Thursday, June 25, 2009

Thunderstorms and heavy rain possible Friday night

A trough of low pressure over Saskatchewan will be advancing towards southern Manitoba Friday into Friday night. Southerly winds ahead of the trough will bring a warm and increasingly humid airmass over southern MB during the day, with thunderstorms developing by late afternoon or evening. The storms may generate heavy rainfall over the Red River valley Friday night into Saturday morning with rainfall amounts of 20-30 mm likely, with 50 mm or more possible in some areas. Some storms may be severe with large hail and damaging winds. Cooler and unsettled weather will follow on Saturday before a drying trend Saturday night into Sunday.


  1. Whats the POP or the threat of severe thunderstorms tommorow like around winnipeg. Any tornado threat?

  2. Storms are developing quite nicely in SK this evening.

    Since the dynamics for our storms will be moving in from SK, I think we are in for a good event tomorrow.

  3. Tomorrow will be a real wait and see game.

    The 00Z NAM shows very poor CAPE in S MB tomorrow afternoon/evening. However, just this morning the same model was showing excellent we won't really know until tomorrow. Bear in mind that some nice storms formed in SK tonight with <2000J/kg of CAPE, generally between 1000 and 1500J/kg.

    We really need to get good heating tomorrow in order to make something happen. Regardless of what happens in terms of severe storms, it looks like S MB will make up for its rain deficit Friday night-Saturday...just when the mosquitoes were starting to get better.

  4. Rob!
    Looks like we are in for a MAJOR rainfall!

    Environment Canada is now calling for between 35- 50 mm for the Red River Valley!

    Flash Flood Watch issued for south of the border!

    Looks out folks ....

  5. Ensembles are giving a 50% chance of at least 25 mm of rain for Winnipeg tonight into Saturday, with a 25% chance we'll see 45 mm on the high end, or 15 mm on the low end. NAM is wettest over us with 75 mm through late Saturday, while GFS is driest at 15 mm. GEM is in between with about 30-50 mm for Winnipeg, although it's showing higher amounts south and east of the city. Whatever the case, looks like a wet Friday night and Saturday coming up.. bad timing for Saturday outdoor activities.

    Severe weather threat for us today will be contingent on amount of insolation we can get. Debris cloud from overnight convection to our west may limit extent of heating over southern MB today, reducing severe weather threat over us. Severe storms more likely over ND especially by evening once cap breaks.

  6. The TWN forecast Radar shows eerily similar to the Elie incidentent .Woodlands Radar of two years ago with one set moving ESE coming off Lake MB then jogging south towards Elie The other, coming from a line just south of Portage La Prairie They looked like they would merge in Wpg until the last 10 minute update. And the rest Justin??

    Todays first line of nastiness on TWN fcst Radar is now shown as thru Winnipeg about 4pm.

  7. Ya these storms are starting to fire up big time even with the presence of all the cloud cover!

    This could be a long day!

  8. Severe Weather Bulletin
    issued by Environment Canada
    at 10:25 am CDT Friday 26 June 2009.
    Watches/warnings in effect for southern Manitoba...

    Severe Thunderstorm Watch for:
    =new= City of Winnipeg
    =new= Steinbach - St. Adolphe - Dominion City - Vita - Richer
    =new= Selkirk - Gimli - Stonewall - Woodlands - Eriksdale
    =new= Dugald - Beausejour - Grand Beach
    =new= Portage la Prairie - Headingley - Brunkild - Carman
    =new= Morden - Winkler - Altona - Emerson - Morris
    =new= Brandon - Carberry - Treherne
    =new= Killarney - Pilot Mound - Manitou
    =new= Melita - Boissevain - Turtle Mountain Provincial Park
    =new= Ste. Rose - Mccreary - Alonsa - Gladstone.

    Severe thunderstorms are possible this afternoon continuing
    into this evening in advance of a cold front approaching from
    the west.

    This is an alert to the potential development of severe
    thunderstorms with large hail and damaging winds.

    Monitor weather conditions..listen for updated statements.
    If threatening weather approaches take immediate safety

    a cold front approaching from western Manitoba will move across the
    province today, triggering thunderstorms as it moves. Some of these
    storms will likely be severe...with torrential downpours, damaging
    winds and large hail being the most likely threats. The threat of
    severe weather will continue through this afternoon into this

    Please refer to the latest public forecasts for further details.


  9. Latest model runs are going insane with the rainfall amounts for YWG and RRV tonight.. 12z NAM showing 90 mm for Winnipeg tonight into Saturday morning.. 12z GEM painting a 103 mm QPF bullseye over Emerson by 12z Saturday morning. Torrential rainfall looking more and more likely for portions of RRV tonight into Saturday.

