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Canada Winter 2015-2016 discussion


Ottawa Blizzard

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8 to as much as 15 cm for toronto and peel areas.  Quick transition through zr and ip to plain rain and drizzle.  

 

20 to 30 cm for Ottawa/Renfrew/Algonquin

 

Any decent icing is relegated to Guelph-east imo.  

 

lol this is new (to me at least). Flatrock, NL? I never even heard of it. I do know it's a long wayz away from BUF.

 

Thanks for your input :)

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Amec Foster Wheeler...combo of contract stuff with terrestrial companies/govt and offshore drilling rigs.

 

Closest EC weather office would be Gander, NL.  There's none in St. John's.

 

Although, I have to say...EC...blah.

 

Agreed with the bolded.

 

Back to the storm...RGEM is really beefed up with the QPF shows widespread 30-40mm across S Ontario. For Toronto, the breakdown is 5-10mm as snow, <5mm as rain, and 15-20mm as ice pellets. I could live with 5-10cm of snow and 5-10cm of ice pellets. Probably too wet though.

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Agreed with the bolded.

Back to the storm...RGEM is really beefed up with the QPF shows widespread 30-40mm across S Ontario. For Toronto, the breakdown is 5-10mm as snow, <5mm as rain, and 15-20mm as ice pellets. I could live with 5-10cm of snow and 5-10cm of ice pellets. Probably too wet though.

Id be surprised to see that much as ice pellets honestly. These tend to thump snow on the edge of the cold dome with strong lift...The high is sliding east with temp nothing to keep the surface from warming aside from in situ.

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Thinking I'll be in for a decent amount of freezing rain in addition to the snow and pellets.

 

Tricky forecast in play, no doubt. Thinking areas west of Toronto will see heaviest accumulations of Freezing Rain (Kitchener-Waterloo, London, Goderich and especially Stratford). I suspect those areas will have more than 0.15" of ZR accretion.

 

Ran BUFKIT for CYKF and the latest NAM shows 4 hours of IP followed by 6 hours of ZR. No snow at all. Ice would be equivalent to over 10-15mm (about a half inch) of precip which would be pretty substantial given the 35kt momentum transfer.

 

I've always found these 4 p-type events kind of cool. There's always a surprise or two in store.

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Id be surprised to see that much as ice pellets honestly. These tend to thump snow on the edge of the cold dome with strong lift...The high is sliding east with temp nothing to keep the surface from warming aside from in situ.

 

Hope so. NAM is indicating all PL, but the thermal profile (per soundings) initially is pretty marginal and could easily be snow. As the WAA strengthens then the depth of the warm layer increases to the point where PL is more likely.

 

Models don't seem to do well at discerning when multiple p-types will be falling at a given location. At least that's the impression I get when looking at p-type maps. Everything's compartmentalized into discrete categories.

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Hope so. NAM is indicating all PL, but the thermal profile (per soundings) initially is pretty marginal and could easily be snow. As the WAA strengthens then the depth of the warm layer increases to the point where PL is more likely.

Models don't seem to do well at discerning when multiple p-types will be falling at a given location. At least that's the impression I get when looking at p-type maps. Everything's compartmentalized into discrete categories.

No youre right ptype stuff is hard. Both because its not always obvious and because of model error when small changes result in big impact outcomes ie zr vs. Ip.

It happened it ottawa this morning. Yesterdays soundings were clearly sleet but warm nose under modeled...and you get zr.

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GFS continues to be our best friend. Seems to evaporatively/dynamically cool us to a predominantly snow event east of the escarpment.

 

Have been a few sneaky, under-forecasted front-end thumps in the past. February 8, 2001 and March 1, 2007 come to mind. Nothing much in the last 7-8 years though from my recollection.

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Thinking I'll be in for a decent amount of freezing rain in addition to the snow and pellets.

 

Tricky forecast in play, no doubt. Thinking areas west of Toronto will see heaviest accumulations of Freezing Rain (Kitchener-Waterloo, London, Goderich and especially Stratford). I suspect those areas will have more than 0.15" of ZR accretion.

 

Ran BUFKIT for CYKF and the latest NAM shows 4 hours of IP followed by 6 hours of ZR. No snow at all. Ice would be equivalent to over 10-15mm (about a half inch) of precip which would be pretty substantial given the 35kt momentum transfer.

 

I've always found these 4 p-type events kind of cool. There's always a surprise or two in store.

 

I agree. Adds a layer of excitement to the whole thing (looking at upsteam obs, checking highway cams to find the transition line, constantly going outside to see if you can hear pinging).

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When taken verbatim, the 0z NAM has little in the way of snow for the GTA. The 700-800mb warm layer looks weak at first but is pretty significant once the main band moves through.

 

850-700mb thicknesses are warm enough to fully melt the precip in the column as sfc temps are flirting with the freezing mark(just above). The saving grace is the cold BL which is probably why p-type algorithms have it as PL before 12z tuesday, instead of RN/ZR.

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Just scanned over hrrr BUFKIT data. The warm layer at ~800mb is >0c at the onslaught of precip and then cools to a snow sounding after a couple of hours. The weird thing is that the t/d spread at 795 mb is 0.6/-31c when light precip starts and becomes 1.3/-10 once the heavy precip moves in. Seems a bit weird. If H8 dew points are that cold(-30c), then it shouldn't be too tough to bulb down to +SN for a while.

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Parents house in Oakville already getting some light (albeit extrememly light) snow falling, lending credence to that lake band on the models.

 

East flow off the lake could help saturate and eat through some of that dry air.

Same thing here in south Mississauga. Just some extremely light snow falling for the last 20 minutes or so. 

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Just took a look at the 19z RAP soundings. Its p-type algorithm is indicating the brunt of the precip in Toronto is going to be in the form of pellets. But when you look at the sounding it has the entire column below freezing up until 4z, when 0.60" of liquid equivalent has fallen.

Means more snow?

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The dirty fantasy with this storm lies in the fact that it's so juicy. All the models are showing around 1" qpf with the front-end thump. So if we can somehow, someway stay predominately snow this has 20cm+ potential. That's not my forecast obviously but it's what the weenie in all of us should be rooting for.

 

uvvs of -20 ubars/s and some elevated CAPE as well. Maybe a rumble of thunder?

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The dirty fantasy with this storm lies in the fact that it's so juicy. All the models are showing around 1" qpf with the front-end thump. So if we can somehow, someway stay predominately snow this has 20cm+ potential. That's not my forecast obviously but it's what the weenie in all of us should be rooting for.

 

uvvs of -20 ubars/s and some elevated CAPE as well. Maybe a rumble of thunder?

Too bad this isn't all snow for us. Areas to the north are going to cash in nicely.

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The dirty fantasy with this storm lies in the fact that it's so juicy. All the models are showing around 1" qpf with the front-end thump. So if we can somehow, someway stay predominately snow this has 20cm+ potential. That's not my forecast obviously but it's what the weenie in all of us should be rooting for.

 

uvvs of -20 ubars/s and some elevated CAPE as well. Maybe a rumble of thunder?

Still think 9 to 12 cm for Peel south to north before changeover.  Not much ip/zr in my estimation.  

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