Monday, May 12, 2008

Rainfall update

Rain moved into southern MB early this morning with a general 10-15 mm mainly along the TransCanada corridor by midday. Another wave of rain has moved into southern MB late today which will mainly affect the Red River valley and southeast MB with another 10-15 mm tonight. A good well needed soaking rain that will help replenish soil moisture levels over southern MB.


  1. We have racked up 12.2mm here in Steinbach. Rainfall rates have reached an incredible 4.6mm per hour! Hopefully this rainfall will get the grass greener, and get those leaves coming a bit quicker.

  2. I measured .5 inch on my plain-jane rain gauge at noon today.

    Chris in Westwood

  3. Ended up with 22 mm in total at my site in Charleswood. YWG airport had 20 mm while the Forks had 27 mm. In general.. a good 20-25 mm across the city over the past 24 hours. Lawns look greener already!

  4. We received 20.8mm here in Steinbach according to my site (console...). The Manitoba Ag station recorded only 14.9mm for some reason, which seems a bit low to me. Other local stations reported between 15 and 20mm, so I believe the actual amount was closer to 20mm.

    Looks like some heat is coming to end the week. Temperatures in the high teens and low twenties sound really nice right about now!

  5. At this point I would like to retract all my pessimistic reports of the coming weather pattern...

    Well I probably wouldn't be doing that if the weather actually was going to be miserable. Obviously I am happy that I was wrong as it looks like a beautiful end-of-the-week and weekend! Highs between 19 and 24 look likely from now until Sunday, which is a much needed break from all these cold Northerly flows we have been trapped in. Actually this will be a North-West flow, but it is coming from Alberta, rather than the Arctic!

    Either way I hope the GFS is right, and we crack twenty degrees again for the first time since April!

    I was looking at last years May temperatures, which were actually similar to this year (so far). Last May started out warm (up to 30C as Rob had mentioned) and slowly went down hill until the end of the month. Highs of only 7 to 15 were common in the second half of the month, only reaching 7C on May 26th! This year looks to be the opposite, with the beginning of the month being colder, while the latter half being warmer.

  6. The rain was great! Just what we needed and I'd like to see more.

    I have a cloud question. I noticed yesterday the cumulous clouds had flat bottoms, like they were sitting on a glass table top. I was curious as to what conditions cause this.

  7. The bottoms (called "bases") of cumulus-type clouds develop at what is known as the lifting condensation level or LCL. This is the height in the atmosphere where rising air reaches its saturation point, and condenses to form liquid water droplets.. or cloud. Some days this happens at a very specific and uniform height, which accounts for the flat bases on those days.

    By the way, there's a trick to estimating the height of these cumulus cloud bases.. just multiply the difference between the temperature and the dew point (called the dew point spread) by 400, and this will give the cloud base height in feet. For example, if the temperature is 18C and the dew point is 3C, then the cumulus cloud base is around 6000 feet ((18-3)*400) This doesn't always work, but it gives a reasonable estimate on most cumulus type days.

  8. Thanks for the explanation about LCL and the flat cloud bases.