NSSL Hot Itemshttp://www.nssl.noaa.gov/news/hotitems/en-usSciencenssl.webmaster@noaa.gov (Vicki Farmer)nssl.outreach@noaa.gov (Susan Cobb)Mon, 03 Aug 15 00:00:00 -0500<![CDATA[2015 PARISE EXPERIMENT]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=228http://www.nssl.noaa.gov/news/hotitems/display.php?id=228Mon, 03 Aug 15 00:00:00 -0500This week, researchers from NOAA’s National Severe Storms Laboratory will launch the 2015 Phased Array Radar Innovative Sensing Experiment to assess the impacts of rapidly updating radar data on forecasters’ warning decision performance. The project will be carried out over the course of six weeks, and will conclude on September 25.

As in previous years, NSSL Research Scientist Dr. Pam Heinselman and CIMMS Researcher Katie Bowden will take the lead on the experiment. They will be working with NOAA National Weather Service forecasters to produce timelines of the warning decision process. Later they will analyze these timelines to determine the situational awareness attained from phased array radar data and how that information was used in warning decisions. The experiment will be conducted in three parts.

The first segment of 2015 PARISE will be conducted like a traditional experiment, according to Heinselman. Thirty National Weather Service forecasters from across the Great Plains region will be assembled to study nine archived cases. These cases will be worked in simulated real-time, using one-, two-, or five- minute phased array radar updates. The forecasters will determine whether or not to warn, based on the situational awareness gained from the radar data. Upon completion of each study, they will provide a detailed account of their warning decision process and overall workload. With more participants and additional case studies this year, the results are expected to be an improvement over previous experiments.

New this year will be the use of eye-tracking technology to better understand the decision-making processes of the forecasters. Eye-tracking technology has been successfully used for analysis in healthcare, air traffic control, and other human-computer interactions. Data pertaining to eye gaze will be gathered from each of the 30 forecasters while they are working on PAR case studies. Analysis of this data is expected to illustrate how update timelines impact forecasters’ decisions.

On the final day of PARISE, researchers will conduct a focus group aimed at generating insightful feedback. Forecasters will have the opportunity to share new ideas that will help shape the future of the PAR network. As radar continues to develop and forecasting resources are enhanced, National Weather Service meteorologists will be better equipped to warn the public of impending severe weather. This, in turn, will support the NWS objective to protect life and property and will help to build a Weather Ready Nation.

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<![CDATA[NSSL researchers lead project to evaluate experimental flash flood products]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=227http://www.nssl.noaa.gov/news/hotitems/display.php?id=227Wed, 08 Jul 15 00:00:00 -0500During July, NOAA National Weather Service forecasters from forecast offices and river forecast centers will assess emerging hydrometeorological concepts and products in the Multi-Radar / Multi-Sensor (MRMS) Hydro Experiment 2015. Their goal is to improve the accuracy, timing, and specificity of flash flood watches and warnings.

MRMS-Hydro is led by NSSL and is part of the 2015 United States Weather Research Program (USWRP) Hydrometeorological Testbed (HMT). Operational activities will take place Monday through Friday for three weeks (July 6 to 24).

During the experiment, participating forecasters will evaluate short-term predictive tools derived from MRMS quantitative precipitation estimates (QPE) and Flooded Locations and Simulated Hydrographs (FLASH) hydrologic modeling framework. Forecasters will also explore the utility of experimental watch and warning products conveying uncertainty and magnitude issued through the Hazard Services software from the Earth Systems Research Lab/Global Systems Division (GSD). Research scientists will investigate human factors to determine operationally relevant best practices for the warning decision making process and the system usability of the Hazard Services platform.

HMT-Hydro will coordinate operations with the third annual Flash Flood and Intense Rainfall experiment (FFaIR) at the NOAA/NWS Weather Prediction Center (WPC) to simulate the collaboration that occurs between the National Weather Service’s national centers, river forecast centers, and local forecast offices during flash flood events.

HMT-Hydro and FFaIR will simulate the real-time workflow from WPC 6-24 hour forecast and guidance products to experimental flash flood watches and warnings issued in the 0-6 hour period. The HMT-hydro team will shift its area of responsibility on a daily basis to where heavy precipitation events and associated flash flooding is anticipated.

