Environment Canada update, Saturday, Dec, 12, 2010 3:59PM

Special weather statement
Issued by Environment Canada Ontario region. 3:59 PM EST Saturday
11 December 2010.

Special weather statement issued 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
Belleville – Quinte – Northumberland
Kingston – Prince Edward
Peterborough – Kawartha Lakes
Stirling – Tweed – South Frontenac
Bancroft – Bon Echo Park
Brockville – Leeds and Grenville
City of Ottawa
Gatineau
Prescott and Russell
Cornwall – Morrisburg
Smiths Falls – Lanark – Sharbot Lake
Parry Sound – Muskoka
Haliburton
Renfrew – Pembroke – Barry’s Bay
Algonquin
Burk’s Falls – Bayfield Inlet.

Winter storm threatening Sunday into Monday..

A low pressure system over Iowa will track east towards the lower Great Lakes and will intensify into a winter storm by the time it reaches Western New York state by Sunday evening.

Precipitation associated with this system is expected to begin in Southwestern Ontario after midnight tonight.. Reaching the greater Toronto area and Eastern Ontario including the national Capital region by Sunday morning.

There is still some uncertainty with regard to its exact track and the type of precipitation associated over southern and Eastern Ontario as this messy low pressure system gets closer. If the low Pressure centre tracks further north than expected..The rain-snow
boundary will also shift north resulting in very little snow near the lower Great Lakes. However if the storm centre tracks further south Than expected..Heavier snow may become an issue for areas near lakes Erie and Ontario.

Latest indications suggest that in regions south of a line from about Sarnia through Vaughan to Cobourg..Precipitation will likely start Out as wet snow or a wet snow and rain mix..Possibly changing at times to rain Sunday. A changeover to all snow is expected Sunday evening as colder air starts to pump in from the north in the wake of the low. Snowfall accumulations are difficult to forecast at thisTime due to the rain versus snow problem..So a range of a couple cm near the Lake Erie and Lake Ontario shorelines to 10 to 15 cm of the white stuff in areas near the line is possible.

In regions southeast of a line from about Peterborough to Ottawa.. Precipitation will likely begin as snow..Then change to freezing rain Sunday morning or early Sunday afternoon. The precipitation will likely change over to rain Sunday evening in Eastern Ontario before
changing back to snow late in the evening or overnight again due to colder air starting to pump in from the north in the wake of the low. With freezing rain expected to be the main precipitation type, a freezing rain warning has been issued for Eastern Ontario and
snowfall accumulation are expected to be 5 cm or less.

North of a line from about Sarnia through Cobourg then northwest of a Line from Cobourg to Ottawa..Precipitation is expected to be mostly or all in the form of snow with significant amounts of 15 to 25 cm quite likely by Monday morning. A winter storm warning has been
issued for regions near and east of Georgian Bay as a result. As the winter storm moves northeast across Extreme Eastern Ontario into Québec Sunday night into Monday morning,. Strong north to northwest winds will develop in its wake. These winds will usher in much colder air and result in blowing snow in some areas by Monday.
Furthermore..Snow squalls are expected to set up yet again in parts of the snow belts to the lee of Lake Huron AND Georgian Bay. HOWEVER THE EXACT LOCATIONS OF THE SNOW SQUALLS WILL DEPEND ON THE WIND DIRECTION..MAKING LOCATIONS DIFFICULT TO DETERMINE AT THIS TIME. SNOW SQUALLS WILL LIKELY PERSIST THROUGH TUESDAY.

MOTORISTS SHOULD NOTE THAT DRIVING CONDITIONS WILL QUICKLY DETERIORATE ON SUNDAY WITH HAZARDOUS WINTER DRIVING CONDITIONS FROM SNOW AND FREEZING RAIN EXPECTED. BLOWING SNOW AND WHITEOUTS FROM BURSTS OF HEAVY SNOW IN SNOWSQUALLS WILL LIKELY BE ISSUES AGAIN ON MONDAY AND TUESDAY. TRAVEL PLANS SHOULD BE ADJUSTED ACCORDINGLY.

ENVIRONMENT Canada CONTINUES TO CLOSELY MONITOR THIS DEVELOPING SITUATION. PLEASE CONSULT THE FREEZING RAIN AND WINTER STORM WARNING BULLETINS FOR FURTHER INFORMATION.
Big Upcoming Snowstorm for the East?

_______________________

By Meghan Evans, Meteorologist
Dec 5, 2010; 11:35 PM ET

Story has been updated 12/6/2010 2:00 pm….

Monster Storm Closes in on 50 Percent Snow Cover by Christmas

A storm that will take shape by the middle of December will cross the country and could end up developing into a major snowstorm for portions of the mid-Atlantic and New England.

There are different storm track scenarios at this point that mean the difference between mostly rain or a potential blizzard along the Interstate 95 corridor from Washington, D.C., to Boston.

So far, Chief Long Range Forecaster Joe Bastardi has been correct with the Winter Forecast for the Northeast with his prediction that late November to December would be cold and stormy for many.

According to Bastardi, “Repetitive cold waves and the threats of storms will keep hitting parts of the East in the weeks leading up to Christmas.”

“One or two of these storms has the potential to become a major snowstorm for portions of the mid-Atlantic and New England, including the storm that may hit the East from December 12-14.”

Expert Senior Meteorologist Henry Margusity has also been warning about how the cold pattern in the East could soon yield the season’s first major snowstorm.

Scenario One: Major Snowstorm for Interior Northeast

In the first scenario, the storm could cause significant snowfall and wind across portions of the Midwest and the Ohio Valley states, impacting places like St. Louis, Chicago, and Indianapolis.

The storm would then cut across the interior Northeast in the first scenario. Mild air would be drawn into the I-95 corridor, making it a rainstorm for the big Northeast cities.

Meanwhile, the interior Northeast, perhaps from Pittsburgh to Buffalo would get a dumping of heavy, disruptive snow, because this region would lie on the cold, northwestern edge of the storm.

Scenario Two: Major Snowstorm for Interstate 95 Corridor

“If the storm brushes up the Eastern Seaboard, several inches of snow could lead to major travel disruptions in the big cities from Washington, D.C. to Philadelphia and New York City to Boston,” according to AccuWeather.com Expert Senior Meteorologist Carl Erickson.

On top of heavy snowfall, blustery winds would add to this winter storm scenario by causing blowing snow and potential whiteout conditions at times.

Lake-effect snow to the lee of the Great Lakes would be likely to accompany this scenario as well with an arctic blast of air blowing across the relatively mild water of the Great Lakes.

Another Possibility

Erickson points out that there is one other possibility with this storm, stating “One other scenario is that the storm takes shape too far off the coast, which would promote a frigid, dry northwesterly flow of air into the Interstate 95 corridor. If this were to occur, there would be potential for even more heavy lake-effect snow downwind of the Great Lakes.”