Tropical Cyclone Precipitation Risk in the Southern United States
Tropical Cyclone Precipitation Risk in the Southern United States

Author: Sandra Michael Shedd

Publisher:

Published: 2015

Total Pages: 83

ISBN-13:

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This thesis works to evaluate the new rainfall algorithm that is used to simulate longterm tropical cyclone precipitation (TCP) climatology throughout the southeastern United States. The TCP climatology is based on a fleet of synthetic tropical cyclones developed using National Center for Atmospheric Research/National Centers for Environmental Prediction reanalysis data from 1980 to 2010 and the Coupled Hurricane Intensity Prediction System (CHIPS) model. The climatology is compared to hourly rainfall estimates from the WSR-88D Next Generation Weather Radar (NEXRAD-II) system. In general the synthetic TCP estimates show good agreement with radar-based observations. The rainfall algorithm appears to perform better at coastal locations versus inland ones, and in general has better agreement in the eastern locations considered in this study. In addition, the spatial dependence of radar rainfall estimates was addressed, and in general more extreme TCP-events exhibited a greater degree of event total precipitation variation at grid box-scale. Finally, preliminary work incorporating streamflow measurements as a metric for assessing TCP risk using the synthetic rainfall climatology was begun. Correlation between both grid box-specific and basin-average radar-based event TCP and surface streamflow measurements (from the U.S. Geological Survey National Water Information System) varied greatly, and was generally moderate, and future work should incorporate more thorough streamflow modeling in order to evaluate these comparisons.

Climatology of Heavy Rainfall Associated with Tropical Cyclones Affecting the Central Appalachians
Climatology of Heavy Rainfall Associated with Tropical Cyclones Affecting the Central Appalachians

Author:

Publisher:

Published: 2005

Total Pages: 86

ISBN-13:

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Over 50 years (1950-2004) of rainfall events associated with tropical cyclones that affected the central Appalachians were examined. Tracks of tropical cyclones (or tropical depression remnants) that passed within 500 km of the National Weather Service Office in Blacksburg, VA were compared with associated rainfall analyses of the Appalachian region in Virginia, West Virginia, and northwest North Carolina. In addition, surface and upper air analyses were examined for each event to help determine the relative influence of factors such as upslope flow, overrunning, and boundary interaction in relation to the cyclone track on the specific location and amounts of precipitation. The speed of movement across or along the Appalachians, as well as intensity of the cyclone (maximum wind speeds) as it passed through the analysis area, was also considered. The events were divided into categories based on the location the tropical cyclone made landfall. The seasonal distribution, e.g., which specific months are favored for tropical cyclone activity in the region, is also shown. These data were compiled in order to provide forecasters with a climatological database of tropical cyclones affecting the area, as well as the rainfall from these events. Results of the study will aid forecasters when assessing the potential effects of future tropical cyclone tracks and their rainfall impact on the Central Appalachians.

The Use of Satellite Microwave Rainfall Measurements to Predict Eastern North Pacific Tropical Cyclone Intensity
The Use of Satellite Microwave Rainfall Measurements to Predict Eastern North Pacific Tropical Cyclone Intensity

Author: Derek A. West

Publisher:

Published: 1998

Total Pages: 224

ISBN-13:

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This proposed study examines the potential use of satellite passive microwave rainfall measurements derived from Special Sensor Microwave/Imager (SSM/I) radiometers onboard the Defense Meteorological Satellite Program (DMSP) constellation to improve eastern North Pacific Ocean tropical cyclone intensity change forecasting techniques. Relationships between parameters obtained from an operational SSM/I-based rainfall measuring algorithm and 12-, 24-, 36-, 48-, 60- and 72-hour intensity changes from best track data records are examined in an effort to identify statistically significant predictors of intensity change. Correlations between rainfall parameters and intensity change are analyzed using tropical cyclone data from three years, 1992 to 1994. Stratifications based upon tropical cyclone intensity, rate of intensity change, climatology, translation, landfall and synoptic-scale environmental forcing variables are studied to understand factors that may affect a statistical relationship between rainfall parameters and intensity change. The predictive skill of statistically significant rainfall parameters is assessed by using independent tropical cyclone data from another year, 1995. In addition, case studies on individual tropical cyclones are conducted to gain insight on predictive performance and operational implementation issues.