NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL.
-
Upload
samuel-boone -
Category
Documents
-
view
215 -
download
0
Transcript of NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL.
NCAR Auto-Nowcaster
Convective Weather GroupNCAR/RAL
Why We Need ANC ?
Detection and extrapolation of surface convergence boundaries ….
….that trigger thunderstorm initiation and impact storm evolution.
The Auto-nowcaster Systemis unique in its ability to provide nowcasts of storm initiation by…..
Example of Auto-Nowcaster Initiation Forecast
1 hour forecast Verification
Initiationnowcasts
extrapolationnowcasts
• Weather Forecast Office Washington DC • Sydney Australia Forecast Office
• U. S. Army White Sands Missile Range
• Central U. S. for the FAA
Where has the Auto-nowcaster been demonstrated ?
Process of being transferred to:• Bureau Meteorology Beijing China
• U.S National Weather Service – Dallas Weather Forecast Office
• AWIPS
AREA WEATHER UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 310 PM CDT SUN APR 10 2005 > WARNING DECISION UPDATE FOR NORTH TEXAS
MESOANALYSIS PROGRAMS SHOW 1000-1500 J/KG CAPE ALONG AND JUST AHEADOF DRYLINE. THUS...CU/DEVELOPING STORMS ALONG/E OF DRYLINE SHOULDCONTINUE TO INTENSIFY. STORM INITIATION TOOL ALSO SUGGESTS HIGHPOSSIBILITY OF DEVELOPMENT FARTHER SW...OVER CORYELL/LAMPASAS COUNTY AREA. DEEP-LAYER SHEAR MORE THAN SUFFICIENT FOR ORGANIZED STORMS AND AT LEAST MID-LEVEL MESOS. AS STORMS EVOLVE INTO THE EVENING...A MORE LINEAR MODE IS EXPECTED.
Auto-Nowcaster atFt. Worth WFO
Data Sets
Radar WSR-88DSatelliteMesonetProfilerSoundingNumerical ModelLightning
Analysis AlgorithmsPredictor Fields
Forecaster Input
Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field
Final Prediction
Flow Chart for the Auto-Nowcaster System
Data Sets
Radar WSR-88DSatelliteMesonetProfilerSoundingNumerical ModelLightning
Analysis AlgorithmsPredictor Fields
Forecaster Input
Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field
Final Prediction
Flow Chart for the Auto-Nowcaster System
Convergence line
Example of fuzzy logicPredictor Field 1
.5
Likelihood
Lifting Zone
Membership Function
Lifting Zone
Lik
elih
ood
Yes
No
.5
0
Convergence
Predictor Field 2Membership Function
Convergence
Lik
elih
ood
.1.2
.3.2
