Updated 8AM Sunday – Will we see snow? Stay off Hump. Winter Storm Warning Continues

Updated 8AM

There has been no accumulation yet.  The heaviest bands of rain should come soon but I do not think we will see any accumulation in town and if we do, it will be very short lived.

THe  hump and Sutton pass are a different story.  It will change minute by minute. As you can see now.

Though it is not bad on the East Coast.  Click through the webcam image on the side of this page to see the nearby cameras. Or go to Alberniweather.ca/webcams.

It looks like the Arctic air just didn’t quite infiltrate enough yesterday to produce that really cold surface layer.  And so… All the models predicting a start with snow have been wrong.  At most Imwould expect no more than 5cm of snow today and probably 30mm of rain.  Then it will be rain all week.

Oh well, you win some and lose some. 🙂

Updated 9:30PM

If you have snow falling in your area, let me know!  (FB, Twitter, Comment or email!)

Here’s the hump in the last hour.  Please don’t drive if you do not need to right now.  It’s not sticking at that spot at that moment, but it could easily be a snowstorm from the Hump through Cameron Lake at any point.

The rain has begun the City and Valley as well. Temperatures are hovering around 2ºC which is still a little warm for the rain to change to snow.

The first heavy bout of rain should happen soon though.. between 9PM and 11PM. So if it is going to cool off, now is the time.  The rain then should taper off a bit until another band comes  Sunday morning.

From Sunday 5AM to 11AM will be the heaviest precipitation and greatest likelihood for snow to fall.  Models are saying 5-10cm.  Only one model is saying 30cm now and it is now stale, it should update soon so we will have to see what it says now.

Updated 4:30PM Saturday. Rain beginning… heavier rain could drag temperatures down but models showing warmer, less snow for Port Alberni.

Very light rain right now in Port Alberni and across the North, Central and East Vancouver Island, just a little ahead of the UWash schedule.

We had a high today of 3.8ºC at Alberniweather.  We have now dropped to 3.4ºC.  We will need to drop at least another 1.5ºC before this rain turns to snow.  As the rain intensifies the temperature may drop.  But we definitely have no received any of the influx of Arctic air that some models predicted.

Here are the latest runs from the models… the rainier models are validating, almost all of the models are showing colder temperatures than we are experiencing right now… so this is at least starting to look like a rain event only at least in the City Port Alberni.  Other areas, especially at higher elevations could and will be different.

• US High Res 8AM (12 hours) 1PM run:
  Temperature over 4.5ºC Saturday evening.
• US Rapid Model AM (18 hours) 11AM run:
  Late start to precipitation and light. 5mm Freezing Rain. Temperature 1.2ªC  (this model is 2 degrees warmer than this model is predicting.)
  
• Canadian Short LAM1 10AM run:
  27mm Rain by Sunday Afternoon. 6ºC
• Canadian Short LAM2 10AM run:
  26mm Rain by Sunday Afternoon. 6ºC
  
• Canadian Regional GEM 10AM run:
• 15cm of Snow plus freezing rain and rain by Sunday Afternoon. 1ºC (this model is 2 degrees too cold as of now)
• Canadian Global GEM 4AM run:
  27cm of Snow by Sunday Afternoon. 0ºC
• Canadian Multi Model consensus 4AM run:
  1.9ºC with 17-29mm of precipitation by 4PM Sunday.
  Could fall as rain or snow depending on rate.
• US NAM model 10AM Run:
  5cm of snow and 19mm of rain by Sunday afternoon.  Temperature 3ºC at 4PM Sunday. (this model is 1 degree too cold as of now)
• US GFS model:
  30mm rain and below 3ºC  (this model is 1 degree too cold as of now)
• UWash model: 32mm of rain and temp up to 4ºC all evening Saturday and into Sunday.

Updated 12:30PM Saturday – Winter Storm Warning – Precipitation will begin around 5PM Saturday.

Given that temperatures are just under 3ºC I think we will start with rain before we get any snow.  The UWash model agrees.

Here is the general precipitation (rain or snow) for 5PM.

The range of model forecasts have not changed too much since this morning.

