Showers and thunderstorms possible tonight into Friday

A developing low pressure system over southern Saskatchewan will tap an increasingly moist and unstable airmass over the Dakotas to trigger scattered thunderstorms over North Dakota today. Some of the storms over the Dakotas are expected to become severe later today into this evening with much of the northern Plains in a slight to moderate risk of severe thunderstorms. As the low pressure system advances east, showers and thunderstorms will spread over southern MB tonight.. with the potential for locally heavy rain (20-30 mm).. intense lightning.. and hail, especially over southwestern MB. This activity will push through Winnipeg and the Red River Valley Friday with drier conditions moving in by evening as a dry slot pushes in. Cooler unsettled weather will return for Saturday in behind the low with brisk northwest winds and a few showers over southern MB.  Highs will likely struggle to reach 20 degrees Saturday. Sunny and warmer weather is expected for Sunday Monday and Tuesday with highs likely approaching the 30 degree mark by the July 1st holiday.

Storms develop over east Winnipeg

Thunderstorms have developed along a lake breeze convergence zone between Lake Winnipeg and Lake Manitoba, setting up right through the middle of Winnipeg. (see radar image) The N-S convection axis cuts right through the middle of the city, with storms pretty much confined to the east end, nothing but blue skies in the west. Localized downpours, and small hail have been reported with the storms. Storms are moving to the south-southeast at about 40 km/h.

Severe tstms over SW Manitoba

A line of severe thunderstorms has developed over SW Manitoba this afternoon, bringing hail as large as ping pong balls between Melita and Virden and loonie size hail just south of Melita. This line is moving east at 40 km/h and has the potential to produce additional large hail and damaging wind gusts of 90 to 100 km/h.  This line will continue moving east through the afternoon, possibly reaching the Red River valley this evening. We'll have to see if these storms remain severe by that time.

Red River update

The Hydrologic Forecast Centre of Manitoba Water Stewardship advises that the Red River continues to rise due to heavy rainfall June 6-12, 2008. The crest is presently at Grand Forks, North Dakota.

At Emerson the river has risen 13 feet since early June and is expected to rise another 6 feet before it crests on June 22. At Ste. Agathe the river has risen 8.7 feet since early June and is expected to rise another 4.9 feet before it crests on June 24. In downtown Winnipeg the river level this morning stood at 8.1 feet above datum, a rise of 1.7 feet since early June. It is expected to crest between 9 and 10 feet above datum June 24-26.

Public Works and Government Services Canada (PWGSC) will continue to operate St. Andrews Dam at Lockport to maintain levels below 8.5 feet (Forks walkway level) in Winnipeg for as long as possible. However a minor inundation of the walkways is expected for a period of one week beginning this weekend.

Levels just upstream of St. Andrews dam have been declining as usual due to opening of the dam. PWGSC will issue information regarding operation of the locks for boat traffic. River levels from Selkirk to Breezy Point will rise 4 to 6 feet above normal summer levels which will not present any significant difficulties.

While the Red River will be well above average for the next few weeks it will remain well within its banks unless additional widespread heavy rain develops during the next few weeks. Boaters and canoeists are advised that the river current will be stronger than usual for the next few weeks, and therefore caution is advised.

Finally! - sunny warm stretch ahead

Well, it's been a long time in coming.. but it finally looks like southern MB will see an extended spell of sunny warm weather this week.  An upper ridge will be building over the Prairies this week, giving warmer temperatures in the mid 20s and more importantly, a lack of precipitation bearing weather systems.  This will finally give southern MB a break from a week of heavy rainfall, and a much needed spell of warm weather. Southern MB has basically been below normal temperature wise for the past 8 weeks.  This upcoming stretch of warmer weather, along with adequate soil moisture in all regions, will go a long way in accelerating crop development which has been slow due to the cool spring.