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Title: Advancements in Lightning-Severe Storm Forecasts and Warnings: Results from the Southern Thunder Alliance


1
Advancements in Lightning-Severe Storm Forecasts
and Warnings Results from the Southern Thunder
Alliance
Steve Goodman NASA Marshall Space Flight
Center Earth Science Office Huntsville, Alabama,
USA
NWS SRH SOO-NASA SPoRT Joint Workshop 11-13 July,
2006 Huntsville Alabama
Photo, David Blankenship Guntersville, Alabama
2
Outline of Presentation
  • Motivation and Background
  • Science and Technology Infusion
  • GOES-R Geostationary Lightning Mapper (GLM)
  • VHF Lightning Mapping
  • Nowcasting-Warning Decision Making
  • WRF Forecasts of Thunderstorm Initiation and
    Lightning Threat
  • Current Plans and the Way Forward

3
Background and Motivation
  • NASA and NOAA working together to save lives
  • Tornado lead time -12 min national average
  • Lightning strikes responsible for gt500 injuries
    per year, 90 of victims suffer permanent
    disabilities and long term health problems,
    chiefly neurological in nature
  • Lightning responsible for 80 deaths per year
    (second leading source after flooding)
  • Aviation weather- airport operations, enroute
    savings 25M/yr
  • In-cloud lightning lead time of impending ground
    strikes, often 10 min or more
  • forest fire initiation, utility crew
    deployment, NEXRAD coverage gaps, improved
    precipitation estimates, hail/wind/flood
    detection,

4
Continuous GEO Total Lightning will identify
severe storm potential
Process physics understood
Ice flux drives lightning
GLM GOES E View
Storm-scale model for decision support system
Physical basis for improved forecasts
Updraft Intensifies
IC flash rate controlled by graupel (ice mass)
production (and vertical velocity)
Demonstrated in LEO with OTD LIS
Vortex Spins-up
Lightning jump precedes severe weather
Lightning improves storm predictability
5
Flash Rate Coupled to Mass in the Mixed Phase
Region Cecil et al., Mon. Wea. Rev. 2005 (from
TRMM Observations)
6
Mapping storm initiation, growth, decay
  • TRMM provides us a huge database of paired
    lightning, radar, IR and passive microwave
    observations (training /
    validation)
  • Over entire tropics subtropics (generalization)
  • Total lightning increases as storm intensifies
    can increase lead time for warning of severe and
    tornadic storms

7
GOES-R Geostationary Lightning Mapper (GLM)
  • July 2006 Status-
  • 3 on-going industry led GLM formulation studies
  • NESDIS sponsored risk reduction- NSSTC lead

8
Southern Thunder Alliance A collaboration among
LMA owner-operators and end users
  • NASA-NOAA-University-Industry Partners
  • SPoRT Center (NASA MSFC/NSSTC)
  • New Mexico Tech and other universities
  • OU/NSSL
  • Vaisala, Inc.
  • WFOs Huntsville (HUN), Nashville (OHX),
    Birmingham (BMX), Fort Worth (FDW), Melbourne
    (MLB), Norman (OUN), Sterling (LWX)
  • NWS/MDL
  • LMA systems located in NWS Southern Region
  • North Alabama
  • OU/NSSL
  • New Mexico Tech Langmuir Laboratory
  • White Sands Missile Range
  • KSC/CCAFS (LDAR II)
  • TAMU (LDAR II)
  • Dallas/Fort Worth (Vaisala LDAR II)

9
North Alabama LMA Coverage NWSFO HUN CWA
10
North Alabama Lightning Mapping Array (LMA)
  • Network of 10 detectors centered about HSV (NMT
    heritage)
  • Computes 4-D location of all electrical
    discharges (flashes) within LMA (CGand IC, CC,
    CA)
  • Flash location overlaid on radar and satellite
    imagery and updated every minute
  • Trend information for individual storms
  • Validation for TRMM LIS
  • NASA Senior Review to extend mission approved
    through 2009

