Shortterm Forecasting

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Short-term Forecasting and WRF Case Study
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
NWS Severe Weather Technology Workshop 12-14 July
2005 Silver Spring, MD
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• Outline of Talk
• Nowcasting Gaps and Opportunities
• WRF-RAMS Case Study- 10 Dec. 2004
• Columbia Project-WRF modeling plans
• Concluding Remarks

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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) TF- final lightning
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Visionary Forecast and Warning Lead Times
NWS Science and Technology Infusion Plan
Lightning Observation and Forecast Benefit
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Nowcasting Defined

• Nowcasting forecasting with local detail, by any
  method, over a period from the present to a few
  hours ahead that includes a detailed description
  of the present weather, and includes the blending
  of extrapolation, statistical, and heuristic
  techniques (includes theory, expert systems,
  fuzzy logic, and forecaster rule of thumb), and
  NWP

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WWRP/Tom Keenan
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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/temperature, texture,
  optical depth

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WRF Configuration

• 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
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WRF Surface Based CAPE 18h fcst valid 18 UTC Dec
10
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WRF Sounding 800 J/kg CAPE
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MIPS Sounding 761 J/kg CAPE

• Low level lapse rates and low freezing level
  efficient for converting CAPE to kinetic energy
• Surface T15C, Td10C
• Max w 19 m/s

UAH MIPS, Kevin Knupp
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WRF 3h Precipitation 18h fcst valid 18 UTC Dec 10
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WRF 3h Precipitation 21h fcst valid 21 UTC Dec 10
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WRF 3h Precipitation 21h fcst valid 21 UTC Dec 10
Question Any lightning, when was it, What was
WRF reflectivity at -15 C?
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WRF Reflectivity (dBZ)18h forecast valid at 18
UTC 10 Dec. 2004
WRF reflectivity cores too shallow
-15 C -
0 C -
850 hPa
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Reflectivity (dBZ)0650h forecast valid at 1850
UTC 10 Dec. 2004
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Ground-truth Report of Dime-Size Hail Owens
Crossroads, Alabama
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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

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KHTX NEXRAD
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ARMOR 1.3 degree PPI scan at 1755 UTC on 10 Dec.
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Particle Identification
Reflectivity dBZ
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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
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LMA Observed Flashes Precede Hail Report
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RAMS Configuration

• 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

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RAMS Configuration
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

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RAMS Configuration
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

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Use of MODIS SST to Improve High Resolution
Modeling of Atmosphere/Ocean Interactions within
the Gulf of Mexico and Florida Coastal Zones
PI William M. Lapenta/NASA Short-term Prediction
Research and Transition Center _at_ MSFC
100,000 Processor Hours awarded March 2005
Award number SMD-Dec04- 0036
Objective of Columbia Usage

• Enables experimental high-resolution atmospheric
  modeling at 2 km resolution on an operational
  basis that would not be possible otherwise
• Unique computational resources allows compilation
  of results for more than a single season
• Allows for subjective impact assessment from
  operational NWS forecast community

Identify the codes to be run on Columbia

• WRF Weather Prediction Model
• ADAS Data Assimilation System

Sea surface temperature fields (K) mapped to a
numerical model 2 km grid near Cape Canaveral,
FL. The RTG is a default field used in most
models. The MODIS SST composite contains
detailed spatial structure that is known to
affect weather near and along coastlines
associated with mesoscale circulations.
Scientific Impact Hypothesis Accurate
specification of the lower-boundary forcing
(i.e., the specification of localized SST
gradients and anomalies) within the WRF
prediction system will result in improved
land/sea fluxes and hence, more accurate
evolution of coastal mesoscale circulations and
the sensible weather elements (i.e., low-level
horizontal transport, temperature trends, clouds,
and precipitation) associated with them.
Key Milestones

• Implement and optimize WRF configuration
  05/05
• Develop Web-based visualization for model output
  05/05
• Conduct simulations on a daily basis
  06/05
• Provide output to FL NWSFOs in AWIPS
  07/05
• Preliminary MODIS SST impact assessment
  10/05
• Present results at AMS Annual Meeting
  01/06
• Prepare manuscript for peer-review publication
  03/06
• Report findings to WRF modeling community
  03/06

Co-Is/Partners
Kate La Casse and Stephanie Haines, University
of Alabama in Huntsville Gary Jedlovec, NASA _at_
MSFC Scott Dembek (USRA) Steven Lazarus, Florida
Institute of Technology
Science Mission Directorate - Project Columbia
Investigation
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Motivation for using High-Resolution MODIS SST
Fields in NWP Models

• SST known to influence coastal mesoscale
  processes
• Can impact warm-season precipitation distribution
• Sea breeze circulations important to heavily
  populated areas (HOU, NYC)
• Strong influence on height of marine boundary
  layer

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Use of High-Resolution MODIS SST Fields in NWP
Models

• SST known to influence coastal mesoscale
  processes
• Can impact warm-season precipitation distribution
• Sea breeze circulations important to heavily
  populated areas (HOU, NYC)
• Strong influence on height of marine boundary
  layer

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WRF vs Eta Forecast, 14 July 2005
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NLDN Observed Lightning, 14 July 2005