<s>
A	O
tropical	B-Application
cyclone	I-Application
forecast	I-Application
model	I-Application
is	O
a	O
computer	O
program	O
that	O
uses	O
meteorological	O
data	O
to	O
forecast	O
aspects	O
of	O
the	O
future	O
state	O
of	O
tropical	O
cyclones	B-Device
.	O
</s>
<s>
Dynamical	O
models	O
utilize	O
powerful	O
supercomputers	B-Architecture
with	O
sophisticated	O
mathematical	O
modeling	O
software	O
and	O
meteorological	O
data	O
to	O
calculate	B-General_Concept
future	I-General_Concept
weather	I-General_Concept
conditions	I-General_Concept
.	O
</s>
<s>
Statistical	O
models	O
forecast	O
the	O
evolution	O
of	O
a	O
tropical	O
cyclone	B-Device
in	O
a	O
simpler	O
manner	O
,	O
by	O
extrapolating	O
from	O
historical	O
datasets	O
,	O
and	O
thus	O
can	O
be	O
run	O
quickly	O
on	O
platforms	O
such	O
as	O
personal	B-Device
computers	I-Device
.	O
</s>
<s>
Four	O
primary	O
types	O
of	O
forecasts	O
exist	O
for	O
tropical	O
cyclones	B-Device
:	O
track	B-Application
,	O
intensity	O
,	O
storm	O
surge	O
,	O
and	O
rainfall	O
.	O
</s>
<s>
Track	B-Application
models	O
did	O
not	O
show	O
forecast	O
skill	O
when	O
compared	O
to	O
statistical	O
models	O
until	O
the	O
1980s	O
.	O
</s>
<s>
Early	O
models	O
use	O
data	O
from	O
previous	O
model	O
runs	O
while	O
late	O
models	O
produce	O
output	O
after	O
the	O
official	O
hurricane	B-Application
forecast	I-Application
has	O
been	O
sent	O
.	O
</s>
<s>
Techniques	O
used	O
at	O
the	O
Joint	O
Typhoon	B-General_Concept
Warning	O
Center	O
indicate	O
that	O
superensemble	O
forecasts	O
are	O
a	O
very	O
powerful	O
tool	O
for	O
track	B-Application
forecasting	O
.	O
</s>
<s>
The	O
first	O
statistical	O
guidance	O
used	O
by	O
the	O
National	O
Hurricane	B-Device
Center	O
was	O
the	O
Hurricane	B-Device
Analog	O
Technique	O
(	O
HURRAN	O
)	O
,	O
which	O
was	O
available	O
in	O
1969	O
.	O
</s>
<s>
It	O
used	O
the	O
newly	O
developed	O
North	O
Atlantic	O
tropical	O
cyclone	B-Device
database	O
to	O
find	O
storms	O
with	O
similar	O
tracks	O
.	O
</s>
<s>
Since	O
1972	O
,	O
the	O
Climatology	O
and	O
Persistence	O
(	O
CLIPER	O
)	O
statistical	O
model	O
has	O
been	O
used	O
to	O
help	O
generate	O
tropical	O
cyclone	B-Device
track	B-Application
forecasts	O
.	O
</s>
<s>
The	O
Statistical	O
Hurricane	B-Device
Intensity	O
Forecast	O
(	O
SHIFOR	O
)	O
has	O
been	O
used	O
since	O
1979	O
for	O
tropical	O
cyclone	B-Device
intensity	O
forecasting	O
.	O
</s>
<s>
It	O
uses	O
climatology	O
and	O
persistence	O
to	O
predict	O
future	O
intensity	O
,	O
including	O
the	O
current	O
Julian	O
day	O
,	O
current	O
cyclone	B-Device
intensity	O
,	O
the	O
cyclone	B-Device
's	O
intensity	O
12hours	O
ago	O
,	O
the	O
storm	O
's	O
initial	O
latitude	O
and	O
longitude	O
,	O
as	O
well	O
as	O
its	O
zonal	O
(	O
east-west	O
)	O
and	O
meridional	O
(	O
north-south	O
)	O
components	O
of	O
motion	O