11
(No Transcript)
12
LMA Imagery in AWIPS
  • 17 height levels
  • Lowest level is composite
  • Auto-loads 2 min grids
  • Grids 1 km x 1 km, or 2 km x 2 km horizontal, 1
    km vertical
  • Future Algorithm- use first VHF pulse to
    identify flash, ratio ICCG grid for more rapid
    storm tendency insight
  • Can dither image with NEXRAD reflectivity and
    velocity, satellite, or any other fields

SVR Upgraded to TOR
13
ARMOR 04-07-05 Winds and HID
ARMOR-88D WINDS
RESEARCH ARMOR HID
OPERATIONAL ARMOR HID
Courtesy Walt Petersen
14
Total Lightning Impacts Decision Making.
  • Has directly contributed to several correct
    severe warning decisions at HUN and BMX
  • 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.
  • Used in Warning Event Simulator (WES) for office
    training

15
May 6, 2003 Case
1236 UTC
16
May 6, 2003 Case
1246 UTC
17
Lightning Hole
Convective surge
Lightning 'hole' and convective surge 'C' in
tornadic storm, 0629 STEPS 2000
Lightning hole (WER)
18
LMA Benchmarking Interim Results
2003-2005 Warning Variable Rankings on Scale of
1-10
Warning Variable All Surveys LMA impact9/19 Severe Storms 80 warnings, 13 surveys Tornado 41 Warnings, 6 surveys
Reflectivity Signatures 9.1 8.7 9.7
LMA Total Lightning 6.7 7.0 6.2
Near storm Environment 5.8 5.2 6.8
Eyewitness Report 5.2 4.1 7.7
Strong Rotation 5.2 3.2 9.3
Boundaries 3.8 3.4 4.5
NLDN CGs 3.7 3.7 4.0
TVS 2.3 1.5 3.8
Previous SVR WX 1.5 0.2 4.5
19
Southern Thunder Workshop 2 Fort Worth, Texas
25-27, 2005
  • One of the Workshop Recommendations
  • Due to cancellation of VORTEX-II Experiment in
    2007, pursue newly available opportunity to
    deploy, evaluate, and assess the scientific and
    technological merits of total lightning mapping
    with the NMT portable LMA in an additional
    operational setting.
  • Why DC Metro Area
  • Transitional climatic regime, yet still many
    severe storms
  • Coverage of 3 major heavily used airports
  • Complex terrain to west, urban environment
  • Sterling WFO history of supporting new
    technology assessments
  • Leverage with on-going TDWR evaluations
  • Proximity of MDL developers to WFO forecasters
  • Access to students, faculty for system
    operations/maintenance
  • Local interest (broadcast community,
    researchers, forecasters)