• US High Res 8AM (12 hours) 8AM run:
  Temperature over 4ºC Saturday evening.
• US Rapid Model AM (18 hours) 11AM run:
  Late start to precipitation and light. Temperature 1.2ªC
  
• Canadian Short LAM1 4AM run:
  32mm Rain by Sunday Afternoon. 4ºC
• Canadian Short LAM2 4AM run:
  32mm Rain by Sunday Afternoon. 4ºC
  
• Canadian Regional GEM 4AM run:
• 18cm of Snow plus freezing rain and rain by Sunday Afternoon. 0ºC
• Canadian Global GEM 4AM run:
  27cm of Snow by Sunday Afternoon. 0ºC
• Canadian Multi Model consensus 4AM run:
  1.9ºC with 17-29mm of precipitation by 4PM Sunday.
  Could fall as rain or snow depending on rate.
• US NAM model 4AM Run:
  5cm of snow and 15mm of rain by Sunday afternoon.  Temperature 1.9ªC could easily all fall as wet snow.
• US GFS model:
  28mm rain and below 2ªC could easily all fall as wet snow.
• UWash model: 32mm of rain and temp up to 4ºC all evening Saturday and into Sunday.

Updated 9:30AM Saturday – Winter Storm Warning now on – Models warming slightly.  Be prepared for everything.

I will update the predictions below as they are updated by the models so check back often. Light Precipitation (snow or rain) will start Saturday 6PM-8PM on the East and Inland sections respectively.  

Here is the most recent (9AM Saturday) Snowfall accumulation map (in inches) from UWash for the 4PM Saturday to 4PM Sunday timeframe.

But then we have the Canadian GEM model… predicting nearly 2 feet now!  I can’t see it happening with current temperatures right now near 2ºC.

https://twitter.com/alberniweather/status/551427543199281152

A Winter Storm Warning is on for Inland and East Coast of Vancouver Island.

Winter storm warning changed from winter storm watch for:F
East Vancouver Island, B.C. (081300)
Inland Vancouver Island, B.C. (081500)
Current details:
Hazardous winter conditions are expected. A significant winter storm will begin to impact the South Coast tonight. Heavy wet snow is expected over higher terrain near the coast and for Inland Vancouver Island. Snowfall accumulations tonight through Sunday morning will range from 5 to 10 cm for lower elevations of Inland Vancouver Island and at elevations near 100 metres on the coast to near 20 cm over higher elevations. The snow will change to heavy rain Sunday afternoon as warm Pacific air invades the region. Rainfall amounts of near 50 mm are forecast for Sunday night through Monday.

Prepare for quickly changing and deteriorating travel conditions. Consider postponing non-essential travel until conditions improve. Take extra care when walking or driving in affected areas. Winter Storm Warnings are issued when multiple types of severe winter weather are expected to occur together. Environment Canada meteorologists will update alerts as required. Please monitor local media or Weatheradio. Email reports of severe weather to pacificstorm@ec.gc.ca or tweet with the hashtag #BCStorm.

 The current Forecast – More snow than rain but most reliable models are warmest.

The models are starting to switch.  I believe 5 of 8 models

Here are what the models are saying… blue I consider a snowy forecast, green I consider a rainy forecast.

• 7AM Saturday run of US High Res Short Term Model (12 hours):  Temperature over 4ºC Saturday evening.
• 8AM Saturday – 2AM run of US Rapid Short Term Model (18 hours to ): Late start to precipitation and light. Temperature 1.2ªC
• Both 10PM runs of Canadian Short Terms (LAM1 and LAM2): 26mm Rain by Sunday Afternoon. 3ºC
  
• 4AM run of Canadian Regional GEM: 18cm of Snow plus freezing rain and rain by Sunday Afternoon. 0ºC
• 4AM run of Canadian Global GEM: 50cm of Snow by Monday Morning. 0ºC
• 4PM run of Multi Model consensus: 1.9ºC with 17-29mm of precipitation by 4PM Sunday.  Could fall as rain or snow depending on rate.
• 4AM Saturday US NAM model:  5cm of snow and 15mm of rain by Sunday afternoon.  Temperature 1.9ªC could easily all fall as wet snow.
• 4AM US GFS model: 28mm rain and 1.2ªC could easily all fall as wet snow.
• 10PM UWash model: 32mm of rain and temp up to 4ºC all evening Saturday and into Sunday.

The majority of the models still seem to predict conditions good for heavy, wet snow.  The hardest thing is the most reliable models, the UWash and Multi-Model Consensus, are only about 1ºC apart.  But that’s all the difference it takes to have heavy rain or heavy snow.

My recommendation is to be prepared for anywhere from 30cm by Sunday night, to no snow and just rain.  All models say that by Sunday night and into Monday, we should be over 3ºC which should mean everything after that falls as rain.

End Saturday 7AM update

Previous Friday forecasts….

The 10AM model runs all have significant snowfall, including the GFS if you consider the temperature is at or just above zero. The Canadian models are going heavy on very cold air coming in on Saturday.

