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The System for Convection Analysis and Nowcasting |
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SCAN Frequently Asked Questions
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What is SCAN?
What are the goals of SCAN?
What are the benefits of SCAN?
Who is involved with SCAN?
What is the SCAN Vision?
Why do we need SCAN?
What are the ingredients for good warning decisions?
What was the pre-AWIPS WFO warning decision environment?
What is the pre-SCAN AWIPS WFO warning decision environment?
What will be the SCAN AWIPS WFO warning decision environment?
What is the SCAN development and implementation pipeline?
What is the SCAN Convective Threat Index (SCTI), how do you access it,
and how do you interpret it?
What is SCAN?
SCAN is the System for Convection Analysis and Nowcasting - an integrated suite of multi-sensor applications
which detects, analyzes and monitors convection and generates short-term probabilistic forecast and warning
guidance for severe weather and flash floods automatically within AWIPS.
What are the goals of SCAN?
- Provide forecasters with accurate, timely, and consistent severe weather and flash flood guidance.
- Develop "smart" computer displays, menus, and GUI's that optimize the utility of AWIPS D2D and are compatible with the warning decision process.
- Supplement forecaster event monitoring with automated, multi-sensor event monitoring.
- Accelerate the rate of technology transfer from research to operations and external users.
What are the benefits of SCAN?
- Key benefit: More accurate, timely, and consistent severe weather and flash flood warnings.
- Longer lead times on warned events.
- Fewer "missed" events (severe weather and flash floods treated concurrently).
- Increased forecaster situational awareness.
- Reduced forecaster fatigue during warning situations.
- Digital/graphical products for external users.
- A well-defined focus for applied research.
Who is involved with SCAN?
- MDL - Project coordination, principle AWIPS software development, field test support.
- NSSL - AWIPS applications development, ORPG development, field test support.
- ADDL - ORPG software development.
- NCAR - Prototypical applications development (i.e., AutoNowcaster), field test support.
- Others - OS, OOS, ER(WBC), APO, OHD, and FSL.
What is the SCAN vision?
No storm undetected, no hazard unwarned! SCAN is a tool to help the WARNING FORECASTER make better decisions.
Why do we need SCAN?
Consider this:
20 cells x 40 attributes x 3 radars x 10 volume scans/hr x 6 hrs =
144,000 things to monitor for one severe weather event!
Consider this:
1500 stream basins x 3 FFGs x 7 QPEs x 3 radars x 10 volume scans/hr x 6 hrs =
5,670,000 things to monitor for one flash flood event!
What are the ingredients for good warning decisions?
- Well-trained forecasters
- Timely, accurate, and reliable guidance
- Good situational awareness
- What is the synoptic situation (SPC)?
- What is the mesoscale situation?
- Where have warnings already been issued (geo-map info)? When will they expire?
- What are spotters and gages reporting?
- Are there any special events taking place?
What was the pre-AWIPS WFO warning decision environment?
Click on the image to see the full-size version.
What was the pre-SCAN AWIPS WFO warning decision environment?
Click on the image to see the full-size version.
What will be the SCAN AWIPS WFO warning decision environment?
Click on the image to see the full-size version.
What is the SCAN development and implementation pipeline?
Click on the image to see the full-size version. Note: OSD is now the Office of Science and Technology (OST) and TDL is now the Meteorological Development Laboratory (MDL).
What is the SCAN Convective Threat Index (SCTI), how do I access it, and how do I interpret it?
The SCAN Convective Threat Index (SCTI) is a numerical representation of the severe weather occurring within a CWA. The SCTI button is located directly below the WarnGen button on the D2D. The SCTI button has a severe weather symbol on it. The button will be colored according to the following criteria:| White | Little or no activity in the CWA |
| Green | General thunderstorms with low severe weather probabilities in the CWA |
| Yellow | Thunderstorms with moderate severe weather probabilities or a mesocyclone or TVS detected in the CWA |
| Red | Thunderstorms with high severe weather probabilities and a mesocyclone and/or TVS detected in the CWA |
| Grey | Invalid index number, which means the SCAN processor is not behaving properly. |
If the mouse cursor is focused over this colored button, a small text tip widget will appear, providing the maximum SCTI value over the CWA and what it represents.
In addition to the SCTI button, the actual grid of SCTI values over the CWA can be viewed via a D2D depictable, selectable from the SCAN section of the radar menus. The following table can be used to interpret the SCTI values:
| 100 | Cell SWP >=70, MESO & TVS |
| 90 | Cell SWP >=70, MESO or TVS |
| 80 | Cell SWP >=70 |
| 70 | 30 <= Cell SWP < 70, MESO & TVS |
| 60 | 30 <= Cell SWP < 70, MESO or TVS |
| 50 | 30 <= Cell SWP < 70 |
| 40 | Cell SWP < 30, MESO & TVS |
| 30 | Cell SWP < 30, MESO or TVS |
| 10 | CG LTG, High VIL, CZ |
See the SCAN 2.0 Development page and the SCAN 2.0 User's Guide for more information on the SCTI.
National Weather ServiceLast Modified: 15 Dec 2000, RLS.