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Decision Brief: Upgrade to HiResWindow


... some of the enhanced reflectivites in northern CT and extending into SE New York. ... Eastern Region - Paul Sisson (SOO Burlington VT) ... – PowerPoint PPT presentation

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Title: Decision Brief: Upgrade to HiResWindow

Decision Brief Upgrade to HiResWindow
Mesoscale Modeling Branch Geoff DiMego Matt Pyle
Eric Rogers 4 September 2007
where the nations climate and weather services
Why Did SPC Start Looking at High Resolution WRF
  • Severe weather types (tornadoes, hail, wind
    damage) can be closely related to convective mode
  • Tornadoes (discrete supercells)
  • Damaging wind (bow echoes and QLCSs)
  • SPC working to increase lead time of watches and
    provide probabilistic information about tornado,
    hail, and wind threats in Day 1 Severe Weather
  • Accurate forecasts require knowledge about
    where and when storms will develop and how
    they will evolve
  • There is a need to better predict convective mode
    and character of storms (stormscale details)
  • Environmental clues (CAPE/shear, etc.) may not be
  • Operational mesoscale models often lack smaller
    scale details

Courtesy of SPC Weiss et. al.
There were some striking successes from the very
  • Beginning in April 2004, Matt Pyle began running
    offline (on development/backup side of NCEPs
    computer) and providing to SPC
  • 00z run each day to 36 hours
  • High resolution WRF-NMM
  • Initially 4.5 km, ultimately 4.0 km resolution
  • Initially central CONUS, ultimately east-central
  • SPC so pleased with the guidance, they would
    not let Matt turn the run off after initial
    Spring Program 2004 and he has been making the
    run every day since.

Example of Explicit 4.5 km WRF-NMM courtesy of
Jack Kain
WRF 24 hour 4.5 km forecast of 1 hour accumulated
precipitation valid at 00Z April 21, 2004 (better
than 12 hour forecasts by operational models)
4.5 km WRF-NMM
Verifying 2 km radar reflectivity
Over the Years, SPC Finds Value in HiRes Guidance
  • Primarily in Convective Mode
  • To lesser extent in location evolution
  • Not surprising, then, they have requested
  • Higher resolution
  • Larger domain
  • More frequent runs

HiResWindow Upgrade12/19/2006 Request from SPC
  • Elevate Matt Pyles daily offline 00z run
  • Twice per day runs at 00z 12z
  • Expanded (East-Central) domain
  • Higher (4 km) resolution WRF-NMM
  • Will get 48 hr guidance instead of 36 hr
  • Will get both WRF-NMM and WRF-ARW
  • New requirements incorporated into plans for 2007
    HiResWindow upgrade

HiResWindow Upgrade 2007
  • Model Upgrades
  • Upgrade WRF-NMM
  • From version 1.3 to 2.2
  • IJK loop storage ordering (5-10 faster)
  • Increase resolution from 5.2 km to 4.0 km
  • Upgrade WRF-ARW
  • From version 1.3 to 2.2
  • Increase resolution from 5.8 km to 5.1 km
  • Expand large domains
  • Roughly double area covered
  • 3 CONUS nests reduced to 2 overlapping
    (West-Central East Central)
  • Allows schedule adjustment to run SPCs preferred
    domain (East-Central CONUS) at both 00z and 12z
  • Post-Processing and New Products
  • Add ability to output simulated reflectivity

HIRES Window 2007 UpgradeDomain Size Changes
New Large Domains 4.0 km for WRF-NMM 5.1 km for
WRF-ARW Small domain size is unchanged
Current Large Small Domains 5.2 km for
WRF-NMM 5.8 km for WRF-ARW
Old vs New Schedule
Retain FOUR routine runs made at the same time
every day. Both cores run for one large domain
and one small domain.
  • Old Schedule
  • 00Z Alaska Hawaii
  • 06Z Western 1/3 CONUS Puerto Rico
  • 12Z Central 1/3 CONUS Hawaii
  • 18Z Eastern 1/3 CONUS Puerto Rico
  • New Schedule
  • 00Z Eastern 2/3 CONUS Hawaii
  • 06Z Western 2/3 CONUS Puerto Rico
  • 12Z Eastern 2/3 CONUS Hawaii
  • 18Z Alaska Puerto Rico

Everyone gets daily high resolution runs if
only if hurricane runs are not needed.
HiResWindow WRF Configurations
(No Parameterized Convection)
Horizontal Grid Spacing (km) 4.0 5.1
Vertical Levels 35 Sigma-Pressure 35 Sigma
PBL/Turbulence MYJ YSU
Microphysics Ferrier WSM3
Land-Surface NOAH NOAH
Radiation (SW/LW) GFDL/GFDL Dudhia/RRTM
Online Sites
  • Matt Pyles online site http//www.emc.ncep.noaa.
  • Online Display at NCEPs Parallel Model Analysis
    and Forecast page established 2 July 2007
  • EMCs verification 7-day time-series. However,
    with the lack of runs due to tropical cyclone
    activity, these are very sparse

