# Presentation: 143338

## NEXRAD Generated 0-2 Hour Convective Forecasts for ATC Use

**Marilyn Wolfson**
**(Presented by J. Evans)**
**28 May 2003**

## Outline

**Convective weather forecasts in use now**
**Enhancements to tracking/extrapolation algorithm used in current algorithms**
**Growth & Decay Trending**
**Storm Classification**
**Near term improvements to better forecast new cell growth**
** ****Forecasts > 2 hours**
**Summary**

## Convective Weather Forecasts

**Tactical Forecasts (0-2 hrs)**
**1 km resolution**
**5-min update rate**
_**Future:**_** Storm-scale numerical ****models w/ data assimilation**

**Strategic Forecasts (2-6 hrs)**
**4-10 km resolution**
**15-120 min update rate**
_**Future:**_** Blend numerical & heuristic forecast techniques**

**RCWF in CIWS (0-2 hr)**

**CWF in ITWS (0-1 hr)**

**CCFP (2, 4, 6 hr)**

**NCWF (1 hr)**

**NCEP RUC Model (2,3,4,5,6 hr)**

**Collaboration between AWC, CWSUs at ARTCCs, airlines**

## Scale Separation Forecast Algorithm

**Radar data**

**Scale separation**

**Track vectors**

**Product display**

**Real-time**

**Scoring**

**NEXRAD radar**

## TCWF 60 Minute Forecast

**TCWF 60 Minute Forecast**

- 60 min. Forecast

- Truth

- Memphis 11 May 2003 – Valid 06:35Z

## Weather Classification Example

**Weather Classification**

**CIWS NEXRAD VIL**

- Weather Classification

- Multi-scale
- Tracking

- Growth and Decay
- Trending

- Convective
- Weather
- Truth

- Air Traffic
- Impacts

**22 August 2002**

## Growth and Decay Trending Algorithm

**Precipitation**

**Growth &**
**Decay Trend Map **

_**Other Feature Detectors**_
** ****Cell growth in a line pattern**
** ****Decay over long time scales**
** ****Elimination of spurious signals**

**Weather Classification**

**Combined Forecast Image**

## Performance of 2002 vs. 2003 CIWS Forecast

**August 22, 2002  2100 UTC**

**CIWS Forecast Accuracy Scoring Trends**

**Detroit**

**2000**

**2100**

**2200**

**2300**

**0000**

**2000**

**2100**

**2200**

**2300**

**0000**

**2000**

**2100**

**2200**

**2300**

**0000**

**Time (UTC)**

**Time (UTC)**

**Time (UTC)**

**Performance of 2002 vs. 2003 CIWS Forecast**

## Further Improvements to the 2-hr Forecast

**Daily solar forcing**
**Convection climatology**** **
**Large scale forcing**
**Rapid Update Cycle numerical model**** **
**Boundary layer forcing**

- 0100

- 0300

## CIWS Multi-Lab Research Testbed

| Operationally used Corridor 2-hr Forecast |  |  |  |  |
| --- | --- | --- | --- | --- |
|  |  |      2-hr Regional Convective Weather Forecast             - Weather Classification
             - Multi-scale Tracking
             -Growth/decay trending
             - Satellite Boundary Detection |  |  |
| Real-time Research Codes |  |  |  |  |
|  |  |  |  |  |
| Growth and Decay Trends

Satellite Feature
Detectors | AutoNowcaster
  -  MIGFA forcing
  -  Initiation, growth
     and decay
  -  Satellite interest |  | Regionalized NCWF
  -  RUC Forcing
  -  Growth & Decay 
 | 3-D Gridded Data
    (NEXRAD PDT)

Level-II Nexrad data via Internet2 |

## Lightning Climatology 

## Energy Available to Fuel Convection

- 975 mb CAPE (J/Kg)

## Example of Boundary Layer Wind Retrieval

**Boundary Layer Winds and Computed Divergence**

**Example of Boundary Layer Wind Retrieval**

**Boundary Layer Winds and Reflectivity (Chicago)**

**NCAR 4-D Variational Retrieval Technique (VDRAS)**

## CIWS Boundary Layer Coverage

**CIWS Boundary Layer Coverage**

**A** **= ASOS Stations**

-  **= NEXRAD not in CIWS (80 km)**

## Forecasts for TFM Automation Tools

**Humans ask for depiction of storms**
** ****- Correctly characterizes convection**
** ****- Often scores poorly at 1-2 hrs**

**Could depict likely areas of storms**
** ****- Convey storm density, forecast uncertainty**
** ****- Infer probability of route impact**

**Deterministic Forecast**

**Probabilistic Forecast**

## ITWS/TCWF Benefits from MEM

**12/18/02 – According to the ATCSCC, the max. delay was 240 minutes, while average delays peaked over 180 minutes at one point. FedEx reported 76 diversions (a record for them), in addition to the high number of ground-stopped planes.  FedEx: "There were periods in which we were able to determine routes to counter the weather, of which ITWS was a big help." Also, "[another radar] was showing level 5-6 cells over the approach end of 36 and ITWS was showing room to maneuver, dodge, and weave to position for approaches to runway 9. Which is what we did... It appeared the other products were behind in timing, location, and display of cells." Obviously, the high update rate of ITWS and accurate forecasting by TCWF were an immense benefit in this fast-moving storm case.**
**2/21/03 - The FedEx GOC called site while the NEXRAD was down and weather was approaching, anxious to get the TCWF product available for planning their overnight push.**
**3/13/03 - Benefits were realized from TCWF in knowing when and for long the airport and various gates would be affected by weather and knowing that the airport would clear before traffic began arriving.**
**4/4/03 - The TCWF product did a good job showing the airport impact would be minimal, which allowed operations to continue at a normal pace. The products were also extremely helpful in minimizing holding/delays. **
**4/16/03 – [A FedEx] dispatcher said he used ITWS and TCWF to monitor the progress of the second convective line.**
**4/20/03 - According to NWA, there would have been at least 5-10 diversions without ITWS. The system also provided key information on where/when/how long to hold [air traffic]. This helped to reduce the delays somewhat. ATC was able to continue in a single-runway operation for a 20-minute period that allowed critical [aircraft] to land without diverting. Without a doubt, [ITWS/TCWF was] helpful in terms of when the airport could resume arrival and departure operations.**
**5/4/03 - Both NWA and FedEx reported that [ITWS/TCWF] was used heavily to assess impacts and avoidance procedures... In particular, they reported that [TCWF] was especially helpful in terms of reroutes and minimizing diversions (at least 5).**
**5/6/03 - ...personnel in the FedEx ramp tower were using ITWS to time ramp operations with breaks in between storms and to determine the extent of the delay in the departing traffic**
**5/16/03 - According to FedEx, there definitely would have been more diversions without [ITWS/TCWF]. They used [ITWS/TCWF] extensively to determine when and how long the airport would be impacted. Finally, they reported that the safety products were extremely helpful in terms of when operations should cease and then resume.**

## Summary

**2003 CIWS 2-hr Tactical Forecast capability maturing**
**Growth and decay trending added**
**Several enhancements being studied to improve 2+ hr forecasts**
**Forecasts of storm initiation**** **
**Numerical models important for both tactical and strategic forecasts**
**Initialization techniques require research**
**Best forecasts will blend numerical and heuristic techniques**** **
**Coupling forecast technology to air traffic decision support tools will be a major focus in the next few years**