View Full Version : Low Pressure Nov 16/17 - SRN ON

11-14-2010, 11:55 AM
A moderate low looks to develop in about 40 hours off the coast of Louisiana that will progress northeast across the Tennessee and Ohio Valley's. By about 7am on the 17th the GFS puts the low over southwest Ontario with pressure at 992mb. By 8pm on the 17th the centre of the low then exits Ontario and begins to dissipate over the St. Lawrence Valley.

Moist air from the Gulf of Mexico will be drawn northeastward with the low, so most of the precip will probably remain as rain, but some areas, especially early morning on the 17th, could see their first measurable snow. Daytime temps look to be within the range of 40F-50F so snow is definitely out of the question when the sun is up. Overnight temps for most areas look to be just above freezing, if not just below in some areas. Ripe temperature for snow showers!

Winds also look to be an issue with sustained winds forecast to be about 30kmh most of the day for inland areas of southern Ontario, and as high as 75kmh along the shorelines of Lake Erie and Lake Ontario. Extreme southwest Ontario looks to escape the worst of the winds, but the shores of Lake Huron could peak at 75kmh, too, around Goderich northward.

It may not be much, but it's something!


*EDIT: Forgot to mention snowsqualls look to develop on the 18th after the low passes through.

11-14-2010, 07:06 PM
18z GFS has decreased temperatures to just above freezing for most of the day on Wednesday. Mixed precip looks likely this run. If it's going to snow then it'd be nice if it would accumulate :whistling:

Pressure remains at 992mb, and speed remains relatively the same. The centre of the low and the area of the lowest pressure looks poised to traverse over a line from Cleveland to Hamilton to Kingston to Montreal.

The wind fields over the lakes have decreased to about 60km, but Lake Ontario remains at 75kmh out on the water. Over land, the wind field has increased and many areas are now in a 50-60kmh area. Could be a decent wind event for some of us, especially east of Stratford, and for much of the GTA.

Also, judging by forecast parameters, isolated thundershowers, possibly even thundersnow, look possible!!

11-16-2010, 01:46 PM
Well, looks like it'll be mainly a rain and wind event. Hopefully someone will see some flakes today/tonight! Or even a crack of thunder...


11-16-2010, 02:42 PM
This is a very potent low pressure. The center of circulation is very defined. Lots of rain and mabye some thunder for us. who knows

11-16-2010, 02:53 PM
This is a very potent low pressure. The center of circulation is very defined. Lots of rain and mabye some thunder for us. who knows

It's deepening as pressure has dropped from 997mb to 995mb. I'm sad I have to work... I'll probably miss any thunder that we may have. :whistling:

11-16-2010, 03:32 PM
pressure down to 993 now

11-16-2010, 05:39 PM
Last i checked it was 992

11-17-2010, 12:23 PM
I ended up with 22mm of rain here. The wind was really strong this morning, but it has since tapered off. Next... :whistling:

11-17-2010, 04:56 PM
I got 34mm here on the mountain. Winds were strong from about 830 until 3

Hurricane Mike
11-17-2010, 10:23 PM
Hey folks,
I found the below on Environment Canada's website regarding rainfall totals from this storm. Enjoy!

A strong low pressure system from Texas tracked northeast across
Southern Ontario and brought a large area of rain to the district
beginning yesterday afternoon and continuing overnight into early
this morning. The heaviest rain was in the Trenton to Kingston area
of Eastern Ontario culminating in a report of 55.7 mm of rain at

Rainfall amounts did vary quite a bit across the district. With
Some of the locally higher amounts due to isolated embedded
thunderstorms which were observed in parts of Southwestern Ontario
and the greater Toronto area.

Strong winds developed in the wake of the system with a gust of 91
km/h being reported at Point Petre this afternoon. This spawned a
wind warning which will be ended by this evening as winds diminish.

Reports received as of 4.30 PM EST are in the table below.

Location rainfall amount

Windsor 23.2
Sarnia 24.9
Harrow 22.6
Blenheim 43.0
Ridgetown 12.6
Delhi 18.6
London 15.0
Goderich 21.4
Mount Forest 14.8
Wiarton 28.8
Elora 15.3
Kitchener 19.9
Univ of Waterloo 21.5
Hamilton mt Hope 22.8
Hamilton botanical gardens 34.5
Vineland 24.4
Port Weller 17.5
Fort Erie 20.0
Toronto Pearson airport 27.8
Toronto North York 30.4
Toronto city 31.4
Toronto Island 31.6
Toronto the beaches 27.5
Toronto East York 32.8
Oshawa 37.2
Buttonville airport 23.2
Vaughan 31.0
Barrie 24.5
Collingwood 19.8
Orillia 24.2
Coldwater 22.0
Muskoka 18.4
Parry Sound 21.0
Peterborough 24.4
Tapley (sw Peterborough) 31.1
Port Hope 34.8
Trenton 44.8
Brighton 25.0
Point Petre 40.2
Kaladar 32.2
Kingston 55.5
Brockville 28.8
Ottawa airport 29.2
Ottawa city 28.3
Kemptville 30.3
Cornwall 22.5
Drummond centre (ne Perth) 38.2
Bancroft 25.0
Petawawa 16.5
Balaclava (sw Renfrew) 32.6
Algonquin Park 17.7