The warm and calm start to Tuesday presents a misleading picture of what the rest of the day will be like. Central and southern Alberta will be the meeting ground for a number of frontal systems in the late morning and early afternoon, and that combined and heightened instability will both initiate and fuel the development of thunderstorms. The first signs of the deteriorating conditions will be building cloud cover and increasing northwest winds. In Calgary, sustained wind speeds of 40 to 60 km/h are expected in the early afternoon with gusts stronger than that. As of 6 a.m. Tuesday, rain was visible in northern Alberta with thunderstorms forming west of Edmonton just after 7 a.m. Storm cells will continue to form along the QEII Highway corridor throughout the morning, before tracking south and east during the afternoon and evening. Some of those cells will likely rapidly intensify and could prompt severe thunderstorm warnings as their potential impact exceeds warning threshold criteria. The greatest threats will include wind speeds up to 100 km/h, hail stones over two centimetres in diameter and pockets of heavy rain. Calgary is expecting rain and will likely see some thunderstorms, but areas north of the city (e.g. around Airdrie) and southeast (around Medicine Hat) will likely be harder hit. Temperatures will be cooler for Wednesday and Thursday with precipitation possible most of the next seven days.
