Pacific Region NCEP Model Review

1. Pacific RegionNCEP Model Review Ken Waters Pacific Region Headquarters Honolulu, Hawaii Dec. 10, 2003

2. Pacific Region • Two forecast offices (Honolulu and Guam) • Five Micronesia WSO’s • One WSO in American Samoa

3. Pacific Region’s Challenge for 2004 • Implementing IFPS in the region • Last region to go operational • Initial Operational Capability (IOC) date is Oct 15, 2004 (CONUS was Oct 1, 2003) • Different challenges for PR due to island-based geography • Most forecast grid points fall over water • Lack of high-resolution model output, particularly for West Pacific • Big concern is the tropical cyclone wind field; recent experience has not gone well for CONUS coastal offices having to deal with this difficult problem

4. Models in the Pacific • Few options for West Pacific: • GFS (80 km run by EMC) • UKMET • NOGAPS • Global Wavewatch • Used extensively by both offices for marine and surf • In addition, for Hawaii: • RSM (10 km run by EMC) • Used to initialize winds in IFPS • MSM (As low as 2.5 km, run by Univ Hawaii) • Currently not available in AWIPS or N-AWIPS; only Web • Eta (8 km run by EMC)

5. WFO Honolulu • Hurricane Jimena • Early Sept. 2003 • Poor initialization on GFS • For several days, GFS kept focusing on a trough southwest of the actual center of the hurricane • Note the wind max located well north of the GFS storm center location Actual Location GFS Location

6. Honolulu – Hurricane Jimena • MSLP also showed center too far south • Eta also showed similar tendency to not initialize on the hurricane • Negative effect on WWIII output making it more difficult to forecast high surf conditions

7. Honolulu - Jimena • Even QuikSCAT showed limitations due to heavy convection around the small center of the hurricane that made analysis difficult

8. Honolulu – Jimena • What was useful was satellite imagery such as this TRMM pass which correctly identified the center

9. Honolulu Comments • GFS MOS (MAV) difficulties • When developing the equations, the only stations available were Honolulu and Hilo • Hilo has much higher precipitation (~150” vs. 25”) • Result is high POPs for Kona, which is at the same latitude as Hilo, but is normally much dryer than Hilo due to orography effects • Therefore, this product is not very useful for the forecast office

10. WFO Guam • Problem noted with GFS creating secondary “TC’s” behind actual developing “TC’s” • Reference correspondence on this between Bill Ward and Hua-Lu Pan • This effect tends to diminish the features in the actual storm • A major impact if GFS is used to initialize IFPS grids

11. WFO Guam • GFS performed very well for Typhoon Parma; this storm lingered across the central Pacific doing loops near Wake Island • Also, good performance for Typhoon Lupit • Office is experimenting now with using GFS to initialize IFPS • First looks indicate problems with weather and sky parameters • Frequently over-forecasts coverage of rain and isolated TS

12. PR Wish List • To run a “local” model for the West Pacific • Possibly either MM5 or WRF, run at PRH by DaNa Carlis, from the NOAA Educational Partnership Program / Graduate Scientist program • Need higher resolution model output for initialization of IFPS (currently using 80 km GFS to initialize grids at 5 km resolution!) • Looking forward to receiving MOS for the Pacific; sometime in 2004 • Improvements in the MAV GFS MOS product for Honolulu • Tropical Cyclone initialization for the GFS

13. Summary • Great job overall on the GFS • Need better model guidance for West Pacific • IFPS issues our primary concerns • Tropical Cyclone winds expected to be problem #1!