Researchers will collect feedback from NWS operational forecasters through comments during their shifts, electronic surveys, de-briefings, and a webinar at the end of each week. NWS feedback is critical for future development and eventual implementation of new applications, displays, and product concepts into AWIPS2 and other operational systems.

HMT-Hydro 2015 provides a real-time environment to rapidly test the latest observational and modeling capabilities so they may be improved and optimized for transition to operational decision-making in the National Weather Service to support a Weather-Ready Nation.

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<![CDATA[Experimental flash flood forecasting system tested by Texas rain event]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=226http://www.nssl.noaa.gov/news/hotitems/display.php?id=226Thu, 04 Jun 15 00:00:00 -0500Recent flooding in Texas and Oklahoma put NSSL’s experimental Multiple Radar Multiple Sensor (MRMS) Flooded Locations and Simulated Hydrograph (MRMS-FLASH) system to a rigorous test, and researchers were pleased.

The real-time MRMS-FLASH hydrologic modeling suite produces forecasts of flash flooding that are compared to historical simulations that use more than a decade of NEXRAD-based inputs at each 1km grid point. On May 25, the City of Houston, Texas, experienced deadly flash flooding. For this event, FLASH predicted extreme water flows out to six hours in advance.

The Coupled Routing and Excess Storage (CREST) distributed hydrologic model, also a part of the MRMS-FLASH modeling suite, generates maps of streamflow and unit streamflow (cubic meters per second per square kilometer) every 15 minutes. Comparisons between the observations of flash flooding in Houston and the maps of unit streamflow show a good correspondence between areas of high unit streamflows and flash flooding.

The FLASH model represents surfaces that do not absorb water, such as in urban zones, and is able to model dynamic soil moisture conditions, and how water will be routed downstream. MRMS-FLASH has run in real-time demonstration mode for several years.

NSSL’s MRMS-FLASH system provides information and services to make communities more resilient, focusing on enhanced water forecasting and delivery services, and also helps support the NWS to evolve its operations.

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<![CDATA[NOAA Scientists tackle mystery of nighttime thunderstorms]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=224http://www.nssl.noaa.gov/news/hotitems/display.php?id=224Wed, 20 May 15 00:00:00 -0500This summer, more than 20 NOAA scientists will stay up late to learn why some thunderstorms form and grow at night, without the energy from the sun's heat. They will be participating in the Plains Elevated Convection At Night (PECAN), a large, intensive field campaign to collect data before and during nighttime thunderstorms in the western Great Plains from June 1 to July 15.

PECAN researchers will deploy instrumented aircraft, ground-based instruments, mobile radars, and weather balloons to learn what triggers these storms, how the atmosphere supports their lifecycle, and how they impact lives, property, agriculture and the water budget in the region. Meteorologists believe these targeted observations will build understanding and ultimately improve forecasts of these sometimes damaging storms.

"Large nighttime thunderstorms are an essential source of summer rain for crops, but also produce widespread and potentially hazardous severe weather, excessive rainfall, flash flooding, and unusually frequent cloud-to-ground lightning," said Conrad Ziegler, a research meteorologist at the NOAA National Severe Storms Laboratory and principal scientist for PECAN. "Weather forecast models often struggle to accurately account for these. The PECAN field campaign will provide us with valuable insights—and improve our ability to save lives and property through more accurate forecasts.”

The PECAN field campaign will involve scientists, students, and support staff from eight research laboratories and 14 universities. The $13.5 million project is largely funded by the National Science Foundation (NSF), which contributed $10.6 million. Additional support is provided by NOAA, NASA, and the U.S. Department of Energy.

Once the sun goes down, the Earth and its lower atmosphere usually loses heat and becomes more stable, an environment not so favorable for supporting thunderstorms. In the Great Plains, however, many summer storms form after sunset, and sometimes without an obvious trigger.

PECAN scientists are interested in large complexes of thunderstorms called Mesoscale Convective Systems that can grow overnight, last for hours and often produce severe and hazardous weather. They will investigate how a low-level river of air triggers thunderstorms and supports storm evolution, what causes storms to grow into MCSs, and how MCSs respond to the surrounding environment.

