April 23rd Eastern Canada Storm, Last Minute Forecasts and OBS Options

[travis3000]

This one should be interesting. I am predicting no accumulation in the downtown Toronto area, however northern regions including North Toronto/Bolton/Vaughan/Richmond Hill/Aurora could see 2-5cm actually accumulate making the roads slushy and ground white. Further north and west amounts will go up. Higher terrain like Orangeville north into Shelburne and towards Dundalk could see 8-15cm of heavy wet snow or more from this. In valleys like Alliston/Tottenham/Beeton, amounts will be lower in the 4-8cm range. Barrie should see 5-10cm based on what I'm seeing with more towards cottage country and Algonquin park. Another factor to consider that nobody has mentioned... winds will be howling from the N and NNW Monday into Tuesday. The cold air being pumped from this system will travel over the unfrozen waters of GB leading to a little lake enhancement especially in locales on the Niagara escarpment downwind of GB, locations like Duntroon, Creemore, Collingwood/Blue Mountains, as well as areas just inland of Thornbury/Collingwood. I wouldn't be surprised to see some locales on the Niagara escarpment between Orangeville/Shelburne/Dundalk north to Collingwood pick up 14-18cm out of this. Similar accumulations are possible east of GB further inland.

This post has been edited by travis3000: Apr 22 2012, 09:02 PM

[travis3000]

Here's my map:

Very hard to forecast given ground is already thawed and that warm April sun. Most of this will melt fairly quickly. I still think that some parts of South/Central Ontario will get up to 15cm. GTA looks like rain mixed with wet snow. Up to 5cm on grassy surfaces is possible in northern GTA with more towards the north and west. Terrain plays a huge role, elevation being key.

 storm_april_23rd.jpg ( 233.93K ) Number of downloads: 7

[Torontoweather]

perhaps one of the more/most accurate runs of the NAM yet IMHO:
00z NAM:

[Canuk]

Here's my map:

Very hard to forecast given ground is already thawed and that warm April sun. Most of this will melt fairly quickly. I still think that some parts of South/Central Ontario will get up to 15cm. GTA looks like rain mixed with wet snow. Up to 5cm on grassy surfaces is possible in northern GTA with more towards the north and west. Terrain plays a huge role, elevation being key.

 storm_april_23rd.jpg ( 233.93K ) Number of downloads: 7

Nice Map Travis

[Torontoweather]

23z HRRR beginning to show the transition over to snow around parts of the horseshoe:

[Torontoweather]

This one should be interesting. I am predicting no accumulation in the downtown Toronto area, however northern regions including North Toronto/Bolton/Vaughan/Richmond Hill/Aurora could see 2-5cm actually accumulate making the roads slushy and ground white. Further north and west amounts will go up. Higher terrain like Orangeville north into Shelburne and towards Dundalk could see 8-15cm of heavy wet snow or more from this. In valleys like Alliston/Tottenham/Beeton, amounts will be lower in the 4-8cm range. Barrie should see 5-10cm based on what I'm seeing with more towards cottage country and Algonquin park. Another factor to consider that nobody has mentioned... winds will be howling from the N and NNW Monday into Tuesday. The cold air being pumped from this system will travel over the unfrozen waters of GB leading to a little lake enhancement especially in locales on the Niagara escarpment downwind of GB, locations like Duntroon, Creemore, Collingwood/Blue Mountains, as well as areas just inland of Thornbury/Collingwood. I wouldn't be surprised to see some locales on the Niagara escarpment between Orangeville/Shelburne/Dundalk north to Collingwood pick up 14-18cm out of this. Similar accumulations are possible east of GB further inland.

Here's my map:

Very hard to forecast given ground is already thawed and that warm April sun. Most of this will melt fairly quickly. I still think that some parts of South/Central Ontario will get up to 15cm. GTA looks like rain mixed with wet snow. Up to 5cm on grassy surfaces is possible in northern GTA with more towards the north and west. Terrain plays a huge role, elevation being key.

 storm_april_23rd.jpg ( 233.93K ) Number of downloads: 7

Given current uncertainties, I can't disagree with you my friend. Nice forecast.

[Derek82]

Wind has really picked up in the last hour.It's going to be a nasty rush hour in the morning

[Brett Anderson]

Better late than never.....

Snowfall forecast map....hopefully this is the last one I have to draw this season!

Snowfall forecast map

[Brett Anderson]

Here's my map:

Very hard to forecast given ground is already thawed and that warm April sun. Most of this will melt fairly quickly. I still think that some parts of South/Central Ontario will get up to 15cm. GTA looks like rain mixed with wet snow. Up to 5cm on grassy surfaces is possible in northern GTA with more towards the north and west. Terrain plays a huge role, elevation being key.

 storm_april_23rd.jpg ( 233.93K ) Number of downloads: 7

Nice map Travis.....you obviously took a good deal of time to make that map....I am thinking 2-4 cm on grass in Toronto but roads just wet. More as you go north, but again main roads basically wet thanks to April sun effect.