20
Circles 150 km radius (approx. 3D coverage)
250 km radius (approx. max range)
21
Strawman DC Metro Lightning Mapping Network
(Oklahoma LMA as template)
Major Airports
Mapping Stations
22
DC Severe Thunderstorms 4 July 2006
Current Date/Time 1155 PM Tue 4 July 2006
Subject Tornado(S)/Severe Thunderstorm(S) /Floods/ High Wind Etc. Severe Thunderstorms Impact National 4th of July Festivities at District of Columbia (D.C.) Mall
Event Description/Time Of Triggering Event For FTR (E.G., Deaths, Injuries, And Damage Occurred) A cluster of severe thunderstorms moved through the D.C. as 80,000 people were gathering on the Mall to attend 4th of July activities. MIC Jim Lee and SOO Steve Zubrick staffed the multi-agency D.C. Command Center to support the national Fourth of July Celebration on the Mall. WFO Sterling provided information to the Command Center and DC emergency management via phone and NAWAS while Jim and Steve provided on-site briefings and support. The 80,000 attendees were evacuated from the Mall in advance of the storm. The evacuation took about 15 minutes, and was a direct result of numerous NWS briefings. The storm blew down trees and tents in and around the mall.
Location District of Columbia
Damage (Include Dollar Estimates, If Possible) Large elm trees and tents were blown down on the Mall. Airborne debris was noted at the height of storm. A peak wind gust of 47 mph was observed at National Airport in associate with this storm.
Outlooks (e.g., SPC and/or HWO), if appropriate The potential for severe thunderstorms was noted in the Hazardous Weather Outlook issued at 355 AM on July 1 the D.C. areas was included in the Day 1, Day 2, and Day 3 outlooks SPC placed the D.C. area in a Slight Risk of Severe Weather on July 3 the severe thunderstorm potential was highlighted in the LWX Area Forecast Discussion (AFD) at 300 PM July 3.
Watches In Effect? Type And Number/ Valid Time Severe Thunderstorm Watch 582 issued at 1240 PM, valid until 900 PM.
Warnings In Effect? Type And Time Issued/ Valid Time Severe Thunderstorm Warning for D.C. issued at 445 PM, in effect until 600 PM.
Verification (Time Severe Weather/Flooding, etc. was first reported in affected County/Area) Lead Time Large elm trees were reported down at 515 PM reported by National Park Service via Jim Lee at the Command Centerwarning lead time 30 minutes.
Service (Significant Briefing, etc.) Numerous briefings were conducted both on-site at the Command Center and via phone/NAWAS by WFo Sterling. During the warning valid period, additional NAWAS briefings were conducted to give D.C. area officials time of arrival and threat information specifically for the Mall areas.
Systems (Issues With AWIPS, WSR-88D, NWR, ASOS, etc.) None.
Staffing Issues None. After evaluating potential threat, WFO Sterling had 5 forecasters and 2 HMT on station for the event, along with MIC Jim Lee and SOO Steve Zubrick providing on-site support at the D.C. Command Center.
Media Attention Unknown at this time.
User Response WFO Sterling received praise from the D.C. Command Center and Smithsonian Folklife Festival immediately following the event for the excellent and timely flow of information and weather support provided by the office.
23
DC Severe Thunderstorms 4 July 2006
I used the DC-LMA web site to view updates on
lightning activity during my shift at the command
center (through about 345 PM). It was VERY
useful, since I had no other "real-time"
lightning data available. I used various links to
NWS forecasts, radar, and satellite data via the
Internet to conduct weather briefings to the
command center staff. In addition, our WFO staff
kept an eye on the DC area via all of the data
available in AWIPS. the DC-LMA data were VERY
useful in monitoring storm activity. I was able
to show the center staff where the lightning was
occurring. In addition, I monitored changes in
lightning coverage/intensity as a rough gauge of
thunderstorm changes in intensity. Steve
Zubrick WFO Sterling (LWX)
24
DC Metro LMA Demo Network 9 July 2006 at 2300 UTC
5-station LMA source density
NEXRAD Reflectivity
25
Enhanced Thunder 19 July 2005 2000Z 2012Z
SPC Experimental Product
NCEP SPC/Schaefer
26
SPC Experimental Product
- Pr (CPTP) gt 1 x Pr (PCPN) gt .01
Uncalibrated probability of lightning
F15 SREF 3-hr COMBINED PROBABILITY OF LIGHTNING
27
Warn on Forecast Concept
Warn-on-forecast (warnings out to 4 hours based
upon observations short term model forecasts)
Courtesy Kevin Kelleher, SDR Grand Challenges
28
WRF Thunderstorm Premises and Objectives
  • Given
  • Precipitating ice aloft is correlated with LTG
    rates
  • Mesoscale CRMs are being used to forecast
    convection
  • CRMs can represent many ice hydrometeors
    (crudely)
  • Goals
  • See if WRF can forecast LTG threat, based on ice
    flux
  • in layers near -15 C.

