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

[bigmt]

Skepticism is warranted but there's the possibility of accumulating snow through portions of Ontario and into Quebec as precip from a possible storm backs in from the east into (cold enough?) air. There's still considerable uncertainty as to what exactly unfolds but here's the latest model info which is pretty interesting for the moment. Will keep updating.

06z GFS @ hour 87:

 gfs_namer_084_850_temp_mslp_precip.gif ( 59.97K ) Number of downloads: 5


06z GFS 24-hour snowfall @ hour 96:

 USA_ASNOW24_sfc_096.gif ( 22.07K ) Number of downloads: 5


06z NAM precip type @ hour 84:

 USA_PTYPE_sfc_084.gif ( 18.13K ) Number of downloads: 1


24-hour snowfall @ hour 84:

 USA_ASNOW24_sfc_084.gif ( 20K ) Number of downloads: 1


00z ECMWF @ hour 96:

 00zeuro850mbTSLPUS096.gif ( 75.59K ) Number of downloads: 2


00z ECMWF snowfall @ hour 87:

 eurosnow87.jpg ( 323.15K ) Number of downloads: 2


00z CMC precip type @ hour 88:

 I_nw_g1_EST_2012042000_088.png ( 42.91K ) Number of downloads: 2


This post has been edited by bigmt: Apr 22 2012, 05:28 PM

[travis3000]

EURO and GFS show snow for my area, NAM and Canadian show it too far east. Time will tell!

[JJ Snowlover]

Oh brother that much snow is possible, I thought maybe 1 - 2 cms. I hope that GFS is in winter wonderland mode again, anything over 11.5 cms would beat our biggest one day snow totals for this winter...

Can you imagine if that happens, most snow from Winter 2012 in Ottawa comes on April 23rd...

[bigmt]

Can you imagine if that happens, most snow from Winter 2012 in Ottawa comes on April 23rd...

A few of the previous years which had impressive early-season heat also featured a late snowfall. Anecdotal evidence isn't worth a whole lot it's still interesting to consider.

Here's images from the updated 12z NAM.

Hour 81:

 nam_namer_081_850_temp_mslp_precip.gif ( 60.21K ) Number of downloads: 2


24-hour snowfall @ hour 84:

 USA_ASNOW24_sfc_084.gif ( 21.7K ) Number of downloads: 7


The NAM's range extends only to 84 hours out so the storm wouldn't be over at this point either.

[weatherman 23]

Just simply amazing!

[TheFrenchman]

Hey guys,

do you think this storm is the signal of a pattern change? a new pattern setting up for the rest of spring and summer ? I mean more of a trough in the eastern part ?

It's really interesting to follow this storm, (why not this past winter!!!) but it's so depressing to look at the 7-days forecast here..... no sun at all and rain everyday!

My feeling is that it will be very long for the next nice stretch of good weather... :S


Bigmt: how about the winds with this storm for Quebec city? strong easterly winds? or is the storm too far south of us ??

[bigmt]

12z GFS @ hour 81:

 gfs_namer_081_850_temp_mslp_precip.gif ( 60.79K ) Number of downloads: 2


48-hour snowfall @ hour 105:

 USA_ASNOW48_sfc_105.gif ( 22.92K ) Number of downloads: 3

Hey guys,

do you think this storm is the signal of a pattern change? a new pattern setting up for the rest of spring and summer ? I mean more of a trough in the eastern part ?

That's an excellent question which I wish I had a reliable answer for but it's difficult to make definitive statements about the whole summer at this early stage. The amplificiation of the pattern in the timeframe of this storm is markedly different from what's been dominant over the past months.

