Final answer:
The formation of thermals and dust devils are most likely in hot, dry conditions. Dust devils occur when warm air above heated ground rises rapidly and begins to rotate. These occurrences are distinct from the effects of low-pressure systems, which often lead to cloud formation and precipitation.
Step-by-step explanation:
The forecast signs of the likely occurrence of thermals and dust devils are most associated with hot, dry conditions. Dust devils are small and short-lived whirlwinds that are most likely to form on hot, dry days when the ground heats the air above it. This rising warm air can begin to rotate if conditions are right, creating a dust devil. They are more likely to occur in hot and sunny weather because the ground heats up quickly, causing the air above it to heat up as well and rise rapidly, potentially leading to the formation of a dust devil. Dust devils are different from low-pressure systems, which are larger scale and impact weather more extensively, usually leading to cloud formation and precipitation due to the ascent of moist air. Moreover, cold, moist conditions are unlikely to lead to thermals or dust devils; instead, these conditions are more conducive to cloud formation and potential rainfall.
In hot, dry areas such as deserts, the low humidity means that dew-point temperatures are also low, indicating that air temperature can drop significantly without water vapor condensing. This lack of condensation further contributes to the extreme temperature range in arid regions, as no heat is released into the air which would otherwise moderate temperature changes.