December 2022 Forecasts And Discussions

[HarrisonSasquatchWx]

Thank you, Corp. Goose.

[Typeing3]

You know, looking at the 12z HRDPS sounding for 0400pm tomorrow. That is VERY close to staying all snow. Probably just model noise, but thought it would be worth pointing out.

Could be ice pellets. Between snow and freezing rain.

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[arbetrader]

12z Euro recap. It begins the snow around midnight or just slightly before. Snows all night and into the morning. Then transitions to sleet and freezing rain from SW to NE over Metro Vancouver starting at 900am. All of Metro Vancouver is under freezing rain by 1100am and then plain rain by 0200pm. The Euro actually is quite robust with the warming and so the Fraser Valley escapes an ice storm for the most part.

I think the biggest issue is that the road surfaces are all still so incredibly cold - perhaps it won't take as long to warm up, however in the past it's taken much longer for the central valley (even Abbotsford) to warm than areas to the west, such as even Langley or Surrey...

Also, Eastern Valley areas, such as Chilliwack/Agassiz, and most especially Hope has a history of hanging onto the cold air in the upper levels for days even after areas like Abbotsford see the changeover - I remember several instances such as this, including the past few cold events...

[Rubus_Leucodermis]

Could be ice pellets. Between snow and freezing rain.
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More like snow in terms of impact. Much less impactful than freezing rain.

[HarrisonSasquatchWx]

The RGEM shows the temperature and dew point rising above zero with heavy rain on Saturday. However, it keeps the NE outflow going through the afternoon. This makes no sense to me. Given the deeply entrenched arctic airmass and the significant cold to draw from in the interior, I'm confused as to how the temperature and dew point would rise above zero in this situation. Perhaps warm air aloft mixing down to the surface? But even at that, I find it hard to believe we could push out this cold with a continuous NE outflow. What are everyone's thoughts?

This will be another good learning experience for you Jr. man to see if does come to fruition how it all plays out.
The fun art of meteorological learning Jr. one more step in becoming our own local from WJr. to Wpro 2.0. luv ya pal keep up the dedication and passion you have for weather.

[Bonovox]

I think the biggest issue is that the road surfaces are all still so incredibly cold - perhaps it won't take as long to warm up, however in the past it's taken much longer for the central valley (even Abbotsford) to warm than areas to the west, such as even Langley or Surrey...

Also, Eastern Valley areas, such as Chilliwack/Agassiz, and most especially Hope has a history of hanging onto the cold air in the upper levels for days even after areas like Abbotsford see the changeover - I remember several instances such as this, including the past few cold events...

Yup, that is usually the case, but precip cuts off pretty sharply with the Euro, alleviating some of the ice accumulation.

[Rubus_Leucodermis]

I think the biggest issue is that the road surfaces are all still so incredibly cold - perhaps it won't take as long to warm up, however in the past it's taken much longer for the central valley (even Abbotsford) to warm than areas to the west, such as even Langley or Surrey...

Also, Eastern Valley areas, such as Chilliwack/Agassiz, and most especially Hope has a history of hanging onto the cold air in the upper levels for days even after areas like Abbotsford see the changeover - I remember several instances such as this, including the past few cold events...

Models often badly botch transition events, particularly in the eastern Valley, by underestimating how tenacious low-level cold can be.

[Typeing3]

Low of -13.1c just after midnight in east Coquitlam. Temp spiked up to about -9.5c at around 4am before falling to -12.5c just before sunrise.

Currently -10.2c, dp -17.3c. Light E breeze.

[Bonovox]

Could be ice pellets. Between snow and freezing rain.
diagram.png

I think that is probably the case, but the whole column briefly falls below freezing. I suspect that won't actually happen though and it will indeed be ice pellets.

[Typeing3]

More like snow in terms of impact. Much less impactful than freezing rain.

Yeah. It's much more common to see in Metro Vancouver rather than freezing rain, thankfully.

Edit: Also for those who are wondering, "Ice Pellets" is the same thing as "Sleet". Canadian vs American terminology.

[Abby_wx]

The RGEM shows the temperature and dew point rising above zero with heavy rain on Saturday. However, it keeps the NE outflow going through the afternoon. This makes no sense to me. Given the deeply entrenched arctic airmass and the significant cold to draw from in the interior, I'm confused as to how the temperature and dew point would rise above zero in this situation. Perhaps warm air aloft mixing down to the surface? But even at that, I find it hard to believe we could push out this cold with a continuous NE outflow. What are everyone's thoughts?


