Sunday, 23 December 2012

Major Storm On The Way For Eastern Canada

Winter Storm Forecast Discussion
A major storm is forecast to form across the southern plains states before running northwards along the spine of the appalachians. This major storm is forecast by all the major forecast models including the EC, GFS, NAM and CMC. As this storm propagates northwards enough cold air will be in place across the north to produce a swath of heavy snow across parts of ontario and quebec wednesday night into thursday. The european and canadian models are further east then the NAM and GFS with this storm developing a secondary low off of the east coast earlier in time. This shifts the highest amounts of QPF into the interior northeast and quebec but also allows higher snowfall ratios to develop within these bands. The GFS and NAM are further west, the NAM the most extreme causing more QPF for southern and eastern ontario but lower snowfall ratios as more warm air is pulled northward. In any case a major snowstorm is headed towards southern and eastern ontario as well as quebec on all the models. At the moment i believe that the middle ground is the way to go and i am in line with the GFS on track with a stronger inland low up the apps into ohio and then a secondary off of the east coast near coastal new jersey. The primary low will have plenty of precipitation to work with as it picks up gulf moisture on its way north. An initial band of heavy snow will develop and move into southern ontario wednesday night continuing into thursday morning before tapering off in the afternoon. Eastern ontario and quebec will begin to be effected a little later by the early morning hours thursday into the evening. This storm will be capable of producing a heavy band of snow on the NW side for a 10-14 hour period. QPF amounts of 0.8-1.3" are likely from niagra falls through toronto and hamilton north along the 401 to quebec city. Amounts will decrease as you move west and areas hardest hit include hamilton and niagra, montreal, ottawa and the western shores of lake ontario. This storm will cause major problems to travel on one of the busiest shopping days of the year so motorist are asked to be prepared. Conditions may be even more dire across the ottawa region where the snow depth is already very high as a result of the previous snow storm. Snowfall ratios will range from 10:1 to as high as 20:1 if the euro is correct causing a general 20-30cm swath along the 401 with higher amounts possible. Totals may be enhanced in areas along the south and west shores of lake ontario including Hamilton, niagra, oakvile and toronto due to LES enhancement. This may be caused by an E/ENE wind forecast to develop around the strengthening low pressure area. As a result some areas may be surprised at the heavy snowfall rates as well as higher accumulations. White out conditions are possible under these snowfall bands with blizzard like conditions on the table.

With all these factors on the table here are my preliminary forecast amounts for cities across the area.
Toronto:12-20cm *WSW and lake enhancement possible*
Hamilton/Burligton:15-25cm *WSW and lake enhancements possible*
Ottawa/Gatineau: 5-15cm
Montreal:15-25cm *WSW possible*
Quebec City:8-15cm
Guelph/Kitchener/Waterloo: 10-20cm *WSW possible*
Windsor/Sarnia: 10-20cm
Barrie: 2-8cm
Parry Sound: trace-5cm
Newmarket: 10-20cm *WSW possible*

1 comment:

  1. I'm Hertz from Accuweather, just letting you know I got your most recent message and thanks for sending it. :) I sent a reply which is mainly a question about February unless one of my January interpretations are wrong. It should be relatively short answer so I'd appreciate if you could get to it when possible. :) Thanks!