Friday, July 06, 2012

Rain over southern Red River valley this morning.. Building heat expected over Prairies next week

A large thunderstorm complex over North Dakota is spreading an area of rain across the Red River valley this morning, generally south of a line from Carman through Brunkild to Steinbach. Rainfall amounts of will range from 10-15 mm near the US border to little or no rain north of St Agathe.(UPDATE: rain has spread up to Winnipeg, although bulk of rain will remain south and east of the city) This system will push east today, with gradually clearing skies expected over the Red River valley this afternoon. Saturday will start off sunny but a weak impulse tracking through the Interlake will likely spawn scattered showers and thunderstorms by the afternoon, especially north of Winnipeg. After that, it looks like we'll be in for an extended spell of warm and dry weather next week as an upper ridge builds over the western Prairies, bringing increasing heat through the week. Temperatures in the low to mid 30s will be widespread over southern Alberta and Saskatchewan early next week, with the heat expected to spread into southern Manitoba by the end of the week.

35 comments:

  1. CWB Weatherfarm mesonet showing about 5-10 mm of rain so far near the US border, with 0.25 mm amounts in Brunkild and Steinbach which pretty much represents the northern extent of the rain shield this morning.

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  2. Getting a little light rain here in Winnipeg.. bulk of it staying to our south.

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  3. Picked up a quick 1 mm here in Charleswood on the NW edge of the pcpn shield .. 2-5 mm to our south and east with up to 10 mm near the us border.

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  4. Interesting, CBC says...
    "Friday.... there will be a few showers in west-central Manitoba but not in the southeast."

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  5. Again, you've got to wonder about what kind of products he's looking at. I feel sorry for the guy.

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  6. According to COCORAHS obs, general rainfall amounts of 25-50 mm common over southern and central ND last night, with up to 70 mm south of Bismarck. COCORAHS is a volunteer cooperative network that collects precipitation readings all over the US, and most recently expanded into southern MB to augment CWB's Weatherfarm data. Great source of pecip data. For a link to COCORAHS obs, click on "COCORAHS" under PRECIP on my main drop down menu bar.

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  7. In southeast MB, Falcon Lake and Hadashville also had about 5 mm, Sprague about 9-10 mm.

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  8. Increasing sunshine starting to warm us back up into the mid to upper 20s. I've hit 29C or better at my station for the past 10 days in a row. Have about 3 hours of heating left for streak to continue..

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  9. Sure are impressed how the GEM model handled that system in ND. Usually a forecast showing up like that in the model if its just on the other side of the border over us is almost always too good to be true with the outcome usually being a complete bust I find 90% of the time. Welcome to Winnipeg. Land of being too far North, South, West and East. Even the models hate us, or tease us with false information!

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  10. Rob,

    Question....

    With the heat coming next week, are we looking at dry heat or unstable humid heat?

    Also, with heat is there any potential for severe storms at some point next week or beyond?

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  11. Anonymous.. Given the westerly flow aloft from an upper ridge, that would tend to favour a drier heat pattern.. but a lot of our low level humidity is locally generated through evaportanspiration and soil moisture, so I'm sure we'll still see some elevated dewpoints with the building heat. We're approaching the period of maximum evapotranspiration contribution from plants and crops as they peak in terms of growth, with ET contribution dropping after mid July into August as crops mature.

    As for severe storms.. still too early to say. It all depends on the strength of the upper ridge as it moves over us. If it's amplified, then severe storm threat is diminished as we'll be capped along with large scale subsidence. If the ridge is flatter, then we'll have more shear to work with and a weaker cap, which would give a better chance of storm development, especially if we lie on the northern edge of the cap. Right now, it appears that the upper ridge will be amplified over the western Prairies early next week, becoming a bit flatter as it heads east over the eastern Prairies and the Great Lakes later in the week.

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  12. GFS is showing 2,000 J/KG or more of instability Tuesday of next week through Saturday or Sunday. Looks like the pattern is going to be fairly stagnant next week. We should have plenty of moisture to work with but will we have the forcing and lift to break the cap?

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  13. Looking at some of the models, we may be seeing a prolonged heat wave beginning next week. Too early to say for sure though.