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There won't be an appreciable warmup in the valley until the south winds break through. It will be a slow trend upwards until we eventually creep above freezing. Metro Vancouver will warm up more quickly since the outflow will get cut off much sooner there.

There will of course be warm air mixing down, but that's a very slow process.

[arbetrader]

Models often badly botch transition events, particularly in the eastern Valley, by underestimating how tenacious low-level cold can be.

Yes I agree, I've seen this particularly in several events in the past. We shall wait and see. Preparing for the worst here - but hoping for the best.

[Typeing3]

EC has included ice pellets in their forecast for tomorrow for Metro Vancouver. Likely would not be mentioned other than if they were thinking we'd be seeing it over a relatively prolonged period of time.

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[HarrisonSasquatchWx]

Models often badly botch transition events, particularly in the eastern Valley, by underestimating how tenacious low-level cold can be.

I can recall in past years when l lived in Vancouver Hope still reporting snow 2 day's after the fact it had turn to rain.
The other thing that irks me is no actual official observation station for Chilliwack which in all honesty is a complete joke, Abbs and then nothing until Hope insane just insane Chilliwack airport is the perfect spot for a 24/7 station.

[Rubus_Leucodermis]

Watch upgraded to a warning:

10:07 AM PST Thursday 22 December 2022
Winter storm warning in effect for:

Metro Vancouver - central including the City of Vancouver Burnaby and New Westminster
Metro Vancouver - North Shore including West Vancouver and North Vancouver
Metro Vancouver - northeast including Coquitlam and Maple Ridge
Metro Vancouver - southeast including Surrey and Langley
Metro Vancouver - southwest including Richmond and Delta

Hazardous winter conditions are expected.

Travel conditions will be challenging due to heavy snow, ice pellets, freezing rain, and heavy rain on snow or ice.

Locations: South Coast.

Time span: This evening to Saturday (Christmas Eve).

Hazards: Heavy snow followed by freezing rain and rain, localized strong winds, and localized windchill due to Arctic Outflow to minus 25, localized flooding in heavy rain.

Remarks: A Pacific frontal system combined with the cold Arctic airmass over B.C. will bring another round of snow to the South Coast starting this evening.

As freezing levels rise, heavy snow will become mixed with ice pellets and then change to rain late Friday over most of Vancouver Island, and Friday night to Saturday over the mainland. Snowfall amounts of 10 to 20 cm are expected. Local blowing snow is possible in strong easterly winds resulting in near zero visibilities.

Furthermore, freezing rain is expected during the transition from snow to rain, which could cause significant impact on road conditions. For inland sections of Vancouver Island, periods of freezing rain could continue into Saturday afternoon.

As the system progresses and warming becomes dominant, heavy rain is expected. Localized flooding due to snow-blocked drains and melting snow is likely.

Visibility will be suddenly reduced to near zero at times in heavy snow and blowing snow. Localized flooding in low-lying areas is possible. Take extra care when walking or driving in affected areas. Ice build-up may cause tree branches to break.

Winter storm warnings are issued when multiple types of severe winter weather are expected to occur together.

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


4:43 AM PST Thursday 22 December 2022
Arctic outflow warning in effect for:

Metro Vancouver - central including the City of Vancouver Burnaby and New Westminster
Metro Vancouver - North Shore including West Vancouver and North Vancouver
Metro Vancouver - northeast including Coquitlam and Maple Ridge
Metro Vancouver - southeast including Surrey and Langley
Metro Vancouver - southwest including Richmond and Delta

Strong outflow winds and cold wind chill values will continue.

Locations: Metro Vancouver and Fraser Valley.

Threat: Bitterly cold temperatures and strong winds.

Wind Chill Values: Minus 25 to minus 20 in Metro Vancouver, Fraser Valley West including Abbotsford and Fraser Valley Central including Chilliwack. Minus 30 to minus 25 in Fraser Valley East including Hope.

Time span: Today and tonight.

Remarks: An arctic front has brought in a cold airmass to the south coast. Strong outflow winds are bringing temperatures 5 to 10 degrees below seasonal normals resulting in wind chill values approaching minus 20 to minus 30 over the Lower Mainland.

Over Metro Vancouver, conditions are expected to improve this afternoon as temperatures rise. However, over the Fraser valley, the extreme cold conditions will continue through tonight.

Ensure that shelter is provided for pets and outdoor animals. Be prepared for unusually cold temperatures and strong winds.

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