Wednesday, May 22, 2013

Nice dry weather for the rest of the week..

After a soggy holiday weekend that dumped 15-50 mm of rain over Winnipeg, and up to 200 mm over the Pembina escarpment west of Morden,  the weather pattern will be a lot drier this week as a ridge of high pressure builds in over the eastern Prairies. This ridge will bring mainly sunny skies and near normal temperatures for the rest of the week, along with low humidity and diminishing winds.. perfect conditions for drying out left over moisture from the weekend. The next chance for rain will be Saturday as a weakening band of showers from Saskatchewan pushes across southern MB. At this point, it looks weak, and the current forecast of "periods of rain" for Saturday looks overly pessimistic.

May 18-20 weekend rainfall totals..  

north end....... 15 mm
Airport ......... 18 mm
Forks ............ 24 mm
Charleswood ... 27 mm
Norwood ........ 31 mm
South Winnipeg ... 30-50 mm

Thornhill .............  205 mm
Darlingford .......... 200 mm
Miami 10SW ...... 125 mm
Morden 6SW ...... 120 mm
Deerwood ........... 100 mm
Morden ...............  90 mm
Somerset .............  80 mm
Winkler ...............  77 mm
Manitou ............... 76 mm
Sprague ............... 73 mm
Carman ................ 68 mm
Emerson .............. 55 mm
Morris.................. 54 mm

Note the heaviest amounts over the western Red River valley along the Pembina escarpment. A persistent northeast upslope flow through the weekend contributed to the locally higher amounts in that area, leading to overland flooding. Note that similar amounts were reported along the escarpment in neighbouring North Dakota with reports of up to 225 mm near Walhalla. This has forced the evacuation of the town of Cavalier, ND due to concerns about a nearby dam failing.


  1. Dewpoint of 21.7C in Elora, Ontario (highest in Canada so far this year)

    Starting to see some summerlike numbers.

  2. Rob, I found a very interesting metar archive on wunderground for Winnipeg with data going back to 1955. Whilst checking it out I have found something astonishing. According to this archived metar, Winnipeg got a thunderstorm on December 31, 1975 at 12:22 PM. Check it our for yourself: (going back to 1955) and I discovered this incredible event.. Check it out for yourself: (sorry it's in french, I don't know how to turn it to english, but the metar is the same anyway so it doesn't matter.. just remember orage=thunderstorm).

    This you think this may have been an error? Or is it actually possible?

  3. Wow maybe I should I have revised my comment before posting sorry about those errors.

  4. Here found it in english after digging through the entire site....

  5. I'd be a little suspicious about that observation. It lists "thunderstorm with rain" yet no rain was recorded that day at YWG airport. Also, it would be strange to have a thunderstorm with rain in the middle of a snow event. I'll have to check further, but it looks like an erroneous observation.

    By the way, this is what the actual METAR looked like. Looks odd..

    SPECI CYWG 311822Z /////KT 8SM TSRA FG SCT009 OVC013 A//// RMK SNW BKF IRLSR06 SLPNO 8/830

  6. Rob, what's situation regarding next week. Are we looking at some heavy rainfall and the season's first thunderstorms especially towards week's end?

  7. I noticed that too Rob.. I suspect it is erroneous as well.

  8. Mike (St.James,Winnipeg)4:22 PM, May 25, 2013

    Rob, what are your thoughts on next week's thunderstorm potential? Any chance we could get our first? I'm losing interest in them already, I haven't seen a good one in months...

  9. Mike.. Might see some elevated tstorms later in the week as a more potent system winds up in the Dakotas.. and pushes a warm front to our south. But overall, just looks generally gloomy and unsettled this week with periodic showers. Really need some sunny warm weather! This weather is too depressing!

  10. Ya I must say this is one of the worst/slowest starts to the thunderstorm season I've ever seen in southern Manitoba.

  11. Rob, are there any indications that we might see sunny warm weather sometime in the next 2 or 3 weeks?

  12. NAM is showing a good shot of instability moving in over RRV Tuesday afternoon with some warmer and more humid air moving in, but other guidance is not as optimistic with that scenario.

    Looks like this May will end up cooler than normal yet again, which is statistically favoured after a cold April (by a 2:1 margin)

    As for any hope for prolonged sunny warm weather in the next few weeks, I can only say I hope so. But we have to also realize we're entering our wettest part of the year (June) so the odds increase of more unsettled weather. The good news for storm lovers is that this may mean a greater chance of thunderstorms, although generally they are more heavy rain producers early in the season than anything else.

  13. RE slow start to thunderstorm season

    I agree. Especially since it ended somewhat early last year with our last storm in the 3rd week of August. Its been over 9 months since our last storm (and that one in late August wasn't even that good of one from what I remember. If you count an actual storm then you're looking at more like 10 months or more!). If the pattern were to repeat itself, then we'd only have 3 months of the year to actually get anything! I hate this pattern that's become of us, with everything seemingly moving around us with that upper flow moving things west, and south of us lately.

    I've recorded some stats on YWG storms from what’s available on EC. The latest thunderstorm start ever recorded since 1953 was June 24th, 1959. Other first late bloomers (or should I say boomers!) were May 31st 1984, May 28th 1987, and more recently May 30th, 2011. So we haven't had that many late starts after May 15th in the last 60 years, which makes this year only the 5th or 6th time we haven't had a recorded thunderstorm before May 15th (FWI last year we had our earliest thunderstorm ever, March 19th).

  14. And normally we have our first thunderstorm by May 1st, according to 60 year stats available on EC for recorded thunderstorms. So 26 days overdue is big

  15. Models have also been peforming pretty mediocre lately for Southern Manitoba. We seem to always lie in a dead zone where models can't seem to come to an agreement on what to give us. One model promises storms while others say no. Go not to far away (south of the border lately) and they seem to have no problem agreeing there.

  16. I forgot to mention a few other late first thunderstorms. There were quite a few of them in the 90's actually. June 3rd, 1992 and 1995 and June 1st, 1997. So we're more like at the 9th or 10th slowest start to our thunderstorm season so far in the last 60 years.

  17. Anonymous... Thanks for those stats! Interesting! I guess it shouldn't come as a big surprise we're having such a slow start to the thunderstorm season this year, after our coldest April in over a century resulting in such a delayed spring. Note also it's been a very slow start to the storm season down south as well, with one one of the lowest tornado counts on record for May (although that certainly didn't make a difference for Moore OK. Just goes to show you, a bad one can hit even in a slow year...)

  18. 1995 was off to a slow start and doesn't appear to have been a particularly active year... but check out the weather observations for August 18, 1995. Thunderstorms were observed almost all day long - pretty unusual!

  19. Oh and just for interest's sake, the latest start to the thunderstorm season, at least as reported at the airport (online records going back to 1953), was in 1958. No thunderstorms reported there until June 28th - no joke.

    Of course, keep in mind that the observations aren't always perfectly complete - so there might have been one or more before that that didn't get noted. I'm not sure. It obviously wasn't a very active period either way though.

    After 1958, the latest recorded "first storms" were in 1992 and 1997 as previously noted.