.	O
</s>
<s>
Within	O
the	O
field	O
of	O
tropical	B-Application
cyclone	I-Application
track	I-Application
forecasting	I-Application
,	O
despite	O
the	O
ever-improving	O
dynamical	O
model	O
guidance	O
which	O
occurred	O
with	O
increased	O
computational	O
power	O
,	O
it	O
was	O
not	O
until	O
the	O
decade	O
of	O
the	O
1980s	O
when	O
numerical	B-General_Concept
weather	I-General_Concept
prediction	I-General_Concept
showed	O
skill	O
,	O
and	O
until	O
the	O
1990s	O
when	O
it	O
consistently	O
outperformed	O
statistical	O
or	O
simple	O
dynamical	O
models	O
.	O
</s>
<s>
In	O
1994	O
,	O
a	O
version	O
of	O
SHIFOR	O
was	O
created	O
for	O
the	O
northwest	O
Pacific	O
Ocean	O
for	O
typhoon	B-General_Concept
forecasting	O
,	O
known	O
as	O
the	O
Statistical	O
Typhoon	B-General_Concept
Intensity	O
Forecast	O
(	O
STIFOR	O
)	O
,	O
which	O
used	O
the	O
1971	O
–	O
1990	O
data	O
for	O
that	O
region	O
to	O
develop	O
intensity	O
forecasts	O
out	O
to	O
72hours	O
into	O
the	O
future	O
.	O
</s>
<s>
In	O
regards	O
to	O
intensity	O
forecasting	O
,	O
the	O
Statistical	O
Hurricane	B-Device
Intensity	O
Prediction	O
Scheme	O
(	O
SHIPS	O
)	O
utilizes	O
relationships	O
between	O
environmental	O
conditions	O
from	O
the	O
Global	O
Forecast	O
System	O
(	O
GFS	O
)	O
such	O
as	O
vertical	O
wind	O
shear	O
and	O
sea	O
surface	O
temperatures	O
,	O
climatology	O
,	O
and	O
persistence	O
(	O
storm	O
behavior	O
)	O
via	O
multiple	O
regression	O
techniques	O
to	O
come	O
up	O
with	O
an	O
intensity	O
forecast	O
for	O
systems	O
in	O
the	O
northern	O
Atlantic	O
and	O
northeastern	O
Pacific	O
oceans	O
.	O
</s>
<s>
A	O
similar	O
model	O
was	O
developed	O
for	O
the	O
northwest	O
Pacific	O
Ocean	O
and	O
Southern	O
Hemisphere	O
known	O
as	O
the	O
Statistical	O
Intensity	O
Prediction	O
System	O
(	O
STIPS	O
)	O
,	O
which	O
accounts	O
for	O
land	O
interactions	O
through	O
the	O
input	O
environmental	O
conditions	O
from	O
the	O
Navy	B-Application
Operational	I-Application
Global	I-Application
Prediction	I-Application
System	I-Application
(	O
NOGAPS	O
)	O
model	O
.	O
</s>
<s>
Within	O
tropical	O
cyclone	B-Device
rainfall	O
forecasting	O
,	O
the	O
Rainfall	O
Climatology	O
and	O
Persistence	O
(	O
r-CLIPER	O
)	O
model	O
was	O
developed	O
using	O
microwave	O
rainfall	O
data	O
from	O
polar	O
orbiting	O
satellites	O
over	O
the	O
ocean	O
and	O
first-order	O
rainfall	O
measurements	O
from	O
the	O
land	O
,	O
to	O
come	O
up	O
with	O
a	O
realistic	O
rainfall	O
distribution	O
for	O
tropical	O
cyclones	B-Device
based	O
on	O
the	O
National	O
Hurricane	B-Device
Center	O
's	O
track	B-Application
forecast	O
.	O
</s>
<s>
A	O
statistical-parametric	O
wind	O
radii	O
model	O
has	O
been	O
developed	O
for	O
use	O
at	O
the	O
National	O
Hurricane	B-Device
Center	O
and	O
Joint	O
Typhoon	B-General_Concept
Warning	O
Center	O
which	O
uses	O
