When you are in the middle of solving a task and the weather keeps you from making the deadline (thunderstorm knocked out the internet);the weather is called a

Barrier.

Explanation:

The weather is called a barrier because it stops you from completing your task within the given time. With this weather condition, you are unable to complete your task due to unavailability of internet which is required for your task. Weather such as thunderstorm can disrupt the internet service to a specific area because thunderstorm can destroy whatever comes in its way so if thunderstorm prevent you from doing your task complete in a given time so it is a barrier.

this protocol provides a detailed procedure for total protein extraction for western blot analysis from achieved samples following trizol isolation of rna.