Friday, August 03, 2012

Wet start to the holiday weekend.. showers and thunderstorms developing today with locally heavy rain possible

A pair of low pressure systems, one over southwest MB this morning and another in the Dakotas, will slowly push eastward today, triggering showers and a few thunderstorms this afternoon into this evening over southern MB.  Depending on how much sunshine we get today, some of these thunderstorms may be strong to possibly severe, with large hail and heavy rain possible.  This system will slowly push into NW Ontario overnight into Saturday, with cooler and showery weather over southern Manitoba behind the system. In all, about 15-25 mm of rain is possible today into Saturday over southern MB including Winnipeg and the RRV, with locally heavier amounts of 25-50 mm possible with stronger or more persistent thunderstorms. Sunnier and warmer weather is expected for the latter half of the holiday weekend.

RAINFALL SUMMARY - Rainfall amounts Aug 3-4, 2012
 
Location            amount

Gimli               42.3 mm
Fisher Branch       37.2 mm
Steinbach           35.5 mm
Birtle              32.9 mm
Swan valley         32.8 mm
Portage la Prairie  32.0 mm
Starbuck            30.6 mm
Brandon             30.2 mm

Winnipeg locations

East st. Paul       50.0 mm
St. Vital           46.0 mm
The forks           35.4 mm
Whyte ridge         32.8 mm
Charleswood         30.5 mm
Airport             26.5 mm

46 comments:

  1. Severe thunderstorm watch issued for RRV and SE MB, including Winnipeg. Numerous showers and thunderstorms developing over western MB and western ND at this hour, with area pushing eastward this afternoon into tonight. Despite the cloud cover, temperatures have warmed into the mid 20s over RRV with dewpoints in the upper teens, which should be enough to support some stronger storms. Stay tuned.

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  2. Are the dynamics good with this system because we will be in the right exit of the jet stream?

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  3. Accord to SPC Mesoanalysis, SBCAPE between 1,000 and 2,000 J/KG in S MB. MLCAPE 1,000-1,500 J/KG. Still some pockets of clearing ahead of the developing clusters in ND. Could get very interesting.

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  4. I mean right entrance

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  5. Tornado watch for Dauphin and Swan River. Cold-core funnels possible.


    TORNADO WATCH FOR:
    DAUPHIN - ROBLIN - WINNIPEGOSIS
    SWAN RIVER - DUCK MOUNTAIN - PORCUPINE PROVINCIAL FOREST.

    FUNNEL CLOUDS OR WEAK TORNADOES THIS AFTERNOON AND EARLY
    EVENING.

    CONDITIONS ARE FAVOURABLE FOR THE DEVELOPMENT OF FUNNEL CLOUDS
    AND TORNADOES. THESE TYPES OF TORNADOES FORM OUT OF WEAK
    THUNDERSTORMS AND ARE USUALLY NOT AS DESTRUCTIVE AS THEIR
    SEVERE THUNDERSTORM COUSIN. THEY ARE DIFFICULT TO TRACK WITH
    DOPPLER RADAR AND CAN APPEAR WITHOUT WARNING. THEY NORMALLY
    MOVE SLOWLY AND CAN LAST FOR MANY MINUTES. THEY OFTEN APPEAR AS
    A GIANT COLUMN OF DUST FROM THE GROUND TO THE BOTTOM OF THE
    THUNDERSTORM. THEIR DESTRUCTIVE POWER IS USUALLY FELT OVER A
    VERY SMALL AREA.

    TREAT ALL FUNNEL CLOUDS AND TORNADOES SERIOUSLY AND AVOID WHEN
    POSSIBLE. SHOULD ONE DEVELOP NEARBY TAKE SHELTER UNDERGROUND OR
    IN A REINFORCED STRUCTURE LIKE A BATHROOM OR INTERIOR CLOSET.
    IF YOU ARE IN YOUR VEHICLE TRY TO MOVE AWAY FROM THE TORNADO AT
    RIGHT ANGLES.

    ENVIRONMENT CANADA CONTINUES TO MONITOR THE SITUATION CLOSELY.
    PLEASE CONTINUE TO MONITOR YOUR LOCAL MEDIA OR WEATHERADIO FOR
    FURTHER UPDATES.

    SHOULD YOU SPOT A FUNNEL CLOUD OR TORNADO...AND ONLY IF IT IS
    SAFE TO DO SO...YOU CAN CALL 1-800-239-0484 TO REPORT YOUR
    SIGHTING. PLEASE NOTE THIS PHONE NUMBER IS FOR REPORTING SEVERE
    WEATHER ONLY.

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  6. More severe thunderstorm warnings out for that line of cells. Some stuff blowing up to the south of the city.

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  7. sigh, better not be another miss.

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  8. Looks like we're going to miss out on the more severe stuff...

    SEVERE THUNDERSTORM WATCH ENDED FOR:
    CITY OF WINNIPEG
    SELKIRK - GIMLI - STONEWALL - WOODLANDS - ERIKSDALE
    DUGALD - BEAUSEJOUR - GRAND BEACH
    PORTAGE LA PRAIRIE - HEADINGLEY - BRUNKILD - CARMAN
    BISSETT - NOPIMING PROVINCIAL PARK - PINE FALLS
    KILLARNEY - PILOT MOUND - MANITOU.

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  9. Lol hopefully we don't end up in that hole in the line to our south and southwest. Getting some lightning strikes and thunder here so it's better than nothing.

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  10. Some rain now. About time for some more.

