Prévisions météo en montagne

Unsettled conditions will dominate BC's weather pattern for the weekend which is largely steered by a quasi-stationary upper low near Bella Bella. Along the coast, onshore flow is expected this morning from the aforementioned upper low, with precipitation expected to lighten in intensity over the day.

A trough of low pressure has set up across B.C. from Smithers to Tumbler Ridge. There is generally good agreement for a continuation of heavy rain associated with the trough and thunderstorms to develop in its wake. The heaviest rainfall is expected during the day but precipitation will carry into tonight as a low pressure system over the Prairies continues to feed moisture into the B.C. Peace River District. Moisture availability and easterly flow mean the eastern slopes of the Rockies will be hit the hardest. A Rainfall Warning was issued by Environment and Climate Change Canada for B.C. Peace River. Additionally, keep apprised of any potential freshet issues with the B.C. River Forecast Centre's website as a Flood Watch was also issued. (Homepage here)

Another low-pressure system will make landfall on the Washington State coast on Saturday and redevelop in southwest Montana on Sunday. Rain from this system will be minimal across southern B.C. near the border except shower are expected in the southeast corner near Cranbrook and Sparwood on Sunday afternoon where wrap-around precipitation will occur.

Looking into the near distant future (with my crystal ball), there is a good possibility of a broad ridge of high pressure moving over B.C. early next week resulting in a warming trend. This ridge will bring dry and seasonal to above seasonal temperatures to the province, which could result in a period of high freezing levels enhancing mid elevation snow melt. More data will be required as to the extent of the warming, but current model guidance suggests temperatures to be above average by at least 2 to 5 degrees from Tuesday to Friday, with temperatures getting successively warmer with each day.

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The 500 mb animation depicted above shows an upper low stalled over the B.C. coast near Bella Bella this morning. As a result, an upper trough associated with this low will bring onshore moisture over the B.C. coast today. If you look around the upper low, you can see blue dashed lines around it, this indicates a cooler airmass along the Central Coast with below seasonal temperatures for today.

Further north, a stagnant lee low over northeastern BC will attempt to track north but will have no avail as a broad ridge of high pressure over Alaska expands to the Yukon and northern BC. This will result in the low spiralling moisture over the same spot in a west-east fashion from Smithers to Dawson Creek.

Come Sunday morning, the broad ridge of high pressure over the Yukon will continue to build and reduce precipitation over northeastern B.C. Further south, The broad upper low that was previously sitting over Bella Bella will track southeast, meaning wet and unsettled conditions from Williams Lake down to the border all day Sunday.

Conditions will dry and warm up early next week as a sharp upper ridge begins to build thereby squeezing the upper trough out of the region. Early guidance suggests above seasonal temperatures.