Sunday, March 22, 2009

Thunderstorms bring heavy rains to western MB.. rain to overspread Red River valley tonight..

A line of showers and thunderstorms brought heavy rain to western MB today, with unofficial amounts of 30-45 mm from southwest MB across the Riding Mountains through Dauphin. This area of convection will be moving off to the north and northeast this evening, but another area of showers and thunderstorms developing over North Dakota will spread over the Red River valley and southeast MB this evening and overnight. 10-20 mm of rain is likely in these areas by Monday morning with locally higher amounts possible in some areas due to thunderstorms. Watch for localized flooding as many ditches are near bank full and will not be able to absorb any excess rainfall. After a break Monday, more rain is on the way Monday night into Tuesday with another 10-20 mm possible, along with a change to snow by Tuesday night into Wednesday.


  1. NWS is predicting 2-2.5 inches of rain for the entire American RRV. The river forecast shows the Red River cresting in Fargo on Friday morning at 40 feet. I don't know how much precipitation that 40 foot crest is based on, but I would guess it is less than 2" of rain.

    The GFS and NAM are showing rain changing to snow early Tuesday morning, meaning that 10 to 20cm would be possible in virtually all of southern Manitoba (with higher amounts farther west).

  2. Looks like a line of showers and embedded thunderstorms have formed ahead of the main area of heavy rain!

    What's that I see on radar!
    A small thunderstorm just formed south of Winnipeg!

    Might hear a rumble or two of thunder on the west side of the city soon!

  3. Rain continues to fall over southwest MB this evening.. rainfall totals now over 50 mm along Hwy 10 and Hwy 21 corridors. EC's station at Dauphin has registered 70 mm, but that is likely double the actual amount since the gauge there still has a Nipher shield attached. A nearby CWB site at Dauphin was recording 29 mm which seems more reasonable.

    Some rainfall readings from the non-nipher CWB mesonet include..

    Rivers....... 55 mm
    Hamiota...... 45 mm
    Minnedosa.... 43 mm
    Rossburn..... 42 mm
    Shoal Lake... 41 mm

    A site at Strathclair has recorded 50 mm. Wasagaming also has recorded over 50 mm. Brandon Airport just missed the heaviest rain, getting 18 mm up to 7 pm.

  4. Amazing... convective cells continue training over western Manitoba.

    First line of showers thru Winnipeg... big blob of convection upstream in N Dakota yet to move thru.

    Cooler, dryer ESE flow continues undercutting the warm moist southerly jet at 850 hPa. Surface dewpoints refuse to budge from around 0 C. We may 'wet bulb out' to 1 or 2 C as the bigger convection moves in... yikes.

  5. Rob...there still is thunderstorms that are forming at this time of night in South western Manitoba!

    A thunderstorm has just formed at the Sask/ Manitoba border!

    Here in the RRV the convective nature is pretty much non - existent!
    A good steady rain is quickly filling in on Southern RRV!

  6. Does anyone know what the amount of precipitation will contribute to the coming surge of water from North Dakota? Is that 1 in 10 chance odd of a 1997 flood getting larger?

  7. Adam..

    I believe Alf Warkentin was saying that if we got 25 mm precipitation in the Red River basin, it would increase the odds of a 1997 type flood to 50%. They'll be issuing an updated flood forecast today so we'll know better then. No doubt though, this week's pcpn has raised the flooding potential..

  8. Looks like a general 5-10 mm across the RRV last night, which is about half of what models were indicating. Bulk of precipitation fell over eastern ND and northern MN where 10-25 mm was reported. GFK and Fargo had about 15 mm last night while I received 6 mm here in Charleswood. Dewpoints never climbed last night as much as I was expecting thanks to a southeast wind that kept advecting drier and cooler air from the east which may have kept our rainfall amounts down.

