Tuesday, 31 July 2012

Hot, Possible Severe T-storm Outbreak Again Today

    (photos of Sunday's storms below)
     The cloudier conditions we are experiencing over south-central and southeastern Manitoba will clear out this afternoon. In Winnipeg, we will see clearing within the next 2 hours. There may be a few showers and rumbles of thunder before the skies clear out, however the best risk will be south of the city. Carman, Morden, Morris, Steinbach and Sprague areas could all see this isolated activity over the next few hours.

     Behind the cloud cover, things will heat up into the low to mid thirties. Many ares are expected to rise between 32 and 34°C. Humidity will also be a little higher today, with dewpoints in the high teens and near 20°C in some cases. That will bring humidex values into the high thirties, approaching 40 this afternoon and early evening, if you are not under a thunderstorm of course.

     Speaking of thunderstorms, there is a good risk of another severe thunderstorm outbreak in parts of southern and central Manitoba today. Using MIST (Moisture, Instability, Shear and Trigger), all these ingredients are in play today. A low pressure system will be pushing into the Interlake late afternoon and early evening, with a cold front south of this. This will be the trigger. Moisture will be sufficient with dews in the 17 to 20°C range, and instability will be good in the couple thousand J/kg. Shear is expected to be significant today, and that is a main reason why today may be another severe windstorm day. Due to this high shear, an isolated tornado cannot be ruled out in the early stages of thunderstorm formation, in western Manitoba and the Interlake.

     There will be strong capping however, and this cap is expected to be quite strong along and south of the Trans-Canada. As a result, the best chance for storms and severe weather will be in western Manitoba, into the Interlake and east/southeastern Manitoba.

     Stay tuned to the comment section below, and my thunder forecast tab for updates today. I may issue some moderate severe risk areas in the Interlake later today once I get a better idea at where storms will form.

     Here's some photos of the storms and the damage they caused on Sunday. Keep in mind, today could feature some of the same conditions:
Storm approaching Winnipeg - I took this pic..  my twitter @jjcwpg
Northwest of Winnipeg. Pic by Scott ..  via twitter @steinbachwx
Taken by Jodi Hafenbrak in Winnipeg
Tree blocking traffic on St. Anne's Rd..  pic by Raymond St. Mars..   via twitter @raydawg189


  1. I have posted my latest thoughts on storm potential today. A moderate risk is in place for parts of the Interlake and western and eastern Manitoba. The best time for storms will be this evening. Storms will have trouble forming with a such a strong cap this afternoon.

  2. I am considering downgrading the moderate risk to a slight risk, however I will wait another hour or two to see if anything forms. The cap is just too strong, surpressing any storm formation so far. There is still a risk for storms however, and I don't want to downgrade the fact that if a storm does form it wouldnt be severe. Rather, any storm that does form WILL have very good chance at becoming severe due to such good dynamics. I'm just concerned that a cap bust may happen, however it is not all over yet.

  3. I have decided to reduce the risk of storms and severe storms for Manitoba. Check the thunder forecast tab for the map and brief details.

  4. Things are FINALLY looking more clear about tonight. Read about it in the thunder forecast tab.

    It is in fact a cap bust for us here, however storms have finally formed east of Swan River into the northern Interlake. The bulk of these are expected to move into the Interlake and eastern Manitoba tonight. Some of these may potentially reach as far south as Winnipeg and southeastern Manitoba, however the chance is not very high.

  5. Today has been a nightmare for forecasting the storms. It's a relief to finally have a little bit more clarity.

  6. I will have July stats/summary up later this morning, after I've done the forecasts.