Tuesday, June 12, 2007
Severe thunderstorms likely across southern MB today..
A hot and humid airmass combined with a slow moving cold front to our west will likely trigger another round of severe thunderstorms over southern MB this afternoon into this evening. A cold frontal trough this morning extends from Arborg through Portage La Prairie to west of Pilot Mound, and this feature will likely focus severe thunderstorm development later today mainly west of the Red River valley, pushing into the Red River valley this evening. Looking at the soundings this morning, the potential is there for massive thunderstorms of 60000 feet with energy values of 3000 j/kg or more! Yesterday, the same trough line produced numerous severe thunderstorms over southeastern SK with quarter to golf ball size hail, and damaging wind gusts to 100 km/h or more. These severe weather threats will likely be repeated today, except this time over southwestern MB. Discrete supercell thunderstorms may also give isolated tornadoes. Exceptionally heavy downpours will also accompany the storms thanks to a very humid airmass in place east of the frontal trough with dewpoints in the 20-22C range. These can lead to locally flooding rainfall rates of 50-100 mm/hr possible. Put it all together, and you have the ingredients for a very active afternoon and evening over southern MB today!
Posted by rob at 9:34 AM