Supporting emergency managers during tropical cyclone approach in Baja California, Mexico

Most of the year, the weather on the southern Baja California Peninsula is mild and dry. However, during the summer, humid air masses that move northward from the tropics provide favorable conditions for the development of localized, convective systems that result in strong winds and heavy rainfall episodes. These conditions may cause significant property damage to the local population and surrounding environment. Tropical cyclones from the eastern Pacific basin may have tracks that approach northwest Mexico and, therefore, are important systems to forecast as early as possible.

Tropical cyclones are common from August through the end of the season. During the last 11 years, including the season of 2013, 22 systems moved over land in western Mexico and 55% of them crossed the peninsula. Prior to the approach of these systems, emergency managers perform activities to prepare the population. As part of the outreach activities provided by several research projects, we assist managers to better understand the observations of storm structure and intensity estimates. This includes the analysis of real-time, high-resolution imagery from the geostationary (GOES) satellites.

Another component of this support is an interpretation of the track forecasts provided by the U.S. National Hurricane Center and the Mexican Meteorological Service. This interpretation includes explaining the benefits, limitations and caution to be exercised with the information stated in the official forecasts. Also, this implies a revision of the available information (advisories, discussions and probabilities) as well as the predictions derived from global-scale models in the ATCF database and regional-scale models such as HWRF. Some of the landfall events are investigated with the local application of the HWRF model, by performing research-mode simulations with position and intensity changes to the initial tropical cyclone circulation.