Hurricane Dorian is moving up the coast and passing Florida, but there’s still a healthy amount of moisture being pulled into the storm. UF tropical storm expert Dr. Corene Matyas checked in with cheddar.com with the latest update on Hurricane Dorian, its impacts in Florida and projected conditions along the U.S. East Coast this afternoon. See the full interview here.
Jingyin Tang and Corene Matyas
Article first published online: 21 May 2018 Atmosphere
ABSTRACT: Accurate observational data and reliable prediction models are both essential to improve the quality of precipitation forecasts. The spiraling trajectories of air parcels within a tropical cyclone (TC) coupled with the large sizes of these systems brings special challenges in making accurate short-term forecasts, or nowcasts. Doppler weather radars are ideal instruments to observe TCs when they move over land, and traditional nowcasts incorporate radar data. However, data from dozens of radars must be mosaicked together to observe the entire system. Traditional single-radar-based reflectivity tracking methods commonly employed in nowcasting are not suitable for TCs as they are not able to capture the circular motion of these systems. Thus, this paper focuses on improving short-term predictability of TC precipitation with Doppler weather radar observations based on: a multi-scale motion vector retrieval algorithm, an optimization technique and a semi-Lagrangian advection scheme. Motion fields of precipitation regions are obtained by a multi-level motion vector retrieval algorithm, then corrected and smoothed by the optimization technique using mass and smooth constraints. Predicted precipitation regions are then extrapolated using the semi-Lagrangian advection scheme. A case study of Hurricane Isabel (2003) shows that the combination of these methods may increase reliable rainfall prediction to about 5 h as the TC moves over land.
Read the full publication at Atmosphere
MATYAS, TANG, ZICK – Using an Object-Based Approach to Quantify the Spatial Structure of Reflectivity Regions in Hurricane Isabel (2003). Part I: Comparisons between Radar Observations and Model Simulations
Corene J. Matyas, Stephanie E. Zick, Jingyin Tang
Article first published online: 25 APR 2018 Monthly Weather Review
ABSTRACT: When a hurricane undergoes extratropical transition (ET), its rainbands evolve from a circular and compact shape to a more elongated, fragmented, and dispersed configuration with an exposed circulation center. This study calculates five metrics to measure these spatial changes in reflectivity regions as Hurricane Isabel (2003) underwent ET. A mosaic of observations from the Weather Surveillance Radar-1988 Doppler (WSR-88D) network is compared to reflectivity simulated by the Advanced Research Weather Research and Forecasting (WRF-ARW) Model. Six simulations are performed by varying the cumulus and microphysics parameterizations to produce a range of reflectivity configurations. A bias correction is applied to model-simulated reflectivity prior to the calculation of spatial metrics because lower reflectivity values are generally underrepresented, while higher values are generally overrepresented. However, the simulation with Kain–Fritsch cumulus and Morrison two-moment microphysics overpredicts reflectivity by 3–4 dBZ at all levels. We demonstrate that the spatial metrics effectively capture structural changes as reflectivity regions became more fragmented and dispersed and the center became more exposed. In this case study, the results were more sensitive to the choice of cumulus physics, compared with the choice of microphysics. The Kain–Fritsch simulations produce shapes that are too circular and solid when compared with WSR-88D observations, as the hurricanes lack distinct outer rainbands. Simulations with Tiedtke cumulus produce an elongated main reflectivity region as in WSR-88D, but with separate inner and outer rainbands that are too dispersed and fragmented. These results demonstrate the value in measuring spatial patterns rather than assessing model performance using visual inspection alone.
Read the full publication at Monthly Weather Review
Geography’s Dr. Corene Matyas and Dr. Joann Mossa recently spoke to several new outlets about the cause and result of Hurricane Irma.
José J. Hernández Ayala, David Keellings, Peter R. Waylen & Corene J. Matyas
Article first published online: 12 SEPT 2017 Hydrological Sciences Journal
ABSTRACT: An extreme value analysis (EVA) point process approach has been implemented to examine the flood characteristics of Puerto Rico when tropical cyclones (TCs) are present in the discharge series and when they are removed from it. Mean daily discharge values that exceeded the 99th percentile thresholds were used in both the TC and non-TC data series. In nine of the 12 stations the maximum discharge was associated with a TC, with hurricanes Hortense (1996), Georges (1998) and Eloise (1975) responsible for most of the maximum peaks at each site. Percentage changes in the generalized extreme value parameters, which include location (central tendency), scale (variance) and shape (skewness), between the TC and non-TC data exhibited a decrease in the majority of stations. Stations in the eastern interior and central region of the island showed the largest decrease in all parameters, in flood occurrences and in return periods when TCs were removed from the series.
Read the full publication at Hydrological Sciences Journal
Hurricane Matthew’s near miss of Florida may result in more widespread damage than a direct hit – according to UF’s Dr. Corene Matyas – who was quoted in an October 7th Tampa Bay Times article. Dr. Matyas’ National Science Foundation (NSF) funded research focuses on rainfall from tropical cyclones.
From the Tampa Bay Times:
“But Florida’s near miss may simply have spread the damage and flooding over a wider swath of the state than a direct hit, warned Corene Matyas, a UF associate professor of geography who investigates the frequency and intensity of hurricanes.
Matthew knuckled along the coast for hundreds of miles, increasing the areas exposed to tropical storm-force winds, storm surge and rainfall, she said.
“The complete picture of damage has yet to emerge,” she said.
Dr. Matyas clarifies that the “Hurricane Matthew tracking parallel to the coast has increased the areas exposed to tropical storm-force winds and water rise from storm surge and wave energy, plus rainfall.”
Read the entire article at the Tampa Bay Times.
In a recent Forbe’s article, recent Geography alum (and Assistant Professor at Virginia Tech) Dr. Stephanie Zick helped explain ‘Why have we seen a ‘blob’ east of Hurricane Matthew’s eye and why it should concern us‘.
In the article, she was quoted as saying: “I think there are multiple factors: 1) the stationary band complex, so there would be confluence downshear (east of the TC center), but combined with, 2) a surge in the trade winds and 3) confluence downstream of the South American landmass/terrain.” and “another factor (albeit more speculative) that I think might be enhancing the convection is a working hypothesis that asymmetries can develop during landfall as drier air from over land moves over the moist boundary layer (modifying moist static stability).”
Read the entire article to see more of Dr. Zick’s analysis.
New Insights into Tropical Convection and Hurricanes using Polarimetric Radar
Speaker: Dr. Michael M. Bell
Assistant Professor, University of Hawai’i at Manoa
Thursday, January 21, 2015
3:00-3:50 PM (Period 8)
Turlington Hall Room 3012
University of Florida
All are welcome to attend.