Pyle Webpage Now Displaying Simulated
Mesoscale Detail this 12 h forecast captures
the reflectivity minimum in eastern NY in the lee
of the Berkshires/Green Mountains, and some of
the enhanced reflectivites in northern CT and
extending into SE New York.
Albany, NY Radar Image
HRW Simulated Radar Reflectivity
Spring Program 2007
Circles denote locations of rotating updrafts
where updraft helicity is at least 50 m2s-2
Observed Composite Reflectivity Courtesy Kain,
Weiss Bright
Forecast Fit-to-Sfc Temperature Obs
Observed Operational Parallel
ARW for 23-30 August
NMM for 18-30 August
Forecast Fit-to-Sfc Wind Obs
Observed Operational Parallel
ARW for 23-30 August
NMM for 18-30 August
Eastern Western QPF scores
Western (WRF-NMM), 8/18 to 8/28
precip to verify during this period
Eastern (WRF-NMM), 8/18 to 8/28
Longer Duration QPF Verification12 Dec, 2006
29 Aug, 2007 (less Feb/Mar)
  • SPC 4km run serving as proxy for Para HRW because
    Opnl Central CONUS run is a 12Z run while the SPC
    run is a 00Z run and they didnt cover exactly
    the same domain - so
  • Each was independently verified against the NAM
    (these individual comparisons to the NAM are
  • The ratio of (ops HRW / NAM) is applied to get a
    relative score for the ops HRW against the NAM
    verifying the SPC run. Not perfect, but it
    levels the playing field.

QPF Verification Summary
  • Parallel HiResW precip (WRF-NMM core) has
    comparable to slightly better ETS and a higher
    bias for heavier precipitation than the current
    production version.
  • Improving the high warm season precip bias in the
    WRF-NMM will become an even more important
    priority between now and when there are 4 km
    Alaska CONUS nests run within the NAM in 2010.

14 August 2007 Example Case
  • The HiresW runs (WRF-ARW and particularly the
    WRF-NMM) provide useful guidance of a convective
    line sagging south on the morning of 14 August
  • Both HiresW runs miss the timing by several hours
    (too slow), but highlight the possibility of
    heavy rain that is absent in the NAM forecast.
  • Ops HiresW WRF-NMM run appears to capture event
    as well, but without instantaneous precipitation
    intensity information a direct comparison is

09 Z
10 Z
11 Z
12 Z
13 Z
14 Z
14 Z
11 Z
NAM forecast valid 12Z
NAM forecast valid 15Z
NMM para hiresw forecast valid 12Z
NMM para hiresw forecast valid 15Z
ARW para hiresw forecast valid 12Z
ARW para hiresw forecast valid 15Z
NMM ops hiresw forecast valid 12Z 3 h
NMM ops hiresw forecast valid 15Z 3 h
Eastern Region Interest
  • 21 June, Jeff Tongue wrote Geoff - This is
    wonderful information! I'm still not clear on the
    timeline for the change to the 00 and 12 runs for
    the Eastern HiRes WIndow? We can wait for OB 8.3
    or what ever to get the data in AWIPS, but
    we're wondering when they'll be available on the
    web? (P.S. I'll subscribe to the ModelEval list
    server - thanks).
  • EMC will attempt to add the hourly BUFR sounding
    data Jeff requested here in the near future when
    we add the hourly gridded output capability for

SPC Feedback
  • List of NWS forecasters who participated in the
    2007 Spring Experiment for one week each
  • Central Region - Matt Bunkers (SOO Rapid City SD)
  • Western Region - Randy Graham (SOO Salt Lake City
  • Southern Region - Eric Platt (Forecaster Midland
  • Southern Region - Ken James (Forecaster Norman
  • Eastern Region - Steve Zubrick (SOO Sterling VA)
  • Eastern Region - Paul Sisson (SOO Burlington VT)
  • Southern Region - Bernard Meisner (SSD SRH Fort
    Worth TX)

SPC Evaluation Steve Weisspart 1
  • SPC had only limited opportunities to examine the
    parallel runs of the HRW WRFs during the summer
    30 day evaluation period. 
  • More importantly, however, we have been utilizing
    the once daily experimental WRF-NMM4 in both the
    annual Hazardous Weather Testbed Spring
    Experiment activities and daily operational
    severe weather forecasting at SPC since April
  • This convection-allowing model was first tested
    during the 2004 Spring Experiment, which focused
    on exploring the utility of high resolution
    versions of the WRF-NMM, as well as WRF-ARW
    models from NCAR and OU-CAPS, to provide useful
    guidance for severe weather forecasters. 
  • Spring Experiments examining WRF-NMM and WRF-ARW
    models were also conducted in 2005 and 2007,
    where intensive tests and evaluations were again
    conducted daily during severe weather episodes
    across the central and eastern U.S. 