12z GFS 500mb anomalies for hour 96:

 USA_GPA_500mb_096.gif ( 26.31K ) Number of downloads: 1


The 00z Euro ensembles from last night still have lower heights for a large portion of Eastern Canada through days 6-10:

 00zECMWFENS6_10day500mbHeightAnomalyNA.gif ( 27.99K ) Number of downloads: 1


Of course I'll be watching intently along with everyone as the summer months arrive to see what sort of pattern emerges. The CFS v2 has been recently hinting at cooler anomalies around the Hudson Bay region for next winter FWIW but that's even farther out to put any stock into. Would make some degree of sense given the current expectations for a weak El Nino.

It's really interesting to follow this storm, (why not this past winter!!!) but it's so depressing to look at the 7-days forecast here..... no sun at all and rain everyday!

My feeling is that it will be very long for the next nice stretch of good weather... :S

Bigmt: how about the winds with this storm for Quebec city? strong easterly winds? or is the storm too far south of us ??

Yep, based on the current interpretation of the storm some blustery winds from the east for you as it intensifies moving into New York state and Eastern Ontario.

[trancen]

This p*bleep*ing match between Henry and Joe on twitter is PRICELESS.. Best laugh I have had about weather predictions ..

[bigmt]

Here's some selected shots from the 12z Euro run.

Hour 72:

 f72.gif ( 95.65K ) Number of downloads: 1


 12zeuro850mbTSLPUS072.gif ( 71.33K ) Number of downloads: 1


Hour 96:

 f96.gif ( 97.05K ) Number of downloads: 0


 12zeuro850mbTSLPUS096.gif ( 69.59K ) Number of downloads: 1


Snowfall @ hour 75:

 eurosnow75.jpg ( 386.67K ) Number of downloads: 1


Snowfall @ hour 84:

 eurosnow84.jpg ( 401.57K ) Number of downloads: 1


Hour 90:

 eurosnow90.jpg ( 388.8K ) Number of downloads: 3

[bigmt]

This p*bleep*ing match between Henry and Joe on twitter is PRICELESS.. Best laugh I have had about weather predictions ..

Not sure if I wanna insert my opinion between them (or if it means much of anything), but since you mentioned it...

Like many things in life the actual outcome probably lies somewhere in between the extremes of shutting down areas of Pennsylvania and nothing at all happening. It's more than a bit ironic to have Henry acting as the conservative 'voice of reason' who implores caution when looking at model information based off of his track record but in another sense it's also refreshing to see him realizing buying into model hype is perilous. A spirited debate without mud-slinging never hurt anyone lol.

[JJ Snowlover]

TWN has updating to 2 - 4 cms for Monday, EC sticking with a temp of +2 and snow or rain.

Either way this will feel like a winter day, just when the leafs start coming out

[bigmt]

HPC snowfall (and icing) probability 4-panel map for day 3, extending throughout Quebec and Ontario now:

 day3_composite.gif ( 39.88K ) Number of downloads: 13


18z NAM @ hour 75:

 nam_namer_075_850_temp_mslp_precip.gif ( 60.81K ) Number of downloads: 2


Hour 84:

 nam_namer_084_850_temp_mslp_precip.gif ( 62.72K ) Number of downloads: 2


24-hour snowfall @ hour 84:

 USA_ASNOW24_sfc_084.gif ( 22.39K ) Number of downloads: 10

[EOsnowmom]

So, it looks like Sunday would be a bad day to plan a trip to town? LOL

[bigmt]

So, it looks like Sunday would be a bad day to plan a trip to town? LOL

Sunday looks alright but Monday doesn't seem as if it will be very nice.

18z GFS @ hour 84:

 gfs_namer_084_850_temp_mslp_precip.gif ( 63.24K ) Number of downloads: 3


48-hour snowfall @ hour 105:

 USA_ASNOW48_sfc_105.gif ( 22.98K ) Number of downloads: 4

[an uncanny otter]

Remember that even if the models show 20 cm of snow falling, that doesn't mean there will be 20 cm of snow on the ground. If snow does fall it will be a heavy, wet snow that has a hard time sticking on roads. We had 25 cm of snow on April 24, 2005, but the depth was never more than 15 cm.

