Monday, June 27, 2011

Warming up this week.. first 30C of the year likely by Thursday..

After a rather cool start to the week, things will be on an upswing this week as an upper ridge of high pressure builds over the Prairies. This will finally allow warmer air over the States to finally push northward into the southern Prairies, with the summer's first 30C readings likely by Thursday.. the last day of June. Before then, look for a cool night tonight as skies clear allowing temperatures to fall into the single digits by Tuesday morning. Tuesday will see sunshine with some afternoon clouds and afternoon temperatures of 22C. Southerly winds will be on the increase for Wednesday with gusty south winds of 40 gusting to 60 km/h pushing temperatures up to the 27C mark in Winnipeg. Thursday looks like the warmest day of the week with temperatures of 30-33C expected over southern MB.. including Winnipeg. If so, it will the first 30C reading of the year in Winnipeg.. almost a year to the day we reached our first 30C last year (a high of 30.2c on July 1st) A cold front will push through Thursday night with the potential for showers and thunderstorms, ushering in cooler but seasonable weather for the weekend.

19 comments:

  1. Could be some significant thunderstorms on Thursday evening/overnight IF the cap breaks.

    Models showing up to 5,000 J/KG of CAPE and around 50 kts of deep shear. If things go, we may have an outbreak on our hands.

    ReplyDelete
  2. Those high CAPE values are being driven by some awfully high model dewpoints of 25C spreading over southern MB and North Dakota Thursday. Those seem unrealistically high, but a southerly flow for two days should get our dewpoints to the 20C mark by Thursday making for a hot and muggy day. Depending on the timing of the cold front, yes.. we could see some severe storms late Thursday.

    ReplyDelete
  3. Looking at the GFS and NAM/WRF for Thursday evening, in my opinion, it looks like we could potentially see a severe weather outbreak.

    Speed and directional shears at most levels look interesting too, so am I wrong in believing there may be some sort of supercell/tornado threat?

    ReplyDelete
  4. I would think that there's a supercell threat on Thursday evening.

    Also consider that extreme southern MB got a pretty nice line of storms on Saturday night with 2,500 J/KG of CAPE, only 25-30 kts of shear and a weak low level jet.

    A lot more energy/dynamics with the upcoming system. Certainly needs to be watched.

    ReplyDelete
  5. I'm so excited!!
    Heat, Humidity, storms, the next few days! My kind of weather :-)

    ReplyDelete
  6. Don't mean to rain on your parade, but the last thing we need are more storms. We are drowning out here and I find it unsettling that people in this province/city are hoping for more bad weather. Give me a break.

    ReplyDelete
  7. That's weather for you. Can't please everyone. If it's not dry it's wet. Unfortunately we can't seem to end up somewhere in between.

    ReplyDelete
  8. 18Z run of the NAM has gone nuts with the dewpoints over ND and southern MB for Thursday.. with values as high as 28C progged into the RRV. That's leading to some insane CAPE values of 5000-6000 j/kg over us Thursday afternoon/evening which look unrealistically high..

    Looking at current dewpoints across NA.. there are no areas anywhere near 25c or higher.. with the highest values of 21-24C near the Gulf. No doubt our dewpoints will be rising over the next couple of days.. but I can't see 28C dewpoints developing over us, especially with such a slow crop year. So I'd be leary of those high CAPE values that the NAM is suggesting Thursday.

    That being said, dewpoints should be climbing to the 20-22C mark by Thursday, so instability values will still be impressive.. perhaps 2000-3000 j/kg along with good shear of 40-50 kts. Timing of cold front will be an issue along with strong pre-frontal cap, although it looks like front will be crossing RRV at max heating time, so things could get interesting around here late Thursday. Convective mode will likely be isolated supercells at first with large hail and a risk of tornadoes, quickly evolving into a multi-cellular squall line with wind and heavy rain as the main threats Thursday night mainly east of Winnipeg. At least, that's how it's looking right now.. we'll have to see how things transpire over the next day or so..

    ReplyDelete
  9. 28C dewpoint into the RRV would be almost unheard of. Oh wait I remember June 2007. They were that high and I almost fainted from the heat and humidity. Postively STEAMY!!

    ReplyDelete
  10. SPC sounds concerned about some severe storms if all the parameters come together! I guess will be talking about big time supercells tomorrow!!

    ReplyDelete
  11. SPC is bullish regarding tomorrow's threat in SC and SE MB. Has a 30% risk for us along with a hatched area, too.

    They mention supercells possible with very large hail. An isolated tornado may develop.

    ReplyDelete
  12. a couple of things..

    Don't be surprised if Winnipeg and I would guess areas north of the Trans-Canada and east of the RRV or highway 12 end up of with below average rainfall for June.

    Regarding the dewpoints, I would not rule out some values of 23-25 C. We have already seen extreme values of 25-27 C back in May in Minnesota. With all the standing water off to our south and west, direct evaporation from the soil should be sufficient to bump up the values.

    The main issue will be the whether the cap can break. From past experience with such cases, it is very difficult to overcome the cap locally due to the flat, featureless terrain that surrounds the city. The best chances are always around the interlake where lake breezes come into play and along the pembina escarpment (differential heating)..

    ReplyDelete
  13. did Winnipeg break a record low temperature yesterday at 3.8?

    ReplyDelete
  14. Dewpoints have really gone up today with vaules around 20C. Lets see how much higher they can go!

    ReplyDelete
  15. Rob!
    What is your latest gut feeling on tomorrow?? Will we see isolated severe storms , or a major widespread outbreak of severe storms tomorrow??
    Any tornado risk???

    ReplyDelete
  16. First official 30C of the year today in Winnipeg with a high of 30.2C this afternoon at YWG airport. My station's first 30C also at 30.3C. Took a while to get here, but we squeezed it in before June was up.

    Looks like anotehr 30C day tomorrow with humidex values likely approaching 40C with dewpoints in the low 20s..

    As for our severe weather threat tomorrow.. still remains to be seen where and when the cap will break. It may be late enough that severe weather will occur mainly east of Winnipeg tomorrow night, but if cap breaks sooner, the severe risk is certainly over the RRV late tomorrow. GEM says we won't see much in the RRV.. Stay tuned..

    ReplyDelete
  17. This is a storm report that SPC recieved tonight!!

    06/29/2011 0625 PM

    Wagner, Phillips County.

    Hail e2.75 inch, reported by public.


    Estimated baseball size hail knocking horses over.

    Interesting observation!

    ReplyDelete
  18. Humidex advisory issued. Stay safe out there!!!

    ReplyDelete
  19. Humidex adv for Winnipeg? Don't see it at EC's web page. BTW, what are the Cdn criteria for a humidex adv?

    ReplyDelete