    Attention now turns to Colorado low system which will bring more rain tonight changing to freezing rain and/or snow Tuesday. Looks like 10-15 mm of rain by Tuesday morning changing to snow by evening, with 5-10 cm possible by Wednesday morning. Heavier snow amounts likely west of RRV. There is also a risk of freezing rain over the RRV Tuesday as colder air undercuts the rain Tuesday morning before the changeover to snow.

  9. Winter Storm watch issued for all of southern Manitoba!!!

    They say in there discussion that the City of Winnipeg will very close to the rain/ now line!

    Rob you think that snow would accumulate with all this standing water????

  10. Reports coming into the NWS...indicate 24 hour totals (thru 7 am) of 1.30 in Moorhead...0.75 in Fargo area...1.90 in Breckenridge...widespread 2-2.50 inches thru 7 am Wahpeton westward thru Richland county... close to 1 inch West Fargo...just over half inch in Grand Forks...2-2.50 inches Fergus Falls MN area.

  11. hey Dan, those numbers aren't good. The mother low hasn't even hit yet. Rob said 15mm for Fargo, so that's off big time.

    I think the 40.1 ft crest from 1897 may be matched this year. I'm actually starting to worry about Fargo and Grand Forks.

    The only thing to hope for now is if we get a really good shot of cold air to slow the melt and runoff!

  12. Anonymous...about the 15mm in Fargo, that's not off big time, if you count the heavier amounts of rain that fell, then yes it is off. But 0.75'' and 0.5'' converted into millimeters isn't off by much...

    But yeah, I am starting to worry about Fargo and Grand Forks

  13. Downstream Fargo and GFK RR tributaries Doubled to Quadrupled flow since 3pm yesterday. Interesting graphic FARGO flooding tool by Houston Engineering at

  14. Rob!
    According to the latest GFS it looks like more and more likely that the cold air will overtake the region and change the rain over to snow sooner than the previous run!

    What are you seeing as of right now for the timing of the rain / snow line!

    Are the other computer models showing colder faster now???

  15. We are forecasting about 1 inch of more rain tonight into early Tuesday for Grand Forks-Hillsboro area about 0.75 inch more in Fargo tonight The American River Forecast Center in Chanhassen uses mostly HPC gridds for their qpf input and their numbers were a bit lower than my thinking but not greatly. It appears that rainfall tonight will not greatly affect Fargo's crest info but if we do indeed get into the def zone rain at GF then it may trend forecast toward higher end of current crest range of 48 to 52.5 ft.

  16. I know this is off topic but....

    If you check out tornado live streaming tracker they show some pretty neat stuff!

    You can see in real time where all the storm chasers are and live streaming video.
    They even have a new google map layout with all new radar overlays!

    AMAZING I wonder if that would up here!!!! LOL

  17. Interesting precip pattern from GFS... not sure I am buying it entirely. Think best bet for heavy snow band to set up will western Dakotas SW Manitoba and possibly the interlake.

    20 - 30 cm is not out of the question for upslope regions of riding mtn etc. Good 700 hPa baroclinicity present and below zero 850 hPa temps in these areas.

    For RRV things get murky... at least as far as GFS is concerned. At first we seem to be in a 'no mans land' between the well defined deformation zone and warm advection/LLJ part of the storm.

    Initially warm nose at 700 hPa is progged over Winnpeg with aforementioned deformation off to the NW. As band works east... a back flow of warm advection at 850 hPa occurs.

    Consequently, the rain/snow band for would stay just west of Winnipeg until at least mid afternoon. I have a feeling it could even bisect the city... what forecasting nightmare.

    Of course this is only from GFS. I am disappointed that EC does not release more parameters from GEM to the public. If NCEP/NOAA can do it.. it seems odd that the powers that be at MSC or EC would not follow that lead.

  18. Weather warning and winter storm warning issued for all of Southern Manitoba!

    Look out folks....this could get interesting!

  19. EC ended winter storm warning for Riding Mtn.. interesting