update on ncar auto-nowcaster juneau, ak. the auto-nowcaster system an expert system which produces...

Update on NCAR Auto-Nowcaster

Juneau, AK

The Auto-Nowcaster System

• An expert system which produces short-term (0-1 hr) forecasts of thunderstorm initiation, growth and decay using fuzzy logic.

• Recent developments have allowed human users (i.e. forecasters) to input information into the system in a relatively quick and simple fashion.

• A test of the updated system in an operational environment is taking place at the Dallas/Fort Worth WFO.

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

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

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

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

Forecaster-tools: Boundary Entry

Forecaster Entered Polygons

• Weather Forecast Office Washington DC (Sterling, VA) • 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/Fort Worth Weather Forecast Office

• AWIPS

Auto-Nowcaster at Ft. Worth WFO

On this day, dryline was moving in from the west. Below is an example of one of the Area Weather Updates that they put out on that day:

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 at Ft. Worth WFO05 April 2005

Ft. Worth WFO 05 April 2005

Forecast: 2003 ZRadar Image: 2003 Z



• On this day there was a dryline moving in from the west.

• Storms developed a couple of hours earlier than originally thought.

• The ANC system captured the initiation of this event with about a 40-50 minute lead time.

• The storms went severe within 30 minutes of initiation (about 50 miles west of DFW Metroplex) with quarter sized hail, strong winds and several mesocyclones.


• This was one of the first events after some modifications had been made to the system based on forecaster feedback (i.e. a CIN predictor field was added to the forecast logic).

• Had this information not been included, the ANC system would have produced several hours of false alarms prior to storms initiating.

• Several forecasters consulted the system during this event and it was used to help with spotter activation.

Our Impressions of the Ft. Worth WFO Deployment

• Users have been very accommodating of new technology.

• Users have done a really good job of entering boundaries.

• Use the system most often early on in the convective events during initiation/development phase.

• Received a lot of very useful feedback from the users.• Have incorporated some of the forecasters ideas

which we feel have led to improved forecasts and are in the process of implementing others.

update on ncar auto-nowcaster juneau, ak. the auto-nowcaster system an expert system which produces...

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