ncar auto-nowcaster convective weather group ncar/ral

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NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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Page 1: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

NCAR Auto-Nowcaster

Convective Weather GroupNCAR/RAL

Page 2: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Why We Need ANC ?

Page 3: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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…..

Page 4: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Example of Auto-Nowcaster Initiation Forecast

1 hour forecast Verification

Initiationnowcasts

extrapolationnowcasts

Page 5: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

• 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

Page 6: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 7: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 8: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 9: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Convergence line

Example of fuzzy logicPredictor Field 1

.5

Likelihood

Lifting Zone

Membership Function

Lifting Zone

Lik

elih

ood

Yes

No

.5

0

Page 10: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Convergence

Predictor Field 2Membership Function

Convergence

Lik

elih

ood

.1.2

.3.2

.1Likelihood

Page 11: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Cumulus clouds

Predictor Field 3

.4-.5

-.5Likelihood

Membership Function

Cumulus cloud type

Lik

elih

ood .4

-1

1.8

-.5

Page 12: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Likelihood 1 Likelihood 2 Likelihood 3

Weight 1 Weight 2Weight 3

ΣFinal combinedlikelihood of initiation

Page 13: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

• 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

Page 14: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 15: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 16: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 17: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 18: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 19: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 20: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 21: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Predictor Fields

Large-Scale Environment

B-L characteristics

Satellite Cloud Typing

Boundary characteristics

Cumulusdevelopment

Storm motion and trends

Page 22: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Predictor Fields

Large-Scale Environment

B-L characteristics

Satellite Cloud Typing

Boundary characteristics

Cumulusdevelopment

Storm motion and trends

Page 23: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 24: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

FAA RCWF Domain June 12, 2003

Forecaster Entered Boundary

Page 25: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Draw Tool

Page 26: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Draw Tool

Page 27: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Draw Tool

Entering a convergence boundary in real time is as simple as this demonstration!

Page 28: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Forecaster-toolsBoundary Entry

Page 29: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Forecaster Entered Polygons

Page 30: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

Ft. Worth WFO April 5, 2005

Forecast Verification

Page 31: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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).

Page 32: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 33: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 34: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

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

Page 35: NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

END

THANK YOU !