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. 


  1. Is there a possibility of severe weather today? I don't really think so.

  2. A slight risk of severe storms over the Brandon/Dauphin areas where some sun is breaking through ahead of an approaching frontal trough. Everywhere else, it's too cloudy and cool.

  3. Rainfall warning posted for areas from Morden to Sprague.. up to 50 mm of rain expected along US border. 15-25 mm forecast for Winnipeg and much of Red River valley tonight. Bad timing for opening of MB summer games this evening in Carman..

  4. For what it's worth, as of Tuesday 10AM - 26mm measured in my back yard using my " Wal*Mart " rain gauge.

    Chris in Westwood

  5. I have recorded 22.2mm as of 11:00 a.m. for the entire rainfall event.

    Thankfully the heavy rainfall forecast quickly evaporated...I don't need more mosquitoes! I only got half of what was originally predicted, finally a good twist on the weather (albeit a very minor one)!

  6. Thanks Chris, Scott..

    Here are some other rainfall totals as of 11 am this morning across Winnipeg. Some impressive amounts especially from the St Vital area through the downtown core.

    Winnipeg airport.. 56 mm
    Winnipeg Forks.... 62 mm

    Unofficial obs:

    St Vital Pollution plant.. 77 mm
    St Vital....... 69 mm
    Island Lakes... 55 mm (as of 7 am)
    U of W......... 52 mm
    Charleswood.... 50 mm
    E St Paul...... 45 mm
    Whyte Ridge.... 43 mm

    Looks like the heaviest swath of rain was along the Hwy 75 and 59 corridors right into Winnipeg.. much lighter amounts east towards Steinbach and west towards Carman.

  7. I guess not all regions were spared from that heavy rain. It seems like Winnipeg has been a rainfall "hotspot" or should I say "wetspot" this year!

    Hopefully the cloud cover will clear off the RRV soon, Brandon is already in the sun as of 12:00 p.m.

    Perhaps some marginally severe storms on Wednesday and Thursday? Residual moisture on those days will combine with much warmer temperatures to create an unstable atmosphere. As the low responsible for the rainfall moves South-East is will drag a couple fronts through our region. I would suspect heavy rainfall, (due to slow storm motion) intense lightning, and large hail would be the main threats...although strong winds are also a possibility. The tornado threat looks to be zero. Storms are forecast in the RRV and points East.

  8. 41.0mm here in East Transcona as of 2:30pm.

  9. Rain just keeps falling along what appears to be a quasi-stationary boundary. The cloud deck is moving slowly the the NNW, and the rainfall is slowly moving with it.

    As of 4 p.m. the precipitation shield appears to be weakening, and the cloud is beginning to break-up around the border (upstream of the cloudy Southern MB regions). Hopefully by early evening some clear breaks will come through!

    Very light rainfall all day has boosted my total to 28.6mm, up from the 22.2mm this morning. I would expect to reach around 30mm before the event is over.

  10. I was just looking through the EC normals and averages climate page and came across something interesting. Steinbach was listed in the averages section. In my opinion it is difficult to get averages when a city had no weather station. Does this mean Steinbach used to have a weather station? Some of the numbers were interesting, like the extreme daily snowfall of 55.5cm in May of 1997! For the most part data is similar to Winnipeg, although the extreme maximum temperature is only 37.5. I think this may be wrong, or is due to the short duration the station was active (if there ever was a station). Could it have been a manual reporting station?

  11. I collected 54 mm over the two days near Grant/Kenaston. What a rainfall. Good stuff, but I guess not good for the harvest. I think that's the fullest my CDN Tire gage has ever gotten!

  12. The next question is will we hit 30 C
    With a good stiff wind out of the south we have a good chance!!