A Weather Moment

Another frontal system tracking across Southern Manitoba today will bring one last shot at precipitation before the sub-tropical high begins to edge northwards and push us back into a hot, dry pattern.

A cold front that brough severe thunderstorms and numerous tornadoes to Saskatchewan yesterday will push across the Red River Valley late this morning into the early afternoon. What sort of weather we’ll see from this depends highly on how much sunshine we’re able to see beforehand.

A rather large MCS will slowly decay as it moves through SW Manitoba this morning on approach to the Red River Valley. Some uncertainty exists as to what this system will do, however, and the result is dramtically different outcomes.

The NAM wants to keep this system quite progressive and push it eastwards fairly consistently. Under this solution, we’ll see a cloudy morning with some showers and thundershowers pushing through late morning/early afternoon. There’s a chance that rain could be fairly heavy under some of the thundershowers. Westerly winds would build in this afternoon flushing out the moisture in the Red River Valley and returning us to much more comfortable dewpoints in the low teens.

The growing trend in allh the other models, though, is for this system to stall out for a while over SW MB / extreme western RRV. If this is indeed what happens, things could be a little more interesting. Should the sun be able to poke through even a bit, that heating combined with the high surface dewpoints (should be in the 20-23°C range tomorrow morning) would build our CAPE values into the 2000 – 3000 J/kg range. That, combined with good deep shear and a SE wind at the surface veering to SW aloft, could provide an environment favorable for strong storms. The main threats would be heavy rainfall due to the slow-moving nature of the system (this threat would be centralized over the Western Red River Valley), strong winds and large hail. Stronger winds pushing in on the backside could favor the development of a squall-line type feature, but if they’re late to the party, a few isolated supercells certainly aren’t out of the question.

My take on all this? I think we’ll see some middle-ground solution play out. I think we’ll have a chance at seeing a bit of sun this morning, and by late morning some showers and thunderstorms will start pushing through the RRV. One can’t ignore the potential that exists for strong convection, and in that regard I would agree with the SPC’s “See Text” analysis for ND into Southern MB. The potential is there, but I wouldn’t say it’s likely. I hope that many places across the RRV see some rain as this front comes through, because it may be our last chance for a while…

After this system, the sub-tropical high will begin to build northwards again, pushing plenty of heat into Southern Manitoba. Daytime highs will remain in the high 20’s to low 30’s through much of the next 7-10 days, with nary a drop of rain in sight for the Red River Valley. After many places have gone two weeks without any measureable precipitation, perhaps not the best of news.

We’ll keep a close eye on the storms this morning and post updates in the comments as the system develops!