AMDAR Forecast Applications

1. AMDAR Forecast Applications JMAMeeting March 23, 2009 Carl Weiss NWS Aviation Services Branch Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

2. Before We Begin… You may have heard aircraft data referred to as ACARS, MDCRS, or TAMDAR… • ACARS (Aircraft Communications, Addressing, and Reporting System) is the name of a datalink service provided by Aeronautical Radio, Inc. that sends data between aircraft and ground stations • MDCRS (Meteorological Data, Collection and Reporting System) is the weather portion of the ACARS data stream provided by seven major U.S. air carriers • TAMDAR (Tropospheric Airborne Meteorological DAta Reporting) data are provided by a private company, AirDat, who uses regional air carriers However, Aircraft Meteorological DAta Relay (AMDAR) is the preferred term by the WMO and NWS. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

3. AMDAR Data Have Many Applications • Aviation • Low level wind shear • Ceilings and visibilities • Icing and turbulence • Winter Storms • Precipitation type • Lake effect snow • Thunderstorms • Convective initiation • Calculation of stability indices • Fire Weather • Mixing heights • Haines indices • Relative humidity forecasts • Marine Forecasts • Small craft and Gale Warnings • Hazardous Materials Support • AMDAR can be used to support HAZMAT teams • Input to local dispersion models Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

4. Aviation Applications • AMDAR soundings in vicinity of airports provide meteorologists a real time view of the atmosphere • This can result in more accurate forecasts of low clouds, fog, low level wind shear and other aviation weather elements • AMDAR flight level data provide important information in flight corridors • TAMDAR aircraft report icing and turbulence data Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

5. Low-Level Wind Shear • AMDAR data can be useful in determining the presence of low-level wind shear (LLWS) • Aircraft ascending or descending in the vicinity of an airport are in an ideal location for depicting low-level wind shear Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

6. Low-Level Wind Shear • An example of this was noted by the forecasters at the Green Bay, WI WFO on the evening of October 29, 2005 • The TAF that night indicated LLWS was forecast to begin after 0600 UTC. TAMDAR soundings from around 0120 UTC showed LLWS already was present Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

7. Low-Level Wind Shear Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

8. Low-Level Wind Shear • The forecaster was able to update the TAF and begin the LLWS more than 3 hours earlier than did the prior forecast • This was mentioned in the Area Forecast Discussion that was issued around 0245 UTC Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

9. Ceilings and Visibilities • AMDAR provides very useful information for forecasting low ceilings and fog that can greatly impact airports • Water vapor information is a very important element, but soundings without it can still be useful Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

10. Ceilings and Visibilities • The Detroit, MI WFO found TAMDAR data useful in forecasting a dense fog event on the evening of February 4, 2005 • Soundings indicated light winds in the boundary layer, moisture near the surface and dry air above • Normally, these are suitable conditions for the formation of low clouds or fog Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

11. Ceilings and Visibilities Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

12. Ceilings and Visibilities Forecasters at Detroit amended their TAF for the 09 to 12 UTC period, reducing visibilities to ½ mile. The METAR observations below show that visibilities dropped even lower. Kdtw 0532z 00000kt 2sm br clr Kdtw 0739z 17003kt 1 3/4sm br r04/1000v3500 Kdtw 0936z 17004kt 1/4sm fg r04/0500v0600 Kdtw 1154z 16004kt 1/4sm fg r04/2800v0600 Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

13. Icing and Turbulence The U.S. Air Force Weather Agency (AFWA) used TAMDAR data to verify an icing forecast from their MM5 model. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

14. Icing and Turbulence Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

15. Icing and Turbulence Is icing occurring over Michigan? Icing PIREPS for all levels 1600-1800 UTC Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

16. Icing and Turbulence Yes! icing near TVC and PLN Yes! Icing near TVC and PLN Automated aircraft reports of icing and turbulence will help AFWA and the AWC in the forecast and verification of these aviation hazards. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

17. Winter Storms • Precipitation type forecasts can be made with greater accuracy with the use of AMDAR data • Frequent soundings show the height of the freezing level, and the presence of elevated warm layers - knowledge of such features is critical for accurate precipitation type forecasts Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

18. Winter Storms (Precipitation Type Forecasts) • On December 15, 2005 forecasters at the Buffalo, NY WFO used AMDAR soundings to identify a substantial warm layer between 2,000 and 5,000 feet above the ground • Because there was such a deep layer of warm air, the forecast was updated to reduce snow accumulations and increase the amount of sleet and freezing rain Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

19. Winter Storms (Precipitation Type Forecasts) Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

20. Winter Storms (Precipitation Type Forecasts) Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

21. Convective Forecasts • AMDAR data have been used extensively in support of convective forecasts • Temperature and moisture data provide the needed information to determine the stability of the atmosphere • Wind data can be used to construct hodographs Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

22. A Convective Non-Event A linear mesoscale convective system was located over eastern Minnesota and western Wisconsin at 1500 UTC on June 7, 2005. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

23. A Convective Non-Event It was thought initially that this elevated convection would become surface based as the system moved east during the day A Severe Thunderstorm Watch was issued for much of Wisconsin at 1530 UTC. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

24. A Convective Non-Event • Shortly after the issuance of the watch, forecasters at the Green Bay, WI WFO noticed that TAMDAR soundings from the watch area appeared much too stable for surface based convection • A sounding from the Central Wisconsin airport at 1512 UTC showed a strong capping inversion, that was unlikely to break • Another sounding at 1923 UTC showed the atmosphere was still much too stable for convection -forecasters then lowered the chance for thunderstorms, and the watch was later dropped Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

