More Showers and Thunderstorms on the way for Parts of southern Manitoba

While temperatures will soar to near 30 degrees today, the Red River Valley should be prepared for showers and possible thunderstorms to develop by mid towards late afternoon. This will result from a low pressure system that will move into the area and tap into heat and moisture.

Temperature outlook from the weathernetwork

According to A Weather Moment " A strong capping inversion will be in place over the Red River Valley, heat and moisture being pumped northwards will be trapped at the surface, allowing our temperature to soar to the 30°C mark and pooling moisture that will push our dewpoints up to around 15°C". Today will will be a glorious day throughout the morning and early afternoon. Although conditions will start to breakdown by late afternoon as a surface low lifts north into Southern Manitoba.

According to A Weather Moment "The surface low will travel along a pre-existing surface trough and be supported by a shortwave ejecting northeastwards from the main upper trough, still anchored through Montana and Wyoming. As well With the heat trapped near the surface, the Lifted Index is expected to drop to the -2 to -8 values, with the lowest values running along a line from Gretna, MB to Bisset, MB and increasing to the southeast of that line. The heat combined with ample moisture is also expected to produce high CAPE values generally from 2000 to 3000J/kg. Increasing mid-level lapse rates with the approach of the shortwave will provide enough destabilization to erode the capping inversion through the afternoon and allow showers and thunderstorms to develop along and ahead of the warm front, initially concentrated near the triple point of the system. The showers and thunderstorms will expand in coverage as the evening progresses and the low-level jet intensifies." 

The severe weather threat is well defined says brad from A Weather Moment,"as EHI values rise to between 1.5-2.0 by late afternoon, which when combined with the presence of 30-35kt of bulk shear certainly presents the chance for supercell storms to develop. A few things hamper my excitement, though:

• Bulk shear isn’t really all that impressive; the really good shear moves through Western Manitoba through the day today, lifting northwards into the Interlake. The shear diminishes to the SE and isn’t particularly strong where the greatest CAPE is. When it comes down to it, it’s likely that we’ll end up with marginally strong shear on top of marginally high CAPE this afternoon, with the most favorable conditions missing each other.
• CAPE values may be too high. The NAM & GFS have been forecasting dewpoints slightly higher than have materialized. The amount of energy for storms to work with is going to be heavily dependant on the dewpoints that develop this afternoon, and if they don’t make it as high as forecast then we’ll be seeing weaker storms.
• Too many storms. With so many marginally severe features, we may see quite a few showers and thunderstorms develop this afternoon as the cap erodes. If too many fire off, then it will be difficult for any one storm to oragnize itself into anything that poses a severe weather threat."

All that being said, a potential for severe weather does exist today across south-central and southeast Manitoba. The main threats should severe weather develop will be hail and/or the possibility of a tornado."

Severe Weather threat as highlighted by Brad

Overall everyone should be on the lookout for severe weather and or Storms, as well updates will be available on Twitter.