Pacific RegionNCEP Model Review

Ken WatersPacific Region Headquarters

Honolulu, HawaiiDec. 10, 2003

Pacific Region

Two forecast offices (Honolulu and Guam)Five Micronesia WSO’sOne WSO in American Samoa

Pacific Region’s Challenge for 2004Implementing IFPS in the region

Last region to go operationalInitial 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 PacificBig concern is the tropical cyclone wind field; recent experience has not gone well for CONUS coastal offices having to deal with this difficult problem

Models in the PacificFew options for West Pacific:

GFS (80 km run by EMC)UKMET NOGAPSGlobal 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 IFPSMSM (As low as 2.5 km, run by Univ Hawaii)

Currently not available in AWIPS or N-AWIPS; only WebEta (8 km run by EMC)

WFO HonoluluHurricane Jimena

Early Sept. 2003Poor initialization on GFSFor several days, GFS kept focusing on a trough southwest of the actual center of the hurricaneNote the wind max located well north of the GFS storm center location

GFS Location

Actual Location

Honolulu – Hurricane Jimena

MSLP also showed center too far southEta also showed similar tendency to not initialize on the hurricaneNegative effect on WWIII output making it more difficult to forecast high surf conditions

Honolulu - JimenaEven QuikSCAT showed limitations due to heavy convection around the small center of the hurricane that made analysis difficult

Honolulu – JimenaWhat was useful was satellite imagery such as this TRMM pass which correctly identified the center

Honolulu Comments

GFS MOS (MAV) difficultiesWhen developing the equations, the only stations available were Honolulu and HiloHilo 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 effectsTherefore, this product is not very useful for the forecast office

WFO GuamProblem noted with GFS creating secondary “TC’s” behind actual developing “TC’s”

Reference correspondence on this between Bill Ward and Hua-Lu PanThis effect tends to diminish the features in the actual stormA major impact if GFS is used to initialize IFPS grids

WFO GuamGFS performed very well for Typhoon Parma; this storm lingered across the central Pacific doing loops near Wake IslandAlso, good performance for Typhoon LupitOffice is experimenting now with using GFS to initialize IFPS

First looks indicate problems with weather and sky parametersFrequently over-forecasts coverage of rain and isolated TS

PR Wish ListTo 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 programNeed 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 2004Improvements in the MAV GFS MOS product for HonoluluTropical Cyclone initialization for the GFS

SummaryGreat job overall on the GFSNeed better model guidance for West PacificIFPS issues our primary concerns

Tropical Cyclone winds expected to be problem #1!