Forecast for Saturday - 5 a.m. - 5 p.m. PDT

Showers along the mainland south coast everywhere south of Bute sound this morning but will be reinforced by an oncoming system. Widespread moderate precipitation will spread from the south coast by noon followed by the north coast in the afternoon. Freezing levels near 1500m in the afternoon for the south. Moderate to strong southerly ridgetop winds will also accompany this system.  10 to 15 mm over the south by end of day. 

Scattered showers from Williams Lake down to Creston this morning.  However, in the afternoon thunderstorm potential will be widespread throughout the entirety of the interior province. Isolated showers with isolated lightning strikes are possible over the northern third of the province, with an organized line developing from Vanderhoof down to Arrow Lakes as the offshore front "activates" the environment. The actual severity of thunderstorms looks marginal, but the threat of lightning activity seems likely. Freezing levels will climb to 2200 m for the Selkirk ranges. Arrow Lakes could see 5 to 15 mm by end of day. 

Fine conditions are again expected. Diurnal freeze-thaw cycles continue, with freezing levels jumping up to near 1500 metres.

Scattered flurries and rain showers throughout the Range. General snowfall accumulations of 2 to 4 cm can be expected, though amounts will be highly variable due to pockets of heavier flurries. Freezing levels will rise to between 2300 m and 2500 m, with light to moderate ridgetop winds from the southwest. There exists the risk of a thunderstorm as well.

Forecast for Saturday - 5 p.m. - 5 a.m. PDT

The low will slide towards the Gulf of Alaska with rain persisting along the entire coastline tonight. Heavy downpours along the central coast of BC can be expected. 

The line of showers will gradually move northeast and end up situated from Dease Lake down to Yoho Park by Sunday morning. Alongside, anticipate gusty southwest winds along the central interior this evening. 

Overall a dry night, but with a frontal system spinning out over the Gulf of Alaska, expect an increase in cloud cover before morning.

Unsettled conditions continue with rain showers or flurries continuing. Any rain showers will transition to flurries in the evening as temperatures cool. Snowfall accumulations will continue to be variable due to localized heavy flurries, though a general 2 to 4 cm is expected. Freezing levels will fall from daytime maximums to 1700 m to 1900 m. Light to moderate ridgetop winds from the southwest, except strong in Waterton Lakes National Park. There is a risk of a thunderstorm early in the evening.

Forecast for Sunday - 5 a.m. - 5 p.m. PDT

A low-pressure system sitting offshore of the North Coast will spread widespread moderate precipitation to the entire coast through the day. Freezing levels will fall to 1000 m by Sunday night over the south. 

An unstable southwesterly flow will bring light to moderate precipitation with western-facing slopes will receiving the highest amounts (primarily late in the day). Gusty southwesterly winds over the north rockies and Peace region in the morning as the line of showers move through. Another round of onshore showers are likely in the afternoon over the central and southeastern interior.

There looks to be a good chance of some light precipitation developing. The frontal system over the Gulf of Alaska pivots into the region. Currently, this system looks relatively weak, and only light precipitation amounts are expected. Freezing levels are lower than previous days, reaching a little above 1000 metres in the afternoon.

An unsettled weather pattern continues to bring scattered flurries, accumulating 2-4 cm. Amounts will be highly variable due to pockets of heavier flurries. Freezing levels will rise to between 2000 m and 2200 m, with winds at ridgetop in the moderate to strong range from the southwest.

On Monday, the low will still rotate offshore, with precipitation will become more scattered over the south coast with freezing levels 800 m rising to 1300 m in the afternoon. 

On Tuesday, the low will slide into Washington resulting in a gradual drying trend over the south. North coast will remain fair weather with an upper ridge building.  

On Monday, lee cyclogenesis will result in widespread precipitation over the Peace region. Although solutions vary, high precipitation over the north rockies can not be ruled out. Further south scattered showers over the SE portions of the province with freezing levels looking to fall Monday night.

On Tuesday, the northern half of the province will continue to dry with the offshore ridge invading. The southern half will be much more unsettled, with occasional showers, especially over SE BC as we await for the low to track further into the states. Moderate ridgetopwesterlies along southern Purcell ranges. 

Yukon - South Klondike:
A frontal system slips southwards. Weak low level southwesterly winds set up later Monday and bring a chance of light precipitation to the region. Freezing levels again rise a little above 1000 metres in the afternoons with mixed precipitation possible. Upper level ridging starts to bring increasing stability on Tuesday. Weak low-level flows continue with a some cloud cover possible near the summit.

On Monday, flurries can be expected across the Range along with a risk of a thunderstorm. Upwards of 5 cm of snowfall accumulation is possible, though amounts will be highly variable due to pockets of heavier flurries. Light to moderate westerly winds at ridgetop will prevail, as freezing levels settle in near 2000 m.

Monday evening into Tuesday, a low pressure system is expected to develop over Alberta. There remains a high amount of uncertainty regarding where the heaviest precipitation will fall, though there is the potential of 10 to 30 cm of snow in some areas. Freezing levels are expected to be near 1800 m. Moderate northerly winds at ridgetop, except moderate to strong westerly winds in Waterton Lakes National Park. Stay informed with upcoming forecasts as confidence increases regarding this system.

Thunderstorms Expand

Ken Dosanjh, Chris G, and Paul S

An offshore system will crash into the coastline spreading widespread showers and ahead of it, possible widespread (low severity) thunderstorms to interior BC. With the remaining weekend looking wet and possibly windy on Sunday over the central and northeast parts of the province. 

The Peace and North Rockies could see higher precipitation associated with a lee low (confidence: low-medium) with a drying trend along the north half of the province starting Tuesday. 

The 500 MB animation depicted above shows an upper ridge over Alberta pointing its axis towards northern BC, thereby maintaining fair weather conditions. However, by noon, an elongated upper trough moves onto the BC coast bringing widespread precipitation to the south coast followed by the interior late afternoon with convection likely over the interior parts.  This will result in a slow-moving upper low offshore keeping the province wet and unsettled for the next few days. Eventually, the upper low will split Monday night, with an upper low offshore and another near the Peace region. 