Dynamic Hurricane Season Prediction Experiment with the
NCEP CFS CGCM
Lindsey Long and Jae Schemm
Climate Prediction Center / Wyle IS
NOAA/NWS/NCEP
October 27, 2009
The 34th Climate Diagnostics and Prediction Workshop,
Monterey, CA
Outline
• Description of the CFS Experiments• Datasets Used• Analysis of storm activity statistics• Focus on the Atlantic and Western North Pacific
basins– Statistics and performance evaluation
• Future plan
CFS T382 Hurricane Season Experiments
• One of the FY07/08 CTB internal projects
• Model Components:– AGCM: 2007 operational NCEP GFS in T382/L64 resolution– LSM: Noah LSM– OGCM: GFDL MOM3
• All runs initialized with NCEP/DOE R2 and NCEP GODAS. – 00Z Initial Conditions from April 19-23– Runs through December 1st
• Tropical cyclone detection and tracking method based on Camargo and Zebiak (2002)– Vorticity max, pressure min, wind max, warm-core system
Datasets
• CFS Hindcasts at T382 (~33km)– 5-Member Ensemble
• April 19th-23rd Initial Conditions
• Output every 6 hours
• 1981-2008, 28 years
• Appropriate ICs for CPC Operational Hurricane Season Outlook
• Observations from the HURDAT and JTWC Best Track Dataset– Tropical depressions and subtropical storms are not
included in storm counts.
Western North Pacific North Indian
Atlantic Eastern North Pacific
Examples of Storm Tracks for 4 NH Basins
Composite of 20 Atlantic Storms With SLP < 990hPa
Max winds, 27 m/s Min Pressure, 984 hPa
Frequency of Minimum Pressure – ATL
AtlanticBasin
Atlantic Tropical StormsMay-Nov, 1981-2008, T382
Obs Clim – 11.4CFS Clim – 10.9
EasternPacific
Eastern Pacific Tropical StormsMay-Nov, 1981-2008, T382
Obs Clim – 16.3CFS Clim – 13.0
WesternPacific
Western Pacific Tropical StormsMay-Nov, 1981-2008, T382
Obs Clim – 24.2CFS Clim – 18.1
JJA Nino 3.4 SST Index
Red = Statistically Significant at 0.95
T382 Correlations
IC=0419 0.72
IC=0420 0.67
IC=0421 0.68
IC=0422 0.57
IC=0423 0.64
April Ensm 5 0.68
T382 Correlations
IC=0419 0.63
IC=0420 0.64
IC=0421 0.73
IC=0422 0.67
IC=0423 0.67
April Ensm 5 0.71 Red = Statistically Significant at 0.95
JJA Atlantic MDR SST Index
T382 Correlations
IC=0419 0.43
IC=0420 0.54
IC=0421 0.66
IC=0422 0.68
IC=0423 0.69
April Ensm 5 0.70 Red = Statistically Significant at 0.95
JJA Atlantic MDR Shear Index
Cool Water Wake - SLP and SSTs Aug 29 - Sep 12, 1981
Correlations Total
IC=0419 0.44
IC=0420 0.33
IC=0421 0.35
IC=0422 0.43
IC=0423 0.54
April Ensm 5 0.61
Anomalous Number of TC: Atlantic Basin
Red = Statistically Significant at 0.95
Correlations Total
IC=0419 0.47
IC=0420 0.58
IC=0421 0.28
IC=0422 0.49
IC=0423 0.59
April Ensm 5 0.62
Atlantic Basin ACE Index
Red = Statistically Significant at 0.95
% o
f Nor
mal
Correlations Total
IC=0419 0.40
IC=0420 0.47
IC=0421 0.01
IC=0422 0.53
IC=0423 0.14
April Ensm 5 0.46
Anomalous Number of TC: Western N. Pacific
Red = Statistically Significant at 0.95
Correlations Total
IC=0419 0.43
IC=0420 0.51
IC=0421 0.33
IC=0422 0.47
IC=0423 0.34
April Ensm 5 0.50
WNP Basin ACE Index
Red = Statistically Significant at 0.95
% o
f N
orm
al
CFS April 2009 ForecastAtlantic Basin
Storm Count and ACE Index
ATL – Below Average Year Predicted
CFS predicted 7.5 storms versus a 10.9 storm climatology.With an ACE Index of only 75% of Normal
Courtesy of Unisys
8 Named Storms for 2009: 6 TSs and 2 Hurricanes28-Yr Climatology = 11.6 Storms
CFS April 2009 ForecastWestern N. Pacific BasinStorm Count and ACE Index
WNP – Above Average Year Predicted
CFS predicted 21.5 storms versus a 18.1 storm climatology.With an ACE Index of 144% of Normal
As of Oct 22, Courtesy of Unisys
24 Named Storms for 2009: 12 TSs and 8 Typhoons, 4 Super Typhoons28-Yr Climatology = 27.3 Storms
Summary
• CFS in T382 resolution exhibits robust climatological seasonal cycle of tropical cyclones over three NH basins.
• Warming trend and intensification of hurricane activity in the Atlantic basin captured in the CFS hindcasts.
• Fair level of skill in predicting interannual variability of seasonal storm activities for the Atlantic and West. N. Pacific basins.
• Provided input for the 2009 CPC Hurricane Season Outlook with real time prediction runs. Plans for an operational implementation in 2010.
