A statistical analysis of high-frequency track and intensity forecasts from NOAA's operational hurricane weather research and forecasting (HWRF) modeling system

Zhan Zhang, Jun A. Zhang, Ghassan J. Alaka, Keqin Wu, Avichal Mehra, Vijay Tallapragada

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

A statistical analysis is performed on the high-frequency (31/3 s) output from NOAA's cloud-permitting, high-resolution operational Hurricane Weather Research and Forecasting (HWRF) Model for all tropical cyclones (TCs) in the North Atlantic Ocean basin over a 3-yr period (2017-19). High-frequency HWRF forecasts of TC track and 10-m maximum wind speed (Vmax) exhibited large fluctuations that were not captured by traditional low-frequency (6 h) model output. Track fluctuations were inversely proportional to Vmax, with average values of 6-8 km. The Vmax fluctuations were as high as 20 kt (10.3ms-1) in individual forecasts and were a function of maximum intensity, with a standard deviation of 5.5 kt (2.8ms-1) for category-2 hurricanes and smaller fluctuations for tropical storms and major hurricanes. The radius of Vmax contracted or remained steady when TCs rapidly intensified in high-frequency HWRF forecasts, consistent with observations. Running-mean windows of 3-9 h were applied at synoptic times to smooth the high-frequency HWRF output to investigate its utility to operational forecasting. Smoothed high-frequency HWRF output improved Vmax forecast skill by up to 8% and produced a more realistic distribution of 6-h intensity change when compared with low-frequency, instantaneous output. Furthermore, the high-frequency track forecast output may be useful for investigating characteristics of TC trochoidal motions.

Original languageEnglish (US)
Pages (from-to)3325-3339
Number of pages15
JournalMonthly Weather Review
Volume149
Issue number10
DOIs
StatePublished - Oct 2021

Keywords

  • Model errors
  • Model output statistics
  • Tropical cyclones

ASJC Scopus subject areas

  • Atmospheric Science

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