Tuesday, April 19, 2011

Precipitation possible Friday and next Tuesday as Red River crest heads north..

A weak system will cross the Dakotas on Friday bringing a band of light rain to the Red River valley. Precipitation amounts are expected to be light with 2-5 mm over most areas of southern MB, and perhaps 5-15 mm over the North Dakota portion of the Red River valley. Precipitation may even be mixed with some wet snow early Friday morning. Things are expected to dry out for the weekend before another stronger system develops by Tuesday over the central Plains briging another round of precipitation and storms mainly south of the border. Some precipitation however is possible over southern MB Tuesday into Wednesday, although the bulk of precipitation is again expected south ot the border. Precipitation amounts should not have a dramatic effect on the levels of the Red River and its expected crests next week into early May. However, the extra precipitation may prolong the length that river levels stay high.

Temperatures will remain cooler than normal through the end of April and likely into the beginning of May as the overall pattern continues to favour a strong storm track south of the border with cooler air over much of the Prairies.


  1. Looks like the US is going to be hammered by numerous severe weather events in the coming weeks. That western trough isn't going anywhere.

    Rob, do you have any thoughts on when our storm season could start?

  2. Derek..

    This spring is reminding me of the one we had in 2009.. another flood year with a slow start to the season. That year saw cool temperatures into early June (including heavy snow in mid May in the Riding Mtns and a severe frost in early June) FWIW, we started getting some severe weather around mid June that year.. whether we see a similar pattern this year is tough to say. But until that storm track and jet stream move north, our convective season will be delayed.

  3. Three other Major Flood/La Nina years were 1950, 1974, and 1996. All had slow starts to the summer season with dismal May weather. Normal May Mean is 12C and the warmest of these 3 was a 9.4C Mean (1996) That was also the year that had a respectable June July August averaging Norm +.6 for those three months.
    1974 had a warm July 21.9C Mean Average with a daily Max avg of 28.9 June was normal pun intended and August was cool.
    1950 whose La Nina didn't end until the spring of 1951 averaged Norm -2 all 4 months combined . The coldest was May at 9.1C and the closest to avg was July at 18.2 a mere 1.3 less. September that year ended a string of 10 months of below average temps similar to 2009.

  4. Rob ..Warmer weather??
    Can we move from here to there w/o a major storm?

  5. Looks like our Friday showers came in a little early.. which is OK since it should mean clearing out faster for the long weekend. At least that looks nice, although I'm not sure we'll see 3 days of straight "sunny" weather.. I think there will be some cloudy periods through there, but no precip.

    Tuesday's rain threat looks less for us as that central Plains storm moves further to our south and east. Luckily we've been dodging most of the heavy precip systems, and hopefully it stays that way through the flood season.

  6. Don..

    Yes, we can certainly move from a cooler pattern to a warmer one without a major storm system. All it would require would be a shift in the jet stream (storm track) to the north of us, which can occur with a long wave trough setting up over the West Coast and a building upper ridge over the Prairies. Many times I see this developing after a cold surface ridge departs to our east, and we get a warm return flow from the southwest.

    More often, a major storm system can herald a pattern change from above normal to colder than normal weather since the storm system is feeding off the large supply of colder air to the west and advects into our region.

  7. Rob, I'm going to Las Vegas tomorrow. I see If I can bring back some of that hot weather with me :-)

  8. Good Luck Dan w/weather lol

  9. NO excessive rain til the end of May!!
    That was the message wishlist I read in todays FreePress re flood prospects.
    So I checked and these are the previous April May NINA Flood Years ......Precipitatation
    ........Apr ..........May
    .....15/30 ...1-10...11-15..15-20..Bal

    Interestingly April 15th to May 10th has been trending lower .
    1950 ..109.6 Total .143.7
    1974....69.4 Total .200.9
    1996....52.8 Total .136.4
    1999....31.0 Total ..97.6