In addition, PECAN researchers will test their hypotheses about how deep waves in the atmosphere form and ripple across the plains, like what happens with water when a stone is thrown in a pond, causing new storms to form after sunset. One type of atmospheric ripple is called a “bore.” Thunderstorms can create bores, but bores can also cause a thunderstorm to suddenly intensify. PECAN is the first modern campaign to study the role of bores and how they trigger and support Mesoscale Convective Systems.

More than 20 NOAA researchers and students will be responsible for gathering data with multiple instruments including the NOAA-X-Pol, a dual-pol mobile radar, two mobile balloon launch vehicles, and two “mobile mesonet” vehicles equipped with weather instruments. New to the fleet is the Collaborative Lower Atmosphere Mobile Profiling System (CLAMPS) designed by NSSL researchers to meet many of NOAA’s and its National Weather Service’s needs for lower atmosphere temperature, humidity and wind profiles. Additionally, one of the three aircraft participating in PECAN will be a NOAA Lockheed WP-3D Orion aircraft, best known for its hurricane hunting missions.

Unique to the experiment is an observation strategy that uses PECAN Integrated Sounding Array (PISA) stations to provide temperature, humidity, and wind profiles about every five minutes. The Department of Energy will provide six out of the eight ground-based upward-looking infrared spectrometer instruments. Dave Turner, NSSL scientist and PECAN steering committee member, will coordinate their operation.

The campaign is based in Hays, Kansas, and will begin each day at 8 a.m. CDT. A team of meteorologists, including retired forecasters from NOAA’s Storm Prediction Center, will work on a forecast for the upcoming night. At 3 p.m., scientists will use the forecast to determine where across northern Oklahoma, central Kansas, or south-central Nebraska to deploy their mobile resources. Teams will then ferry the instruments to the target area, set up, and collect data from dusk until after midnight. When the observation period is complete, they will ferry the instruments back to the base in Hays.

A better understanding of these storms will have relevance for areas beyond the Great Plains, because clustered nighttime thunderstorms are common in various regions scattered across the globe.

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<![CDATA[NOAA Scientists tackle mystery of nighttime thunderstorms]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=225http://www.nssl.noaa.gov/news/hotitems/display.php?id=225Wed, 20 May 15 00:00:00 -0500This summer, more than 20 NOAA scientists will stay up late to learn why some thunderstorms form and grow at night, without the energy from the sun's heat. They will be participating in the Plains Elevated Convection At Night (PECAN), a large, intensive field campaign to collect data before and during nighttime thunderstorms in the western Great Plains from June 1 to July 15.

PECAN researchers will deploy instrumented aircraft, ground-based instruments, mobile radars, and weather balloons to learn what triggers these storms, how the atmosphere supports their lifecycle, and how they impact lives, property, agriculture and the water budget in the region. Meteorologists believe these targeted observations will build understanding and ultimately improve forecasts of these sometimes damaging storms.

"Large nighttime thunderstorms are an essential source of summer rain for crops, but also produce widespread and potentially hazardous severe weather, excessive rainfall, flash flooding, and unusually frequent cloud-to-ground lightning," said Conrad Ziegler, a research meteorologist at the NOAA National Severe Storms Laboratory and principal scientist for PECAN. "Weather forecast models often struggle to accurately account for these. The PECAN field campaign will provide us with valuable insights—and improve our ability to save lives and property through more accurate forecasts.”

The PECAN field campaign will involve scientists, students, and support staff from eight research laboratories and 14 universities. The $13.5 million project is largely funded by the National Science Foundation (NSF), which contributed $10.6 million. Additional support is provided by NOAA, NASA, and the U.S. Department of Energy.

Once the sun goes down, the Earth and its lower atmosphere usually loses heat and becomes more stable, an environment not so favorable for supporting thunderstorms. In the Great Plains, however, many summer storms form after sunset, and sometimes without an obvious trigger.

PECAN scientists are interested in large complexes of thunderstorms called Mesoscale Convective Systems that can grow overnight, last for hours and often produce severe and hazardous weather. They will investigate how a low-level river of air triggers thunderstorms and supports storm evolution, what causes storms to grow into MCSs, and how MCSs respond to the surrounding environment.

