Intelligent Use of LAPS By Steve Albers 30 March 2000
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
“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
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
Problems with Local Data • Poor Maintenance • Poor Communications • Poor Calibration Result ----------------> Inaccurate, Irregular, Observations
Quality Control Methods • Gross Error Checks Rough Climatological Estimates • Statistical Models Buddy Checking • Dynamical Models Use of meso-beta models
Requirements for QC Scheme • Runnable in weather offices on small workstations • Adaptable to ongoing model improvement • Adaptable to daily variations in model skill
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
LAPS Overview • LAPS Grid • Horizontal Resolution = 10 km • Vertical Resolution = 50 mb • Size: 61 x 61 x 21
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.
Overview of AWIPS 4.3 LAPS Improvements: • Improved surface analyses (T, Td, Wind, P, Etc.) • Improved use of METARS in cloud analysis and surface precipitation type • Improved diagnosis of freezing rain • Y2K improvements
Overview of AWIPS 5.0 LAPS Improvements: • Graphical User Interface (GUI) • Displays what data got into the analyses • Domain Relocatability • Surface Stations • More local (LDAD) station data • Blacklist capability
Candidate Future Improvements: • GUI - Domain Resizability • Surface Obs QC • MSLP background model comparison (laps_sfc.x) • Turning on Kalman Filter QC (sfc_qc.exe) • Handling of surface stations with known bias • Stability Indices • Wet Bulb Zero, K, Total Totals, Showalter, LCL • Improved use of radar reflectivity • Multiple radars?
Candidate Future Improvements (cont.) • Use of visible satellite in cloud analysis • Use of 3.9 micron satellite in cloud analysis • LI/CAPE/CIN with different parcels in boundary layer • New SPC method for computing storm motions feeding to helicity determination
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
Analysis Information LAPS analysis discussions are near the bottom of: http://laps.fsl.noaa.gov/presentations/presentations.html Especially noteworthy are the links for • Satellite Meteorology • Analyses: Temperature, Wind, and Clouds/Precip. • Modeling and Visualization • A Collection of Case Studies
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
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
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
Case Study Example An example of the use of LAPS in convective event 14 May 1999 Location: DEN-BOU WFO
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."
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.
CAPE Maximum persists in same area 2200 UTC
CIN minimum in area of CAPE max 2200 UTC
Convergence and Equivalent Potential Temperature are co-located 2100 UTC
How does LAPS sfc divergence compare to that of the RUC? Similar over the plains. 2100 UTC
Case Study Example (cont.) • The next images show a series of LAPS soundings from near LBF illustrating some dramatic changes in the moisture aloft. Why does this occur?
LAPS sounding near LBF 1600 UTC
LAPS sounding near LBF 1700 UTC
LAPS sounding near LBF 1800 UTC