climatology	O
and	O
persistence	O
to	O
predict	O
wind	O
structure	O
out	O
to	O
five	O
days	O
into	O
the	O
future	O
.	O
</s>
<s>
During	O
1972	O
,	O
the	O
first	O
model	O
to	O
forecast	O
storm	O
surge	O
along	O
the	O
continental	O
shelf	O
of	O
the	O
United	O
States	O
was	O
developed	O
,	O
known	O
as	O
the	O
Special	O
Program	O
to	O
List	O
the	O
Amplitude	O
of	O
Surges	O
from	O
Hurricanes	B-Application
(	O
SPLASH	O
)	O
.	O
</s>
<s>
In	O
1978	O
,	O
the	O
first	O
hurricane-tracking	O
model	O
based	O
on	O
atmospheric	O
dynamics	O
–	O
the	O
movable	O
fine-mesh	O
(	O
MFM	O
)	O
model	O
–	O
began	O
operating	O
.	O
</s>
<s>
In	O
the	O
early	O
1980s	O
,	O
the	O
assimilation	O
of	O
satellite-derived	O
winds	O
from	O
water	O
vapor	O
,	O
infrared	O
,	O
and	O
visible	O
satellite	O
imagery	O
was	O
found	O
to	O
improve	O
tropical	O
cyclones	B-Device
track	B-Application
forecasting	O
.	O
</s>
<s>
The	O
Geophysical	O
Fluid	O
Dynamics	O
Laboratory	O
(	O
GFDL	O
)	O
hurricane	B-Device
model	O
was	O
used	O
for	O
research	O
purposes	O
between	O
1973	O
and	O
the	O
mid-1980s	O
.	O
</s>
<s>
Once	O
it	O
was	O
determined	O
that	O
it	O
could	O
show	O
skill	O
in	O
hurricane	B-Device
prediction	O
,	O
a	O
multi-year	O
transition	O
transformed	O
the	O
research	O
model	O
into	O
an	O
operational	O
model	O
which	O
could	O
be	O
used	O
by	O
the	O
National	O
Weather	O
Service	O
for	O
both	O
track	B-Application
and	O
intensity	O
forecasting	O
in	O
1995	O
.	O
</s>
<s>
By	O
1985	O
,	O
the	O
Sea	O
Lake	O
and	O
Overland	O
Surges	O
from	O
Hurricanes	B-Application
(	O
SLOSH	O
)	O
Model	O
had	O
been	O
developed	O
for	O
use	O
in	O
areas	O
of	O
the	O
Gulf	O
of	O
Mexico	O
and	O
near	O
the	O
United	O
States	O
 '	O
East	O
coast	O
,	O
which	O
was	O
more	O
robust	O
than	O
the	O
SPLASH	O
model	O
.	O
</s>
<s>
The	O
Beta	O
Advection	O
Model	O
(	O
BAM	O
)	O
has	O
been	O
used	O
operationally	O
since	O
1987	O
using	O
steering	O
winds	O
averaged	O
through	O
the	O
850	O
hPa	O
to	O
200	O
hPa	O
layer	O
and	O
the	O
Beta	O
effect	O
which	O
causes	O
a	O
storm	O
to	O
drift	O
northwest	O
due	O
to	O
differences	O
in	O
the	O
coriolis	O
effect	O
across	O
the	O
tropical	O
cyclone	B-Device
.	O
</s>
<s>
The	O
larger	O
the	O
cyclone	B-Device
,	O
the	O
larger	O
the	O
impact	O
of	O
the	O
beta	O
effect	O
is	O
likely	O
to	O
be	O
.	O
</s>
<s>
Starting	O
in	O
1990	O
,	O
three	O
versions	O
of	O
the	O
BAM	O
were	O
run	O
operationally	O
:	O
the	O
BAM	O
shallow	O
(	O
BAMS	O
)	O
average	O
winds	O
in	O
an	O
850	O
hPa	O
to	O
700	O
hPa	O
layer	O
,	O
the	O
BAM	O
Medium	O
(	O
BAMM	B-Application
)	O
which	O
uses	O
average	O
winds	O
in	O
an	O
850	O
hPa	O
to	O
400	O
hPa	O
layer	O
,	O
and	O
the	O
BAM	O
Deep	O
(	O
BAMD	B-Application
)	O
which	O
is	O
the	O
same	O
as	O
the	O
pre-1990	O
BAM	O
.	O
</s>
<s>
For	O
a	O
weak	O
hurricane	B-Device
without	O
