Intelligent Use of LAPS

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Intelligent Use of LAPS

• By
• Ed Szoke
• 16 May 2001

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LAPS

• A system designed to
• Exploit all available data sources
• Create analyzed and forecast grids
• Build products for specific forecast applications
• Use advanced display technology
• ?All within the local weather office

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Why do analysis in the local office?
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THE CONCEPT OF THE LOCAL DATA BASE IS CENTRAL TO
FUTURE OPERATIONS?THE MOST COMPLETE DATA SETS
WILL ONLY BE AVAILABLE TO THE LOCAL WFO. THE NEW
OBSERVING SYSTEMS ARE DESIGNED TO PROVIDE
INTEGRATED 3-D DEPICTIONS OF THE RAPIDLY CHANGING
STATE OF THE ENVIRONMENT.?
-Strategic plan for the modernization and
associated restructuring of the National Weather
Service
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Data Acquisition and Quality Control
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Local Data

• Local Data may be defined as that data not
  entering into the National Database
• Sources
• Highway Departments
• Many States with full or partial networks
• Agricultural Networks
• State run, sometimes private
• Universities and Other Schools
• Experimental observations
• Private Industry
• Environmental monitoring
• State and Federal Agencies
• RAWS

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Problems with Local Data

• Poor Maintenance
• Poor Communications
• Poor Calibration
• Result ---------------- Inaccurate,
• Irregular,
• Observations

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Quality Control Methods

• Gross Error Checks
• Rough Climatological Estimates
• Statistical Models
• Buddy Checking
• Dynamical Models
• Use of meso-beta models

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Requirements for QC Scheme

• Runnable in weather offices on small workstations
• Adaptable to ongoing model improvement
• Adaptable to daily variations in model skill

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Requirements for QC Scheme (cont.)

• SOLUTION The KALMAN FILTER
• Adaptable to small workstations
• Accommodates models of varying complexity
• Model error is a dynamic quantity within the
  filter, thus the scheme adjusts as model skill
  varies

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LAPS Overview

• LAPS Grid
• Horizontal Resolution 10 km
• Vertical Resolution 50 mb
• Size 61 x 61 x 21

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The blue colored data are currently used in AWIPS
LAPS. The other data are used in the "full-blown"
LAPS and can potentially be added to AWIPS/LAPS
if the data becomes available.
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Sources of LAPS Information

• The LAPS homepage http//laps.fsl.noaa.gov
• provides access to many links including
• What is in AWIPS LAPS?
• http//laps.fsl.noaa.gov/LAPB/AWIPS_WFO_page.htm

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Analysis Information

• LAPS analysis discussions are near the bottom of
• http//laps.fsl.noaa.gov/presentations/presentatio
  ns.html
• Especially noteworthy are the links for
• Satellite Meteorology
• Analyses Temperature, Wind, and Clouds/Precip.
• Modeling and Visualization
• A Collection of Case Studies

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3-D Temperature

• Interpolate from model (RUC)
• Insert sonde, RASS, and ACARS if available
• 3-Dimensional weighting used
• Insert surface temperature and blend upward
• depending on stability and elevation
• Surface temperature analysis depends on
• METARS, Buoys, and LDAD
• Gradients adjusted by IR temperature

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3-D Clouds

• Preliminary analysis from vertical soundings?
  derived from METARS and PIREPS
• IR used to determine cloud top (using temperature
  field)
• Radar data inserted (3-D if available)
• Visible satellite used

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LAPS Snow Cover and Precip. Type
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LAPS 3-D Water Vapor (Specific Humidity) Analysis

• Interpolates background field from synoptic-scale
  model forecast
• QCs against LAPS temperature field (eliminates
  possible supersaturation)
• Assimilates RAOB data
• Assimilates boundary layer moisture from LAPS Sfc
  Td analysis
• Scales moisture profile (entire profile excluding
  boundary layer) to agree with derived GOES TPW
  (processed at NESDIS)
• Scales moisture profile at two levels to agree
  with GOES sounder radiances (channels 10, 11,
  12). The levels are 700-500 hPa, and above 500
• Saturates where there are analyzed clouds
• Performs final QC against supersaturation

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Products Derived from Wind Analysis
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Case Study Example

• An example of the use of LAPS in convective event
• 14 May 1999
• Location DEN-BOU WFO

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Quote from the Field

• "...for the hourly LAPS soundings, you can go to
  interactive skew-T, and loop the editable
  soundings from one hour to the next, and get a
  more accurate idea of how various parameters are
  changing on an hourly basis...nice. We continue
  to find considerable use of the LAPS data
  (including soundings) for short-term convective
  forecasting."

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Case Study Example

• On 14 May, moisture is in place. A line of storms
  develops along the foothills around noon LT (1800
  UTC) and moves east. LAPS used to diagnose
  potential for severe development. A Tornado Watch
  issued by 1900 UTC for portions of eastern CO
  and nearby areas.
• A brief tornado did form in far eastern CO west
  of GLD around 0000 UTC the 15th. Other tornadoes
  occurred later near GLD.

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NOWRAD and METARS with LAPS surface CAPE 2100 UTC
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For this part we will go to a web presentation to
show this example in detail
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This example showed how LAPS can be used for
Nowcasting. LAPS is also ideal for
initializing a local model, since the analysis
should capture features better than just simply
using a background lower resolution model.
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Why Run Models in the Weather Office?

• Diagnose local weather features to enhance
  conceptual models
• sea/mountain breezes
• modulation of synoptic scale features
• Take advantage of high resolution terrain data to
  downscale national model forecasts
• orography is a data source!

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Why Run Models in the Weather Office? (cont.)

• Take advantage of unique local data
• radar
• surface mesonets
• Have an NWP tool under local control for
  scheduled and special support
• Take advantage of powerful/cheap computers

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Some examples of a local model are shown
next. The topography of Colorado leads to a wide
variety of weather...and a local model can be of
great value to helping to forecast the resulting
weather. Some forecast problems include
-orographic precipitation -"Denver Cyclone"
-"Longmont Anticyclone"
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SFM forecast showing details of the orographic
precipitation, as well as capturing the Longmont
anticyclone flow on the plains
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LAPS analysis for 1500 UTC
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LAPS Summary

• You can see more about our local modeling efforts
  at
• http//laps.fsl.noaa.gov/presentations//pre
  sentations.html

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The increasing amount of output for the
forecaster to look at from the different models
(such as a local model) can be overwhelming and
difficult to comprehend during an operational
forecast shift. So it is desirable to explore
new ways to examine model and analysis
grids. One new way we are working on is called
"D3D" for Display in 3 Dimensions (versus
"D2D"). Our D3D work can be further viewed on
our homepage at http//d3d.fsl.noaa.gov
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D3D example showing an isosurface of relative
humidity
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Example of Powerful Sounding Tool in D3D