Thursday, August 28, 2008

Summer's last hurrah?

It looks like the fine summer-like weather we've enjoyed through much of August will close out the month this weekend with another round of summer-like warmth, especially over SE MB. But as if on queue, a sharp cold front will move across southern MB late Sunday or Monday bringing in much cooler and wetter weather just as the calendar flips to September. The details..

An upper ridge will build over southern MB on Saturday giving us a fine start to the Labour day weekend. Saturday will see plenty of sunshine across southern MB with temperatures in the mid to upper 20s along with increasing southerly winds.  This upper ridge is forecast to build over Ontario over the long weekend, while cooler unsettled weather moves in over the western Prairies. The dividing line between these two airmasses will set up right through southern MB on Sunday along a cold front that is expected to drop southward across the Interlake and stall from southwest MB through Winnipeg into the Pinawa area.  There will be a dramatic temperature difference across this front with summerlike temperatures of 27-30C to the south and east, and more fall-like temperatures of 20C to the north and west along with clouds and a chance of showers. Current forecasts for Winnipeg call for a high of 30C on Sunday, but I'm a little skeptical we'll get that high with that Interlake front so close to us (major bust potential Sunday because of this front). I think areas south and east of Winnipeg will have a better chance of seeing 30 degree temperatures on Sunday (including the Whiteshell, Lake of the Woods and the southern Red River valley), while places like Grand Beach through Gimli to the Riding Mtns will be considerably cooler on Sunday (highs only near 20C).

For holiday Monday, models indicate this cold front will sweep through southern MB, bringing in cooler weather for all areas but the extreme southeast along with a good chance of rain, possibly heavy in parts of southwest MB into the Interlake.  All in all, looks like the best bet for a warm dry long weekend will be toward the SE corner of the province (e.g. Whiteshell, Lake of the Woods and southern Red River valley), while cooler and wetter weather moves in by Sunday to areas further north and west (especially SW MB through the Interlake). As always.. stay tuned…the forecast for this long weekend will be a tricky one.   

Tuesday, August 26, 2008

Windy and warm today.. risk of thunderstorms tonight

Windy and warm conditions are on tap today as a gusty southerly flow develops ahead of a sharp cold front pushing through Saskatchewan. Southerly winds will gust up to 70 km/h this afternoon up the Red River valley, as temperatures climb into the upper 20s. Scattered showers and thunderstorms will develop ahead of the approaching cold front this evening and tonight, with a slight risk of severe thunderstorms over portions of western MB this evening with strong wind gusts as the main threat. The storms may produce some heavy rain, but any storms that develop will be moving rapidly which will diminish the heavy rain threat.. good news for areas hard hit by last week's locally torrential rains.

Thursday, August 21, 2008

Showers/thunderstorms on tap tonight into Friday

A cold front approaching from Saskatchewan will trigger a band of showers and thunderstorms over southern MB beginning this afternoon and continuing through tonight into Friday. The heaviest activity in terms of thunderstorms is expected to develop over southwest MB later today then move northeast through the Interlake tonight. Locally severe thunderstorms are possible along this swath with the potential for large hail and damaging winds along with local rainfall amounts of 20-40 mm. Showers and scattered thunderstorms will be spreading across the remainder of southern MB tonight into Friday with rainfall amounts of 10-20 mm possible. Noticeably cooler weather will move in behind this cold front for Friday and Saturday with high temperatures some 10-15 degrees cooler than the 30 degree weather of the past week. Warmer weather is set to return to southern MB by Monday.

Monday, August 18, 2008

Winnipeg finally hits 30 degree mark - latest date on record

The temperature at Winnipeg airport hit 30.2C on Saturday August 16th, the first official 30 degree day of the summer at Winnipeg's official weather reporting site.  This marks the latest date that Winnipeg has reached the 30 degree mark since records began in the city in 1872.  The previous latest date for hitting 30C was July 24th back in 1927 and in 1882.  Thus, this year was over 3 weeks later than the previous latest date.   The average date for hitting 30C is around June 4th based on Winnipeg climate data since 1872.

Note that Winnipeg airport observations began in 1938.  Before that, weather readings were taken at St John's College in St Boniface from 1872-1938. 



2008...AUG 16…. 30.2C…..138   
1882…JUL  24…. 30.0C…..115   
1927…JUL 24….. 32.2C…..115
1920…JUL 19….. 31.7C…..110
1967….JUL 15…. 30.0C…..106


Thursday, August 14, 2008

Another summery weekend on tap!

If you enjoyed last weekend's summery weather, you're going to like this weekend as well as Mother Nature serves up another stretch of sunny hot weather over southern MB. An area of unsettled weather over SW Manitoba today will give way to sunshine Friday that will last through the weekend into early next week as an upper ridge of high pressure builds over the Prairies. Daily highs will be near 30 degrees each day giving the Winnipeg airport site its best chance yet to finally hit the 30 degree mark this summer (I'm betting we'll hit 30 this weekend) Summer of 2008 ain't over yet!

Monday, August 11, 2008

Heavy rain possible over portions of Red River valley tonight

A slow moving trough of low pressure over SW Manitoba will feed a southerly flow of moist unsettled air over southern MB today and tonight resulting in widespread showers and embedded thunderstorms.  The slow moving and persistent shower activity will result in locally heavy rain as showers and thunderstorms advect over the same area (an effect known as "training") . Showers and thunderstorms will be most frequent over eastern ND today where flood watches are in effect due to the potential for 50 to 75 mm of rain in some areas. This area of heavy rain is forecast to spread northward into the Red River valley this evening and tonight, with 25 mm or more possible in areas mainly south and west of Winnipeg (although Winnipeg may also see significant amounts if the rain area expands further north).  Note that locally heavy downpours this morning produced 32 mm of rain in Snowflake, 66 mm in Manitou, and 62 mm near Miami so a repeat performance is possible again tonight in some areas of the Red River valley. 

Wednesday, August 06, 2008

Finally! - Extended stretch of sunny warm weather ahead

It's been a rarity this summer, but it looks like southern MB will have an extended period of sunny warm weather ahead this week.. possibly lasting right through the upcoming weekend.  A large upper ridge of high pressure is forecast to build over the Prairies this week which will help to maintain sunny and stable conditions from the Rockies into northwest Ontario.. a nice change from the persistent unstable airmass that has brought almost daily shower and thunderstorm activity across the Prairies this summer. Temperatures in southern MB will be pleasantly warm this week.. in the 25-27c range climbing into the upper 20s to low 30s over the weekend. The GFS is even indicating a high of 33C for Winnipeg by Sunday. Perhaps YWG airport will finally hit that elusive 30C mark yet this summer!   Whatever the case.. it finally looks like some nice beach weather ahead this week and weekend over southern MB.     

Monday, August 04, 2008

Sun disappears for long weekend

Well.. bad timing, but today is the third day in a row of cloudy skies and local shower activity over the Red River valley and SE MB.. all due to convection over the northern Plains that has spilled over into southern MB. Rainfall has been minimal in the Winnipeg area, but persistent cloud and temperatures in the low 20s has made this last long weekend of summer not very summerlike. It looks like summer heat just can't get established this year over the southern Prairies as the jet stream remains stalled over the northern Plains.. with time running out for it to shift any further north.