.1Likelihood
Cumulus clouds
Predictor Field 3
.4-.5
-.5Likelihood
Membership Function
Cumulus cloud type
Lik
elih
ood .4
-1
1.8
-.5
Likelihood 1 Likelihood 2 Likelihood 3
Weight 1 Weight 2Weight 3
ΣFinal combinedlikelihood of initiation
• Environmental conditions (RUC)– Frontal likelihood– Layered stability– CAPE (max between 900 and 700 mb)– Mean 875 to 725 mb Relative
Humidity• Boundary-layer
– Convergence– LI (based on METARS)– Vertical velocity along boundary
(maxW)– Boundary-relative steering flow– New storm development along
boundary• Clouds
– Clear or Cumulus– Vertical develop as observed by drop
in IR temps
Blue Regions - Little chance of storm development
Green Regions - Moderate likelihood
Red Regions - Areas of forecast initiation
Predictor Fields used for Combined Likelihood of Initiation
Lifted Index
-1
-0.5
0
0.5
1
-5 -4 -3 -2 -1 0 1 2 3 4 5
oK
Inte
rest
875 - 725 mb Mean Relative Humidity
-1
-0.5
0
0.5
1
0 20 40 60 80 100
%
Inte
rest
Vert_Sum
-1
-0.5
0
0.5
1
0 5 10 15
Count of "unstable" 25mb levels
Inte
rest
Cape
-1
-0.5
0
0.5
1
-500 0 500 1000 1500 2000
J Kg-1
Inte
rest
60 Minute Initation (rules with satellite data)
Wt: 0.17Range: -0.085 to 0.17
Wt: 0.20Range: -0.20 to 0.02
Wt: 0.17Range: -0.17 to 0.17
Wt: 0.10Range: 0 to 0.10
Frontal Likelihood
-1
-0.5
0
0.5
1
0 0.2 0.4 0.6 0.8 1
Interest
Inte
rest
Convergence
-1
-0.5
0
0.5
1
-0.1 -0.05 0 0.05 0.1
10-3s-1
Inte
rest
Wt: 0.08Range: -0.02 to 0.08
Wt: 0.16Range: -0.08 to 0.16
Sat_Cu
-1
-0.5
0
0.5
1
0 1 2 3 4 5 6
Interest
Inte
rest
Rate Of Change (ROC) IR Temp Rate
-1
-0.5
0
0.5
1
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
Interest
Inte
rest
Max W
-1
-0.5
0
0.5
1
-0.5 -0.25 0 0.25 0.5 0.75 1
m s-1
Inte
rest
60 Minute Initation (rules with satellite data) Cont.
Boundary Relative Steering Flow
-1
-0.5
0
0.5
1
-20 -15 -10 -5 0 5 10 15 20
m s-1
Inte
rest
Wt: 0.20Range: -0.2 to 0.2
Wt: 0.20Range: 0 to 0.20
Wt: 0.20Range: 0 to 0.20
Initiation along Boundary
-1
-0.5
0
0.5
1
-0.5 -0.25 0 0.25 0.5 0.75 1
Interest
Inte
rest
Wt: 0.25Range: 0 to 0.25
Wt: 0.15Range: 0 to 0.15
60 Minute Initation (rules with satellite data) Cont.
Lake:Wt: 0.10Range: -0.10 to 0
Sat_Clear:Wt: 0.40Range: -0.40 to 0
Boundary Collision:Wt: 0.12Range: 0 to 0.12
Initiation Levels:
