Wednesday, 16 July 2014

Hot, Humid & Stormy Weather On The Way

     If you do not like the heat, I suggest you enjoy today while you can! Nothing but sun and light winds today with a high around 25-26°C.

     Mother Nature cranks up the thermostat starting tomorrow as a southerly flow returns. Highs around 30-31°C are expected. Humidity will also be on the increase, but will not be extremely high just yet. There is the risk for an isolated shower or storm late in the day, but the risk is not very significant.

     A strong southerly flow sets up ahead of a low pressure system in central Manitoba on Friday. Very warm air will be moving in, allowing for highs around 31-34°C in the RRV. This, combined with dewpoints close to 20°C, will give humidex values near 40. Perhaps good news to some, winds will be strong out of the south up to 40 km/h, which may make it a tad easier to cool off.

     The first main severe threat will be on Friday as a strong cold front is expected to slice through southern Manitoba. Severe thunderstorms are likely with this feature, with all modes of severe weather possible. Stay tuned in the comments below for updates in the next couple days.

Forecasted scenario by the 06Z NAM weather model this morning for Friday afternoon. Cold front to slice southern Manitoba. Colour contours are the average dewpoint temperature in °F from the surface to 30 mb above the surface (roughly the lowest 300 metres of the atmosphere).


     Slightly cooler conditions are possible on Saturday behind the front, with highs in the high 20's. The ''cooler'' conditions will be short-lived as hot and humid weather returns by Sunday. More thunderstorm chances may come early next week, but it is too early to be more specific than that.

50 comments:

  1. Given what you've said, JJ, so much for the completely 'sunny' forecast friday from ec.

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    1. It should be fairly sunny to start the day, but yeah, there should be at least a chance of showers and storms in there. Perfectly sunny certainly is misleading for the general public.

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  2. Yeah, that sunny forecast for Friday is way too optimistic. A sunny forecast when there's actually a significant threat of storms possibly severe just shows just how far behind the U.S we in Canada are when it comes to forecasting. But that's automated forecasting for you.

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  3. Although, to be fair, there is considerable disagreement between some of the models for Friday. If you believed the GEM, the risk for thunderstorms on Friday could certainly be a lot lower.

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  4. I think Euro/NAM are more realistic for Friday given the instability the heat and humidity and favorable upper level winds along the with the cold front and strong dynamical forcing. These should combined to provide sufficient lift for strong storms later Friday. But as is usually the case, we'll have to wait and see. But it is unusual to see this much disagreement within models for an event that's only 2 days out. Euro and NAM are similar for Friday while GFS and GEM are not.

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  5. aGreat feature of your aBlog Jj is missing a few days and then questioning or commenting w/o clutterring up the new subject. As long as you can garrantee Sunshine for noon at the pavilion on Saturday the bride and the Alberta wedding party will be ecstatic. They comment about the humidity every time they come here.

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    1. I've known people from Alberta and I always hear them say the same about the humidity. 13°C+ dewpoints appear extreme to them, but are an almost every day occurrence at this time of year here in Winnipeg. Personally, I don't really notice the humidity until dewpoints reach close to 20°C.

      As for your wedding event, rain isn't expected midday on Saturday thankfully. Although, given the disagreement in model land, let's hope that doesn't change.

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    2. Almost perfect weather conditions and the gorgeous new extension to Leo Mol Gardens combined for a great ceremony.Thanks Jjc.

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    3. Hope there weren't too many mosquitoes! Looks like the weather worked out really good, not too hot!

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  6. Friday looks like a potentially very good chase day in Southern MB and according to SREF the best tornado potential appears to be in the RRV. We'll see.

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  7. Still lots of uncertainty about what will occur this weekend. Seeing the new NAM model run this evening, it appears another severe thunderstorm event would be possible late on Saturday. This is just from 1 model run so far, so will have to wait and see if the idea continues tomorrow. It appears southern Manitoba will really be in a battle ground this weekend as this warm and humid air mass battles cooler and drier air trying to push east. Multiple rounds of storms, some severe are possible Friday through to early next week.

