Thursday, December 29, 2011

Clippers and cold

There will be a one-two punch of clippers.   The first one will mostly pass us to the south and give us a dusting tomorrow.   The second on Saturday may be a bit messy with a possible freezing rain and snow.    Following this second clipper there will be a brief warm up, where temps will pop above for a half a day before a cold front comes crashing through on Sunday that will bring true Arctic air.   Be prepared for a true cold snap for a few days next week, i.e. a few days like today.

Tuesday, December 27, 2011


As of 9:45 PM, it's raining.   There was a promising start with a quick inch of snow in the space of an hour but it then changed over to rain, and hasn't stopped.    It'd better change back or I'll make the bellow of the bitterly bummed out.

Monday, December 26, 2011

Tomorrow and the weekend

Looks like the models have shifted west as hoped and we're expecting a thump of snow tomorrow, starting tomorrow morning in southern Ontario and in the afternoon in Ottawa, intensifying as it comes.   It will reach peak intensity overnight Tuesday so we will wake up on Wednesday to a nice 6-12" layer of snow.   Look for snow amounts on the Env. Can . afternoon forecast (3:30PM) to go up (currently a measly 5cm) as their latest model output has finally shifted the storm west.   

For the weekend, there's looks to be a clipper coming through that'll give us another few cms.

Update:  5:30PM Monday.  Storm watch from Env. Canada:

Ottawa North - Kanata - Orléans
3:14 PM EST Monday 26 December 2011
Winter storm watch for
Ottawa North - Kanata - Orléans issued

..Potential for heavy wet snowfall in excess of 15 cm during Tuesday night..

A developing low over the southern states will track northeast along the Appalachians Tuesday and intensify as it tracks into Southern Quebec on Tuesday night. In advance of this system, precipitation mainly in the form of light rain, will spread into the watch area Tuesday afternoon. As the low intensifies the rain will change into heavy wet snow during Tuesday evening. Before the snow ends Wednesday morning, total snowfall amounts in excess of 15 cm are possible with the highest amounts expected closer to the Quebec border.

In addition, as the low moves into Quebec a sharp Arctic cold front will cross the area overnight Tuesday into Wednesday morning. The much colder air behind the front means that temperatures will drop sharply from near zero to well below freezing in a matter of hours. While this may result in some slippery surfaces it is unlikely that widespread flash freeze conditions will occur as too much snow will have fallen. Either way, the combination of the snowfall and plummeting temperatures will make for a difficult Wednesday morning commute.

Saturday, December 24, 2011

This Coming week

We'll get a dusting tomorrow afternoon/evening.

All the models are in general agreement about a storm on Tuesday.   I think this is a mostly snow event with accumulation of 10 cm or so.   

There's also a system next week but some disagreement on the track.

Merry Christmas all.

Update: late Christmas Eve.   The latest models have the Tuesday system pushed south and east.  Ahhh...  Here's hoping for an Westward correction.

Thursday, December 22, 2011

Not much happening.

Yeah, about that Christmas storm, it's not happening.   Both the Canadian and the Euro fell off the wagon in yesterday's run.   The problem essentially is that storm energy in the northern jet stream isn't phasing (joining) with energy in the southern jet stream to create a bigger/potent storm.   So all you're left with is two systems that are a whole lotta nothing, just meh.

And I am not seeing anything of note for a while.   We may get a little dusting tomorrow as a meh system passes to the south and another dusting on Sunday from a meh system passing to the north.   The Euro is trying to phase something for the New Years weekend but we'll see.

I had a quick look (don't have time for an extensive look) at past years with similar atmospheric and La Nina conditions.   I was able to find a year with similar Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and La Nina conditions.   And I couldn't find one that was real close.   The closest would be the 92/93 and 94/95 winters but they were neutral to El Nino years.   Both of those winters had mild starts in the east side of North America to January.   Then February was brutally cold.    I'm not saying that will happen given the remaining differences but it's a possibility.

Wednesday, December 21, 2011

The ice rain

It started about 11 AM this morning in Bells Corners.    There was about a 1/8 to 1/4" accumulated ice as had Barrhaven when I came home.   I also heard Stittsville had significant accumulations.

