Cool start to June with frost risk tonight..

After a soggy end to May, a ridge of high pressure will bring clearing skies and drier weather this weekend over southern Manitoba to start off the month of June. Temperatures however will be below normal, with daytime highs only in the mid teens today and Sunday, some 7C below normal for this time of year. As the ridge builds in over southern Manitoba tonight, clear skies and diminishing winds will give ideal conditions for areas of frost overnight across much of southern Manitoba including Winnipeg. Temperatures will be dropping to the 0 to +2C mark tonight, with a good risk of frost overnight into early Sunday in many areas. Sunny skies and light winds will make for more pleasant conditions Sunday, as afternoon temperatures climb to the 16C mark. Dry weather is expected into early next week before another disturbance brings a threat of more rain by mid week.      

..Soggy end to May over southern Manitoba..

A slow moving storm system over the Dakotas brought another round of heavy rainfall to southern Mnaitoba over the past two days, less than 2 weeks after  a similar rainfall event brought drenching rains to the same area over the Victoria Day weekend. General rainfall amounts of 30 to 60 mm were widespread mainly along and south of the TransCanada highway  with locally heavier amounts  of 80 to 125 mm along the western Red River valley. 

At my site in Charleswood, I recorded a storm rainfall total of 43 mm, while 50 to 70 mm was reported over the south end of the city. La Salle reported 54 mm.  Unofficial reports of 80 to 125 mm were received for areas along the western Red River valley from the Austin and MacGregor areas to west of Miami to the US border. Overland flooding was once again reported in the Morden area due to heavy rains along the Pembina escarpment. This area was flooded over the Victoria day weekend as well with local amounts of 100 to 200 mm of rain during the 3 day rainfall event.   

Rainfall storm totals to 1 am Saturday since the rain began Thursday morning..   

  
ENVIRONMENT CANADA STATIONS  
  
DEERWOOD .................. 81 MM  
MORDEN .................... 69 MM  
PORTAGE LA PRAIRIE ........ 63 MM  
CARMAN .................... 52 MM  
EMERSON ................... 42 MM  
WINNIPEG FORKS ............ 40 MM  
WINNIPEG AIRPORT .......... 38 MM  
PINAWA .................... 37 MM  
GRETNA .................... 36 MM  
GIMLI ..................... 35 MM  
CARBERRY .................. 29 MM  
MELITA .................... 24 MM  
PILOT MOUND ............... 22 MM  
BRANDON ................... 19 MM  
SPRAGUE ................... 13 MM  
MCCREARY .................. 11 MM  
DAUPHIN ...................  6 MM  
  
MANITOBA AGRICULTURE SITES (MAFRI)  
  
TREHERNE .................. 68 MM  
PORTAGE LA PRAIRIE EAST ... 67 MM  
RESTON .................... 56 MM  
CARMAN .................... 55 MM  
STARBUCK .................. 54 MM  
WINKLER ................... 53 MM  
MORRIS .................... 49 MM  
ST ADOLPHE ................ 42 MM  
MANITOU ................... 42 MM  
LETELLIER ................. 41 MM  
DELORAINE ................. 41 MM  
GLADSTONE ................. 39 MM  
ST PIERRE ................. 37 MM  
ELM CREEK ................. 37 MM  
ALTONA .................... 36 MM  
SELKIRK ................... 30 MM  
STEINBACH ................. 26 MM

Unsettled week ahead..

The weather pattern will be getting more unsettled over southern MB this week as an upper ridge of high pressure starts building over eastern North America, while a long wave upper trof sets up over the west. This will set up a storm track across the northern Plains and southern Prairies this week, with periodic weather systems bringing occasional rounds of showers and possible thunderstorms.  The first wave of precipitation is expected this afternoon into tonight over southern MB as a band of showers over North Dakota spreads northeast. Another impulse over the Dakotas will threaten more showers and possibly thunderstorms over southern MB later Monday through Monday night into early Tuesday with locally heavy rain possible. Drier weather is expected midweek before a more potent system developing over the Dakotas brings more showers and thunderstorms later in the week. Overall, not the greatest week if you're looking for a prolonged stretch of sunny warm weather!  But then, this is not unusual for this time of year. On average, June is the wettest month of the year over southern MB, as increasingly warmer and more humid air to our south tries to spread north, and interacts with weather system crossing the Prairies.     

Nice dry weather for the rest of the week..

After a soggy holiday weekend that dumped 15-50 mm of rain over Winnipeg, and up to 200 mm over the Pembina escarpment west of Morden,  the weather pattern will be a lot drier this week as a ridge of high pressure builds in over the eastern Prairies. This ridge will bring mainly sunny skies and near normal temperatures for the rest of the week, along with low humidity and diminishing winds.. perfect conditions for drying out left over moisture from the weekend. The next chance for rain will be Saturday as a weakening band of showers from Saskatchewan pushes across southern MB. At this point, it looks weak, and the current forecast of "periods of rain" for Saturday looks overly pessimistic.

May 18-20 weekend rainfall totals..  

Winnipeg
north end....... 15 mm
Airport ......... 18 mm
Forks ............ 24 mm
Charleswood ... 27 mm
Norwood ........ 31 mm
South Winnipeg ... 30-50 mm

Thornhill .............  205 mm
Darlingford .......... 200 mm
Miami 10SW ...... 125 mm
Morden 6SW ...... 120 mm
Deerwood ........... 100 mm
Morden ...............  90 mm
Somerset .............  80 mm
Winkler ...............  77 mm
Manitou ............... 76 mm
Sprague ............... 73 mm
Carman ................ 68 mm
Emerson .............. 55 mm
Morris.................. 54 mm

Note the heaviest amounts over the western Red River valley along the Pembina escarpment. A persistent northeast upslope flow through the weekend contributed to the locally higher amounts in that area, leading to overland flooding. Note that similar amounts were reported along the escarpment in neighbouring North Dakota with reports of up to 225 mm near Walhalla. This has forced the evacuation of the town of Cavalier, ND due to concerns about a nearby dam failing.

Unsettled weekend.. locally heavy rain possible at times.. but rain-free periods as well

3 day precipitation outlook (Fri - Mon)
from HPC, amounts in inches
showing heaveist rain of 75+ mm
south of the US border

A complex weather pattern will be setting up over the Northern US plains this weekend,  which will be impacting the weather over southern MB for the May long weekend.  A series of disturbances will be triggering showers and scattered thunderstorms over North Dakota and northern Minnesota over the the next few days, some of which may bring areas of heavy rain to southern MB.  Models however are having a tough time coming to a consensus as to when and where most of the precipitation will be falling over southern MB. It appears there will be an initial band of showers and thunderstorms developing tonight over North Dakota and spreading into southern MB overnight into Saturday, with the potential for locally heavy rain in showers or scattered thunderstorms.  On Sunday, a stronger system developing over South Dakota will move into northwest Minnesota, triggering more widespread showers and thunderstorms south of the border. This area of precipitation is expected to push over southeast MB Sunday night into Monday, although models having varying opinions on how far northwest this second wave of showers will spread. Some models are indicating that most of the heaviest precipitation will stay over extreme southeast MB and miss Winnipeg and the RRV. Other models are indicating that showers will push into Winnipeg and the southern Interlake by holiday Monday. Thus, the forecast for the latter half of the holiday weekend is still in doubt. Bottom line: not the best holiday weekend, but not a total washout either. Note however, that the potential for locally heavy rain (50 mm or more) is possible this weekend for parts of southern MB including the Red River valley.  (Consult  HPC precipitation forecasts for updated trends on expected precipitation patterns this weekend)