This study develops an observation-based mechanistic heat transfer model that can be extended to the whole boiling curve to reflect real physical phenomena on a heated surface. In addition to hot spot formation, this study focuses on dry patch behaviors, which actually directly trigger CHF occurrences. For that purpose, hot spot distribution and the critical number of hot spots are further considered to determine the kinds of dry patches, whether reversible (quenchable) or irreversible (unquenchable). To assess the prediction performance, CHF data that include combined effects are used for data comparisons. The developed model predicts well for large dimensions at a vertical orientation, suggesting potential applications to large-scale facilities.