Arctic Blast To Freeze The Province With Cold, Snow, Rain & Wind

Updated: Saturday, October 18th, 2020 @ 5:45 AM

Valid: Friday, October 17th, 2020 @ 11 PM

Forecaster: James Follette

A large trough of low pressure that is bringing relentless bitter cold air to much of Northern British Columbia, Alberta, Saskatchewan, Manitoba, and Northern Ontario. Will continue to deepen today as it digs even further south over the coming days which will allow for more cold air to funnel in.

The first snow of the season arrived today for many parts of the province, including the Interior. Higher elevations could pick up as much as 10cm by Midnight Sunday.

Once the snow stops, there will be a series of low pressures that will spread snow and rain showers at times for a few days, then by Thursday, we’ll see a big blast of cold air with highs struggling to hit the freezing mark for many areas, including the coast of Vancouver.

A storm system will bring a messy mix bag of weather to the province on Friday with potential for heavy snow inland, mixed bag, and heavy rain on the coast, and very strong winds.

It could be near Halloween by the time that we will see things warm up back to seasonal again, which is around 13*C for this time of year.

The jet stream is what divides cold and warm air and steers the storms and systems. A large High to the south of our province and a storm system off our coast is helping in keeping us in the middle (for now) notice how by Tomorrow and through Wednesday that the jet flattens? that means much colder air and with a storm off the coast, we are looking at more snow on the way, and rain on the coast. Either way though, we will be seeing some very bitter cold air through the week and possibly to start next week as well!

One of the forecast model tools we use in forecasting and especially in winter forecasting is the 500mb Heights or also known as the 1000-500mb Thickness level. This will give us an idea of what air mass will be around, values of 522 and below indicate a polar air mass, this is where you will get the coldest temperatures and likely snow, 534-540 is known as the rain/snow line. normally 534 would be a mix of rain or snow or just snow and 540 would be a mix of rain and snow or just rain, anything above 540 is usually rain. Then there is 570 and above, that is your Tropical airmass, the hot, humid & sticky air mass from the south.

We’ll be right on that rain/snow line for a good while here in the Interior. Northern parts of the province will see the colder airmass values, and warmer along the coast. The extreme cold is currently over Alberta.

By mid-week, the jet stream flattens and the colder air with height values closer to 528 will bring a chance of snow again to the Interior and as far south as Vancouver West.

Temperatures will be dropping over the next several days, with the coldest air hitting at the end of the week. Temperatures over Northern parts of the province will see temperatures fall to as low as -25*C and highs struggling to get to -5. As for the Interior, Central, and South, temperatures will plummet into the low to mid 5’s for highs with on/off snow and rain showers and wake up to temperatures of near or slightly below the freezing mark. Lower elevations in the city centres will be warmest and likely not see any snow.

For coastal areas, temperatures over the next few days will hover neat 10 degrees than by late week, we will see temperatures drop sharply to the low 5’s.

Overall, the story is that we will see temperatures be below normal by as much as 5 to 10 degrees much of this week!

The 24-hour Temperature change from yesterday will start to fall about near 4 degrees cooler, once we get into Monday-Tuesday, we’ll see 24-hour temperature changes by as much as 20 to 30 degrees colder!

Here’s the Short term forecast, looking at the FutureCAST, we are looking at the RGEM model here and we can see snow exiting this afternoon, as High pressure lingers a little keeping the Northern parts of our province dry. Then as a large High pressure settles over North Eastern parts of the province, the North East winds will shift in colder air to much of the province with exception to the coast, we’ll see scattered showers and snow flurries tonight and again tomorrow. Rain showers on the Vancouver coast.

It’s Thursday into Friday when the big changes happen, still early on those details, but could be looking at a messy size storm, and some record frigid cold air for the Okanagan deserts, especially in northern parts of province.

How much snowfall can we expect? Through Tonight, a widespread 5 to 10cm is expected for mostly higher terrains, lower terrains will see less or just rain, some isolated areas will see only a few cms. further north will see up to 2cm, and the Southeast sections of the province can see as much as 20cm in the higher elevations!

As we fast forward the snowfall totals into Wednesday, we can see additional amounts of snow for Northern parts of the province with up to 20cm possible by end of Wednesday.

Let’s take a look now at your forecast for Tonight!

Greater Vancouver area looking at Rain once again tonight, lows still mild! around 7 degrees. Rain/snow mix for Kamloops, except rain in the city, to snow in the higher elevations, could pick up as much as 10cm! Lows down to -1 tonight, near 0 in the city.

Prince George is beautiful with a few clouds, cold! -7 degrees and +2 in Kelowna with snow snow flurries!

Here is a look now at your Vancouver 7 day forecast!

Looking at rain ending later this morning or noon hour, then rather mostly cloudy skies, some peaks of sunshine. highs only around 10 today, a chance of showers tomorrow and a tad milder! around 12 degrees, then we dry it out for Tuesday through Thursday as high pressure, a very large one! lot’s of dry air with this and the models are predicting pressure as high as 1050mb! If you have a barometer at home, the 1050mb is the borderline of entering into the Very dry section. Those Northeast winds from the high pressure will send down cooler air again with temperatures dropping to near 10, 11 on Friday with rain and rain/snow mix, except snow in Vancouver West. and wet snow or mix for Saturday and a high of ONLY 4 degrees!

For Kamloops and the Thompson river areas and Interior, we are looking at a very miserable and cold, wintry like forecast! Looking at snow ending this morning in the high elevations, rain clearing in the lower elevations. high of 4 today! Showers at times tomorrow and warmer at 8, but still below our normal of 12! Tuesday is when it goes down hill! chance of flurries and 5, Wednesday, a chance of flurries and 4, cloudy and 2 on Thursday, Snow, could be a lot! on Friday with highs near freezing, -9 on Friday morning! very cold on Saturday and a chance of flurries or snow… highs only at -4! and lows near -10.

There could be relief though by the last week of October heading into Halloween!