National Weather Association 42nd Meeting September 17, 2017 An Introduction to Real Time Aircraft Soundings for Broadcast Meteorologists and Storm Chasers Rich Mamrosh – NWS Green Bay, Wisconsin

Introduction The NWS provides public access to real time soundings and flight level data from 135 UPS and Southwest Airlines aircraft. The aircraft are equipped with water vapor sensors that produce around 1,000 soundings each day. The data are being provided by MADIS in netCDF format and eventually via interactive web page. This presentation will begin with a short history of aircraft weather data, followed by forecast applications and ideas for broadcast meteorologists and storm chasers.

History of Aircraft Weather Data Aircraft have been used as platforms for collecting meteorological data since the dawn of aviation. Installation of modern communications systems allow commercial aircraft to automatically transmit meteorological data. An increasing number of airlines around the world share wind and temperature data with the NWS and other national meteorological services. A meteorologist collects weather data from instruments attached to an aircraft in 1919.

History of Aircraft Weather Data There are nearly one million temperature and wind reports from around the world each day. Average daily AMDAR data since 2007 These data are used in the HRRR, NAM, GFS, and ECMWF models. Global AMDAR data for 24 hour period

History of the WVSS Program In order to complement wind and temperature data, UPS Airlines and the NWS partnered to install water vapor sensors on six UPS 757 aircraft between 1997 and 1999. The units measured relative humidity using a thin film capacitor similar to NWS radiosondes. It was called the “Water Vapor Sensing System”. Air intake for WVSS system UPS Airlines 757 aircraft

History of the WVSS Program 1996-2003 Field studies showed that the WVSS compared favorably to radiosondes, but the sensors needed to be replaced too frequently to be used on commercial airlines. WVSS Sounding from May 1997 Data from 2001 comparison Next – WVSS-II

History of the WVSS Program 2004-Present A new sensor was developed by Spectrasensors that uses a diode laser to measure water vapor mixing ratio. It requires little or no maintenance and is of higher quality. The WVSS-II was installed on twenty five UPS aircraft between 2004 and 2005. Components of WVSS-II system WVSS-II Diode Laser

History of the WVSS Program 2004-Present Field experiments determined that WVSS-II compared very favorably to high quality radiosonde data, prompting the purchase of additional sensors. CIMSS mobile sounding unit Radiosonde/WVSS-II comparison

History of the WVSS Program There are now 135 UPS and Southwest Airlines aircraft with WVSS-II sensors. The NWS currently purchases these data from Rockwell Collins, who owns the sensors and manages the network. This partnership makes the data publically available. WVSS-II data for 24 hours ending at 10z August 30, 2017.

History of the WVSS Program WVSS-II is different from TAMDAR It should be noted that the NWS participated in a NASA sponsored experiment to collect relative humidity and other data from commercial aircraft called TAMDAR (Tropospheric Airborne Meteorological Data Report) from 2004-2008. Panasonic Aviation Systems is now the sole owner and provider of TAMDAR data. The NWS currently purchases selected TAMDAR data, though they are not publicly available. Next – Data Acquisition

Data Acquisition - netCDF Request a MADIS account (no cost) at https://madis.ncep.noaa.gov/data_application.shtml Access to all WVSS-II data is available in netCDF format at https://madis-data.ncep.noaa.gov/madisPublic/data/point/acars/netcdf If you only want the sounding data, it is at https://madis-data.ncep.noaa.gov/madisPublic/data/point/acarsProfiles/netcdf The data can be used to run local models, produce various forecast products and create custom sounding display pages.

Broadcast Meteorologists If they can download the netCDF data and produce soundings, they can use the soundings to refine forecasts for their broadcast region. Graphically show the state of the atmosphere as it effects convective initiation, formation of fog, transition from rain to snow, etc. Educate their audience on how upper air data are used to forecast various weather phenomena.

Broadcast Meteorologists - Convection NWS meteorologists have utilized WVSS-II to determine convective initiation, intensity, and heavy rain potential. Broadcast meteorologists can now do the same. Here is an example of how the Houston NWS staff used WVSS-II for a convective event.

Broadcast Meteorologists - Convection AREA FORECAST DISCUSSION NWS HOUSTON/GALVESTON TX 1026 AM CDT THU JUL 3 2014 .DISCUSSION... AMDAR SOUNDINGS SUGGEST WE WILL HAVE THUNDERSTORM DEVELOPMENT TODAY WITH LIFTED INDICES AROUND -5 AND CAPES 2000 TO 3000 J/KG ONCE CONVECTIVE TEMPS ARE REACHED (AROUND 90F). SOUNDINGS SHOW VERY LITTLE WIND OR WIND SHEAR SO WE SHOULD HAVE SLOW MOVING PULSE TYPE STORMS.