well-developed	O
central	O
thunderstorm	O
activity	O
,	O
BAMS	O
works	O
well	O
,	O
because	O
weak	O
storms	O
tend	O
to	O
be	O
steered	O
by	O
low-level	O
winds	O
.	O
</s>
<s>
As	O
the	O
storm	O
grows	O
stronger	O
and	O
associated	O
thunderstorm	O
activity	O
near	O
its	O
center	O
gets	O
deeper	O
,	O
BAMM	B-Application
and	O
BAMD	B-Application
become	O
more	O
accurate	O
,	O
as	O
these	O
types	O
of	O
storms	O
are	O
steered	O
more	O
by	O
the	O
winds	O
in	O
the	O
upper-level	O
.	O
</s>
<s>
If	O
the	O
forecast	O
from	O
the	O
three	O
versions	O
is	O
similar	O
,	O
then	O
the	O
forecaster	O
can	O
conclude	O
that	O
there	O
is	O
minimal	O
uncertainty	O
,	O
but	O
if	O
the	O
versions	O
vary	O
by	O
a	O
great	O
deal	O
,	O
then	O
the	O
forecaster	O
has	O
less	O
confidence	O
in	O
the	O
track	B-Application
predicted	O
due	O
to	O
the	O
greater	O
uncertainty	O
.	O
</s>
<s>
Tested	O
in	O
1989	O
and	O
1990	O
,	O
The	O
Vic	O
Ooyama	O
Barotropic	O
(	O
VICBAR	O
)	O
model	O
used	O
a	O
cubic-B	B-Algorithm
spline	I-Algorithm
representation	O
of	O
variables	O
for	O
the	O
objective	O
analysis	O
of	O
observations	O
and	O
solutions	O
to	O
the	O
shallow-water	O
prediction	O
equations	O
on	O
nested	O
domains	O
,	O
with	O
the	O
boundary	O
conditions	O
defined	O
as	O
the	O
global	O
forecast	O
model	O
.	O
</s>
<s>
By	O
1990	O
,	O
Australia	O
had	O
developed	O
its	O
own	O
storm	O
surge	O
model	O
which	O
was	O
able	O
to	O
be	O
run	O
in	O
a	O
few	O
minutes	O
on	O
a	O
personal	B-Device
computer	I-Device
.	O
</s>
<s>
The	O
Japan	O
Meteorological	O
Agency	O
(	O
JMA	O
)	O
developed	O
its	O
own	O
Typhoon	B-General_Concept
Model	O
(	O
TYM	O
)	O
in	O
1994	O
,	O
and	O
in	O
1998	O
,	O
the	O
agency	O
began	O
using	O
its	O
own	O
dynamic	O
storm	O
surge	O
model	O
.	O
</s>
<s>
The	O
Hurricane	B-Application
Weather	I-Application
Research	I-Application
and	I-Application
Forecasting	I-Application
(	O
HWRF	B-Application
)	O
model	O
is	O
a	O
specialized	O
version	O
of	O
the	O
Weather	B-Application
Research	I-Application
and	I-Application
Forecasting	I-Application
(	O
WRF	O
)	O
model	O
and	O
is	O
used	O
to	O
forecast	O
the	O
track	B-Application
and	O
intensity	O
of	O
tropical	O
cyclones	B-Device
.	O
</s>
<s>
Despite	O
improvements	O
in	O
track	B-Application
forecasting	O
,	O
predictions	O
of	O
the	O
intensity	O
of	O
a	O
tropical	O
cyclone	B-Device
based	O
on	O
numerical	B-General_Concept
weather	I-General_Concept
prediction	I-General_Concept
continue	O
to	O
be	O
a	O
challenge	O
,	O
since	O
statistical	O
methods	O
continue	O
to	O
show	O
higher	O
skill	O
over	O
dynamical	O
guidance	O
.	O
</s>
<s>
Other	O
than	O
the	O
specialized	O
guidance	O
,	O
global	O
guidance	O
such	O
as	O
the	O
GFS	O
,	O
Unified	B-Application
Model	I-Application
(	O
UKMET	O
)	O
,	O
NOGAPS	O
,	O
Japanese	O
Global	O
Spectral	O
Model	O
(	O
