Environmental changes like a change in barometric pressure, can definitely trigger migraine.  Intractable migraines are triggered by many of the same things that trigger regular migraines. While doctors don’t completely understand what causes migraines, they can agree that several key components play a significant role as migraine triggers: genetics, lifestyle, environment, and body chemistry.

They believe that when there is an upset or imbalance in any of these components, it causes changes within the brainstem which impacts how it interacts with the trigeminal nerve. The trigeminal nerve is the largest of the cranial nerves and, as the name implies, is comprised of three nerve branches: the maxillary nerve, the ophthalmic nerve, and the mandibular nerve.

The maxillary nerve and ophthalmic nerve are sensory nerves in the face and head while the mandibular nerve does double duty managing sensory functions as well as supplying motor function like biting and chewing. The largely sensory aspect of this nerve gives it the potential to be a substantial pain pathway.