WRF Weather Research and Forecast Model CRM
Cloud Resolving Model
Additional Forecast Interests CI - convective
initiation Ti - First lightning (35 dBZ at -15C,
glaciation) Tp - Peak flash rate VIL (Mass) Tf
- Final lightning
29
WRF Thunderstorm and Lightning Forecasts Methodol
ogy
  • Use high-resolution (2-4 km) WRF simulations to
    prognose
  • convection
  • Develop diagnostics from model output fields to
    serve as a
  • proxy for LTG
  • Create 0-6 h forecasts of LTG threat based on WRF
    data
  • Compare WRF forecasts with actual reflectivity
    and LTG
  • and other observations using HSV area
    assets
  • Subjectively and objectively evaluate WRF
    capabilities for
  • forecasting LTG

30
WRF Thunderstorm and Lightning Forecasts 10
December 2004
31
WRF Configuration 10 December 2004 Case Study
  • 4km horizontal resolution
  • 37 vertical levels
  • Dynamics and physics
  • Eulerian mass core
  • Dudhia SW radiation
  • RRTM LW radiation
  • YSU PBL scheme
  • Noah LSM
  • WSM 6-class microphysics scheme
  • Explicit convection
  • 24h forecast initialized at 00 UTC 10 December
    2004 with AWIP212 NCEP EDAS analysis
  • Eta 3-h forecasts used for LBCs

Cloud cover 18h forecast valid at 18 UTC 10 Dec
2004
32
WRF vs Eta Surface-based CAPE 18h fcst valid 18
UTC Dec 10
33
WRF Sounding 800 J/kg CAPE
34
MIPS Sounding 761 J/kg CAPE
  • Low level lapse rates and low freezing level
    efficient for converting CAPE to kinetic energy
  • Surface T15C, Td10C
  • Similar CAPE to MIPS, but
  • for different reasons
  • High-res RAMS storm
  • Max w 19 m/s

UAH MIPS, Kevin Knupp
35
WRF vs Eta 3h Regional Precip. 21h fcst valid 21
UTC 10 Dec 2004
36
WRF vs Eta 3h Local Precip. 21h fcst valid 21 UTC
10 Dec 2004
Question Any lightning, when was it, What was
WRF reflectivity at -15 C?
37
WRF Reflectivity (dBZ) at -15 C (4.0 km) 1200 UTC
forecast valid at 1850 UTC 10 Dec 2004
38
x1 Reflectivity (dBZ), Temperature (C), and
Pressure (hPa) 1200 UTC forecast valid at 1850
UTC 10 Dec 2004
Max dBZlt 40 dBZ
39
x2 Reflectivity (dBZ), Temperature (C), and
Pressure (hPa) 6h 50m forecast valid at 1850 UTC
10 Dec 2004
Max dBZ50 dBZ wmax only 4 m/s But no hail
reaches the surface
40
Ground-truth Report of Dime-Size Hail Owens
Crossroads, AL, 10 Dec 2004
41
At 1755 IC fl. rate 3/minute in southern
cell No ICs in northern cell at 1755 No CGs in
either cell for 20 minutes centered on 1755 Only
3 CGs detected for duration of storms
42
LMA Observed Flashes Precede Hail Report
43
High-res RAMS Validation Run
Reflectivity
  • 500 m horizontal resolution
  • Height, Dz is variable, from 250 m at bottom to
    750 m at 20 km height
  • Domain 75 km x 75 km x 24.5 km
  • Time, Dt 4 s, five acoustic steps between
  • Smagorinsky subgrid mixing scheme
  • 5-class precipitating hydrometeors
  • Rain, snow, aggregates, graupel, hail
  • Initialized with 3K warm bubble, radius12 km at
    z0
  • 120 min simulation, initiation effects dominate
    until t60 min

Note wmax reaches 19 m/s
44
RAMS Graupel Cross-Section
Graupel
  • 500 m horizontal resolution
  • Height, Dz is variable, from 250 m at bottom to
    750 m at 20 km height
  • Domain 75 km x 75 km x 24.5 km
  • Time, Dt 4 s, five acoustic steps between
  • Smagorinsky subgrid mixing scheme
  • 5-class precipitating hydrometeors
  • Rain, snow, aggregates, graupel, hail
  • Initialized with 3K warm bubble, radius12 km at
    z0
  • 120 min simulation, initiation effects dominate
    until t60 min