GSM	O
)	O
,	O
European	O
Centre	O
for	O
Medium-Range	O
Weather	O
Forecasts	O
model	O
,	O
France	O
's	O
Action	O
de	O
Recherche	O
Petite	O
Echelle	O
Grande	O
Echelle	O
(	O
ARPEGE	O
)	O
and	O
Aire	O
Limit´ee	O
Adaptation	O
Dynamique	O
Initialisation	O
(	O
ALADIN	O
)	O
models	O
,	O
India	O
's	O
National	O
Centre	O
for	O
Medium	O
Range	O
Weather	O
Forecasting	O
(	O
NCMRWF	O
)	O
model	O
,	O
Korea	O
's	O
Global	O
Data	O
Assimilation	O
and	O
Prediction	O
System	O
(	O
GDAPS	O
)	O
and	O
Regional	O
Data	O
Assimilation	O
and	O
Prediction	O
System	O
(	O
RDAPS	O
)	O
models	O
,	O
Hong	O
Kong/China	O
'	O
s	O
Operational	O
Regional	O
Spectral	O
Model	O
(	O
ORSM	O
)	O
model	O
,	O
and	O
Canadian	O
Global	B-Application
Environmental	I-Application
Multiscale	I-Application
Model	I-Application
(	O
GEM	O
)	O
model	O
are	O
used	O
for	O
track	B-Application
and	O
intensity	O
purposes	O
.	O
</s>
<s>
Some	O
models	O
do	O
not	O
produce	O
output	O
quickly	O
enough	O
to	O
be	O
used	O
for	O
the	O
forecast	O
cycle	O
immediately	O
after	O
the	O
model	O
starts	O
running	O
(	O
including	O
HWRF	B-Application
,	O
GFDL	O
,	O
and	O
FSSE	O
)	O
.	O
</s>
<s>
Most	O
of	O
the	O
above	O
track	B-Application
models	O
(	O
except	O
CLIPER	O
)	O
require	O
data	O
from	O
global	B-Application
weather	I-Application
models	I-Application
,	O
such	O
as	O
the	O
GFS	O
,	O
which	O
produce	O
output	O
about	O
four	O
hours	O
after	O
the	O
synoptic	O
times	O
of	O
0000	O
,	O
0600	O
,	O
1200	O
,	O
and	O
1800	O
Universal	O
Coordinated	O
Time	O
(	O
UTC	O
)	O
.	O
</s>
<s>
These	O
models	O
are	O
interpolated	B-Algorithm
to	O
the	O
current	O
storm	O
position	O
for	O
use	O
in	O
the	O
following	O
forecast	O
cycle	O
–	O
for	O
example	O
,	O
GFDI	B-Application
,	O
the	O
interpolated	B-Algorithm
version	O
of	O
the	O
GFDL	O
model	O
.	O
</s>
<s>
Trackwise	O
,	O
the	O
GUNA	O
model	O
is	O
a	O
consensus	O
of	O
the	O
interpolated	B-Algorithm
versions	O
of	O
the	O
GFDL	O
,	O
UKMET	O
with	O
quality	O
control	O
applied	O
to	O
the	O
cyclone	B-Device
tracker	O
,	O
United	O
States	O
Navy	O
NOGAPS	O
,	O
and	O
GFS	O
models	O
.	O
</s>
<s>
The	O
TCON	O
consensus	O
is	O
the	O
GUNA	O
consensus	O
plus	O
the	O
Hurricane	B-Device
WRF	O
model	O
.	O
</s>
<s>
In	O
early	O
2013	O
,	O
The	O
NAVGEM	B-Application
replaced	O
the	O
NOGAPS	O
as	O
the	O
Navy	O
's	O
primary	O
operational	O
global	O
forecast	O
model	O
.	O
</s>
<s>
For	O
intensity	O
,	O
a	O
combination	O
of	O
the	O
LGEM	O
,	O
interpolated	B-Algorithm
GFDL	O
,	O
interpolated	B-Algorithm
HWRF	B-Application
,	O
and	O
DSHIPS	O
models	O
is	O
known	O
as	O
the	O
ICON	O
consensus	O
.	O
</s>
<s>
GFS	O
,	O
the	O
Japanese	O
GSM	O
,	O
the	O
Coupled	O
Ocean/Atmosphere	O
Mesoscale	O
Prediction	O
System	O
(	O
COAMPS	O
)	O
,	O
the	O
UKMET	O
,	O
the	O
Japanese	O
TYM	O
,	O
the	O
GFDL	O
with	O
NOGAPS	O
boundary	O
