Update 10PM Thursday Special Weather Statement Issued – Friday Downgraded to Showers – Saturday Upgraded to Downpour. Beware Difficult Forecasts.

Updated 10PM

Special weather statement has been continued.

 

Update 6PM – Special Weather Statement Issued Flooding Possible.

Here is the full statement please read all.

Issued at 2015-08-27 22:55 UTC by Environment Canada:
Special weather statement issued for:
East Vancouver Island, B.C. (081300)
West Vancouver Island, B.C. (081400)
Inland Vancouver Island, B.C. (081500)
Current details:
Heavy rain over the South Coast this weekend.

A major change in the weather pattern will develop on Friday. The high pressure system that has trapped wildfire smoke over Southern B.C. will finally shift east thanks to a pair of incoming storms. The storms will merge two jet streams into a single river of sub-tropical moisture that will bathe the South Coast with the first significant rainfall in months.

Weather models are indicating 80 to 120 mm of rain over the South Coast between Friday night and Monday morning. 20 to 30 mm of rain is expected to carry over into the mountainous regions of the interior during the same period.

Due to the drought conditions over these regions, the soil has a reduced capacity to absorb water. Heavy rainfall thus increases the risk of flash flooding. Additionally, given the recent prolonged dry period, road surfaces may become slippery resulting in poor driving conditions.

To mitigate the risk of flash flooding, make sure drain spouts and sewer covers are free of debris , so water can freely drain. During heavy rains, avoid roadway underpasses, drainage ditches, low lying areas and water collection areas. They can unexpectedly flood or overflow. Do not try to drive across a flooded road. You cannot tell the condition of the road under the water.

The public is advised to monitor future forecasts and warnings as warnings may be required or extended.

 

 

I am going to try a new method of displaying the graphics.  Please let me know what you think by emailing alberniweather@gmail.com or leaving a comment or Twitter/FB.  Don’t be shy.

The models seem to be jumping all over the place with these forecasts, so take everything that is said down below with a grain of salt.  However, we are now well within the 3 day window where the forecasts are traditionally very good.  So make preparations as necessary.

Immediate Forecast backs off – Spotty Showers now all day Friday.

I was worried this might happen and it appears to have indeed happened.  The stream of moisture bringing the bulk of the rain has now slip even further south.  We have been left with a secondary band delivering isolated showers through Friday.

Here is a slideshow of the system showing 3hr accumulations from 11PM Saturday-2AM Friday and onward.

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And here is the final accumulation up to 5PM Friday afternoon.  Our total is only up to about 4mm.
wa_pcp24.36.0000-10

 

But Saturday now Means Business

The trade off in the model appears to be the forecast for Saturday which all of a sudden seems a lot more organized than it did yesterday.

I’ll do the pictures in traditional form this time.  Let me know which you prefer.  Again the action starts between 11PM and 2AM and the rain does not let up until after 8PM Saturday.

wa_pcp3.45.0000-4 wa_pcp3.48.0000-3 wa_pcp3.51.0000 wa_pcp3.54.0000 wa_pcp3.57.0000-3 wa_pcp3.60.0000 wa_pcp3.63.0000-3

Those images don’t need much explanation, the firehose is turned squarely on us.

Here is the total accumulation from 5PM Friday through 5PM Saturday… this leaves off a bit but gets the worst of it.

wa_pcp24.60.0000-7

We are perfectly in the cross hairs for up to 60mm (2.5″) of rain.  If we get all of that watch out.  There will be consequences, possible flooding.

There is also a possibility for some gusty winds.  You can see the small, but powerful low coming ashore in Oregon on Saturday morning below.  I don’t expect too much wind activity here.

wgsfc.48.0000

This forecast could change. But due to the severity, I will be keeping a close eye.  If Environment Canada issued a Statement or Rainfall Warning I’ll post it here in an update.  Next post will be tomorrow afternoon/evening to see how the forecast for Saturday changes.

Sunday Backs off, more rain Sunday night into Monday

There are still showersbut it backs off overnight and into Sunday morning.  Another pulse comes through Sunday night into Monday but we’ll see how the forecast changes.

