Ontario Weather Review - September 2006
Summer has now ended, but two distinct trends continued in September: dry conditions in Northern and Central Ontario and warmer temperatures throughout the northwest part of the province.
The dry conditions experienced through Northern and Central Ontario are part of a continuing trend. Looking back, these areas have generally been recording precipitation levels well below normal since June. For example, Thunder Bay's readings were only 61% of normal, despite an above-average July rainfall. In some cases, such as Kenora and Dryden, below-normal precipitation has been noted since April. Those two locations recorded just 63% of normal, numbers not seen in 30 years. Given these conditions, it is not surprising that so many forest fires are currently being fought in these areas.
Although conditions have now cooled for the province, the monthly mean temperatures were within two degrees of normal across the province.
Severe Weather
September was a relatively quiet month with respect to severe weather in the province.
The month got off to a wet start as the Labour Day weekend saw the remnants of Hurricane Ernesto brush Southern and Eastern Ontario. General rainfall amounts of 20 to 40 millimetres fell across the region. A few locales, including the Ottawa area, received in excess of 50 millimetres of rain.
The 18th tornado of the season occurred in Essex County on September 6, about 20 kilometres south of Windsor near the shores of Lake Erie. The tornado only touched down briefly and did minor damage. It was rated as a Fujita Scale Zero tornado with winds of approximately 100 kilometres per hour.
On September 13, a series of slow-moving and heavy rain-producing thunderstorms over the Newmarket area caused some local flooding. Rainfall amounts during the day were estimated at between 50 and 100 millimetres in that area.
During the morning hours of September 24, a rapidly developing low pressure system moved through Central Ontario. Just to the south of the track of this disturbance, brief but intense gusts of wind of approximately 100 kilometres per hour were reported. The strong winds resulted in downed trees and tree limbs, causing power outages to a number of areas in Cottage Country and Eastern Ontario. In some cases, this again affected areas that had already experienced weather-related power outages from damaging storms this past summer.
Unusual precipitation readings (in millimetres):
| Location |
Precipitation |
Normal |
Difference |
Wettest Since |
| London |
176 |
97.7 |
78.3 |
1996 |
| Ottawa |
159.8 |
85.3 |
74.5 |
1986 |
| Petawawa |
139.2 |
79 |
60.2 |
1981 |
| Waterloo Wellington |
141 |
85.8 |
55.2 |
1996 |
| Chapleau |
140.4 |
87.8 |
52.6 |
2002 |
| Hamilton |
123.2 |
82.1 |
41.1 |
1996 |
| Trenton |
117.5 |
87.6 |
29.9 |
2004 |
| Location |
Precipitation |
Normal |
Difference |
Driest Since |
| Dryden |
32 |
90.4 |
-58.4 |
1989 |
| Thunder Bay |
39.4 |
88 |
-48.6 |
2003 |
| Sioux Lookout |
52.3 |
95.3 |
-43 |
2002 |
| Moosonee |
47.8 |
90 |
-42.2 |
1996 |
| Kenora |
53.2 |
81.2 |
-28 |
2001 |
| Muskoka |
84.5 |
111.3 |
-26.8 |
2005 |
|