conditions	O
,	O
the	O
Air	O
Force	O
Weather	O
Agency	O
(	O
AFWA	O
)	O
Model	O
,	O
the	O
Australian	O
Tropical	O
Cyclone	B-Device
Local	O
Area	O
Prediction	O
System	O
,	O
and	O
the	O
Weber	O
Barotropic	O
Model	O
.	O
</s>
<s>
The	O
JMA	O
has	O
produced	O
an	O
11-member	O
ensemble	O
forecast	O
system	O
for	O
typhoons	B-General_Concept
known	O
as	O
the	O
Typhoon	B-General_Concept
Ensemble	O
Prediction	O
System	O
(	O
TEPS	O
)	O
since	O
February	O
2008	O
,	O
which	O
is	O
run	O
out	O
to	O
132hours	O
into	O
the	O
future	O
.	O
</s>
<s>
It	O
uses	O
11global	O
models	O
,	O
including	O
five	O
developed	O
at	O
Florida	O
State	O
University	O
,	O
the	O
Unified	B-Application
Model	I-Application
,	O
the	O
GFS	O
,	O
the	O
NOGAPS	O
,	O
the	O
United	O
States	O
Navy	O
NOGAPS	O
,	O
the	O
Australian	O
Bureau	O
of	O
Meteorology	O
Research	O
Centre	O
(	O
BMRC	O
)	O
model	O
,	O
and	O
Canadian	O
Recherche	O
en	O
Prévision	O
Numérique	O
(	O
RPN	O
)	O
model	O
.	O
</s>
<s>
It	O
shows	O
significant	O
skill	O
in	O
track	B-Application
,	O
intensity	O
,	O
and	O
rainfall	O
predictions	O
of	O
tropical	O
cyclones	B-Device
.	O
</s>
<s>
The	O
Systematic	O
Approach	O
Forecast	O
Aid	O
(	O
SAFA	O
)	O
was	O
developed	O
by	O
the	O
Joint	O
Typhoon	B-General_Concept
Warning	O
Center	O
to	O
create	O
a	O
selective	O
consensus	O
forecast	O
which	O
removed	O
more	O
erroneous	O
forecasts	O
at	O
a	O
72‑hour	O
time	O
frame	O
from	O
consideration	O
using	O
the	O
United	O
States	O
Navy	O
NOGAPS	O
model	O
,	O
the	O
GFDL	O
,	O
the	O
Japan	O
Meteorological	O
Agency	O
's	O
global	O
and	O
typhoon	B-General_Concept
models	O
,	O
as	O
well	O
as	O
the	O
UKMET	O
.	O
</s>
<s>
A	O
2010	O
report	O
correlates	O
low	O
sunspot	B-Application
activity	O
with	O
high	O
hurricane	B-Device
activity	O
.	O
</s>
<s>
Analyzing	O
historical	O
data	O
,	O
there	O
was	O
a	O
25%	O
chance	O
of	O
at	O
least	O
one	O
hurricane	B-Device
striking	O
the	O
continental	O
United	O
States	O
during	O
a	O
peak	O
sunspot	B-Application
year	O
;	O
a	O
64%	O
chance	O
during	O
a	O
low	O
sunspot	B-Application
year	O
.	O
</s>
<s>
In	O
June	O
2010	O
,	O
the	O
hurricanes	B-Application
predictors	O
in	O
the	O
US	O
were	O
not	O
using	O
this	O
information	O
.	O
</s>
<s>
The	O
accuracy	O
of	O
hurricane	B-Application
forecast	I-Application
models	O
can	O
vary	O
significantly	O
from	O
storm	O
to	O
storm	O
.	O
</s>
<s>
For	O
some	O
storms	O
the	O
factors	O
affecting	O
the	O
hurricane	B-Application
track	I-Application
are	O
relatively	O
straightforward	O
,	O
and	O
the	O
models	O
are	O
not	O
only	O
accurate	O
but	O
they	O
produce	O
similar	O
forecasts	O
,	O
while	O
for	O
other	O
storms	O
the	O
factors	O
affecting	O
the	O
hurricane	B-Application
track	I-Application
are	O
more	O
complex	O
and	O
different	O
models	O
produce	O
very	O
different	O
forecasts	O
.	O
</s>
