Charles H. Paxton

Resonant Interaction between an Atmospheric Gravity Wave and Shallow Water Wave along Florida's West Coast

On 25 March 1995, a large solitary wave, seemingly from nowhere, washed ashore along the normally tranquil Gulf Coast of Florida from Tampa Bay to south of Naples. On this Saturday morning, many be...

The record-breaking 2015 hurricane season in the eastern North Pacific: An analysis of environmental conditions

The presence of a near-record El Nino and a positive Pacific Meridional Mode provided an extraordinarily warm background state that fueled the 2015 eastern North Pacific hurricane season to near-record levels. We find that the western portion of the eastern North Pacific, referred to as the Western Development Region (WDR; 10°–20°N, 116°W–180°), set records for named storms, hurricane days, and Accumulated Cyclone Energy in 2015. When analyzing large-scale environmental conditions, we show that record warm sea surface temperatures, high midlevel relative humidity, high low-level relative vorticity, and record low vertical wind shear were among the environmental forcing factors contributing to the observed tropical cyclone activity. We assess how intraseasonal atmospheric variability may have contributed to active and inactive periods observed during the 2015 hurricane season. We document that, historically, active seasons are associated with May–June El Nino conditions, potentially allowing for predictability of future active WDR seasons.

Weather, Ocean, and Social Aspects Associated with Rip Current Deaths in the United States

ABSTRACT Paxton, C.H. and Collins, J.M., 2014. Weather, ocean, and social aspects associated with rip current deaths in the United States. The purpose of this research is to provide a better understanding of the physical and social aspects of rip currents in ocean areas that will lead to better forecasts, better governmental policies in beach areas, and ultimately to save lives. The primary factors associated with rip current formation on beaches are variations in the local beach bathymetry, wind-generated waves of significant wave height typically 1 m or higher, and lower tidal stages. The methodology followed for this study included a review of demographics from over 500 rip current drowning reports along the Atlantic Ocean, Pacific Ocean and Gulf of Mexico coasts of the United States. This research indicated that tourists are often the victims and rescuers often become the victims. For each state or sub-state area where rip current drownings are prevalent, an analysis of social aspects and associated ocean and weather patterns was conducted using buoy and tide data and composite weather patterns. It is important to understand the evolution of these fatal events with respect to the trends of wave height, period, and pressure patterns and resulting surface wind fields that produce the waves.

How the Swells of Hurricane Isabel Impacted Southeast Florida

AMERICAN METEOROLOGICAL SOCIETY | 1065 A unique series of events occurred that sent large waves to the southeast coast of Florida. The waves generated by powerful Hurricane Isabel broke along a narrow 10-mi (16.1-km) stretch of beaches along southern Palm Beach County on 16 September 2003. Th is transformed what would usually have been a tranquil late summer beach day into a day of enormous, dangerous surf that local surfers and beachgoers will remember for a lifetime (Fig. 1). Within a few miles north and south along the coast, the surf was much smaller. Several days earlier, Hurricane Isabel was a category-5 storm moving westward and spinning at peak intensity hundreds of miles east-southeast of the Bahama Islands. Hurricane Isabel’s strong winds produced large ocean swells that traveled west-northwest toward the Bahama Islands. Although observational data are lacking in the wavegeneration area, these swells were likely made larger as Isabel moved west over a long stretch of ocean in the direction of the strongest winds, producing a longer fetch. Th e large swells impacted the beaches of Eleuthra and Abaco Islands, shielding most of the southeast Florida coastline. However, between those two Bahama islands is the narrow but deep Providence Channel, and this allowed the large swells to propagate between the islands and ultimately into the southeastern Florida coast near Delray Beach, producing large surf of 10–14 ft (3.0–4.3 m).

Explaining the spatial variability of summer rainfall in Pinellas County, Florida using ArcGIS

Pinellas County is a peninsula on the west coast of Florida that receives sea breeze driven convective rainfall during the summer months. To improve forecasting of local mesoscale phenomena, the spatial variability of summer rainfall in Pinellas was examined in relation to dominant wind directions and speeds, atmospheric stability, and atmospheric moisture content for the months of June, July, and August from 2003 to 2007. Radiosonde data from the Ruskin, Florida National Weather Service (NWS) Station, Pinellas County rain gauge data, and radar-estimated rainfall totals from the NWS Advanced Hydrologic Prediction Service were used to examine different meteorological parameters and their relationships with the spatial variability of summer precipitation across the peninsula. Dominant daily wind direction categories were divided into six 60 degree increments: 1–60°, 61–120°, 121–160°, 161–240°, 241–300°, and 301–360°. Precipitable water had a significant positive correlation with precipitation in four of the six wind direction categories (61–120°, 121–180°, 181–240°, and 241–300°). Higher wind speeds associated with a southerly wind direction revealed significant positive relationships with precipitation. Composites of radar-derived rainfall estimates indicate that rain fell primarily in the center of the peninsula under a variety of wind directions, often with two daily maxima. Composites also show that the greatest potential for high precipitation amounts comes with westerly winds (241–300°).