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  11. I'm in south end, and the clouds to the south/southeast have a bit of a green tint to them. Getting closer too, it will be a close call.

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  12. Thunder in St. James now.

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  13. Looks like southern and eastern parts of the city will get the heaviest rain with this most recent line moving in now.

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  14. Dunno about the stronger storm off to the SW of the city...

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  15. What don't you know about it? It looks pretty blaa to this untrained eye.

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  16. About if it'll hit us or not.

    Looking like it will.

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  17. Lots of thunder with that cell approaching. It looks nasty from my view

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  18. Looks like a tornado just north of Fargo.

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  19. Very dark to the southwest. South end might get hit hard soon.

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  20. Nightfall is about to hit south end. Extremely dark clouds, wow!

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  21. Extremely heavy rain now.

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  22. Very heavy rainfall in La Salle. My windows wells on the west side filled almost to the bottom of the window! That has never happened before.

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  23. Brief, heavy wind gusts and very heavy rain here in Lord Roberts.

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  24. Heavy downpour in Charleswood with about 9 mm of rain in 15 minutes, 12 mm total so far. Strong wind gusts to 55 kmh. No hail. Storm easing now..

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  25. Today's two storms total in South St. Vital = 30 mm

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  26. According to Weathfarm mesonet, southern and eastern Winnipeg got hit the hardest with 20-30 mm of rain as of 730 pm. Only about 2-5 mm over the NW Perimeter.

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  27. more like 30-40 mm for central Winnipeg

    Daniel

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  28. henderson area we were having real heavy rain bout 10-15 min ago

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  29. 13 mm here in fort garry

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  30. Grand total of 27mm here in St. Bonifice.

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  31. Airport Auto (XWG) only had 3.8 mm between 7-8 pm (and 0.6 mm in the 2 hrs before that)

    SACN70 CWAO 040100
    XWG SA 0100 AUTO8 M M M 038/18/18/3111+23/M/0038 PCPN 3.8MM PAST HR
    PK WND 2527 0019Z 8013 46MM=

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  32. Bissett had 63 mm over the last 24 hrs, with more on the way. Looks like the GEM model wasn't overdoing it after all.

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  33. Rainfall reports around Winnipeg yesterday..

    E St Paul ....... 38 mm
    St Vital ........ 33 mm
    Transcona ....... 27 mm
    St Boniface ..... 27 mm
    Forks ........... 22 mm
    Whyte Ridge ..... 13 mm
    Charleswood ..... 13 mm
    YWG airport ..... 4 mm
    West perimeter .. 3 mm

    56 mm reported from Lockport (COCORAHS obs) with 38 mm in Gimli.

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  34. Another 5-15 mm over the city this morning, on top of the 5-35 mm yesterday. General amounts of 10-50 mm over the past 24 hours. 23 mm at my place since yesterday afternoon.

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  35. Wow and more torrential downpours this morning to add to those amounts. Raining almost as heavy as last night just a few moments ago.

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  36. Pft just got a loud and sharp clap of thunder in south end. Didn't see that coming, but to be expected with those downpours I suppose.

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  37. Looks like bulk of rain is tapering off now.. another 17 mm this morning at my place for a 24 hour total of 30 mm. General amounts of 15-25 mm recorded across the city today, highest amounts over the southwest end (White Ridge/Ft Richmond areas)

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  38. It seems to me that the amounts of rain or snow reported at the airport are almost always less than the amounts reported by neighbourhood observers in the city, and that high temperatures are almost always lower. Am I right about this and if so, what is the explanation?

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  39. With Joe's topic, will we ever get good precip measurements again? The data quality is so 200 years ago! It's very hard to compare the 21st century with data from 1800's and 1900's, as snow/rain is hard to distinguish in the spring/fall. Or do we have to wait for more funding?

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  40. This is weird Brandon 31C and Winnipeg 23C for Wednesday?

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  41. Speaking of poor airport observations, note that current dewpoint readings from YWG airport are incorrect. YWG currently reporting a dewpoint of 20C when it's more like 10. Problem has been noted by EC, awaiting repair..

    As far as precip readings are concerned, the airport does seem to have a somewhat dry bias compared to other city reports, but that could be explained by the airport's well exposed site. The site is exposed to more wind which can sometimes lead to lower rainfall readings compared to more sheltered and less wind prone areas in the city. (wind affects rainfall by blowing rain across the guage instead of straight into it) The airport site does not take any snowfall measurements any longer, but wind causes the same effect for snowfall readings at well exposed sites (i.e lower amounts)

    The main issue with YWG airport pcpn readings is with those phantom reports of 0.5 mm on clear days due to "wind pumping" causing erronous readings. Unfortunately these false readings are not deleted from the official climate records due to lack of proper quality control of climate data. Poor quality control is the main problem with EC climate data right now.

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  42. Thanks Rob

    Another thing I noticed is ever since 2002, there's a lot of ''E'' (estimated) and ''M'' (missing) symbols in the data. This really ruins the data as well. We literally have to guess how much precip. actually fell on those days to make any comparison to past years. This creates confusion and different interpretations from different people.

    It's all just a yucky mess...

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  43. I see the Perimeter shield managed to vaporise some of that rainfall that was headed for the city.

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  44. Either that or it was virga even when it went through the city.

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  45. False dewpoint reading of 23C at YWG airport resulting in a humidex of 39C this hour. NOT! Dewpoint is actually around 12C. Humidex is not a factor today.

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  46. Too bad I missed the rain. I've been looking forward to that. Yorkton had rain on Friday night/Saturday morning, otherwise it was a great weekend.

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