OVERVIEW
Hurricane Diagnostics/Verification
Workshop
4-6 May 2009
Co-hosted by
Naomi Surgi, Mark DeMaria, Richard Pasch,
Frank Marks
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
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? PERFECT !
Are these systematic model biases?
the season?
Vary w/basin? Artifact of
Related to initial errors; physics?
Most importantly (once identified) HOW TO FIX?
Some examples
HWRF
GFDL
HURRICANE FAY
HWRF
Several models had skillful 5 day
forecasts when Gustav was still
east of Jamaica targeting the
central LA coast
H. GUSTAV
Most model forecasts did
not target Galveston for IKE
landfall until ~ 36 hrs. before
landfall
H. IKE
GFDL
HWRF
HURRICANE BERTHA
GLOBAL vs. Regional
NORBERT
Hurricane
Flossie
HWRF
Track
Fcst 081200
FLIP FLOP
HWRF Track
Fcst 081212
TS BARBARA
GFDL, AVNO, UKM,
NGPS, HWRF
None of the
models
could get a
grip on this
forecast!
Hurricane
Henriette
GFDL
Nearly a
perfect
forecast…..
HWRF 126H FORECAST OF HURRICANE DEAN
HWRF forecast both landfall intensities
CAT2
CAT5
Can you trust this
forecast?
We’re making progress…but
many difficult problems ahead
Felix - Vmax (kts)
Franklin - Vmax (kts)
Humberto 2007 9/09-9/12
Dennis
Track
impacts
intensity
Wilma
Interesting way research
models show forecasts
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)
Obs
GFDL model
NHC
Forecast
Global models
Katrina Landfall
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
High-res models
(1.6km)
Obs
HWRF model
GFDL model
NHC
Forecast
Global models
Katrina Landfall
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?
Housekeeping
Agenda
Enough time for discussion
THANK YOU HFIP for support