Stephen S. Weygandt

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In this two-part study, a single-Doppler parameter retrieval technique is developed and applied to a real-data case to provide initial conditions for a short-range prediction of a supercell thunderstorm. The technique consists of the sequential application of a single-Doppler velocity retrieval (SDVR), followed by a variational velocity adjustment, a(More)
  • Stensrud, Norman, +16 authors Jason P Tuell
  • 2009
Warnings about convective-scale hazards are currently based on observations, but the time has come to develop warning methods in which numerical model forecasts play a much larger role. T he National Oceanic and Atmospheric Admin-istration's (NOAA's) National Weather Service (NWS) issues warnings when there is a threat to life and property from weather(More)
In this two-part study, a single-Doppler parameter retrieval technique is developed and applied to a real-data case to provide model initial conditions for a short-range prediction of a supercell thunderstorm. The technique consists of the sequential application of a single-Doppler velocity retrieval (SDVR), followed by a variational velocity adjustment, a(More)
A regional ensemble Kalman filter (EnKF) system is established for potential Rapid Refresh (RAP) operational application. The system borrows data processing and observation operators from the gridpoint statistical interpolation (GSI), and precalculates observation priors using the GSI. The ensemble square root Kalman filter (EnSRF) algorithm is used, which(More)
A coupled ensemble square root filter–three-dimensional ensemble-variational hybrid (EnSRF–En3DVar) data assimilation (DA) system is developed for the operational Rapid Refresh (RAP) forecasting system. The En3DVar hybrid system employs the extended control variable method, and is built on the NCEP operational gridpoint statistical interpolation (GSI)(More)
41 42 A coupled EnKF-En3DVar hybrid data assimilation system is developed for the 43 operational Rapid Refresh (RAP) forecasting system. The three-dimensional ensemble-44 variational (En3DVar) hybrid system employs the extended control variable method, and is built 45 on the NCEP operational Grid-point Statistical Interpolation (GSI) 3DVar framework. It is(More)