West is burning

This satellite image taken Monday evening July 30 shows large smoke plumes from Montana forest fires spreading into southern SK and southern MB. Residents may have noticed a hazy appearance to the sky today, as well as a redder than usual sunset or sunrise. This is due to the presence of smoke particles spreading through a layer in the mid atmosphere, about 10000 ft or so. The smoke layer will likely persist over southern MB on Tuesday before a northwest flow clears out the smoke layer on Wednesday.

Note also several other smoke plumes from forest fires over western Montana and the BC/Alberta border.. a result of several weeks of hot dry weather that has baked the upper Rockies and western Prairies. Forest fires have also been a problem over northern MB as well this month.

Heat rebuilding across southern Prairies

After a couple of days reprieve, hot weather is again returning to much of the southern Prairies this weekend, including southern MB. Temperatures in southern MB will hit the 30c mark again today with even hotter temperatures of 35c for Sunday into Tuesday. Fortunately, it looks like the humidity levels will not be as oppressive as last week's heat wave which saw dewpoints climb into the mid to upper twenties. Dewpoints over the next few days should be in the more moderate 15-20c range which combined with 35c temperatures will still make for uncomfortable conditions, with afternoon humidex readings in the 40-43c range. However, local areas such as the western Red River valley may once again see higher humidex values due to humidity input from crops (especially corn)

Record hot and humid day over Southern MB

Special weather statement from Environment Canada, Winnipeg - July 25 2007.. (graph showing heat index and dewpoints from Rob's Obs)

HOT AND MOIST AIR FROM THE CENTRAL UNITED STATES CONTINUED TO FLOW INTO SOUTHERN MANITOBA ON WEDNESDAY. THE HIGH TEMPERATURES COMBINING WITH THE EXTREME HUMIDITY LED TO RECORD HIGH TEMPERATURES AND RECORD HIGH HUMIDEX VALUES OVER SOUTHERN MANITOBA TODAY. WINNIPEG SET AN ALL TIME RECORD FOR THE HIGHEST HUMIDEX READING EVER RECORDED AT THE WINNIPEG AIRPORT. HUMIDEX VALUES PEAKED AT 47 LATE THIS AFTERNOON BREAKING THE ALL TIME WINNIPEG RECORD OF 46.1 SET BACK ON JUNE 27, 1996. AS WELL CARMAN, MANITOBA UNOFFICIALLY SET AN ALL TIME CANADIAN RECORD HIGH HUMIDEX WHEN VALUES CLIMBED TO 53 LATE THIS AFTERNOON, BREAKING THE RECORD PREVIOUSLY HELD BY WINDSOR, ONTARIO OF 52.1 SET ON JUNE 20, 1953.

THE HUMIDEX IS AN INDEX (A COMPUTED VALUE AS OPPOSED TO SOMETHING MEASURED) DEVISED TO DESCRIBE HOW HOT OR HUMID WEATHER FEELS TO THE AVERAGE PERSON. THE HUMIDEX COMBINES THE TEMPERATURE AND HUMIDITY INTO ONE NUMBER TO REFLECT THE PERCEIVED TEMPERATURE. IT TAKES INTO ACCOUNT THESE TWO IMPORTANT FACTORS TO BETTER DESCRIBE HOW STIFLING THE AIR FEELS THAN EITHER TEMPERATURE OR HUMIDITY ALONE.

THE FOLLOWING ARE THE UNOFFICIAL NEW MAXIMUM TEMPERATURE RECORDS AS OF 5:00 P.M. WEDNESDAY JULY 25.

GILLAM 28.8 28.1 1983
PINAWA 34.3 34.0 1989
GRETNA 33.2 32.2 1961
CARMAN 34.0 28.1 1997

THE FOLLOWING ARE LOCATIONS THAT CAME CLOSE TO BREAKING THEIR MAXIMUM TEMPERATURE RECORDS.

GIMLI 32.1 33.1 1989
ISLAND LAKE 29.6 29.7 1989
THOMPSON 27.4 28.7 1989
CHURCHILL 28.2 30.0 1929
FISHER BRANCH 30.5 32.2 2003
WINNIPEG 35.3 36.7 1931

Severe thunderstorm approaching Winnipeg

At 4:30 pm radar displayed a rapidly developing thunderstorm approaching Winnipeg from the southwest. A severe thunderstorm warning has been issued for this cell. Radar indicates possible rotation with this storm which may indicate tornadic potential. Very strong downdraft winds and torrential downpours are likely. This storm has developed right along the cold front which is just approaching Winnipeg as of 4:30 pm.

Another scorcher - but relief on the way

It's another scorcher over the Red River valley, with 1 pm temperatures of 33C in Winnipeg and a humidex of 45C.. the steamiest day of the heat wave so far. But relief is on the way as a cold front approaches from the west. As of 1 pm, the front was just about through Brandon with showers and thunderstorms west of the front. Temperatures drop significantly behind the front with values near 20C near the SK border as of 1 pm. The front should be moving through Winnipeg later this afternoon with noticeably cooler conditions and some rain moving in this evening.