March 30-31 Eastern Canada Storm, Cogitation: Short Range [1-3 days out] forecasts Options

[gschep]

Will I need the plows for this or just salt?

Plow?!?!?! Burn it off!!!

[Torontoweather]

It may seem strange to even be thinking about the potential for snow to fall after the intensity of warm air we saw earlier in the month, but this is the weather for you!
This is a particularly difficult situation to assess given the fact that ground temperatures are warm, however the precipitation/snow could be falling at a fairly heavy rate which would greatly aid in the accumulation process, as well as evaporational cooling.
However, I still think that air temperatures 2M above the ground (know as surface temperatures) will be too warm during the day, and ground temperatures will be too warm for anything significant to accumulate. However, this isn't to say that tomorrow evening's and Saturday morning's driving will be easy. If the snow falls at some of the rates currently anticipated by some models, visibility could be greatly reduced Friday evening and into the overnight period into early Saturday. I expect the heaviest precipitation to fall between 5-10 p.m. Friday evening. I emphasize precipitation, as I am still uncertain as to which areas will receive snow, which rain, which ice pellets and which a wonderful mixture.
Unfortunately, two of the short-range higher resolution numerical models are currently down/not updating which would be very useful right now in forecasting, but I'll do my best.
Forecast:
I expect precipitation to start as rain in most places in southern Ontario tomorrow afternoon, but temperatures should begin to drop fairly significant once precipitation starts. It should transition over to snow first in the Kitchener-Waterloo region, and then in the GTA and Toronto (north of downtown). Wet snow should then continue through the evening Friday, and taper off early morning Saturday. Kingston will likely not receive much in the way of precipitation if anything at all, and places like London, Sarnia and Windsor will likely receive mostly rain. I expect a bit more of a mix possibly in the Niagara region, particularly southern portions, after the initial wave of rain.
Amounts:
Toronto downtown: 2-5cm fall (trace-3cm accumulates)
Toronto north of downtown(about St.Clair I'd say for this one) to Steeles: 4-8cm fall (2-5cm accumulates)
Hamilton: 5-10cm fall (3-6cm accumulates)
Niagara: 4-8cm fall (2-5cm accumulates)
Burlington: 3-8cm fall ( 2-5cm accumulates)
Newmarket: 5-10cm fall (3-8cm accumulates)'
Barrie: 6-12cm fall (4-8cm accumulates)

Depending on how things change over the next 12 hours or so, I may update this forecast sometime tomorrow afternoon.
Otherwise, drive safely everyone!

[Torontoweather]

00z NAM:
What falls:


What sticks:

[gurtej101]

that doesn't look that bad for bramtpon , i guess im neither sad or happy

[weatherman 23]

Nice write-up Torontoweather!

This post has been edited by weatherman 23: Mar 29 2012, 10:11 PM

[bigmt]

06z NAM @ hour 21:

 nam_namer_021_850_temp_mslp_precip.gif ( 60.57K ) Number of downloads: 1


Total snowfall @ hour 26:

 USA_ASNOWPER_sfc_026.gif ( 24.69K ) Number of downloads: 6


07z HRRR composite reflectivity @ hour 15:

 cref_t7sfc_f15.png ( 106.17K ) Number of downloads: 0


08z RUC composite reflectivity @ hour 16:

 cref_t7sfc_f16.png ( 76.98K ) Number of downloads: 4

[bigmt]

12z NAM @ hour 15:

 nam_namer_015_850_temp_mslp_precip.gif ( 60.61K ) Number of downloads: 1


Precip type @ hour 13:

 USA_PTYPE_sfc_013.gif ( 17.26K ) Number of downloads: 2


Total snowfall @ hour 20:

 USA_ASNOWPER_sfc_020.gif ( 22.76K ) Number of downloads: 4

[tml78]

So is this system still a 1 cm event for the GTA or can we still expect 2-4 cm from this system??

[TriC]

Looking forwords to some thunderstorms in Southwestern ontario out of this system. lots of Lightning Activity moving in..

