Predictions of Tropical Cyclone Formation Using a 13-km Global and a 3-km Globally Nested Model

The prediction of tropical cyclone (TC) formation is an important
component of early warning and preparedness activities for forecasters,
emergency managers, and the communities they serve. In recent years,
global numerical weather prediction (NWP) models have shown skill in
forecasting the time and location of TC formation.

This poster will highlight the TC formation performance during the
2022 Atlantic hurricane season of both a global configuration and a
higher resolution, globally nested configuration of an NWP model
that has been developed at the NOAA Geophysical Fluid Dynamics
Laboratory (GFDL). The configuration of the System for High-resolution
prediction on Earth-to-Local Domains (SHiELD) uses a 13-km horizontal
domain for global predictions. The T-SHiELD configuration is designed
for application in tropical regions, in particular for TC prediction,
and it uses a higher resolution 3-km domain over the Atlantic Basin
that is nested within a 13-km global, parent domain.

Comparisons of TC formation skill between the two model
configurations will be shown. In addition, storm-centric diagnostics
that are computed along the track of an incipient TC disturbance will
be compared for metrics such as low-level vorticity, low- and mid-level
relative humidity, moisture divergence, omega, vertical shear, SST
and others. A focus of this study is to determine how these factors
may be impacted by both the differences in horizontal resolution and
by the fact that the coarser resolution, global SHiELD configuration
uses a parameterized deep convective scheme while the T-SHiELD
configuration allows for explicit deep convection within the higher
resolution Atlantic nest region.