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Record-Shattering Heat

For southern and central Manitoba the weather last week went beyond the unusual and into the realm of extreme weather. Unless you were away or never left your home, you could not help but notice the incredibly warm summer-like temperatures that dominated our weather for much of last week. After all was said and done, we didn t just see just a few temperature records fall, but instead, we saw nearly every village, town and city crush their previously recorded highs.

After a cool last couple of days in September, temperatures began to warm once again as October got underway. This warm weather was the result of a large blocking pattern that set up over North America. Deep low pressure was in place over both the West and East coasts and helped to develop a large area of high pressure over our region. As the high strengthened and slowly began to drift to the East, we saw temperatures climb, and by Oct. 5, the assault on the record books took place. I have included a list of high temperatures recorded across southern and central Manitoba on Oct. 5. I randomly checked about half of these high temperatures and discovered that all of them had easily beaten their previous temperature records for that date by several degrees. So I think it is pretty safe to say that most, if not all of these sites broke their high-temperature records for this date.

It is pretty unusual not only to see this many places break their temperature records, but to also see records broken by several degrees. Usually when a temperature record is broken, it is broken by a few tenths of a degree and on a few unusual days a record is broken by a full degree. For most of these records we saw the record broken by 3, 4 and even 5! But what made this record-breaking heat go from the unusual to the extreme was the fact that several places also broke the record for the hottest October day ever recorded. Again, after checking this record for several locations with lengthy temperature records, I found that once again, nearly every site had broken this record as well.

There was one other temperature record that was also broken at most locations, and this one is never really mentioned in other weather news stories. This record is for the minimum or overnight lows recorded on Oct. 5 and 6. The record-warm minimum overnight lows for most areas on these dates averaged around the 12-13 C mark. A number of locations easily broke these records on both of these dates with overnight lows in the 14-16 C range. Unlike the daytime-high records, though, these records didn t beat the all-time warm minimum temperature recorded. For most locations, that record was set around Oct. 2, way back in 1897.

Combine these all-time record highs with record-warm overnight minimums and that means really warm days, especially for early October. This can be seen when you look at the number of cooling degree days we have seen this month. Typically in October we record less than one cooling degree day. The last time we had a really warm October (just last year) we saw six cooling degree days. This year we have had 14 cooling degree days more than we saw in May!

If the heat wasn t enough for you last week, then maybe the wind was. Late last week, as the strong ridge of high pressure slowly pulled off to the East, a strong area of low pressure developed to our west. The pressure gradient between these two systems created very strong southerly winds across most regions, beginning on Oct. 5, and culminated across the Red River Valley on Oct. 7, with wind speeds reported in excess of 100 km/h. All in all, it was one heck of a week!

The weather is not looking as dramatic over the next few weeks, but it looks less and less like we ll see an early taste of winter this year, as the models show warmer-than-average temperatures lasting right through to the end of the month.

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ta ble 1: high temps

Town

Dugald

Portage

Gladstone

Carman

Treherne

St. Pierre

Teulon

Winkler

Morden

Steinbach

Woodlands

Fisher Branch

Morris

Eriksdale

Moosehorn

Ste. Rose

Gretna

Winnipeg

Brandon

Emerson

Carberry

. wed ., oct . 5, 2011

High (oC)

33.1

32.8

32.3

32.2

32.1

31.9

31.9

31.9

31.8

31.8

31.8

31.6

31.5

31.4

31.4

31.4

31.3

31.1

30.9

30.9

30.8

Pilot Mound

Souris

Selkirk

Killarney

Boissevain

Virden

Melita

Pierson

Minnedosa

Hamiota

Grandview

Sprague

Arborg

Birtle

Ethelbert

Russell

Pinawa

Roblin

Swan River

Gimli

Swan Valley

30.7

30.7

30.4

30.0

29.9

29.9

29.8

29.8

29.7

29.6

29.4

29.3

28.9

28.9

28.1

28.0

27.9

27.6

26.9

26.7

25.3

About the author

Co-operator contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the U of W. He operates a computerized weather station near Birds Hill Park.

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