# Presentation: 516565

## Short-term Forecasting

**Short-term Forecasting**
**and WRF Case Study**

- Photo, David Blankenship
- Guntersville, Alabama

**Steven J. Goodman, W. Lapenta, K. La Casse,**
**E. McCaul, and W. Petersen**
- NASA Marshall Space Flight Center
- Earth and Planetary Science Branch
- Huntsville, Alabama, USA

- SPoRT Science Advisory Committee Meeting
- 21 November 2005

## NWS STIP Solutions

| Theme | Service Gap | Solution | Impact |
| --- | --- | --- | --- |
| Severe Weather | Specification of pre-storm environment, boundaries, severe WX signatures | WRF, DA, ensembles, lightning data, SCAN, higher res. satellite obs. | Improved POD, lead-time, FAR, more precise boundary observations |
| Aviation Weather | Timing and location of convection, probabilistic information for DSS | WRF, ensembles, DA, hourly updates, NCWF (radar + lightning) | 50% increase POD, greater operational utility |

_**NWS STIP Solutions**_
- (Science and Technology Infusion Plan)

- Weather Research and Forecast, WRF
- Data Assimilation, DA

- _Additional Forecast Interests_
- CI - convective initiation
- Ti - First lightning (35 dbZ at -15C, glaciation)
- Tp – Peak flash rate  VIL (Mass)
- Tf - Final lightning

## Flash Rate Coupled to Mass in the Mixed Phase Region

**Flash Rate Coupled to Mass in the Mixed Phase Region**
**Cecil et al., Mon. Wea. Rev. 2005 (from TRMM Observations)**

## Lightning Connection to Thunderstorm Updraft, Storm Growth and Decay

-  Total Lightning —responds to updraft velocity and concentration, phase, type of hydrometeors, integrated flux of particles
-  WX Radar — responds to concentration, size, phase, and type of hydrometeors- integrated over small volumes
-  Microwave Radiometer — responds to concentration, size, phase, and type of hydrometeors — integrated over depth of storm (85 GHz ice scattering)
-  VIS / IR — cloud top height and temperature, texture, optical depth

## WWRP/Tom Keenan

## Enhanced Thunder

- 19 July 2005
- 2000Z – 2012Z

- NCEP SPC/Schaefer

- SPC Experimental Product

##   - Pr (CPTP) >= 1 x Pr (PCPN) >= .01”

**F15 SREF 3-hr COMBINED**
**PROBABILITY OF LIGHTNING**

-   **- Pr (CPTP) >= 1 x Pr (PCPN) >= .01”**

**Uncalibrated probability**
**of lightning**

- SPC Experimental Product

## North Alabama Nowcasting

**North Alabama Nowcasting**
**Short-term  Forecasting Test Bed**

## WRF Thunderstorm and Lightning Forecasts:10 December 2004 

## 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 LBC’s

- Cloud cover
- 18h forecast valid at 18 UTC 10 Dec. 2004

## Observed Thunderstorm Precipitation and Lightning10 December 2004,  1700-2125 UTC KHTX NEXRAD, LMA, NLDN

## WRF Surface Based CAPE

**WRF Surface Based CAPE**
**18h fcst valid 18 UTC Dec 10**

## WRF Sounding ~ 800 J/kg CAPE

**WRF Sounding ~ 800 J/kg CAPE**

## MIPS Sounding ~ 761 J/kg CAPE

-  Low level lapse rates and low freezing level efficient for converting CAPE to kinetic energy
-  Surface T=15C, Td=10C
-  Max w= 19 m/s

- UAH MIPS, Kevin Knupp

## WRF 3h Precipitation

**WRF 3h Precipitation**
**18h fcst valid 18 UTC Dec 10**

## WRF 3h Precipitation

**WRF 3h Precipitation**
**21h fcst valid 21 UTC Dec 10**

## WRF 3h Precipitation

**WRF 3h Precipitation**
**21h fcst valid 21 UTC Dec 10**

- _Question_: Any lightning, when was it,
- What was WRF reflectivity at -15 C?

