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 34 th 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 –Runs through December 1 st 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 19 th -23 rd Initial Conditions Output every 6 hours , 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 PacificNorth Indian AtlanticEastern 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

Atlantic Basin Atlantic Tropical Storms May-Nov, , T382 Obs Clim – 11.4 CFS Clim – 10.9

Eastern Pacific Eastern Pacific Tropical Storms May-Nov, , T382 Obs Clim – 16.3 CFS Clim – 13.0

Western Pacific Western Pacific Tropical Storms May-Nov, , T382 Obs Clim – 24.2 CFS Clim – 18.1

JJA Nino 3.4 SST Index Red = Statistically Significant at 0.95 T382Correlations IC= IC= IC= IC= IC= April Ensm 50.68

T382Correlations IC= IC= IC= IC= IC= April Ensm Red = Statistically Significant at 0.95 JJA Atlantic MDR SST Index

T382Correlations IC= IC= IC= IC= IC= April Ensm Red = Statistically Significant at 0.95 JJA Atlantic MDR Shear Index

Cool Water Wake - SLP and SSTs Aug 29 - Sep 12, 1981

CorrelationsTotal IC= IC= IC= IC= IC= April Ensm Anomalous Number of TC: Atlantic Basin Red = Statistically Significant at 0.95

CorrelationsTotal IC= IC= IC= IC= IC= April Ensm Atlantic Basin ACE Index Red = Statistically Significant at 0.95 % of Normal

CorrelationsTotal IC= IC= IC= IC= IC= April Ensm Anomalous Number of TC: Western N. Pacific Red = Statistically Significant at 0.95

CorrelationsTotal IC= IC= IC= IC= IC= April Ensm WNP Basin ACE Index Red = Statistically Significant at 0.95 % of Normal

CFS April 2009 Forecast Atlantic 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 Hurricanes 28-Yr Climatology = 11.6 Storms

CFS April 2009 Forecast Western N. Pacific Basin Storm 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 Typhoons 28-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.

OBS IC=0419 IC=0420 IC=0421 Tropical Storm Origins, SON IC=0422IC=0423

Tropical Storm Origins, SON OBS IC=0419 IC=0420IC=0421 IC=0422IC=0423

Four NH Ocean Basins

Future Work Currently applying tracking method to CFSR Running additional T382 simulations using July ICs and a 4 member free running CMIP simulation