Shelf clouds spotted in Cape Breton Tuesday; May heat continues

I always love getting pictures sent in of unique cloud formations! A number from Cape Breton on Tuesday featured shelf clouds, which are a type of arcus cloud. This type of cloud is characterized by a smooth, arced line at the base of what is usually a convective cloud. A convective cloud is the type to produce pop-up showers or thunderstorms. The shelf cloud doesn’t necessarily need to come along with falling rain or an active thunderstorms though.

The shelf cloud in Cape Breton Tuesday didn’t come with much rain or a thunderstorm. It may have been associated with what was left of a small thunderstorm that passed across P.E.I. hours earlier.

A shelf cloud spotted near Sydney, N.S. (Courtesy: Stan Peach)

Heating up

Wednesday will once again feature unseasonably warm temperatures across the Maritimes. High temperatures away from the coast will soar into the mid-to-high twenties for a large part of the Maritimes. A modest level of humidity in the air will produce humidex values making it feel near or into the low-thirties for those areas. An active sea breeze — a wind onshore off cooler ocean water — will keep exposed coastal areas with high temperatures mostly ranging 15-to-20 C.

Unseasonably warm and humid weather for the month of May. (Source: CTV News Atlantic)

Conditions in the Maritimes will remain warm and slightly humid through Friday. Less humid air is expected to filter into the region by Saturday. High temperatures are set to cool back towards monthly averages on the weekend.

Showers, risk of thunderstorms

Warm, humid weather provides energy for pop-up showers and thunderstorms. A few spotty showers or small thunderstorms could develop in southern New Brunswick and the interior of Nova Scotia Wednesday afternoon into early evening. Edmundston and the northwest of New Brunswick, Moncton and the southeast, as well as northern areas of mainland Nova Scotia, will have a chance of showers or thunderstorms developing overnight. These showers or thunderstorms will be widely scattered and very hit-and-miss by nature.

Showers with a risk of thunderstorms overnight for a few spots of the Maritimes. (Source: CTV News Atlantic)

A weather front arriving into New Brunswick during the day on Thursday will produce periods of rain. One round will come across the province Thursday morning into early afternoon. A second round will develop late afternoon into evening. There will be a chance of showers Thursday morning for Prince Edward Island followed by scattered showers in the afternoon. Scattered showers are expected in eastern areas of Nova Scotia. Once again the rain and showers will be accompanied by a risk of thunderstorms.

Periods of rain with a risk of thunderstorms for New Brunswick Thursday. A chance of showers for both Nova Scotia and Prince Edward Island through the day. (Source: CTV News Atlantic)

Along with lightning, the thunderstorm could produce some localized rain totals of 20-to-40 mm. That is most likely in New Brunswick.

When thunder roars, head indoors. Wait 30 minutes after the last rumble of thunder before heading back out.

Updates on any active showers and thunderstorms, along with forecast timelines, are shared nightly on CTV News Atlantic at 5, 6, and 11:30 p.m.