A very interesting set-up, especially so late in the season. Definitely possible that it can happen but considering that all of these "big storms" aimed at Toronto have fallen apart at the last second, I would restrain my excitement until it actually starts to fall.

It would be hilarious for Toronto's biggest storm of the season to happen in late April. Could it be enough to spare it from setting another all-time low record?

This post has been edited by an uncanny otter: Apr 20 2012, 07:36 PM

[travis3000]

I just cannot fathom a snowfall right now. We've already had like 10 days over 20C here! I feel like winter was months and months ago! I won't believe a thing until my grass turns white.

[Removed_Member_thehammer_*]

no chance this will happen in the Golden Horseshoe...further north, or in the mountains of PA/NY it very well could though. It's been over 20 here all week. LOL

[bigmt]

06z GFS @ hour 66:

 gfs_namer_066_850_temp_mslp_precip.gif ( 62.35K ) Number of downloads: 2


48-hour snowfall @ hour 90:

 USA_ASNOW48_sfc_090.gif ( 23.1K ) Number of downloads: 2


06z NAM @ hour 66:

 nam_namer_066_850_temp_mslp_precip.gif ( 62.89K ) Number of downloads: 2


24-hour snowfall @ hour 84:

 USA_ASNOW24_sfc_084.gif ( 21.43K ) Number of downloads: 4


00z ECMWF @ hour 72:

 00zeuro850mbTSLPUS072.gif ( 76.34K ) Number of downloads: 0


Snowfall @ hour 63:

 eurosnow63.jpg ( 431.09K ) Number of downloads: 0


00z CMC @ hour 77:

 I_nw_g1_EST_2012042100_077.png ( 45.21K ) Number of downloads: 2


HPC forecast chart for Monday:

 noaad3.gif ( 168.02K ) Number of downloads: 2


4-panel snowfall map for day 3:

 day3_composite.gif ( 39.85K ) Number of downloads: 8


The track of the LP center looks as if it may end up being too close at hand for portions of E ON and S QUE to produce much in the way of straight snowfall.

[Ryan45]

Lol go figure eh??? La nina all winter and we get squat... it turns to el nino last week and we get a snowstorm...

[bigmt]

TWN's take on the storm.

http://t.co/2OEol0Fq

 SpringStorm_April20_art_7_7663.jpg ( 27.21K ) Number of downloads: 0

"A strong area of low pressure will develop along the U.S. eastern seaboard Sunday into Monday," says Chris Scott, a meteorologist at The Weather Network. "The primary interest with this storm is the possibility for late-season wet snow west of the track."

The system could affect larger population centres in southern Quebec and Ontario.

Temperatures will be above freezing in most areas, which means that any wet snow that does fall will have a difficult time sticking, especially to roadways.

Still, some slushy accumulations are possible. Wet snow in excess of 10 cm is possible over higher terrain between Toronto and Montreal.

East of the low track, 25-50 mm of rain is possible in southern Quebec into New Brunswick. Areas along and west of the track (for example, eastern Ontario through Montreal) will likely see a combination of rain and snow, with a melted equivalent of 25-50 mm.

Winds may gust in excess of 70 km/h. The primary impact would be wind in combination with any wet snow that may fall across eastern Ontario, reducing visibility.

Henry's vision of events.

http://www.accuweather.com/en/weather-blog...re-storms/64309

 590x451_04211106_severe1.png ( 200.78K ) Number of downloads: 0

The cold conveyor belt snow will develop in West Virginia Sunday night and Move into western PA/NY and Ontario Monday. The snow will last about 8 hours and will depend on elevation, time of day, intensity and surface temps. Higher elevations have the best chance of seeing 6 inches or more of snow, but I think in general, the valley locations will 1-3 inches of snow. During the day Monday, the snow may have a hard time accumulating during the day Monday due to the high sun angle. For the snow to accumulate, the snow must come down at the rate of an inch per hour.