CR CR = Crescent Reef PI = Pearl Island CP = Commisioner’s point BDA = Bermuda Intl. BDA CP PI

using daily 30-h forecasts m/s using daily 30-h forecasts (first 6 h discounted) Mean wind (racing hours only) for June 2016 from forecasts

Standard deviation in wind speed (racing hours only) for June 2016 m/s

using daily 30-h forecasts WRF low res runs June 2016: selected sites using daily 30-h forecasts (first 6 h discounted) N.B. periodic behaviour…more later

WRF low res runs June 2016: selected sites Knowing the wind speed at PI, you have a reasonable chance of estimating speed at CR and CP wind speed site 2 (m/s) wind speed site 1 (m/s)

comparison of low-res and high-res (AG) runs No systematic offsets?

How did the (low-res) model perform?

! using daily 30-h WRF forecasts (first 6 h discounted) Mean daily wind speeds at Bermuda Airport using daily 30-h WRF forecasts (first 6 h discounted) !

WRF Pearl Island wind speed : June 2016 N.B. time in days N.B. times and scales in hours

day of month (1 – 30) on x-axis Junes 1981 – 2010 from ERA-20C 30 30 30 Speed at Bermuda (kts) 30 30 day of month (1 – 30) on x-axis

Wavelet analyses for selected Junes from ERA-20C reanalysis 2010 2009 2008 N.B. times and scales in days 2007 2006 2005

MSLP 18Z ERA-20C 1901 – 2010 (3330 samples) First 3 EOFs explain 92% of the variance in the data. MEAN EOF1 EOF2 EOF3

2006 – 2010 inclusive

x Mean from the re-analysis … Relation between principal components and wind speeds?

June 2016 appears “typical”* in terms of wind speeds and “periodicity” SUMMARY June 2016 appears “typical”* in terms of wind speeds and “periodicity” No systematic differences (found so far) between high-res and low-res runs, although more rigorous analysis needed. Low-res runs did well (very well?) at predicting wind speed at BDA ERA data shows there are detectable patterns (in SLP) …predictability? * compared with recent Junes in ERA-20C