## WRF Reflectivity (dBZ)at -15 C (4.0 km)

**WRF Reflectivity (dBZ)****at ****-15 C (4.0 km)**
**1200 UTC forecast valid at 18:50 UTC 10 Dec. 2004**

## Max dBZ< 40 dBZ

**x1:  Reflectivity (dBZ), Temperature (****°****C), and Pressure (hPa)**
**1200 UTC forecast valid at 18:50 UTC 10 Dec. 2004**

**Max dBZ< 40 dBZ**

## Max dBZ~50 dBZ

**6h 50m forecast valid at 18:50 UTC 10 Dec. 2004**

**Max dBZ~50 dBZ**

## Ground-truth Report of Dime-Size Hail

- Owens Crossroads, Alabama

## 10 December Hail Case

**10 December Hail Case**
**ARMOR collected data!**
**First time ZDR used on television!**

** ****Cold upper-low**
** ****GOES 2057 J/kg CAPE in a layer about 7.5 km deep**
** ****GOES sounding too warm and moist near surface, likely cloud contaminated **
** ****Dime to quarter-sized hail reported in SE Madison county and in S. Tennessee**

## ARMOR 1.3 degree PPI scan at 17:55 UTC on 10 Dec. 04

**Particle Identification**

***Reflectivity [dBZ]***

## At 17:55 IC fl. rate ~ 3/minute in southern cell

**At 17:55 IC fl. rate ~ 3/minute in southern cell**
**No IC’s in northern cell at 17:55**
**No CG’s in either cell for 20 minutes centered on 17:55**
**Only 3 CG’s detected for duration of storms**

## LMA Observed Flashes Precede Hail Report

**LMA Observed Flashes Precede Hail Report**

## RAMS Configuration

- 500 m horizontal resolution
- Heightz 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, t = 4 s, five acoustic steps between
- Smagorinsky subgrid mixing scheme
- 5-class precipitating hydrometeors:
- Rain, snow, aggregates, graupel, hail
- Initialized with 3K warm bubble, radius=12 km at z=0
- 120 min simulation, initiation effects dominate until t=60 min

## RAMS Configuration

- 500 m horizontal resolution
- Heightz 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, t = 4 s, five acoustic steps between
- Smagorinsky subgrid mixing scheme
- 5-class precipitating hydrometeors:
- Rain, snow, aggregates, graupel, hail
- Initialized with 3K warm bubble, radius=12 km at z=0
- 120 min simulation, initiation effects dominate until t=60 min

- Graupel

## RAMS Configuration

- 500 m horizontal resolution
- Heightz 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, t = 4 s, five acoustic steps between
- Smagorinsky subgrid mixing scheme
- 5-class precipitating hydrometeors:
- Rain, snow, aggregates, graupel, hail
- Initialized with 3K warm bubble, radius=12 km at z=0
- 120 min simulation, initiation effects dominate until t=60 min

- Hail

## WRF Thunderstorm and Lightning Forecasts:1 May 2004 

## 1h WRF forecast valid at 01 UTC 1 May 2004 using MODIS SSTs

**A**

**B**

## Cross-section of reflectivity on sigma levels 1h WRF forecast valid at 01 UTC 1 May 2004

**A**

**B**

## Slide 32

## LIS Ground Truth - Florida 1May 2004 (Day 122) 03:03 UTC

**LIS Ground Truth - Florida ****1May 2004 (Day 122) 03:03 UTC**

## NLDN Observed Lightning, 1 May 2004

## Slide 35

## Slide 36

## Slide 37

## Slide 38

## Slide 39

## WRF Thunderstorm and Lightning Forecasts:Motivations to study the 1-3 May 2004 Florida Cases 

- High resolution 2 km WRF database
- Validation of convective processes with TRMM LIS and ancillary data sets
- Examine the “Warn on Forecast” framework for lightning threat: WRF-Nowcaster-LMA