# Presentation: 143310

## LMA Assessment

- Dennis Buechler

## Total Lightning Impacts Decision Making

**Has directly contributed to several correct severe  warning decisions at HUN and OHX.**
*“...**the LMA density map gives you a great overall view of where storms with intensifying updrafts are located.  So it gives you a good map of where to concentrate attention.”*
*“**I believe the flash density rates were the primary factor in holding off on a warning.”*
**Data archived by WFO**
**Used in Warning Event Simulator for office training and research**

## Operational Evaluations

**Web based LMA survey developed for the WFOs**
**Completed after an  event in which the LMA data was used**
**Survey also available at other WFOs (OHX, BMX, FWD)**

**Operational Evaluations**

## Slide 4

## LMA Benchmarking: ResultsNovember 2003 through November 2005

**28 surveys filled out by HUN and OHX, none yet from BMX: 1 in 2003, 8 in 2004, 19 in 2005**
**Severe Weather Scenarios **
**Large Hail**
**Tornadoes**
**Straight Line Winds**
**Cells Embedded in Lines**
**Supercells**
**Microburst-producing single pulse summer TRW**

## LMA Benchmarking:OHX (Nashville) Results

**5 Surveys in 2005**
**All indicated the data useful identifying cells with strongest updrafts- helped forecaster identify storms needing more attention**
**LMA data used to verify other data- radar, eye-witness reports- used by forecasters in the warning decision**
**2 reports: warning lead time increased by 2-3 min**
**Forecasters gaining confidence in using the data**

## LMA Benchmarking:HUN (Huntsville) Results

**23 Surveys completed; 19 used in analysis**
** ****1 case: problems with data**
** ****3 cases: data not updating properly**
**In 11 cases there was a positive impact - increased warning lead time of 1-9 min**
**In remaining 8 cases, either no impact on warning decision or forecaster warned based on other available data**
**In 2005, 9 of 12 surveys indicated improvement in lead time with LMA**

## LMA Benchmarking: Interim ResultsRankings on Scale of 1-10

| Warning Variable | All Surveys
LMA+ impact=13/24
1.8-2.4 min | Severe Storms
88 warnings, 16 surveys
2.2-2.9 min | Tornado
50 Warnings, 8 surveys
1.1-1.4 min |
| --- | --- | --- | --- |
| Reflectivity Signatures | 8.8 | 8.6   (1) | 9.3   (2) |
| LMA Total Lightning | 6.5 | 6.8   (2) | 5.8   (5) |
| Near storm Environment | 5.6 | 4.9   (3) | 7.1   (3) |
| Strong Rotation | 5.3 | 3.1   (7) | 9.5   (1) |
| Eyewitness Report | 4.8 | 3.8   (5) | 6.9   (4) |
| NLDN CGs | 4.0 | 3.8   (4) | 4.4   (7) |
| Boundaries | 3.8 | 3.4   (6) | 4.5   (6) |
| TVS | 2.3 | 1.4   (8) | 4.1   (8) |
| Previous SVR WX | 1.4 | 0.3   (9) | 3.5   (9) |

## Greatest LMA impact in operations

**Low to moderate severe events**
**At greater distances from the radar**
**Sub radar interval cell information**
**Detecting initial cloud to ground strikes**
**Local case studies have shown lead times on the order of several (3-5) minutes**
**Increased lead times for TAF updates and Airport Weather Warnings**

## WES Cases for Training and Research

| Date | Storm Type | Event/Wx |
| --- | --- | --- |
| 5/6/03 | Supercells | W/T/FF |
| 5/1/04 | Squall Line | W/T |
| 8/20/04 | Multicell | W/T |
| 10/18/04 | Supercell | T |
| 12/10/04 | Low top Hailstorm | H |
| 2/21/05 | Supercells | H |
| 7/2/05 | Multicell | Null |
| 7/27/05 | Multicell | W |

**WES Cases for Training and Research**

**Selected archived WES cases of different types of weather events (including a null case) for use in training and further research.**

**T – Tornado**
**W – Strong Winds**
**FF – Flash Flood**
**H – Large Hail**
**Null – No SVR**

## Summary

**Surveys and forecaster feedback indicate that LMA data is useful: **
** ****Improved situational awareness**
** ****Improved forecast confidence**
** ****Longer estimated warning lead times**
** ****Surveys useful in reviewing events **
** ****Surveys valuable for choosing case studies**
** ****Encourages feedback**