Two more days of heat then comes Rain – The Joy and Work of the Martin Mars

While the specific details have changed slightly, the models have still held firm on the potential for real, drenching rain starting Friday and lasting into next week.

Until we see you again Hawaii.

 

First, I want to say something about the Martin Mars which is, as of today, no longer on contract with the Province of BC.

The crew did an incredible job on the fires that they were called to and not only that, the very fact this plane was the in the air gave great happiness to thousands, maybe even a million, in this province. There is a deep, unconditional love for both Martin Mars aircraft in the Port Alberni area and beyond and it is due to their valiant history, their overwhelming power, and their mission to serve and protect the public from the most terrible of dangers. 

There are not many things in the world that evoke such pure joy and feeling of security from such a broad cross-section of society. I would say we really don’t know how lucky we are… but… I think we do, or we wouldn’t all run outside at the first hint of rumble from those 2500 Horsepower Engines.  There are things that governments purchase or do that are for the emotional and social well being of society.  In those respects, and in these very unsettling times, setting aside the facts of their devastating effect on fires, the social value of the Mars program, I believe, has proven once again to be truly immeasurable.

As the climate changes and the weather becomes more uncertain, we will need that proven strength and feeling of comfort more often. I hope that when the numbers — 60-75c per litre dropped and 3 of 4 fires (Nelson, Cowichan and Great Central) stopped in their tracks — are tallied at the end of this season that the efforts and value of the Martin Mars program and her crew shine through enough for the Province to do the right thing.

OK, back to the weather:

Wednesday and Thursday last hot days

If you have been spending a lot of time at the lake, you will likely want to get out there today and/or tomorrow.  The rains this weekend will definitely cool the lake. :) We should get up to 28°C today and a little less Thursday under Sunny skies.

Rain bands shift, focus on South, West and North Island and Vancouver

Between Friday and Tuesday the forecast is for slightly more than 60mm. There may also be windy periods but I will not address those until we are closer and have more precise model output on Friday.

The current picture looks like this:

The first pulse of rain has shifted south a bit and is now focused primarily on the South Island and Vancouver.  I worry a little about this because we have seen this pattern a couple times this summer and the anticipated rain has dried up completely.  It does seem that this one is for real though, so lets hope.

It will start raining in Victoria and Vancouver first around sunrise Friday morning.

image

 

The rain will spread North and West to Port Alberni by afternoon on Friday while it continues unabated in Victoria and Vancouver. Note we are jusy on the north edge so there is a possibility this misses us. Lets hope not.image

 

The rainfall intensifies towards the north through the afternoon on Friday and we should definitely be wet by this time while southern areas might see their first break.  This, however, is the strongest period of rainfall for Friday.  Total accumulation is predicted around 4mm. Not much, but it is a start.  We need every drop.
image

 

It starts to get more interesting on Saturday when the rain showers are much more disorganized, but widespread. Serious showers occur in the 8-11AM timeframe in our area and in all sectors.image

Things get more purposeful in the evening on Satursday as we see a bigger push from the West delivering a healthy 8mm between 5-8PM. Total accumulation for Saturday (5AM Sat-5AM Sun) is around 20mm. That’s more like it.
image

On Sunday we have more widespread showers again particularly in the afternoon delivering another 15mm or so before clearing for a bit.image

We get another signficant push from the west late Monday night. Perhaps 20mm will fall Monday up to 5AM Tuesday focusing mainly just before midnight.

 

image image

And finally, above we have Tuesday again bringjng showers in the afternoon,  Totals for the day are small and uncertain at this point though. Maybe 8mm at the most which brings us to just under 70mm for the whole affair.

Our normal rainfall amount for August and September is 40 and 60mm respectively.  We could go from “drought” to above normal rainfall for the month in a matter of days. I will not pretend to know whether that truly gets us out of “drought” conditions, or if this is just going to flush straight rough he system and we return to the dry, clear pattern of the past many months. After this storm passes there is 25mm expected to fall between Sept 1-10.

That’s it for now folks, have a great Wednesday!