[gurtej101]

will Brampton pickup any accumulations ?

[tml78]

I got a weird feeling that the GTA will see mostly rain... City news @11 just mentioned that the future radar is now showing more rain then it did before... I hope they are wrong as it would be nice to get one last snow-fall of the season!!!!

[TriC]

Latest NAM has really backed off on the snowfall amounts.

Attached File(s)

 namsnow.gif ( 24.72K ) Number of downloads: 3

 

[gurtej101]

interesting looks like mostly a rain event for the gta now

[JJ Snowlover]

Snowing quite hard currently west of Ottawa, about a dusting to a 1 cm accumulation, temp at 0c with flickering power....ughhh honestly this should have happend in December...

[bigmt]

A picture from this morning, soggy wet snow:

 IMG_0287.JPG ( 254.43K ) Number of downloads: 2


07z HRRR composite reflectivity @ hour 12:

 cref_t7sfc_f12.png ( 125.13K ) Number of downloads: 2


Precip type:

 ptyp_t7sfc_f12.png ( 115.4K ) Number of downloads: 2


Special weather statement from EC.

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

A developing weather system will bring cold temperatures, a mix of
precipitation and strong winds to much of Southern Ontario today.

Precipitation has moved into Eastern Ontario and will spread westward
to reach the Toronto area by dawn and as far west as London by
afternoon. The rain is forecast to quickly change to wet snow as
temperatures fall to just above zero for most locales. For many
regions, the wet snow will persist through tonight and into Tuesday
before gradually tapering off. Over parts of Eastern Ontario,
however, the snow will change back to rain this afternoon or evening,
with some ice pellets possible during the transition.

While significant amounts of snow will fall, it is expected that
actual accumulations on the ground will be limited due to the air
temperatures remaining just above zero, and the warm ground
temperatures at this time of year. The greatest snowfall amounts are
expected over the Dundalk Highlands and over the Haliburton,
Muskoka, and Algonquin regions, where total accumulations in the 10
to 15 cm range are possible by Tuesday morning. Lesser amounts are
expected elsewhere, with only a few slushy centimetres likely for
most regions.

This weather system will also bring in strong northerly winds today,
with gusts up to 70 km/h forecast for most locales. These northerly
winds will keep temperatures in the low single digits, well below the
normal of 12 to 14 at this time of year.

[Ryan45]

Let the games begin!

[bigmt]

The rate & intensity of the snowfall is surprising. Tree limbs are sagging under the weight.

 IMG_0291.JPG ( 152.88K ) Number of downloads: 1


Nobody has been brave enough to tackle the roads as of yet.

 IMG_0293.JPG ( 154.46K ) Number of downloads: 0


Some shots from the 00z Canadian illustrating how it sees the storm unfolding through today and tonight.

 I_nw_r1_EST_2012042300_015.png ( 56.2K ) Number of downloads: 0


 I_nw_r1_EST_2012042300_021.png ( 57.79K ) Number of downloads: 1


 I_nw_r1_EST_2012042300_030.png ( 60.66K ) Number of downloads: 2


Hour 78 of the 06z GFS shows the smaller system moving in from the west later this week:

 gfs_namer_078_850_temp_mslp_precip.gif ( 61.44K ) Number of downloads: 0


The current storm hasn't made a lot of progress at that point, decaying over Hudson Bay.

[EOsnowmom]

We got 5cm (2") down of heavy snow. Still lightly coming down, pretty wet.

Best part is I got my snow day and the kiddies are home!

[winter48]

The rate & intensity of the snowfall is surprising. Tree limbs are sagging under the weight.

 IMG_0291.JPG ( 152.88K ) Number of downloads: 1


Nobody has been brave enough to tackle the roads as of yet.

 IMG_0293.JPG ( 154.46K ) Number of downloads: 0


Some shots from the 00z Canadian illustrating how it sees the storm unfolding through today and tonight.

 I_nw_r1_EST_2012042300_015.png ( 56.2K ) Number of downloads: 0


 I_nw_r1_EST_2012042300_021.png ( 57.79K ) Number of downloads: 1


 I_nw_r1_EST_2012042300_030.png ( 60.66K ) Number of downloads: 2


Hour 78 of the 06z GFS shows the smaller system moving in from the west later this week:

 gfs_namer_078_850_temp_mslp_precip.gif ( 61.44K ) Number of downloads: 0


The current storm hasn't made a lot of progress at that point, decaying over Hudson Bay.

Nice pics bigmt! Any ideas if we will still see snow here in Hamilton/Burlington? Not much is happening yet.

[bigmt]

Nice pics bigmt! Any ideas if we will still see snow here in Hamilton/Burlington? Not much is happening yet.

I think you'll see some flying, but it's an uphill battle to get much in the way of accumulation (outside of higher elevations). A few cm's possibly.