Mesoscale: Initiating

Mechanisms that will get parcels to the LFC (air-mass boundaries, terrain, frontogenesis, gravity waves, surface heating, etc...)

What to look for:

 

- Fronts (severe TS often occur in the warm sector of a mid-latitude low or on the cool side of a warm or stationary front within 300 kilometers of the front).

 

- Other boundaries: Sea breeze fronts, ouflow boundaries, gravity waves

Surface
Orography
Insolation - Lack of clouds

What to look for:

 

- Low RH at 700 mb (lack of clouds - solar heating affects buoyancy) or dry advection at 700 mb. Consistent with the presence or arrival of a lid (capping inversion or a quasi-isothermal layer).