    Meanwhile morning storms are still going strong, and WW issued for much of southern MB as they progress east. Juiciest airmass though is still building over ND which will fuel intense thunderstorms south of the border that will drift north and give heavy rainfall over us. Should be an interesting 24 hours!

  10. This rain will be bad timing for tomorrow's Rock on the Range concert at the stadium. Billy Talent's "Rusted from the Rain" will be quite the appropriate tune tomorrow!

  11. Rob!
    Environment Canada has just issued a Special Weather Statement !

    Concerning very heavy rainfall!!

    50 mm in severe thunderstorms this evening, followed by 30 -60 mm tonight into Saturday with embedded thunder!

    Oh my......better get the sump pump ready!!!!

  12. Rob I note the Winnipeg/Mb interactive wundermap has everything on Hwy 3 from Carman to Oak Bluff and Charleswood as 20/21C While Morden east to Emerson and up Hwy 75 to just north of Morris is 25 to 28C
    . Is that space in between the Bullseye you referred to??

  13. I don't really like how things are shaping up. Debris cloud/weak thunderstorms have destroyed any chance of daytime heating. CAPE values are slowing building in through the south-central portion of the province, but it is unclear as to whether the instability will continue to expand. Shear is good, but doesn't help much in a stable atmosphere. We have a strong trigger to work with, which is positive.

    Don't ask me what will happen, because I have no idea. Monday was supposed to be a good severe day, but it turned out bad. Maybe today will turn out good, because we expect it to be bad.

  14. Rainfall warning issued for areas southwest of Winnipeg!

    Another is 31 C in Grand forks as of 1:00 p.m

    It is amazing how much rain will cool the air down from 26 to 21 C in a matter of a hour!

  15. Rainfall warning issued for Winnipeg area!

    50 - 100 mm of rain!
    Why does Environment Canada not issue flash flood watch or warnings like the National weather service????

  16. Does Justin have his Storm tracker Video feed live??
    He can park and watch. TWN Beta Radar Forecast places that large collection of cells currently just east of Turtle Mountain to reach South West corner of Wpg at 750pm .

  17. Elevated convection in association with LLJ persisted thru out the day. I would expect radar coverage to increase in response to nose of strengthening LLJ (to near 50 kts), deep moisture transport (850 hPa Tds of 15 C) and an interesting coupled jet structure at 300 hPa (we will be between a right entrance and left exit region). The heavier precip should end by 6 am tomorrow as LLJ moves off east and we get into more of a deformation zone under the upper low.

  18. Daniel..

    EC does not issue flood watches or warnings. In Canada, flooding statements are the responsibility of the province. Manitoba Water Stewardship has issued a high water watch for the southern RRV and southeast Manitoba with the possibility of overland flooding.

    By the way, 12z ensembles gives a 50% chance of 50 mm of rain within 12 hrs for Winnipeg.. which is the highest ensemble average I've seen for us.

  19. A pair of tornadic supercells have formed in North Dakota.

    Not likely to make it into Southern Manitoba with tornado potential...

    Radar is sure starting to "light up"

  20. Here is a three model average for rainfall in S MB (GFS, GEM, NAM):

    Winnipeg : 83mm
    Brandon : 7mm
    Steinbach: 50mm
    Portage : 61mm
    Morden : 65mm

    The model estimates are really all over the map. The GFS and NAM seem to be closest, but there are still some major differences. I doubt any of the models will get this right, since precip amounts will be determined by how many thunderstorms move over a particular area. That is why I did a three model average.

  21. I hope we will at least get some lightning tonight. I don't think I have seen any lightning at all this year. It's kinda insane really.

  22. I can't believe how many thunderstorms are erupting south of the border!

    Numerous tornado warnings are in effect right now!

    Could even be a tornado threat along the international border this evening!

  23. Very sharp cutoff to the precip this evening... lines up very well edge of LLJ from RUC. Although LLJ ramps up to 40 kts overnite, nose of jet practically remains stationary. Therefore I think the bulk of the precip will accumulate where it is raining right now. This is going to be a real headache in terms of QPF for the city. South of the TransCanada may well see up to 75 mm... north of Winnipeg may just end up with 10 - 15 mm... do you agree Rob?

  24. Looks like heaviest rain axis is setting up over southern RRV into SE MB this evening.. with heavy rain axis shifting over entire RRV including Winnipeg overnight as an area of moderate to heavy rain over central ND spreads north. Models still indicating a good 50-75 mm for Winnipeg by Saturday morning.. although that may be on the high side based on current radar trends.

  25. 20.0mm in Steinbach so far.

  26. Looks like the first batch of heavy rain has finally made it across the border!

    Look for heavy rain in Winnipeg in the next hour!