45
RAMS Hail Cross-Section
Hail
  • 500 m horizontal resolution
  • Height, Dz is variable, from 250 m at bottom to
    750 m at 20 km height
  • Domain 75 km x 75 km x 24.5 km
  • Time, Dt 4 s, five acoustic steps between
  • Smagorinsky subgrid mixing scheme
  • 5-class precipitating hydrometeors
  • Rain, snow, aggregates, graupel, hail
  • Initialized with 3K warm bubble, radius12 km at
    z0
  • 120 min simulation, initiation effects dominate
    until t60 min

Note some hail reaches surface
46
WRF Thunderstorm and Lightning Forecasts 22
April 2005
47
WRF Reflectivity at -15C 22 April 2005
48
WRF Graupel Flux at -15C 22 April 2005
49
LMA Flash Extent Density 22 April 2005
50
WRF Thunderstorm and Lightning Forecasts 30
March 2002
51
WRF Reflectivity at -15C 30 March 2002
52
WRF Graupel Flux at -15C 30 March 2002
53
LMA Flash Extent Density 30 March 2002
54
Conclusions 1.
WRF forecasts of deep convection are useful, but
of variable quality - Timing and intensity of
convection are depicted fairly well - Location
and morphology of storm systems sometimes
wrong 2. WRF convection is deep enough, with
sufficient reflectivity, to suggest
lightning 3. WRF updraft strengths on 2-4 km
grids often too weak, relative to observed
weather and high-res RAMS simulations 4. WRF
microphysics still too simple need more ice
categories 5. Finer model mesh may improve
updraft representation, and hydrometeor
amounts 6. Biggest limitation is likely errors in
initial mesoscale fields
55
Future Work 1.
Expand catalog of simulation cases to obtain
robust statistics 2. Develop quantitative metrics
for LTG forecasts - Need link between graupel
flux and lightning probabilities, rates 3.
Compare LTG threat parameter against
environmental variables- CAPE, LI, etc. 4.
Enhance accuracy of WRF forecasts 5. Hot start
WRF applied to archived North Alabama WES cases
56
2006 Nowcasting and Assessment Plans
  • Thunderstorm Forecasts/Lightning Threat
  • Analysis of SPoRT WRF 2 km simulations
  • Analysis of 22 April 2005 Alabama event with OU 2
    km WRF
  • Complete 10 December 2004 North Alabama Case
    study
  • Complete P. Gatlin M.S. thesis
  • Develop AWIPS lightning threat product and
    assessment (LMANLDN)
  • North Alabama (additional) WES Cases
  • Develop more extensive training case for other
    WFOs based on the 6 May 2003 outbreak
  • Quantitative analysis of archived WES severe
    event cases
  • NCEP SPC 2007 Spring Program participation/collabo
    ration
  • Hazardous Weather Test bed- NASA-UAH/SPC-NSSL
    Collaboration
  • LMA Extensions
  • DC LMA Demo- NWS OST, Eastern Region
  • GTRI Extension of NALMA to Atlanta (2 stations)
  • NCAR Autonowcaster/4DWX at RTTC (LMA ARMOR)
  • GOES-N Science Test, November 2006
  • GOES R nowcasting experiment- NY area

57
  • Shared interest to improve forecasts by infusing
    new technology and applying emerging research
    techniques
  • Identify goals and objectives of collaboration
  • Improve warning decision making
  • Increased confidence and situational awareness
  • Increase lead time, reduce false alarms
  • Lightning hazard forecast and warning
  • Need to have advocates in the WFOs

58
LMA Web Calendar
59
Web Sites
  • http//weather.msfc.nasa.gov (SPoRT, Workshops)
  • http//branch.nsstc.nasa.gov (North AL, DC Metro
    LMA)
  • http//lightning.nmt.edu (OK LMA)
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