experimental aviation grids at national weather service marquette michigan n.
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Experimental Aviation Grids at National Weather Service Marquette, Michigan

Experimental Aviation Grids at National Weather Service Marquette, Michigan

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Experimental Aviation Grids at National Weather Service Marquette, Michigan

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  1. Experimental Aviation Grids at National Weather Service Marquette, Michigan Steven Fleegel NWS Marquette, MI Great Lakes Operational Meteorology Workshop Webinar Series May 14, 2013

  2. Overview • Started as a part of experimental Fire Weather grid creation in February 2012 • Creating Ceiling and Visibility grids • Tools and Procedures were modified and created in Graphical Forecast Editor (GFE) to use a consensus approach • Averaged the derived model ceilings and explicit model visibilities • Completely hands off for forecasters

  3. Overview - cont. • This proved useful to the forecasters in giving a rough idea on potential ceiling/visibilities across the County Warning Area (CWA) • Very helpful with timing • Created hourly through first 12 hours and then every 3 hours after that through 72 hours • Originally created every 3 hours through 60 hours

  4. What was done in GFE • Added Ceiling and Visibility (Vsby) grids to the Forecast (Fcst) database • Originally, the ceiling grids were derived on the fly and calculated based off model RH • Ceiling grids were converted to background processing (smartInits) with the transition to calculations based on RH with respect to Ice (March 2013) • Vsby grids were also converted to smartInits at this time • This conversion allowed the consensus calculations to be enhanced • Hourly calculations in the first 12 hours • Hourly model data when available and interpolated 3 or 6 hour model data. • Weights to increase emphasis on preferred models

  5. Models Included Ceiling Visibility NAM12 MET Guidance NAM 4km Nest MAV Guidance (Beyond 12-hours) WRF-ARW (local 20km and 5km) HRRR HRRR (Previous) Gridded LAMP Gridded LAMP (Previous) NCEP WRF-ARW East NCEP WRF-NMM East • NAM12 • MET Guidance • GFS40 • MAV Guidance (beyond 12-hours) • RAP X2 • RAP (Previous) • WRF-ARW (local 5km) X2 • RuMM1/2 (3 hourly local 3km WRF-ARW initialized off RAP) • Gridded LAMP • Gridded LAMP (Previous) GFE and AWIPS data limitations exclude using GEM (NH and Regional), ECMWF, NCEP WRFs Ceiling data

  6. How the Forecasters see the Data • Example of a Ceiling grid in GFE • Uses a color table to match Categorical Amendment Criteria (CAC) • Help forecasters quickly see areas of concern

  7. What was done in AvnFPS • The data is also available to the Aviation forecasters through the AvnFPS TAF Editor • Forecaster feedback has been positive to this addition • Helps them with timing for TAFs • Did have to make minor background adjustments due to local labeling • Will likely be transitioning towards more consistent labeling with AWIPS 2 Vsby Sky Ceiling

  8. Case Study – March 11, 2013 Low pressure system moving northeast through the Great Lakes region

  9. March 11, 2013 – 00Z Ceiling Visibility Surface Chart

  10. March 11, 2013 – 06Z Ceiling Visibility Surface Chart

  11. March 11, 2013 – 12Z Ceiling Visibility Surface Chart

  12. Quick Verification Background Categorical Amendment Criteria (CAC)

  13. March 11, 2013 - Verification KSAW – Sawyer International Airport 3/10 – 18Z 3/11 – 00Z 3/10 – 06Z 24hrs Out 12hrs Out 6hrs Out MVFRMust File AlternateIFRAlternate Landing MinsAirfield Landing Mins

  14. KCMX – March 19th, 2013 Snow KCMX – Houghton County Memorial Airport March 17, 2013 – 18Z Forecast • Low pressure system moving east out of the Northern Plains and across Lake Superior • Hit alternate landing minimum visibilities within an hour or two at 30 hours out • Extremely useful for Outlook portion of TAF forecast

  15. Shallow Moisture Case – 03/08/2013 Light winds and lingering moisture trapped below subsidence associated with high pressure over the Great Lakes

  16. Shallow Moisture Case – cont. Model initial conditions – March 08, 2013 00Z RAP GFS NAM

  17. Shallow Moisture – cont. • With the reliance on model data, the Aviation Grids struggled • Forecasters also struggled with timing of wind becoming offshore • Forecaster Aviation discussion mention timing uncertainty on clouds • 00z TAF had conditions scattering out at 02Z • But at least the TAF forecast had the right idea

  18. Verification • In order to quantify the biases and identify areas of improvement, verification was started in February 2013 • Caveats • Local NDFD Verification • Only Hourly obs at the top of the hour • Looks at ceiling height with no restriction by cloud cover • Looked at 2 of our 3 TAF sites • Left out KIWD (Ironwood, MI) due to inconsistent observations • Stats on Demand (NWS Verification) • 5min obs and calculation • Has in-between obs (Specials)

  19. KSAW – 0-6hr Verification

  20. KCMX – 0-6hr Verification

  21. KSAW – 6-24hr Verification

  22. KCMX – 6-24hr Verification

  23. Aviation Grids – Performance • Positives • Synoptic systems • As long as there is model consistency • Visibility • Values and timing • Model derived data versus calculated like ceilings • Recently improved ceilings in lake effect areas • Due to relative humidity calculations with respect to ice

  24. Aviation Grids - Shortcomings • Shallow Moist Layers • Models have same issue • Plus, with GFE only having data every 25mb, it is easy for those shallow layers to be missed • Timing the end of lake effect snow and clouds • Models have same issue • Very low ceilings • Due to the way the consensus is averaged • One model showing 20,000 foot ceilings can quickly raise the other models consensus of 500 feet • Doesn't represent lower ceilings or vertical visibility (VV) due to Blowing Snow (BLSN) or heavy snow (+SN) • Potential improvement based off Forecast • Tool could use BLSN or +SN to adjust ceiling values to increase consistency with the forecast

  25. CAC Category Distribution - KSAW • Issue with lack of lower ceilings can be seen in frequency comparisons • Biased towards VFR conditions • Misses IFR and lower • Visibility has a fairly even distribution in all categories

  26. Recent Improvements • Changes made at the beginning of March have improved lower ceiling errors • RH with respect to Ice • Hourly Calculations in the first 12 hours • Has greatly reduced the high bias for MVFR and lower Ceilings

  27. Future Work • Main focus will be improving Ceiling forecasts for IFR and lower conditions • Perform Summertime convection verification • Incorporate some influence of the Forecast to visibility and ceiling • Generate experimental TAFs like some NWS Eastern Region offices • Would help simplify verification, since it would be incorporated into Stats on Demand

  28. Future Work – cont. • Expand Gridded Database to web for aviation customers • Point and Click and Forecast Graphics • Similar to Jackson, KY, Charleston, WV, etc.

  29. Conclusion • Visibility Grids – Definitely shows skill • Verification over last two months indicates that it is as good or slightly better than our TAFs • Ceiling Grids – Showing improvement • But still struggles with IFR and lower values • A good start • Believe that using this as a starting point and then adding forecaster intervention would create a superior product for the TAF sites and our CWA as a whole

  30. Contact Information • Steven Fleegel – • NWS Marquette, MI