The 4PM Forecast by EC shows 2-4cm of snow officially for Saturday night and “Snow” comes before “Rain” in significance for Sunday.

I will update again if the Warnings change or when the UWash models update around 7PM tonight.

End of 4PM Update.  See further down for detailed forecasts and other links.

Winter Storm Watch in Effect – Air Quality Advisory In Effect

Environment Canada has issued a lengthy, nearly poetic but serious watch status for Inland Vancouver Island.  It is worth reading in full.

What is a Winter Storm Watch? “Winter Storm Watches are issued when multiple types of severe winter weather are expected to occur together.”

10:36 AM PST Friday 02 January 2015
Winter storm watch in effect for:

Inland Vancouver Island
The first major winter storm of 2015 will beget a messy meteorological medley on the BC Coast Saturday.

The remnants of the the Arctic air that brought a cold, sunny and memorable end to 2014 will linger along the coast this weekend. On Saturday, a strengthening high pressure system over Yukon will deepen the Arctic air in northern BC, then shove another dose of the frigid air south and west through the BC Interior.

By Saturday morning, after summiting the coastal passes, and forced downhill and seaward by gravity, dense and bone-chilling Arctic air will be pouring out the inlets and valleys of the North Coast. Simultaneously, a Pacific warm front packing plenty of moisture, a warm layer of air aloft and correspondingly high freezing levels, will slowly smother the North Coast, blanketing the South Coast Saturday night.

The combination of outgoing Arctic air at low elevations and incoming Pacific air at higher elevations, will create a montage of rapidly changing winter conditions that will eventually have planners, road crews, and the public from Stewart to Hope scrambling to avoid, mitigate and otherwise work around the weather.

The first few flakes will fly Saturday on the North and Central Coasts. Strong and drying outflowing air will delay significant accumulations of snow until Sunday when the force of incoming warm wet Pacific air overwhelms the dry.

On the South Coast, the winter charm will begin Saturday night. Near the coastline, snow or mixed rain and snow will develop late in the evening. The precipitation will spread inland where colder air will sustain snow through the night. Eventually the warmer air will spread inland and that warm layer of air aloft will create freezing rain where sub-freezing air remains trapped in the South Coast Valleys and inlets. In Vancouver and Abbotsford, accumulations will likely only occur at higher elevations prior to a rapid change-over to rain.

As more Pacific air floods onto the coast Sunday, snowfalls will be heavy in some inland regions and freezing rain will create locally treacherous travel conditions. A steady flow of warm moist air will persist through the early part of the week.

Stay tuned for updates and a warning or two. It’s going to be a busy few days at the weather office and everyone will need to pay attention.

The Air Quality Advisory and open burning restrictions 15km from Port Alberni City Hall are still in effect as well and likely will be until the major snow/rain comes on Saturday night/Sunday.

First Freezing Rain and light Snow on Friday

It has already mostly passed, but there was some snow out Sproat Lake and freezing rain early this morning in town but it should be mostly done.  There was only a little bit of drizzle falling on my drive from Port Alberni to Nanaimo this morning before 8AM.

This morning’s model image shows the threat of precipitation ending for the Alberni Valley before noon but lingering on the East side of the Island as the front slides south. It will not amount to significant accumulation of any sort but could cause slippery driving conditions.

Real Action Starts Saturday Night.

In pictures:

The main action won’t start until Saturday night though.

Light snow should begin in the late afternoon or evening on Saturday.  The severity of the weather for the weekend and the amount of snow we receive will depend a bunch on how cold it stays on Saturday afternoon and evening.  The longer we stay within a degree or two of freezing, or below, the more snow we will receive and the messier the transition.

Things get really interesting Sunday and overnight into Monday.

Notice in the middle image above that the temperature (the top red and green lines, are hovering very near zero until Monday morning.  That means any precipitation we get can easily fall as snow between now and then and the heavier the precipitation falls, the more it will ‘drag down’ the temperature, and fall as wet, evil, snow and slush.

The graph above says 22cm of snow and 28mm of rain.  The UWash model on the bottom says no snow.  So clearly, this could end up as either 40mm of rain or 40cm of snow depending on where you are and what the weather actually gives us.

Not a great scenario for weather forecasts to try to predict.  The main goal here is to be prepared and that is why the Winter Storm Watch was issued.  I would expect heavy snow, heavy rain, and probably some freezing rain as well before the end of the weekend.

Enjoy Saturday….  😉 

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Alberniweather Blog (Chris)

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