Broadcast Meteorologists - Convection Soundings can be modified to expected afternoon conditions. An afternoon temperature of 90F (32C) is sufficient to break the cap and convection to begin. Note stability Indices. The extremely light wind field favors slow moving storms with little or no organization This slide shows an unstable atmosphere once the temperature reaches 90F, along with very weak winds that favor slow moving storms with heavy rain. WVSS-II Sounding from HOU at 1649Z July 3, 2014

Broadcast Meteorologists - Convection This is a radar animation that shows thunderstorms forming as the temperature reaches 90F. They move slowly and produce heavy rains. Temperatures in Houston rose to 90F at noon, and slow moving thunderstorms began, just as the WVSS-II soundings suggested. Next – Weakening Thunderstorm

Broadcast Meteorologists - Convection A line of strong thunderstorms is moving towards Tulsa, but weakening A WVSS-II sounding from Tulsa shows why Tulsa, OK This slide shows a radar loop of a line of thunderstorms approaching northeast Oklahoma. The WVSS-II sounding from Tulsa suggests that the storms will weaken as they move into a more stable environment. Prompting this “Tweet” From NWS Tulsa WVSS-II sounding reveals a capped, stable atmosphere.

Broadcast Meteorologists - Precip. Type Broadcast meteorologists can use the soundings to explain precipitation type to their audience. This animation shows environments that produce different types of precipitation, and aircraft sounding examples of each. Click through the four types.

Storm Chasers and Spotters Storm chasers and well educated spotters can use the soundings to determine the current state of the atmosphere, including stability, shear, temperatures aloft, and water vapor content. The soundings will complement the NWS special 18z radiosonde launches. The availability of WVSS-II soundings throughout the day and night increases their utility.

Storm Chasers and Spotters Strong low level winds east of the remnants of Hurricane Harvey were expected to produce sufficient shear for severe thunderstorms over the Southeastern States, despite modest instability. The 1630Z SPC Day 1 outlook for August 31, 2017 did an excellent job of forecasting the location of severe storms later in the day. SPC Day 1 Outlook 1630Z Preliminary Damage Reports

Storm Chasers and Spotters The NWS launched a supplemental radiosonde in Birmingham at 18z, as did Eglin AFB in Florida. In addition to the radiosondes, WVSS-II soundings were available at Birmingham, Tallahassee, Atlanta, Columbia, Nashville, and Jacksonville. 18z special radiosonde launches denoted by stars SPC Day 1 Outlook 1630Z WVSS-II soundings available

Storm Chasers and Spotters Additional WVSS-II soundings were available between 18z and the next regular radiosonde launches at 00Z Atlanta (5) Birmingham (4) Columbia Jacksonville Memphis Nashville (6) Tallahassee This slide shows that 19 WVSS-II soundings were available between 19z and 24z August 31st. Soundings such as these will be very useful to storm chasers and spotters Flight paths of WVSS-II aircraft 19-24z 8/31/2017

WVSS-II Future Plans and Ideas The NWS intends to expand the number of WVSS-II equipped aircraft as funding permits. Aircraft that serve smaller airports in the Plains and Rockies are especially desirable. Aircraft based observations are a very important data source, as the primary source of upper air data come from radiosondes, whose spatial and temporal resolution is less than ideal. In addition, there are major airports distant from any radiosondes. These airports have found aircraft data to be crucial to their forecast efforts. Airports with WVSS-II soundings for 24 hours ending at 09z December 31, 2014.

Suggestions Broadcast meteorologists could ask their service providers to produce TV ready WVSS-II graphics from netCDF data. This graphic could show why there is freezing rain is being reported at the surface. 10,000’ 8,000’ 6,000’ 4,000’ 2,000’ Surface

Suggestions Storm chaser web pages and the SPC could provide real time soundings and use WVSS-II soundings for case studies.

Suggestions An application that displays soundings on smart phones would be very valuable to storm chasers and spotters.

WVSS-II Resources NWS AMDAR Program Curtis Marshall curtis.marshall@noaa.gov MADIS WVSS-II Web Page MADIS netCDF Data madis-support@noaa.gov Forecast Applications Rich Mamrosh richard.mamrosh@noaa.gov WVSS-II Sensor Details Bryce Ford bford@SpectraSensors.com ARINC Rockwell Collins – airline and network coordination jeannine.hendricks@rockwellcollins.com Short video that describes the WVSS-II program https://www.youtube.com/watch?v=8alU5PMMXmo Aircraft data course from COMET (free registration) https://www.meted.ucar.edu/avn_int/amdar/

Thank You Rich Mamrosh National Weather Service 2485 South Point Road Green Bay, WI 54313 (920) 497-8771 richard.mamrosh@noaa.gov