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  8. Yeah this may turn into the first real severe weather outbreak at least for the RRV which have for the most been missing out on storms so far this season. Friday could be quite interesting then after that it's unclear but folks should be aware that if your out at the lake or relaxing at the beach this weekend you need to know that not only will it be hot and humid there will be a risk for potential dangerous storms at any point through the weekend. Hopefully consensus on this becomes clearer tomorrow. Not getting excited about this yet but I have too say that this looks like the best setup so far this year for storms and potential tornadoes with the warmer and more humid air over us and the cooler not too far to the west trying to move in as JJ mentioned.

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  9. 4 KM NAM is stunning for Friday evening. If it pans out, there will be good potential for tornadoes right here in the RRV and Winnipeg.
    Could be good chase material. So we'll see.

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  10. Yikes, I'm not liking this thick haze we are seeing this morning. This is making temperature forecasts for today very tricky. If it remains thick like this for most of the day, we'll likely only reach high 20's. If it clears out, a 30°C day would be likely.

    Very windy tomorrow out of the south with sustained winds of 35 to 50 km/h and gusts up to 60 km/h. Assuming there isn't any unexpected haze, we should manage to reach around 31-33°C before the storm risk increases. The risk for severe thunderstorms remains for mid afternoon through to early evening for us. It will be humid along with the heat, with humidex values in the high 30's.

    The storm risk for Saturday has really fizzled out. Looks like last night's run was too aggressive. It will be cooler, likely only reaching around 25-26°C.

    Very hot weather returns Sunday and Monday with highs around 32-33°C or so on Sunday and 33-35°C on Monday. It will also be quite humid, so overall, very uncomfortable days. There might be a risk for storms, but the risk is still pretty uncertain.

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  11. Interesting WX Discussion regarding day 2 convective outlook from PASPC FOCN 45 regarding high SBCAPE of near 3000/jkg and likelyhood of supercell development later in the day tomorrow. Could get quite interesting by tomorrow evening.

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  12. Shear may not be quite as strong as today in Alberta but tornadic potential may still exist regardless.

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  13. High of only 27.6°C at the airport so far today. As a result, it's pretty obvious this thick smoke has kept our temperatures lower than they could have been today. My concern is now if this smoke sticks around again tomorrow. If it keeps our temperatures a lot lower than expected, capping may be even stronger than expected.

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  14. I agree. This smoke may impede heating tomorrow if it's still here which could kill storm development.

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  15. jJ, given what you and anon have said about the storm risk tomorrow, do you think that would change the main thrat of the storms. ( would the smoke dry it up more and thus resulting in less precip? )
    Thanks

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    1. Even with the smoke, all modes of severe weather remain possible. I wouldn't be concerned about less rain because of it.

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  16. JJ, where can I find forecasts for capping levels? I'm curious to know about tomorrow's storm risk...

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    1. You can determine if there is capping by looking at a sounding like this one:
      http://climate.cod.edu/flanis/model/fsound/index.php?type=00|NAM|US|sfc|30mbdewp|21|*133,162*|false
      Actually, this example for tomorrow is basically uncapped. NAM shows basically uncapped soundings right along the front tomorrow afternoon which would be good. However, it's hard to predict how much smoke would impact things.

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  17. Found an interesting article on when wildfire smoke and thunderstorms collide http://earthobservatory.nasa.gov/IOTD/view.php?id=78497 , we had a day or 2 like this back in 2010 we had storms occur at the beach we were at regardless of smoke.

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  18. http://www.nbcnews.com/id/48154166/ns/technology_and_science-science/t/photos-shot-thunderstorm-sucks-wildfire-smoke/#.U8h3_PldWII

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  19. Interesting to note a severe hail storm struck singapore in June 2013, when there was haze and smoke present nonetheless humidity was still a factor and they altogether likely created an enhancement for storms. Will be interesting to see how it goes tomorrow... http://www.westernpacificweather.com/2013/06/25/haze-smoke-and-the-singapore-hail-storm/ (Click my name as well).