I think it was a good call cancelling school this morning.

Welcome to Winter

Astromonically speaking, we will enter the Winter season tonight as the Winter Solstice begins at 12:30 AM.   So there is a lot of winter yet so don't despair.

Latest warning

Ottawa North - Kanata - Orléans
4:44 AM EST Wednesday 21 December 2011
Freezing rain warning for
Ottawa North - Kanata - Orléans continued

Freezing rain beginning later this morning.

A low pressure system originating in Texas is forecast to track over Lake Ontario this evening. Precipitation ahead of this low has spread into Southern Ontario and will reach the National Capital Region by noon.

The precipitation will encounter colder air in Eastern Ontario and will likely begin as snow or freezing rain. The precipitation is expected to change over to rain after a few hours over regions near the Kawarthas and Haliburton Highlands. However regions near the Ottawa River could experience an extended period of freezing rain of 6 hours or more.

Freezing rain amounts will likely be in the 5 to 10 millimetre range. The precipitation is expected to taper off in Eastern Ontario late this evening.

Tuesday, December 20, 2011


Update: an non-Quicktime version:

This week again

I waited to post until all the models output their 12Z runs.
First, later tomorrow: it is looking like Env. Can. is right on this one, that'll be a mix of freezing rain and snow.   Hopefully more snow than rain that'll stick around.  
Weekend storm:  the GFS has fallen off the bandwagon for the Christmas storm.  However, the Euro is still showing, even strengthening, the storm in the US NE and Maritimes.   The Euro is supported by the Canadian (which makes me nervous) and by the Japanese somewhat.   If the Euro is correct, then we won't get much of anything in Ottawa.   Hopefully it's right about the storm but shifts to the left (of the map) :).

So there is a model war going on between two of the more accurate mid-range models...  Let's see who wins.

Monday, December 19, 2011

This week

To date this winter has been so much of a non-winter that even my wife is complaining about the lack of snow.  She figured moving to Ottawa was a guarantee to have a white Christmas.   Unfortunately there are no guarantees with the weather.  

Take the current situation in the SW US.   They having a blizzard right now.   Whodathunk parts of New Mexico, Texas, Kansas, Oklahoma and Colorado would have tonnes more snow than we?  But that's this situation.

But we may be able to pull a white Christmas out of the hat.   The storm that is currently bashing the SW US will cut to the Great Lakes but weakening as it comes.   I think we will get more snow than rain but not much of either.   A system has appeared on the models for this weekend (Christmas Eve/Day).   The Euro/DGEX have it going south and east of so that NE US and the Maritimes get a good dumping.  But the GFS has us getting a piece of the storm Christmas Eve.

To be sure, I'll be watching the each model outputs with baited breath.   Most models give two runs per day, some give four.

Wednesday, December 14, 2011

Next week

It's looking like we'll get some snow next week in batches.   The first two systems have fair agreement among the models:  a clipper passing to the north on Monday will likely give us some snow showers.   A system passing to our south on Wednesday will likely have precipitation that will hit us in the form of snow.   This system on Friday/Saturday is under debate.   The GFS backed off a Christmas Eve storm (see yesterday's post) but the Euro is now bullish for something fairly significant happening on the Friday.

One thing's fairly certain is that we'll some snow at some point which is more than we can say for this winter so far.

Monday, December 12, 2011

The result of Durban

Long and short, the agreement they came to agree to talk again and try to come to an agreement by 2015 that comes into effect in 2020 that will have less stringent requirements that Kyoto had.

All I know is, if Greenpeace is unhappy, I am happy.

As an aside, I have a hunch that 2020 date was chosen since are more than a few CAGW skeptical scientists who think we will have a 20 year plus negative trend in Global temperatures by that point, which I hope will be the case.   If so, than the natural vs manmade climate change proportion will be up-ed, defying all current Global Climate Models.

Update:  Interesting analysis of Durban here.

Friday, December 9, 2011

Can we get some winter please?

