Investigating Dynamical and Microphysical Mechanisms in a Squall Line that Interacted with Terrain During the IPHEx - NOAA HMT-SEPS Field Campaign in the Southern Appalachians

The Integrated Precipitation and Hydrology Experiment (IPHEx) is a ground validation
field campaign for the new Global Precipitation Measurement (GPM) satellite, sponsored by
NASA’s Precipitation Measurement Missions (PMM) Program. The IPHEx 2014 field campaign
took place over the southern Appalachian Mountains, with a specific focus on the Pigeon River
Basin in western North Carolina and eastern Tennessee. IPHEx coincided with the NOAA
Hydrometeorology Testbed (HMT) – Southeast Pilot Study (SEPS), which focused on improving
quantitative precipitation estimation (QPE) and forecasting (QPF) in the same region. This
region has ample long-term precipitation and hydrological monitoring networks, and additional
instrumentation was deployed during an Intensive Observational Period (IOP) between 1 May
and 15 June 2014. The NOAA X-band Polarimetric (NOXP) radar and NASA S-band dualpolarimetric
(NPOL) radar were deployed during the IPHEx IOP and will be the focus of the
analysis presented. These dual-polarization radars allowed high-resolution visualization of
dynamical and microphysical mechanisms present in the complex mountainous environment of
the IPHEx domain that otherwise are poorly observed by operational NEXRAD radars,
especially within the Pigeon River Basin. We present results on how orographic terrain
influenced the evolution of precipitation over the southern Appalachians during a squall line
passage on 15 May 2014.