SPC Evaluation Steve WeissPart 2
  • Since 2004, the model has been periodically
    upgraded, including in early 2007 when NMM
    physics were standardized, grid length was
    decreased to 4 km, the domain was expanded, and
    model run time was optimized.  Most importantly,
    the early success of the WRF-NMM4 in spring 2004
    resulted in the model output being distributed to
    SPC operational forecasters in real-time, and
    over the last three years they have evaluated its
    performance and utility for a wide variety of
    geographic, seasonal, and synoptic regimes over
    the central and eastern states.  Most of our
    attention has focused on the ability of the
    WRF-NMM4 to resolve smaller scale features such
    as convective storms through the use of simulated
    reflectivity fields.  Compared to operational
    mesoscale models that incorporate convective
    parameterization, the WRF-NMM4 has been found to
    provide unique information about details of
    convective initiation, intensity, evolution, and
    mode (or morphology), which are critical aspects
    to severe weather forecasting.  The accurate
    prediction of convective mode (such as discrete
    cells, lines, or multicell complexes) is directly
    related to the occurrence of  tornadoes, large
    hail, and damaging winds, which tend to occur
    preferentially with specific convective modes. 
    In this area alone, SPC forecasters have found
    that the near-stormscale resolution of the
    WRF-NMM4 has substantially contributed to more
    confident and skillful forecasts of specific
    severe weather threats.  This has been aided by
    the extraction of gridded information concerning
    the dynamic structure of model-generated
    supercell thunderstorms, which are convective
    storms with persistent rotating updrafts.  The
    value of the WRF-NMM4 has been especially evident
    during strongly forced situations that are
    associated with severe weather outbreaks. (See
    attached powerpoint file entitled NWA 2006
    WRF-NMM4 Outbreaks that contains a presentation
    given at the NWA Meeting in fall 2006.) 

SPC Evaluation Steve WeissPart 3
  • Since late 2006, SPC has had access to a
    real-time 4 km version of the ARW that is run
    once daily at NSSL.  SPC forecasters have been
    using both models in their severe forecasting
    mission, and have identified various strengths
    and weaknesses with both models but have learned
    how to use these performance characteristics to
    their advantage.  For example, the NMM appears to
    display a high convective storm/precipitation
    bias whereas the most recent ARW versions have a
    slight low bias.  Of course, the
    convection-allowing WRF models are relatively
    early in their development and considerable work
    remains, such as improving physics and
    development of cutting-edge data assimilation
    systems that are specifically designed for high
    resolution models with grid lengths lt 4 km.  But
    we have also seen considerable evidence during
    the last three years that operational severe
    weather forecasters at SPC have benefited from
    the daily availability of the WRF-NMM4 output,
    and more recently WRF-ARW4 output, and these
    benefits are reflected in improved SPC forecast
    products on important severe weather days.  See
    the attached powerpoint file entitled WRF-NMM
    and WRF-ARW Use at SPC, which was part of a
    presentation given at the 2007 AMS WAF/NWP
    Conference in June. Furthermore, the increasing
    number of WFOs running local experimental
    limited-area WRF models and viewing the WRF-NMM4
    online web page strongly suggests that local
    forecasters believe there are advantages to
    having routine access to operational high
    resolution model output. 

SPC Evaluation Steve WeissPart 4
  • After using the WRF-NMM4 in operational severe
    weather forecasting for more than three years,
    the SPC strongly supports upgrading the High Res
    Window slot with the latest versions of the
    WRF-NMM4 and WRF-ARW5, and running them twice
    daily at 00z and 12z over an expanded
    central/east region, and once daily at 06z over
    an expanded west/central region.
  • Recommendation Implement as proposed XXX
  • The need for hourly grids slipped through the
    cracks for the HRW upgrade, as we had assumed
    that the hourly output frequency of Matt Pyles
    experimental run would automatically transfer to
    the HRW.  We agree with the advice of NCO to
    implement the proposed version in September and
    then provide hourly grids early in FY08.  We are
    concerned, however, that with the approach of the
    secondary fall severe weather season over the
    southeast/Ohio Valley region from late October
    into December, there may be a need to continue
    Matts experimental run until the hourly grids
    can be implemented in the HRW.  This has been
    discussed in several email exchanges earlier
    today with Brent Gordon.
  • EMC has agreed to continue running Matt Pyles
    experimental run with hourly output until this
    capability can be added to the Production run.

OSIP / SREC Progress at Silver Spring
  • OSIP Project 07-012
  • Cleared Gate 2
  • Directed to SREC
  • Worked with regions to pare SBN output by 23 May
    to just over 900mb per cycle
  • Made list for AWIPS Build OB8.3, then dropped due
    to resource limitations
  • Accepted as part of OB9