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Seasonal Forecast for Summer 2013 for Hong Kong. 9 Apr 2013, FOCRAII, Beijing H W Tong Hong Kong Observatory . Seasonal Forecast at HKO . Temperature and rainfall Most (or two most) likely category No. of TC entering the 500 km range of Hong Kong (for internal use only).
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Seasonal Forecast for Summer 2013 for Hong Kong 9 Apr 2013, FOCRAII, Beijing H W Tong Hong Kong Observatory
Seasonal Forecast at HKO • Temperature and rainfall • Most (or two most) likely category • No. of TC entering the 500 km range of Hong Kong (for internal use only)
Review of 2012 JJA forecast Jun 2012 was well forecast However, Aug 2012 was expectedly dry
Aug 2012 – CFSv2 & JMA-CGCM vs actual MSLP JMA-CGCM CFSv2 Actual
Methodology • El Niño/La Nina consideration • Large-scale circulation pattern forecast by major centers (CFSv2, JMA-CGCM, ECMWF) • Forecasts from major centers • Statistical downscaling (from NCEP CFSv2) • Simple regression • Principle component regression
ENSO Status Neutral in JJA
500Z (upper) & MSLP (lower) Jun 2013 NCEP JMA ECMWF(non-normalized)
850 Wind (upper) & Temp (lower) Jun 2013 NCEP JMA ECMWF (non-normalized)
500Z (upper) & MSLP (lower) Jul 2013 NCEP JMA ECMWF(non-normalized)
850 Wind (upper) & Temp (lower) Jul 2013 NCEP JMA ECMWF (non-normalized)
500Z (upper) & MSLP (lower) Aug 2013 ECMWF(non-normalized) NCEP JMA
850 Wind (upper) & Temp (lower) Aug 2013 NCEP JMA ECMWF (non-normalized)
Short summary Above normal temperature ? Below normal rainfall ?
Statistical downscaling Normal to warm Normal to dry
JJA temperature forecasts from major centers Normal to above normal
JJA rainfall forecasts from major centers Normal to dry 19
Number of tropical cyclones entering the 500 km range of Hong Kong HK
Normal 21
Statistical downscaling 2-3 TC in JJA, near normal