf

along the Downeast coast Saturday, particularly Hancock county.

Have issued a High Surf Advisory for the Downeast coast for

Saturday. An occluded front will approach from the west later

Saturday. High pressure centered near Newfoundland will remain

ridged across the region tonight into Saturday. However, the

ridge across the region will be narrowing Saturday between the

systems to the east and west. Expect mostly clear skies north,

partly cloudy Downeast, early tonight. Clouds then increase

across the region overnight. The northwest edge of the rain

shield with the ocean low will also reach the southeast corner

of the forecast area later tonight, particularly Washington

county. Patchy fog is also expected across the forecast area

later tonight into early Saturday. Uncertainty still exists

regarding the western edge of the rain shield with the ocean

low. The steadier rain Saturday will occur across Washington

county, with lesser rain chances to the north and west. Have

included a chance of showers across the remainder of eastern

Maine Saturday mostly during the afternoon. However, the

possibility exists that rain could either remain entirely to the

east across New Brunswick or back across the remainder of

eastern Maine. Low temperatures tonight will range from around

50 to the lower 50s north, to the lower to mid 50s Downeast.

High temperatures Saturday will range from the mid to upper 60s

east, to the upper 60s to around 70 west.......

9:26 PM ADT Friday 6 September 2024

Rainfall Warning in effect for:

Halifax County - east of Porters Lake

Heavy rain tonight and Saturday morning.

Locations: western Nova Scotia and mainland Atlantic coastal counties.

Total rainfall: 40 to 60 mm, except locally 100 mm in areas of heaviest rain possible.

Maximum wind gusts: southeasterly 60 to 80 km/h.

Time span: tonight until Saturday afternoon.

Similar storms in the past have caused:

- road shoulder erosion and washouts

- flooding of basements, especially in poor drainage areas

- scattered utility outages

Remarks: An area of low pressure containing tropical moisture will bring significant rainfall to the province. General amounts of 40 to 60 mm is expected but significantly higher amounts are possible in localized heavy downpours.

Heavy downpours can cause flash floods and water pooling on roads.

Watch for possible washouts near rivers, creeks and culverts.

Rainfall warnings are issued when significant rainfall is expected.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to NSstorm@ec.gc.ca or tweet reports using #NSStorm.