25. A Convective Non-Event 1512 UTC Sounding 1923 UTC Sounding Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

26. A Convective Non-Event • The thunderstorms that prompted the severe thunderstorm watch never became surface based as they moved east • Forecasters had been misled by model soundings that predicted the cap would erode sufficiently for surface based storms to form • Misleading forecast guidance became a less frequent issue as more forecasters used AMDAR data Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

27. A Convective Non-Event RUC Forecast (black) was much less stable than TAMDAR sounding (purple) Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

28. Fire Weather • Accurate fire weather forecasts require an understanding of atmospheric stability, wind and moisture • The large spatial and temporal gaps in radiosonde data make this difficult • locations distant from radiosondes are at particular disadvantage • AMDAR data can fill many of these gaps and are now used increasingly in fire weather forecasts Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

29. Fire Weather • Forecasters found AMDAR data useful in expanding a *Red Flag Warning in effect for Northern and Central Wisconsin on the afternoon of July 15, 2006. • Very dry air could be seen on TAMDAR soundings earlier in the day when the Red Flag Warning was issued. Later soundings indicated sufficient dry air in other parts of the forecast area to expand the warning * Temperature >75°F, RH <25%, winds of 25 mph Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

30. Fire Weather AREA FORECAST DISCUSSION...UPDATEDNWS GREEN BAY WI200 PM CDT SAT JUL 15 2006 .UPDATED...ADDED AREAL COVERAGE FOR THE RED FLAG HEADLINES. RH/S ALREADY IN THE 20 PCTS EARLY THIS AFTERNOON AND WINDS NEAR CRITERIA OVER NW WI. TAMDAR SOUNDING THIS AM FROM RHI SHOWS A VERY DRY AIR MASS TO MIX DOWN WITH NEAR CRITIERIA WINDS. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

31. Fire Weather Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

32. Marine Applications • Surface winds and resulting waves are influenced greatly by both winds aloft and stability • Unstable air helps mix down strong winds above the boundary layer, while stable conditions hinder mixing • AMDAR data are ideal for determining both winds aloft and atmospheric stability Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

33. Marine Applications • AMDAR data have been used in the Great Lakes region and along the coastlines of the United States for marine forecasts • The following is an example from October 3, 2004. The Chicago, IL WFO forecasters used AMDAR data to determine that the atmosphere was sufficiently unstable to mix down 35 knot winds to the surface • Based on this information, they wisely decided to continue the Gale Warning that had been issued earlier in the day Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

34. Marine Applications AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 715 PM CDT SUN OCT 3 2004 .MARINE...SHIP REPORTS OF GALES THIS EVENING FROM THE SOUTHWEST. SURFACE ANALYSIS AND USING THE ACARS SOUNDING FROM ORD AT 2230 UTC SHOW STRONG WINDS ALOFT AND BEHIND THE FRONT. WILL KEEP THE GALE WARNING FOR OVERNIGHT. WHW Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

35. Marine Applications Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

36. Hazardous Materials Support • AMDAR data are used frequently by the National Transportation Safety Board in the investigation of aviation and marine accidents • AMDAR data were used in support of the September 11th disaster • AMDAR data can be used in local models to predict the drift of hazardous materials Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

37. Hazardous Materials Support • HYSPLIT - Hybrid Single Particle Lagrangian Integrated Trajectory model is an Air Resources Laboratory (ARL) model used for computing air parcel trajectories in dispersion and deposition simulations • HYSPLIT dispersion model simulations were run centered over the Miami International Airport starting at 01 UTC on the evening of November 27, 2008 • The model was first run using just the 12km NAM. The model was run again, using temperature, dewpoint, and wind information from commercial aircraft. • The outputs from the HYSPLIT runs are quite different, especially in the first two hours, and likely due to the inaccurate model forecast of the low level winds by the NAM. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

38. Hazardous Materials Support Aircraft sounding from Miami International Airport Sounding from an aircraft equipped with a WVSS2 water vapor sensor Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

39. Hazardous Materials Support HYSPLIT Output The figure on the left is the output of HYSPLIT run with the 18Z NAM, while the one on the right is the same HYSPLIT run with aircraft data. There are significant differences, especially in the first hour. The HYSPLIT model forecasts the pollutant to drift to the northeast from the start, while the HYSPLIT model with aircraft data forecasts the pollutant to go in the opposite direction for the first hour before drifting to the northeast. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

40. Hazardous Materials Support Afterthe first hour The first hour of the HYSPLIT model brings the pollutant over the Virginia Gardens and Miami Springs areas. The first hour of the HYSPLIT run with aircraft data brings the pollutant in the opposite direction, over the Fountainbleau and Sweetwater areas. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

41. Hazardous Materials Support After hour two The second hour of the HYSPLIT model forecasts the pollutant entirely northeast of the source location. The second hour of HYSPLIT run with aircraft data forecasts the pollutant almost entirely southwest of the source point. Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

42. Hazardous Materials Support Results • If this had been an actual event, using model data only in the HYSPLIT run could have led to the wrong area being warned • The HYSPLIT run with only model data was probably incorrect because the NAM model did not accurately forecast the weak sea breeze that reached the Miami area during late afternoon • It would appear that manually entered data from aircraft, VAD Wind Profiles or radiosondes can result in improvements to the HYSPLIT model forecasts Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.

43. Questions? Carl Weiss National Weather Service, W/OS23 SSMC2, Rm. 13326 1325 East-West Highway Silver Spring, MD 20910 USA (301) 713-1726x149 carl.weiss@noaa.gov Supporting the Nation’s commerce with information for safe, efficient, and environmentally sound transportation.