Western Hemisphere Record Reconnaissance Observations in Hurricane Patricia

On 23 October 2015 both a USAF Reserve WC-130J and a NOAA WP-3D measured record intensities across a variety of parameters in Eastern Pacific Hurricane Patricia.

Among the new Western Hemisphere records established:

A NOAA WP-3D N43RF "Miss Piggy" dropwindsonde released into the eye at 1733 UTC measured a surface pressure of 883 millibars with 45 knots of wind at splash (leading to the NHC Advisory pressure estimate of 879 mb). The 883 mb is the lowest in-situ measurement of surface pressure ever recorded in this hemisphere. The accompanying 700 mb Geopotential Height of 2043 meters is the lowest ever calculated in the NHC AOR. During this same penetration, the warmest 700 mb Flight Level Temperature ever measured by an aircraft in the eye of a hurricane was also recorded with a 10 second average of 31.7C (which included a 1 Hz peak of 32.2C).

Approximately 11 hours earlier, a USAF Reserve aircraft from the 53rd Weather Reconnaissance Squadron measured the highest values for Brightness Temperature (Tb) ever seen with the Stepped Frequency Microwave Radiometer (SFMR). The SFMR recorded values of Tb ranging across the six frequencies from a Tb0 (4.74 GHz) of 244K to a Tb5 (7.09 GHz) in excess of 275K. These extreme readings yielded peak 10 second average surface winds in excess of 90 meters per second. Similar values for Tb and derived surface winds were recorded by the NOAA WP-3D.

Flight level winds as high as 191 and 192 knots (10 second averages) were recorded by the WP-3D and WC-130J respectively. This included a 1 Hz peak gust of 204 knots on N43RF. These are among the strongest winds ever reliably measured by reconnaissance aircraft and similar to those seen in Hurricane Allen (1980) and Western Pacific Super Typhoon Megi (2010).

The NOAA WP-3D experienced significant turbulence both inbound through the northwest eyewall and outbound through the southeast eyewall during the 1733z penetration. Updraft vertical velocities of +26.11 m/s and downdrafts of -16.25 m/s were recorded. A full suite of Tail Doppler Radar reflectivity and velocity products were collected for analysis.

Data gathered by both aircraft provides a unique opportunity to examine the structure of the most intense tropical cyclone ever seen in the NHC AOR. This presentation will briefly describe how the measurements described above were obtained and how derived parameters are calculated.