4-6 May 2009

Co-hosted by

Naomi Surgi, Mark DeMaria, Richard Pasch, Frank Marks

4-6 May 2009

Co-hosted by

Naomi Surgi, Mark DeMaria, Richard Pasch, Frank Marks

OVERVIEW

Hurricane Diagnostics/Verification Workshop

OVERVIEW

Hurricane Diagnostics/Verification Workshop

Purpose of Workshop:

To bring together expertise in the hurricane research and operational communities to launch a concerted diagnostics activity to improve NHC’s numerical guidance

Objective/Goals:

to provide feedback to both operational model developers and to hurricane forecasters for near term transition into operations and to research modelers to develop useful methods for assessing forecast quality in various phases of model development.

Observations from both satellite and in situ platforms…… and model verification are critical to assist this effort

Max Mayfield left this for me on my desk (after he Max Mayfield left this for me on my desk (after he worked a mid shift)…………worked a mid shift)…………

!!!!!!

Statistical

Dynamical

Over the past decade(s) – LOTS of model data has been generated by the various global and regional operational hurricane models, e.g. the NCEP GFS, NOGAPS, UKMO, the GFDL model and for the past two seasons the HWRF.

For GFDL, HWRF….for track AND intensity

Bad forecasts, good forecasts (sometimes very surprisingly so)…..

But little feedback as to why…..

Also, sometimes model biases are noted, e.g. GFS northward bias in central tropical ATL; NOGAPs strong westerly bias; GFDL strong intensity bias (sheared environments); ……

HWRF?

Are these systematic model biases? Vary w/basin? Artifact of the season?

Related to initial errors; physics?

Most importantly (once identified) HOW TO FIX?

PERFECT !

Some examples

HWRFGFDL

HURRICANE FAY

H. GUSTAV

HWRF

Several models had skillful 5 day forecasts when Gustav was still east of Jamaica targeting the central LA coast

Most model forecasts did not target Galveston for IKE landfall until ~ 36 hrs. before landfall

H. IKE

HWRF GFDL

HURRICANE BERTHA

GLOBAL vs. Regional

NORBERTNORBERT

HWRF Track

HWRF Track

Hurricane Flossie

Fcst 081200

Fcst 081212

FLIP FLOP

TS BARBARATS BARBARA

GFDL,GFDL, AVNO,AVNO, UKM,UKM, NGPS,NGPS, HWRFHWRF

None of the models could get a grip on this forecast!

Hurricane Hurricane HenrietteHenriette

GFDLGFDL

Nearly a Nearly a perfect perfect forecast….. forecast…..

HWRF 126H FORECAST OF HURRICANE DEAN

CAT5

CAT2

HWRF forecast both landfall intensities

Can you trust this forecast?

We’re making progress…but We’re making progress…but many difficult problems ahead many difficult problems ahead

Felix - Vmax (kts)Felix - Vmax (kts) Humberto 2007 9/09-9/12Humberto 2007 9/09-9/12

Franklin - Vmax (kts)Franklin - Vmax (kts)

DennisDennis

WilmaWilma

Track Track impacts impacts intensityintensity

Interesting way research Interesting way research models show forecastsmodels show forecasts

Need to be very careful……Need to be very careful……

Research model forecasts of storm intensity for Hurricane Katrina showing benefit of high (1.6 km) resolution

High-res models (1.6km)

NHC Forecast

Obs

Katrina Landfall

GFDL model

Global models

High-res models (1.6km)

NHC Forecast

Obs

Katrina Landfall

GFDL model

Global models

Research model forecasts of storm intensity for Hurricane Katrina showing benefit of high (1.6km) resolution

Intensity Forecast of Hurricane Katrina 0000 UTC 27 August 2005

HWRF model

HWRF

IN FACT:

• From 114 hrs to 60 hrs before landfall, seven HWRF forecasts predicted rapid intensification of Hurricane Katrina, predicting Category 5 Hurricane

• Three HWRF forecasts predicted Category 3 landfall for Hurricane Katrina

• Three HWRF forecasts of max. intensity coincided with observed maximum intensity

Operational models are becoming very complex….

Coupled to ocean, waves, land surface model

Same issues…..

We must begin to identify systematic biases

What observations do we have? Are still needed?

Workshop objective:

When we leave here……

What are the activities? WHO is going to do what?

HousekeepingHousekeeping

AgendaAgenda

Enough time for discussionEnough time for discussion

THANK YOU HFIP for supportTHANK YOU HFIP for support