[JJ Snowlover]

What's with the HRRR and the RUC coming so close to E.Ont? Stay away, please

[bigmt]

USA radar coverage:

 radusa.jpg ( 433.05K ) Number of downloads: 1


Ontario radar:

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Satellite imagery:

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14z HRRR precip type @ hour 10:

 ptyp_t7sfc_f10.png ( 109.29K ) Number of downloads: 1


Accumulated snowfall @ hour 15:

 acsnw_t7sfc_f15.png ( 85.63K ) Number of downloads: 1

[bigmt]

So is this system still a 1 cm event for the GTA or can we still expect 2-4 cm from this system??

I'd expect a few cm's, maybe 5 or so for some sections but it will be tough (not impossible if it comes down quickly) to get it to accumulate.

Looking forwords to some thunderstorms in Southwestern ontario out of this system. lots of Lightning Activity moving in..

Yeah, you're right.

 lit.jpg ( 80.9K ) Number of downloads: 0

[an uncanny otter]

Wow, we are getting the sleet storm from heck right now. Heavy sleet and ice pellets for almost an hour now. 1 cm of accumulation. Thunder and lightning as well. This is so bizarre.

[elder05]

Wow, we are getting the sleet storm from heck right now. Heavy sleet and ice pellets for almost an hour now. 1 cm of accumulation. Thunder and lightning as well. This is so bizarre.

bizarre, but sounds awesome! enjoy!!!

[elder05]

I'd expect a few cm's, maybe 5 or so for some sections but it will be tough (not impossible if it comes down quickly) to get it to accumulate.
Yeah, you're right.

i think it should accumulate in many area's because of the intensity. these thunderstorms are moving north into the cold air and quickly turning into snow or sleet.

should be fairly intense in some locales....

[an uncanny otter]

These thunderstorms are really powerful! Frequent lightning and some heavy thunder with torrential rains. I'd say these are even approaching severe limits down here judging by how hard the rain is coming down.

[bigmt]

http://www.weatheroffice.gc.ca/warnings/SW..._e.html?prov=on

WOCN11 CWTO 301930
Special weather statement
Updated by Environment Canada
At 3:30 PM EDT Friday 30 March 2012.
---------------------------------------------------------------------
Special weather statement for:
City of Toronto
Windsor - Essex - Chatham-Kent
Sarnia - Lambton
Elgin
London - Middlesex
Simcoe - Delhi - Norfolk
Dunnville - Caledonia - Haldimand
Oxford - Brant
Niagara
City of Hamilton
Halton - Peel
York - Durham
Huron - Perth
Waterloo - Wellington
Dufferin - Innisfil
Grey - Bruce
Barrie - Orillia - Midland.

A mixed bag of precipitation for Southern Ontario.


---------------------------------------------------------------------
==discussion==
A disturbance from the American Midwest will track just south of Lake
Erie this evening giving a variety of inclement weather to Southern
Ontario.

A light snowfall is expected north of a line from Central Lake Huron
to Toronto with a mixed bag of rain and snow to the south.
Over Extreme Southwestern Ontario showers and thunderstorms,
accompanied by small hail, will taper off this evening.

In the greater Toronto area wet snow is expected to develop early
this evening then end after midnight. Northern portions of the
Toronto region can expect 2 to 4 cm, with little or no snow
accumulation expected over southern sections of the city.

Late this evening there will be the risk for some freezing rain in a
swath from Southern Lake Huron to Niagara, especially over higher
elevations.

Locally hazardous road conditions can be expected in the
precipitation this evening as temperatures fall to near
Or just below freezing in many locales. In addition, poor
visibilities can be expected in bursts of heavier snow.

18z NAM total snowfall @ hour 18:

 USA_ASNOWPER_sfc_018.gif ( 20.81K ) Number of downloads: 2

[blizzardOf96]

When will the snow start in the GTA, I see a donut hole on the radar is that a bad sign?

[stormchaser22]

Ice pellets beginning to fall here in Beeton.

[bigmt]

When will the snow start in the GTA, I see a donut hole on the radar is that a bad sign?

Shouldn't be long now, within the next hour or so. Could be a close call for mixing depending on exact location.