Intelligent Use of LAPS

1. Intelligent Use of LAPS By Ed Szoke and Steve Albers 16 December 1999

2. 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

3. Why do analysis in the local office?

4. “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

7. Data Acquisition and Quality Control

8. 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 • Experimental observations • Private Industry • Environmental monitoring

10. Problems with Local Data • Poor Maintenance • Poor Communications • Poor Calibration Result ----------------> Inaccurate, Irregular, Observations

11. Quality Control Methods • Gross Error Checks Rough Climatological Estimates • Statistical Models Buddy Checking • Dynamical Models Use of meso-beta models

12. Requirements for QC Scheme • Runnable in weather offices on small workstations • Adaptable to ongoing model improvement • Adaptable to daily variations in model skill

13. 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

15. LAPS Overview • LAPS Grid • Horizontal Resolution = 10 km • Vertical Resolution = 50 mb • Size: 61 x 61 x 21

16. LAPS Analysis Software • Analysis package has been in each version of WFO-Advanced delivered to PRC and NWS • LAPS in current build (AWIPS 4.2) is primitive • Awaiting requirements for build 5.0, such as resizeability, relocatability, advanced quality control techniques, etc.

17. 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/LAPS/AWIPS_WFO_page.htm

18. Initially (Version 4.0) NOT MUCH! AWIPS SURFACE SATELLITE RADAR SOUNDING PROFILER BACKGROUND MODEL 4.1 METARS 8bit IR Only None Inactive Network RUC (Can use Eta) 4.2 LDAD** Same Low-level Inactive Network RUC (Can use Eta) Z, Level 3 RPG, No V Full All Derived Mulitple RAOBS RASS Other Models LAPS Soundings Radars Boundary 10bit IR All levels Layer & VIS Z and V Profilers ** if Available

20. 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."

21. The Component of LAPS There are 3 main components 1) Temperature (http://laps.fsl.noaa.gov/albers/laps/talks/temp/sld001.htm) 2) Moisture (http://laps.fsl.noaa.gov/albers/laps/talks/cloud/sld001.htm) 3) Wind (http://laps.fsl.noaa.gov/albers/laps/talks/wind/sld001.htm) See Steve Albers discussion at: http://laps.fsl.noaa.gov/presentations/presentations.html

22. 3D Temperature • Interpolate from model (RUC) • Insert sonde and RASS if available • normally radius of influence not used unless more than one sounding • Insert surface temperature and blend upward • depending on stability and elevation • Surface temperature analysis depends on • METARS and LDAD • Gradients adjusted by IR temperature

23. 3D Moisture • 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

28. Products Derived from Wind Analysis

29. Case Study Example An example of the use of LAPS in convective event 13-14 May 1999 Location: DEN-BOU WFO

30. Case Study Example (cont.) • Late on the 13th we see moisture returning in far eastern CO on “screaming” southerly flow. A Severe Thunderstorm Watch was issued at 4 PM (2200 UTC) for portions of northeast CO and nearby areas. • Note the change in the moisture near LBF

31. LAPS surface CAPE with CIN and METARS

32. LAPS sounding near LBF 2300 UTC

33. LAPS sounding near LBF 0000 UTC

34. LAPS sounding near LBF 0100 UTC

35. Case Study Example (cont.) • On the next day, 14 May the 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.

36. NOWRAD and METARS with LAPS surface CAPE 2100 UTC

37. NOWRAD and METARS with LAPS surface CIN 2100 UTC

38. Dewpoint max appears near CAPE max, but between METARS 2100 UTC

39. Examine soundings near CAPE max at points B, E and F 2100 UTC

40. Soundings near CAPE max at B, E and F 2100 UTC

41. RUC also has dewpoint max near point E 2100 UTC

42. LAPS & RUC sounding comparison at point E (CAPE Max) 2100 UTC

43. CAPE Maximum persists in same area 2200 UTC

44. CIN minimum in area of CAPE max 2200 UTC

45. Point E, CAPE has increased to 2674 J/kg 2200 UTC

46. Convergence and Equivalent Potential Temperature are co-located 2100 UTC

47. How does LAPS sfc divergence compare to that of the RUC? Similar over the plains. 2100 UTC

48. LAPS winds every 10 km, RUC winds every 80 km 2100 UTC

49. 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?

50. LAPS sounding near LBF 1600 UTC