The arrival of the cold and snow is continually getting delayed and delayed.   In last Friday's post I discussed the NAO and PDO where at that time they were predicted to head towards the neutral and negative state.   And yes they've come down from their lofty heights but not as far down as predicted and, unfortunately for cold and snow lovers in our area, they are currently predicted to do a U-turn right back to significate postive levels.  

So that piddly little snow we had this week, yeah it's going to go melt this coming week as the models have become less enamoured with a trough in the east over the coming week.

Maybe the following week....

Wednesday, December 7, 2011


Remember when Global Warming was going to melt all the Russian permafrost, releasing tonnes of potent GHG methane into the atmosphere making Global Warming worse, melting more permafrost, etc etc?    Well, nevermind.

White Christmas?

My last couple of posts ties into this quite nicely actually.    Everybody is looking at the operational models and not the ensembles which are saying two different things.

I see a white Christmas for 99% of Canada.  Besides, that is already the case:

Storms and rumours of storms

Firstly, the disparity between the operation run and ensemble run of the GFS continues today.  

However, to the more interesting (;)) stuff... A couple bigger storms have appeared on the horizon.. The first one is next weekend which may lay down a signficant snow:

Then there is another one....for Christmas Eve?   Now that would be fun, wouldn't it?

Tuesday, December 6, 2011


I've been just comparing the 6Z operational run of the GFS model for day 6-10 500 mb height anomolies (essentially where the ridges and troughs lie) with the GFS ensemble (same model, slightly different input parameters) mean for day 6-10 500mb height anomolies and they are the polar opposite:

GFS operational 6Z run:
GFS Ensemble 6Z run:


The operational run would indicate a warm up for us and the ensemble would indicate cooler weather for us.   I am leaning towards the ensemble for two reasons.  First the ensemble mean is a better indicator of future trends than a single run of the GFS.  Secondly, there is support for the ensemble from other models:


Canadian Ensemble (Day 8):

So I still see support that we won't see any major thaws for a while.   Whether snow is included is unknown.

Is that all there is?

That's pretty much what my six year old son said this morning.   His actual words were "when are we getting a lot of snow?"  Yes, it was somewhat disappointing to see the accumulation amounts this morning.  However, they were within predicted amounts, just on the low side.   If this system happened just a couple weeks from now, there would have been a LOT more snow.   But it wasn't.

So when are we getting a lot of snow?   Hmmm...I don't know but I know we miss it regularly:

It's turned to snow.

As of midnight, the rain has turned over to snow.  It's not sticking yet as the surface temperature is still above 0 C but that'll change in the next hour or two.   We should wake up to snow covered ground.

Monday, December 5, 2011

Is this it?

Could tonight's snow be the one that sticks around indefinitely?    Could be.   I am not seeing any major thaw like temperatures over the next couple weeks.   By that time, the "normal" temperatures are low enough that any above normal period will still be below freezing..hopefully. :)

Snow very likely

It's been interesting to watch the Env. Can. forecast go from no mention of snow before yesterday to yesterday's forecast of 2cm of snow for tonight to today's forecast of 2-4+ cms for tonight into tomorrow.

However there is a chance that we could still miss out.   The NAM model is keeping most of the snow south of the Ottawa region so that Kemptville would get more than us.

Fingers crossed.

PS.  note that my Nov. 28th post made the call for snow.

Friday, December 2, 2011

When's the cold and snow coming?

Yeah, good question.  A couple weeks ago, I would have said now.   But things haven't panned out that way.   A couple of atmospheric conditions/indexes, the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) are stubbornly remaining positive.   As a result, very little Arctic air is allowed to remain in the Eastern North America region and no storms of note are coming up the eastern seaboard.

But there is hope.   As indicated in the links above, these indices are predicted to approach negative territory in a week or so.   So I think the seasonal temperatures will come next week.  As for snow, that'll depend on the storm track and the arrival of cold.   So it's looking like late Monday/Tuesday where we may get some snow...but not a lot.

For readers from Southern Ontario (I know you're out there) in the typical snow belt regions, look for significant Lake-Effect-Snow events happening late next week.