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  20. I think the trough with it it's associated fronts will overcome the smoke issues tomorrow. Lots of instability at play here.

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  21. JJ, whats the latest on todays severe weather?

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  22. Although there is still a bit of haze, it appears a lot of thinner than it was yesterday. I don't think it will be a concern today. Severe thunderstorms are very likely along the cold front this afternoon and evening. A few supercells can't be ruled out in the early stages of development this afternoon, especially west of Winnipeg and in the Interlake. A squall line of some sort is likely to evolve late afternoon and evening for eastern areas of southern Manitoba. For Winnipeg, the best threat for storms will be between 4 and 7 pm. Due to the abundant sunshine for the first part of the day, a 30°C day is possible in Winnipeg.

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  23. For tomorrow, lots of sun and cooler highs only reaching around 26°C or so. There is the potential for thunderstorms early in the day on Sunday as a trough of low pressure swings through. A hot one nonetheless, likely reaching 31-33°C. The trough will likely be too far east to get redevelopment of storms here later in the day.

    Monday doesn't look as hot as it did before as a warm front remains to our south. Highs likely in the high 20's.

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  24. JJ with the debris cloud moving into Manitoba is there a chance it could stop storm development today?

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    1. I don't expect a major impact on wether or not storms will develop. There's already a lot of cumulus developing near the Saskatchewan border which is to watch for development today as the front moves east.

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  25. Winds now of the southeast. That is very significant. If these winds continue to stay out the southeast ahead of the front that could mean potential tornadoes. Look for an initiation time of 4-5 PM or possibly a little before for storm development and it's fireworks from there.

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  26. Watch for strong surface based convection to develop in another hour or so as elevated stuff hits boundary just East of Portage.

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  27. nothing yet, not going to get it...

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  28. I wouldn't give up yet Mike. Still time. May not be til after 5 PM for initiation.

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  29. It does look like the cap may be holding on tougher than expected at least for now.

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  30. Cold front just entering the RRV now near Portage so the next hour will telling as to what's going to happen or not.

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  31. Initiation is imminent. first signs of the line of storms is popping up in ND. Will fill in here in MB very quickly in the 30 to 60 minutes.

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  32. Towers now going up near Portage so we'll see what happens.

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  33. Cell now firing near Elie moving east.

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  34. Yes, initiation will be quite soon, lots of stuff trying to go in the RRV right now. Going to be a very close call for Winnipeg wether we get anything or not.

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  35. Well, looks like Winnipeg will be getting into the action as multiple cells are developing just to our west. Could get interesting soon!

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  36. Warning now includes Winnipeg. Could be interesting.

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  37. Kind of a strange observation coming from YWG Airport. Funnel Cloud with 7 PM Update. That's odd.

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    1. In the METAR observation, it reports a funnel cloud overhead north side of city to the northeast of the airport.

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  38. A dissapointment for us here in south St Vital, being the odd ones out with this evening's storm. Only received a few big raindrops here so just a trace mm of rainfall. Wasn't even enough to fully wet the road.

    Large hail reported in central parts of the city with golf ball sized hail according to twitter reports.

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  39. Looking at the departing cell from south-central wpg., to the ENE, I can see what looks like a lowering of sorts. Slight rotation when looking through binoculars. Could this be?? Also, nickel to toonie size hail earlier, but just briefly. Love the blog!

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    1. I could see lots of low clouds as well with the storm; looked like scud from here. However, we certainly don't get a very far view from inside the city unfortunately.

      And thanks, glad to you hear you like my blog :)

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  40. Well, that's it for this thunderstorm event. The airport has now had 12 thunderstorm days so far this year. Same here in South St Vital. Next chance for some rain and storm activity is tomorrow night and early Sunday, but the risk for thunderstorms is not as high as today. Severe activity unlikely.

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