Using the System in Hot Summer Climates: Special Challenges

The synoptic-based Heat/Health System (developed at the University of Delaware) has been running in Phoenix for five summers. Use of the System continues to be a growing experience, partly because of the extreme summer climate, but also because of complexities caused by intense “dry heat” episodes contrasted with periods of modestly high temperatures combined with high dew points. For these reasons, several modifications, unique to Phoenix, have been made to the System. One of these involves the inclusion and fine tuning of a record high temperature curve which is frequently approached; if temperatures are near that curve, the Phoenix WFO issues a Heat Advisory regardless of the system guidance. Other modifications have been made or are under consideration and will be discussed in this presentation.

One system enhancement being investigated involves the possible re-evaluation of the effect of high temperatures and high humidities during the North American Monsoon. Preliminary data indicate certain segments of the Arizona population are more significantly impacted by such air masses. The possibility of targeting these groups in unique ways will be investigated. Concurrent with this is the expansion and refinement of the System to Yuma, Arizona – where temperatures in excess of 100 degrees combined with dew points in the mid 70s are frequent occurrences. The complexities of dealing with extraordinarily high temperatures and low humidity followed by modestly high temperatures and high dew points will be explored. Additionally, the performance of the System during the 2005 heat wave will likewise be reviewed.