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  14. Weak thunderstorm cell west of Winnipeg near Elie moving east toward the city. Could clip southwest part of city between 12:30-1 pm if it holds together. Not much to it though at this point with a few ltng strikes and some brief rain..

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  15. Looks more like a Starbuck - Sanford - La Salle trajectory.. again, not much of a storm.. maybe a couple mm of rain.

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  16. Winnipeg force shield strikes again!

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  17. Humidex of 47C in Windsor yesterday... new record once again this year in Canada.

    And the low this morning was 27C (with a humidex of 38C)...

    Truly an amazing heat wave down south.

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  18. Wind shifted to the NE in Windsor off Lake St Clair.. temp dropped from 35C to 31C past hour. That could be it for them.

    Meanwhile, Indianapolis just hit 40C (104F).. they're projecting a high of 107F which would be an all time record high for them (106F during the granddaddy of all heat waves.. July 1936) Yes, an historic heat wave through that area.. which some are saying is a hint of things to come in a warming climate.

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  19. Does it look like the storms will miss us again today?

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  20. Mike.. Activity today will be widely scattered hit and miss stuff with more support to our north through the interlake areas with that short wave moving through the northern Interlake, as well as local lake breeze boundaries. Most places won't see anything in the south, but a few storms are possible where we can get a local trigger to initiate some lift for convection. Very weak surface features to get anything going today. Any storms that do fire up may give some small hail and wind, along with locally heavy rain due to slow motion.

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  21. So now we're too far south! We were too far north just a few days ago.

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    1. Welcome to Winnipeg. Land of too far north, south, east and west. Just can't catch a break

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  22. Cell off to the NW of Winnipeg over south end of Lake Manitoba. 35000 foot tops with a developing anvil. Some lightning stikes showing up on the lightning detector, but nothing major so far severe wise. Will keep an eye on it.

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  23. Cell collapsing.. new cell developing NW of Gladstone. Pulse type storms. Better storms well north.

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  24. Heard a few faint distant rumbles of thunder in south end as that cell passed to our south. Better than nothing I guess!

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  25. Loonie size hail reported just south of the south Perimeter earlier this evening, with toonies in Landmark and St Anne's. Up to 25 mm of rain just south of Sanford. Pretty good storms just missing Winnipeg to the south. Even stronger storms east of Lake Winnipeg today.. Better luck next time folks. ;)

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  26. Lol we were too far north and south on the same day...

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  27. Note that even though the current forecast is calling for straight sunshine over the next 7 days in Winnipeg, models are showing the potential for some thunderstorms over southern MB Wednesday into Thursday as a weak upper trof rounds the upper ridge moving across the eastern Prairies. That could set off some convective activity over southern MB including Winnipeg (in fact, forecasts for neighbouring regions of Winnipeg do show a 30% POP those days)

    We may not see anything, but just bear in mind that conditions may not be as "Sunny" as currently indicated by the forecast.

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  28. 38.4C in Ashcroft, BC today with a RH of 9%...

    Ouch!!!

    That is the warmest temperature in Canada this year.

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  29. Ashcroft BC is located in the Thompson River valley in the southern BC interior, between Lillooet and Kamloops. This area is almost desert like with very little annual precip (one of the driest areas in all of Canada) and routinely, one of the hottest places during the summer. The dry climate results in very low humidities, which makes the summer heat more tolerable out there. In July 1941, this area recorded temperatures as high as 44.4C (112F), second highest temperature ever recorded in Canada. If Canada's all time high of 45.0C is ever threatened, this is one area of the country that could do it.

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  30. Are we on a pace to set a new record for =>30C?

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  31. So is the long range SCRIBE biased towards sun just for Wpg then? Due to the small size of the forecast region?

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  32. Garth.. I don't think that's the issue. SCRIBE is based on a point forecast for all regions, so it shouldn't make a difference whether it's a city or a large region. (Unless SCRIBE groups some regions together, which increases the odds of a region getting a POP) For whatever reason, SCRIBE Global seems to have a dry bias for Winnipeg especially with scattered convective type pcpn, which SCRIBE seems to play down with post processing. Also, sometimes the precip chances are at night, which the text forecast ignores in the long range since it's based only on daytime weather (silly to do that given the uncertainty in timing as you go out in time) Anyways, I'd put more faith in the actual model output than the sometimes questionable SCRIBE post processing.

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