Transcript NCAR WRF/ARW REAL TIME HURRICANE FORECASTS 2005 The WRF ARW model was run at 4km resolution with no convective parameterization for five hurricanes.

NCAR WRF/ARW REAL TIME
HURRICANE FORECASTS 2005
The WRF ARW model was run at 4km resolution with no convective
parameterization for five hurricanes during the 2005 season. The
storms were selected on the basis that they were threatening the
United States and all were selected before their ultimate intensity
was known.
The storms were: Katrina, Maria, Ophelia, Rita and Wilma.
The following statistics were prepared by Mark DeMaria and the
intercomparisons are homogeneous, in that the same forecasts
are used in all cases.
I emphasize that this is a limited data set of only five cyclones. A
much more comprehensive set is required for definitive results,
however these are most encouraging.
ESSL
Background
•
The forecast numbers were:
Period
Number
•
•
•
0
12
24
36
48
72
96
35
35
35
31
28
19
2
The periods out to 72 hours contained sufficient numbers of forecasts
to provide reasonable statistics. The 96 hour statistics need to be
treated with caution.
The model was initialized mostly with GDFL, though there were a few
occasions where the GFS was used as the GFDL was not available.
Note that the GFDL uses a bogus cyclone and we consider that this
had a marked effect on the first 24-36 hour forecasts with WRF-ARW.
The horizontal boundary conditions were from the GFS.
Note that this is the straight research model, with no attempt having
been made at optimization or tuning of physical parameters
ESSL
Intensity Predictions
45
SHF5
40
OFCL
35
Error (kt)
30
DSHP
GFDL
FSSE
25
NWRF
20
NCHG
15
10
5
0
0
12
24
36
48
60
72
84
96
Forecast Tim e
•
•
WRF is the black column. The other forecast technique names are indicated in the following
slide.
Early in the forecast period, WRF is in the pack, a result that we consider would be very
much improved by use of a proper initialization. At longer time periods WRF is outstanding.
ESSL
Intensity Acronyms
•
•
•
•
•
•
•
SHF5 is a statistical forecast scheme
OFCL is the official forecast
DSHP is a statistical forecast scheme
GFDL is the GFDL model run at 9km resolution
FSSE is the Florida State Super Ensemble
NWRF is the NCAR WRF-ARW model
NCHG is straight persistence
ESSL
Track Predictions
600
500
CLP5
OFCL
NWRF
AVNO
Error (nm)
400
GFDL
NGPS
300
UKM
FSSE
200
100
0
0
12
24
36
48
60
72
84
96
Forecast Tim e
•
•
WRF is the black column. The other forecast technique names are indicated in the following
slide.
WRF-ARW has excellent forecast accuracy at all time periods, being generally very similar
to the official forecasts.
ESSL
Track Acronyms
• CLPR is a statistical climatological and persistence
forecast scheme
• OFCL is the official forecast
• NWRF is the NCAR WRF-ARW model
• AVNO is the global NCEP Aviation Model
• GFDL is the GFDL model run at 9km resolution
• NGPS is the Navy Global Prediction System
• UKM is the UK Met office Global Model
• FSSE is the Florida State Super Ensemble
ESSL