The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
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1. introduction
2. products of the DWD radar network
3. tornado detection by automatic algorithms
4. GuST - an automatic guidance prototype
5. the future of nowcasting severe weather
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
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R
O
D
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C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
comparison radar -> satellite
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
comparison radar -> satellite
+ better resolution (in time and space)
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
comparison radar -> satellite
+ better resolution (in time and space)
+ more information about storm structures
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
comparison radar -> satellite
+ better resolution (in time and space)
+ more information about storm structures
comparison radar -> conventional ground observations
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
comparison radar -> satellite
+ better resolution (in time and space)
+ more information about storm structures
comparison radar -> conventional ground observations
+ better coverage (in time and space)
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
comparison radar -> satellite
+ better resolution (in time and space)
+ more information about storm structures
comparison radar -> conventional ground observations
+ better coverage (in time and space)
- less information about storm threads
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
1
I
N
T
R
O
D
U
C
T
I
O
N
today, Doppler radar is by far the most efficient and
highest resolution data source for thunderstorm and
tornado nowcasting
IT IS (ALMOST) NOT POSSIBLE TO SEE A TORNADO
DIRECTLY IN CONVENTIONAL DOPPLER RADAR DATA!
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
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the DWD
Doppler radar network
-> 16 stations
-> full coverage within
a 125 km radius
-> all of them have
doppler functionality
-> resolution up to 1 km
and 5 minutes
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
reflectivity composite
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June 23rd 2005
1645 UTC
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
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standard products
• low-res reflectivity (~250 km radius ,6 classes)
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
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D
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C
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S
standard products
• low-res reflectivity (~250 km radius ,6 reflect. classes)
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
O
D
U
C
T
S
standard products
• low-res reflectivity (~250 km radius ,6 classes)
• high-res reflectivity (~125 km radius, 16 classes)
- characteristic cell structures
- hook echoes
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
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S
radar signatures in tornadic environments
• high-res reflectivity
- hook echo
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
O
D
U
C
T
S
radar signatures in tornadic environments
• high-res reflectivity
- hook echo
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
O
D
U
C
T
S
standard products
• low-res reflectivity (~250 km radius ,6 classes)
• high-res reflectivity (~125 km radius, 16 classes)
- characteristic cell structures
- hook echoes
• high-res Doppler velocity (~125 km radius)
- mesocyclones, TVS
- bow echoes
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
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D
U
C
T
S
radar signatures in tornadic environments
• Doppler velocity mesocyclone
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
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D
U
C
T
S
radar signatures in tornadic environments
• Doppler velocity mesocyclone
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
2
P
R
O
D
U
C
T
S
radar signatures in tornadic environments
• Doppler velocity bow echo
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
3
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E
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C
T
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N
Automatic detection and nowcasting of radar signatures
• goals
- maximizing POD while minimizing FAR
- minimizing RMSE of the output
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
3
D
E
T
E
C
T
I
O
N
Automatic detection and nowcasting of radar signatures
• predefined set of rules and thresholds
- thresholds/assumptions may be suboptimal/incorrect
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
3
D
E
T
E
C
T
I
O
N
Automatic detection and nowcasting of radar signatures
• predefined set of rules and thresholds
- thresholds/assumptions may be suboptimal/incorrect
• discriminant analysis
- assumption: distributions are Gaussian
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
3
D
E
T
E
C
T
I
O
N
Automatic detection and nowcasting of radar signatures
• predefined set of rules and thresholds
- thresholds/assumptions may be suboptimal/incorrect
• discriminant analysis
- assumption: distributions are Gaussian
• multiple linear regression
- assumption: relations are linear
+ physical understandable and configurable
transformations of predictors
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
3
D
E
T
E
C
T
I
O
N
Automatic detection and nowcasting of radar signatures
• predefined set of rules and thresholds
- thresholds/assumptions may be suboptimal/incorrect
• discriminant analysis
- assumption: distributions are Gaussian
• multiple linear regression
- assumption: relations are linear
+ physical understandable and configurable
transformations of predictors
• polynomial regression
- assumption: relations are polynomial
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
3
D
E
T
E
C
T
I
O
N
Automatic detection and nowcasting of radar signatures
• predefined set of rules and thresholds
- thresholds/assumptions may be suboptimal/incorrect
