Homographs are words that are spelled the same regardless of pronunciation (they may be pronounced the same or differently). Homonyms are words that are both spelled and pronounced the same. Therefore a homonym is both a type of homograph and a type of homophone. To be correct I believe the Venn diagram should have one circle labeled homograph and the other labeled homophone. The intersection should be labeled homonym.
An Excessive Heat Warning is issued when heat indices are expected to reach at least 105 degrees, except at least 110 degrees over Delmarva and far southern New Jersey (Salem, Cumberland, Cape May, and Atlantic Counties).
1 The body temperature may rise to a dangerously high level in a short time and cause death.  Worker exposure to hot kitchen environments. Temperatures can reach 105 to 110 degrees while cooking in front of hot grills. Exposure to excessive heat may lead to heat exhaustion, heat stroke, and possible death.