11/21/2006
Is our Weather More Extreme?
Anne-Marie PalfreemanEnvironment Canada
11/21/2006
Is our weather more extreme?
• Review of recent “extreme” weather • Was it “extreme”? • Influences on our weather perceptions• Climate Change or variable weather?
11/21/2006
Extreme Weather…
2004–– Very cold JanuaryVery cold January–– Greatest oneGreatest one--day March rainfallday March rainfall–– Greatest oneGreatest one--day May snowfallday May snowfall–– Coldest summer on recordColdest summer on record–– Record earliest Record earliest ““FallFall”” frostfrost
11/21/2006
Extreme Weather…
2005–– Two heavy snowfalls in three days Two heavy snowfalls in three days
Dec 30Dec 30--Jan 1 Jan 1 –– Heavy rains in spring and summerHeavy rains in spring and summer–– Record severe weather seasonRecord severe weather season
11/21/2006
Extreme Weather…
2006–– The warmest January ever in most The warmest January ever in most
locations in Southern and Central locations in Southern and Central ManitobaManitoba
–– Record warm AprilRecord warm April–– Very dry summer in Southern MBVery dry summer in Southern MB–– Active severe weather SeasonActive severe weather Season
11/21/2006
Is this Extreme?
11/21/2006
January Mean Temperature - Winnipeg Warmest 2006 (-7.4) Coldest 1875 (-27.0)
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pera
ture
TemperatureNormal
11/21/2006
Thompson - Annual precipitation 1968-2005
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Amou
nt (m
m)
Record Dry in 2003 (367.9 mm) - Record Wet in 2005 (894.2 mm)
Annual precipNormal
11/21/2006
Marquette - Annual Precipitation 1970-2005
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Year
Am
ount
(mm
)
Record Dry in 1976 (359.1 mm) - Record Wet in 2005 (789.6 mm)
Annual PrecipNormal
11/21/2006
Summer (June-Aug) Precipitation at Portage la Prairie
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1941 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
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ount
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Driest 2006 (85 mm) - Second Driest 1961 (92.7 mm) Wettest 1944 (456.4 mm) - Second wettest 2005 (386.6 mm)
Summer precipNormal
11/21/2006
Severe weather events in Manitoba 1984-2006
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19841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006
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nts
Quietest year 1985 (21 events) - Busiest year 2005 (99 events)
TornadoesHailTotal Annual EventsAverage Annual Events
11/21/2006
Influences on Our Weather Perceptions
Media: 1. Weather events on all scales are more
often reported and repeated, and with a greater sense of them being “abnormal”.
2. Commentary from non-weather people relating future global warming to an increase in severe weather events
11/21/2006
Influences on Our Weather Perceptions
Modern Lifestyle and Economy: 1. Weather events tend to have a larger
impact on our daily activities…tight time scheduling
2. Weather events have larger economic impacts… agriculture, transportation, damage to property/vehicles, infrastructure, etc.
3. Losing our “memory” for past weather events due to information overload
11/21/2006
Is it Climate Change?
11/21/2006
What We Know • Temperature Changes - increasing more
over Prairies and the Arctic than the rest of Canada
• Precipitation Changes - increasing in Canada but little change over the Prairies
• Summer Severe Weather – no significant increasing or decreasing trend
• Winter Weather – fewer blizzards and cold spells
11/21/2006
Temperature ChangesChanges in temperature are unevenly distributed
Degrees C
Trends for 1950-98
11/21/2006
Insert figure
Precipitation ChangesPrecipitation Changes
11/21/2006
What We Might Know • Temperature Changes - current winter and
spring trends will continue, and we may see hotter summer weather
• Precipitation Changes – current trends will continue, and we may have an increase in heavy precipitation events
• Winter Weather – current trends will continue, and we might see more precipitation events
• El Nino/La Nina – maybe more frequent
11/21/2006
Future TemperaturesTemperature patterns will change substantiallyby 2050
11/21/2006
Future PrecipitationChanges in precipitation patterns by 2050 areuncertain, but will be complex
11/21/2006
What We Don’t Know • Summer Severe Weather – far too complex to
make reasonable predictions • Other Seasonal Storms – some thought that
there might be an increase in heavy precipitation events, but maybe more in coastal areas than over the prairies
• Seasonal Distribution of Precipitation Events– even though yearly precipitation may not change, seasonal trends are difficult to forecast
11/21/2006
What is the Bottom Line?
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