  27. Good example of back building convection down around the Grand Forks area earlier today.. so far that is where all the instability and LLJ has been focused.

    As Rob suggested, the models hint at nudging the LLJ a bit further north starting around midnight. With better forcing and elevated instability/ deep moisture being advected into our region.. the heavier showers will try to push north. Will be a close call for Winnipeg, but its safe bet to say south of highway 1 will see the highest totals...

  28. Large discrepancy in rainfall across Winnipeg.. with heaviest rain falling east of the Red River. Here in Charleswood I picked up only another 10 mm since midnight, for a storm total of 25 mm. East end of the city has picked up 30-50 mm since midnight, with 40-60 mm storm totals.

    Areas south and east of Winnipeg have picked up the most rain with storm totals of 60-90 mm from Morris through Steinbach.

  29. I have picked up a storm total of 72.4mm. My yard has ponds everywhere.

  30. The Devils Lake MADIS reports 154.5 mm

  31. Hi from down south...

    From reports into the area Walsh county ND (Grafton-Park River) hardest hit with rainfall with 4-7 inches in many areas....heaviest central into southwest part of the county. Grand Forks got just shy of 3 inches total. Real ugly looking outflow clouds last night into the city...with funnels and rotation in spots along the leading edge but rotation was short lived.

  32. Looks like then areas in south eastern Manitoba and northern North Dakota got a month's worth of rain....wait even more!

    I watching the live coverage of Grand Forks storms last night on WDAZ

    Yes that was quite the storm last night!

    Here in Winnipeg....not even a flicker of lighting!

  33. Rob!
    Are you getting some very strong winds???

    Here across the river by the Grace Hospital were are getting some very strong gusts of wind!

  34. Warm advection convection has moved off into NW Ontario while deformation zone still affecting interlake and western RRV...

    Forcing from LLJ seemingly bisected the city last nite. While deformation band set up from Portage NE to the interlake. Almost like a very narrow dry slot set up over western Winnipeg and the airport.

    Models show 500 hPa shear axis and area of midlevel deformation moving east as low slowly nudges east. Therefore I expect steady precip to move back into Winnipeg and linger perhaps until dark.

  35. Lots of severe thunderstorms starting to fire in South western Manitoba!

    That took me by surprise!

  36. Those thunderstorms are occurring in a region of significantly lower mid level moisture (850 Td's around zero vs 10 C for us) allowing for sunshine, and colder mid level temperatures leading to destabilization.

  37. A very narrow ribbon of heavier rain running right through Winnipeg will help boost Winnipeg's rainfall total!

    A quick 15 mm if this ribbon of rain continues!

  38. Rob...
    How much rain have you picked up so far????

  39. 52mm here in Transcona

  40. 82mm so far in Steinbach...and it just keeps raining!

    If those thunderstorms west of Winnipeg stay together and expand, many places will exceed 100mm.

  41. I'm told 6 inches of standing water in Ponemah (Winnpeg Beach) and now this at 5:15pm



  42. Tornado warning for southern Manitoba.

  43. Picked up another 10 mm since this morning.. I'm up to 35 mm in west Winnipeg as of 9 pm. This is about half the total amount that fell in the east end of the city.. where 60 to 70 mm was common. Areas north and east of the city really got soaked today.. with amounts of 60 to 70 mm since midnight. Looks like the eastern Interlake, southern RRV, southeast MB including Whiteshell got the most rain with 70-90 mm totals.

    Some EC climate observer reports include..

    Pinawa........84 mm
    St Labre......78 mm
    Oakbank...... 75 mm

    Winnipeg Forks picked up 48 mm.

  44. Rob what was with that tornado report to the south?

  45. 9 foot waves on Lake Winnipeg south basin this evening. Strong winds of 50 G 70 out on the lake, translating into 80 G 100 on land.

  46. Chris..

    That tornado warning was based on radar rather than an actual report of a touchdown. I don't think a tornado was actually ever spotted with that cell. However, if radar suggests a strong possibility of a tornado occurring or forming, EC can issue a tornado warning regardless if one has actually been sighted. This is a more proactive approach for tornado warnings that is used extensively in the States.

  47. This storm is very reminiscent of last year's mid summer bomb that brought rain and high winds to southern MB on July 13th (during Folk festival). That system was an unseasonably strong 984 mb low that moved east of Berens River and brought 50-75 mm over the northern Interlake, and 90-95 km/h northwest winds on Lake Winnipeg and Lake Manitoba.

  48. Picture of funnel cloud from Plum Coulee posted on TWN this evening...can't seem to view this from work...Rob can you and if so, does it look like a FC? (DAF)

  49. Sorry Dan.. signed off before I saw your post. Checked TWN site but I didn't see anything on it..