0.70 => Init 10.90 => Init 21.20 => Init 3
Lifted Index
-1
-0.5
0
0.5
1
-5 -4 -3 -2 -1 0 1 2 3 4 5
oK
Inte
rest
875 - 725 mb Mean Relative Humidity
-1
-0.5
0
0.5
1
0 20 40 60 80 100
%
Inte
rest
Vert_Sum
-1
-0.5
0
0.5
1
0 5 10 15
Count of "unstable" 25mb levels
Inte
rest
Cape
-1
-0.5
0
0.5
1
-500 0 500 1000 1500 2000
J Kg-1
Inte
rest
60 Minute Initation (rules without satellite data)
Wt: 0.19Range: -0.095 to 0.19
Wt: 0.20Range: -0.20 to 0.02
Wt: 0.19Range: -0.19 to 0.19
Wt: 0.10Range: 0 to 0.10
Frontal Likelihood
-1
-0.5
0
0.5
1
0 0.2 0.4 0.6 0.8 1
Interest
Inte
rest
Convergence
-1
-0.5
0
0.5
1
-0.1 -0.05 0 0.05 0.1
10-3s-1
Inte
rest
Wt: 0.08Range: -0.02 to 0.08
Wt: 0.18Range: -0.09 to 0.18
Max W
-1
-0.5
0
0.5
1
-0.5 -0.25 0 0.25 0.5 0.75 1
m s-1
Inte
rest
60 Minute Initation (rules without satellite data) Cont.
Boundary Relative Steering Flow
-1
-0.5
0
0.5
1
-20 -15 -10 -5 0 5 10 15 20
m s-1
Inte
rest
Wt: 0.21Range: -0.21 to 0.21
Wt: 0.21Range: 0 to 0.21
Initiation along Boundary
-1
-0.5
0
0.5
1
-0.5 -0.25 0 0.25 0.5 0.75 1
Interest
Inte
rest
Wt: 0.30Range: 0 to 0.30
60 Minute Initation (rules without satellite data) Cont.
Lake:Wt: 0.10Range: -0.10 to 0
Sat_Clear:Wt: 0.40Range: -0.40 to 0
Boundary Collision:Wt: 0.14Range: 0 to 0.14
Initiation Levels:
0.70 => 25 dBZ0.90 => 30 dBZ1.20 => 32 dBZ
60 Minute Growth and Decay
Boundary Relative Steering Flow
-1
-0.5
0
0.5
1
-20 -15 -10 -5 0 5 10 15 20
m s-1
Inte
rest
Wt: 0.30Range: -0.3 to 0.3
Lake:Wt: 0.20Range: -0.20 to 0
Wt: 0.21Range: -0.21 to 0.21
Wt: 0.15Range: -0.0375 to 0.15
Wt: 0.20Range: -0.20 to 0.20
Normalized growth rate 60m - 45dBZ
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1 1.5 2
hr-1
Inte
rest
Normalized growth rate 60m - 30dBZ
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1 1.5 2
hr-1
Inte
rest
dBZ Max 60m
-1
-0.5
0
0.5
1
30 35 40 45 50 55 60
dBZ
Inte
rest
Growth/Decay Levels:
< -0.75 => decay 6km-0.75 to -0.55 => decay 4km-0.55 to -0.35 => decay 2km-0.35 to 0.20 => steady0.20 to 0.50 => grow 2km0.50 to 70 => grow 4km>0.70 => grow 6km
Predictor Fields
Large-Scale Environment
B-L characteristics
Satellite Cloud Typing
Boundary characteristics
Cumulusdevelopment
Storm motion and trends
Predictor Fields
Large-Scale Environment
B-L characteristics
Satellite Cloud Typing
Boundary characteristics
Cumulusdevelopment
Storm motion and trends
Why do we need a forecaster in the loop??
• Forecasters see the larger picture– Conceptual Models
– Ignore bad data points
– Understand limitations of NWP and observations
FAA RCWF Domain June 12, 2003
Forecaster Entered Boundary
Draw Tool
Draw Tool
Draw Tool
Entering a convergence boundary in real time is as simple as this demonstration!
Forecaster-toolsBoundary Entry
Forecaster Entered Polygons
Ft. Worth WFO April 5, 2005
Forecast Verification
Evaluation of Initiation Cases - 2004
• Forecaster on duty• Convection within ANC domain
that increased (based on area coverage) >20% in an hour.
• Covered an area of 3,000 km2
(Valid Time).
Initiation/Growth Cases
• 34 Case Days (Ranging from 18 to 210 min – not always consecutive)
• Divided into 3 categories:– Initiation along line (13)– Initiation in a region (6)– Primarily Growth (15)
Initiation along line
Initiation in region
Growth
60 min Time Interval
Bias vs. POD for ALL Initiation/Growth Cases
0
0.5
1
1.5
2
2.5
10% 15% 20% 25% 30% 35% 40% 45% 50% 55%
POD
Bia
s
Persistence ANC Forecast Growth/Decay Initiation level 2 Initiation level 1
Extrapolation
Different types of initiation
0
0.5
1
1.5
2
2.5
10% 15% 20% 25% 30% 35% 40% 45% 50% 55%
Persistence ANC Forecast Growth/Decay Initiation level 2 Initiation level 1
Extrapolation
Red : All CasesYellow : Initiation - lineCyan : Initiation - regionOrange : Growth
• Forecasts for growth show the most skill
• Initiation of linear storm systems show most improvement over extrapolation
Initiation - LineAll
GrowthInitiation- Region
POD
Bia
s
END
THANK YOU !