Mountain Snows, But Driving Woes

total quantitative precipitation forecast by NOAA for next 72 hours. Yeah, #YVR, we're expected to have some of the heaviest precipitation rates on the whole continent in the coming days

total quantitative precipitation forecast by NOAA for next 72 hours. Yeah, #YVR, we're expected to have some of the heaviest precipitation rates on the whole continent in the coming days

Hi all! Took the week off from blogging, mostly because the weather has been a bit mundane.

Sorry about that, but I'm back.

But we have some exciting and potentially disrupting weather for this weekend especially for the Mt. Washington area on Vancouver Island. 

But first, I want to highlight a really, really amazing cloud formation spotted this week, by Darren Springer in the Lake Tahoe region. It doesn't get much better than this. Text book example folks:

Surfing in the sky, anyone? Click the video below for the recent Lake Tahoe sighting:

But what's causing this cloud formation and type of atmospheric wave?

Well, the official type of instability is called Kevin-Helmholtz (K-H), and occurs when upper layers of the atmosphere move faster then the area shown to be saturated (the cloud). You need steep lapse rates (changes in temperature with respect to height). And boom, paired with wind sheer (changing wind direction with height), these marvellous sky waves take flight. 

Computer Simulation of K-H waves, source unknown but posted by Alabamawx.com

Computer Simulation of K-H waves, source unknown but posted by Alabamawx.com

Mountain Snows

Current SFC analysis shows a potent Warm front approaching BC coast from the SW. The front cooks to stall 

Current SFC analysis shows a potent Warm front approaching BC coast from the SW. The front cooks to stall 

The period of heaviest snows for the Vancouver Island mountain ranges will occur tomorrow morning 5am-8am. 

The 4km-WRF model above highlights just how potentially heavy the snowfall will be tomorrow morning. In less time than it would take you to watch the first Lord of the Rings movie (208 minutes), up to 15 cm is forecasted to fall on the Vancouver Island Mountains.

The mesoscale NAM model is also showing a similar solution, so this is a heads up to snow clearing contractors and people skiing at Mt. Washington tomorrow. 

Road conditions will be very treacherous tomorrow morning for the higher levels of Strathcona Parkway. 

Freezing level looks to be approximately 800-900 metres although snow will be able to accumulate a couple hundred metres lower than these elevations, so keep that in mind too. 

I've annotated a Google Map showing key elevation changes on the climb up Mt. Washington. Yellow indicates higher risk of potential travel issues for tomorrow morning with compact snow and limited visibility. 

A rough guide for which parts of Strathcona Parkway will receive significant accumulating snow and very poor visibilities. Freezing levels are dynamic, so drive for conditions, always use recommended tires and follow chain regulations.  

A rough guide for which parts of Strathcona Parkway will receive significant accumulating snow and very poor visibilities. Freezing levels are dynamic, so drive for conditions, always use recommended tires and follow chain regulations.  

I'm only issuing this warning as a caution, since the ski hills are expected to be very busy because of Spring Break with many inexperienced drivers climbing the mountain this weekend and throughout next week as well.

This forecast will change, and the latest computer model guidance this evening could tweak conditions for tomorrow. 

To all the teachers and students off on break stay safe and enjoy your time off!

#50ShadesofVan