• discriminant analysis
- assumption: distributions are Gaussian
• multiple linear regression
- assumption: relations are linear
+ physical understandable and configurable
transformations of predictors
• polynomial regression
- assumption: relations are polynomial
• neural networks
+ detects patterns out of “noisy” data
- qualitative physical understanding is difficult
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• intentions:
- integrating as much data sources as possible
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• intentions:
- integrating as much data sources as possible
- calculation of forecasts by MLR approach
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• intentions:
- integrating as much data sources as possible
- calculation of forecasts by MLR approach
- providing guidance information about current cells
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• intentions:
- integrating as much data sources as possible
- calculation of forecasts by MLR approach
- providing guidance information about current cells
- creating unique warnings and advisories for
all counties and locations
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• system structure
RAD/
LIGHT
pd
DET
NWP
OBS
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• predictands:
- cell forecast motion vectors up to 2 hours
- hail size
- precipitation amount
- wind gusts
- lightning frequency
- possibility of rotation/tornado embedded in the storm
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• system structure
RAD/
LIGHT
pd
DET
NWP
OBS
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• input:
- radar and lightning data
- CONRAD cell detection
- CONRAD hail categories, shear detection
- NWP data (GME)
- spotter network observations
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• input:
- radar and lightning data
- CONRAD cell detection
- CONRAD hail categories, shear detection
- NWP data (GME)
- spotter network observations
• derived predictors:
- up to 10 past motion vectors
- hail size
- rain rate, wind gusts
- lightning frequency
- fields of numerical model
- some others
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• system structure
RAD/
LIGHT
pd
DET
NWP
OBS
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• system structure
RAD/
LIGHT
DET
NWP
OBS
(HIST)
pd
MLR
cof
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• system structure
RAD/
LIGHT
DET
NWP
OBS
(OPER)
(HIST)
pd
MLR
cof
OPER
fc
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• system structure
RAD/
LIGHT
DET
NWP
OBS
(OPER)
(HIST)
pd
MLR
POSTPROC
cof
Products,
Displays,
Warnings
OPER
fc
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
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D
A
N
C
E
Guidance System for Severe Thunderstorms - a prototype
• output:
- guidance text for every current (detected) cell
- unique warning texts for more than 80.000
counties and locations including predictands and
arrival times
- graphical displays
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
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U
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D
A
N
C
E
Guidance System
for Severe
Thunderstorms
guidance display
of the tornadic
thunderstorm
producing the
Micheln
F3-tornado
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
G
U
I
D
A
N
C
E
Guidance System
for Severe
Thunderstorms
guidance display
of the tornadic
thunderstorm
producing the
Micheln
F3-tornado
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
4
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*******************************************************************************
SEVERE THUNDERSTORM CELL INFORMATION
ISSUED at 16.45 UTC 23.06.2004
ID 200406231645
14 51.8567 11.8965
NEAREST RADAR STATION umd
*******************************************************************************
VALID immediately
A severe thunderstorm has been detected in county
Köthen...
...near Rajoch
or about 11 km W of Aken
or about 24 km W of Dessau
...moving to the NE with 30 km/h
This severe thunderstorm is capable of producing
...HEAVY PRECIPITATION OF ABOUT 30 L/QM WITHIN SHORT TIME
...LARGE HAIL OF ABOUT
3 CM IN DIAMETER
...STRONG GUSTS OF ABOUT 100 KM/H
...SIGNIFICANT LIGHTNING
***STRONG ROTATION IS OBSERVED WITH THIS STORM***
The following counties may be affected with this storm within two hours:
Schönebeck
at 17.10 UTC with PROB 75
Jerichower Land
at 16.45 UTC with PROB 95
Anhalt-Zerbst
at 17.10 UTC with PROB 50
And the following locations may be affected within one hour:
Barby
at 17.00 UTC with PROB 85
Zerbst
at 17.10 UTC with PROB 60
Genthin
at 18.25 UTC with PROB 60
*******************************************************************************
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
5
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U
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E
The future of radar nowcasting tornadoes in Germany
•
further improvement of the radar network and
the related products
- 5-minute update cycle
- 1km resolution or using polar coordinates
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
5
F
U
T
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E
The future of radar nowcasting tornadoes in Germany
•
further improvement of the radar network and
the related products
- 5-minute update cycle
- 1km resolution or using polar coordinates
•
using automatic algorithms for tornado detection
and tracking as guidance
- NinJo, CONRAD, GuST
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
5
F
U
T
U
R
E
The future of radar nowcasting tornadoes in Germany
•
further improvement of the radar network and
the related products
- 5-minute update cycle
- 1km resolution or using polar coordinates
•
using automatic algorithms for tornado detection
and tracking as guidance
- NinJo, CONRAD
•
integration of spotter network data and
storm chaser sightings in those guidance
systems
The use of Doppler radar products for
nowcasting tornadoes
DWD workshop on tornado forecasting, February 24th 2005, Langen
5
F
U
T
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R
E
Thank you very much for your attention!