In addition, PECAN researchers will test their hypotheses about how deep waves in the atmosphere form and ripple across the plains, like what happens with water when a stone is thrown in a pond, causing new storms to form after sunset. One type of atmospheric ripple is called a “bore.” Thunderstorms can create bores, but bores can also cause a thunderstorm to suddenly intensify. PECAN is the first modern campaign to study the role of bores and how they trigger and support Mesoscale Convective Systems.

More than 20 NOAA researchers and students will be responsible for gathering data with multiple instruments including the NOAA-X-Pol, a dual-pol mobile radar, two mobile balloon launch vehicles, and two “mobile mesonet” vehicles equipped with weather instruments. New to the fleet is the Collaborative Lower Atmosphere Mobile Profiling System (CLAMPS) designed by NSSL researchers to meet many of NOAA’s and its National Weather Service’s needs for lower atmosphere temperature, humidity and wind profiles. Additionally, one of the three aircraft participating in PECAN will be a NOAA Lockheed WP-3D Orion aircraft, best known for its hurricane hunting missions.

Unique to the experiment is an observation strategy that uses PECAN Integrated Sounding Array (PISA) stations to provide temperature, humidity, and wind profiles about every five minutes. The Department of Energy will provide six out of the eight ground-based upward-looking infrared spectrometer instruments. Dave Turner, NSSL scientist and PECAN steering committee member, will coordinate their operation.

The campaign is based in Hays, Kansas, and will begin each day at 8 a.m. CDT. A team of meteorologists, including retired forecasters from NOAA’s Storm Prediction Center, will work on a forecast for the upcoming night. At 3 p.m., scientists will use the forecast to determine where across northern Oklahoma, central Kansas, or south-central Nebraska to deploy their mobile resources. Teams will then ferry the instruments to the target area, set up, and collect data from dusk until after midnight. When the observation period is complete, they will ferry the instruments back to the base in Hays.

A better understanding of these storms will have relevance for areas beyond the Great Plains, because clustered nighttime thunderstorms are common in various regions scattered across the globe.

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<![CDATA[Scientists gather to talk about using Unmanned Aerial Systems for weather research]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=223http://www.nssl.noaa.gov/news/hotitems/display.php?id=223Mon, 11 May 15 00:00:00 -0500Unmanned Aerial Systems (UASs) are becoming increasingly important as instrument platforms for remote and in-situ observations of the atmosphere just above the ground. Their adaptability, potential ease of deployment, and low cost make them an attractive research option. NSSL scientists will participate in the annual meeting of the International Society on Atmospheric Research using Remotely-piloted Aircraft (ISARRA) in Norman, Oklahoma, May 20 to 22 to share knowledge about using these aircraft systems to observe and monitor the atmosphere.

Topics presented by NSSL include using UASs as part of a composite observing system for predicting the formation and evolution of severe convective storms, roles for UAS in the 2016 VORTEX-Southeast project, and ground radar support of UAS operations with Multi-function Phased Array Radar (MPAR).

Using UASs for research is a developing endeavor. A University of Colorado (CU) UAS team successfully probed the rear-flank downdraft of a tornadic supercell in northeast Colorado during the second Verification of the Origins of Rotation in Tornadoes Experiment in 2009. With NSSL support, in June 2013, a CU, University of Nebraska-Lincoln, and NSSL team flew a UAS in coordination with an NSSL mobile mesonet (vehicle with atmospheric instruments) to sample outflows from several supercells in northeast Colorado.

These interactions support the NOAA goal of investing in observational infrastructure, and NOAA’s science mission to understand and predict changes in climate, weather, oceans and coasts.

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<![CDATA[Forecasters to evaluate sets of advanced weather models that can depict thunderstorms]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=222http://www.nssl.noaa.gov/news/hotitems/display.php?id=222Wed, 22 Apr 15 00:00:00 -0500Experiments designed to improve National Weather Service severe weather forecasts will be conducted in the 2015 Spring Forecasting Experiment from May 4 through June 5, part of the NOAA Hazardous Weather Testbed (HWT) Experimental Forecast Program. The effort is a joint project between the Storm Prediction Center (SPC) and NSSL/CIMMS to support NOAA’s goal to evolve the National Weather Service and build a Weather-Ready Nation. The interactions between operational forecasters, model developers, and research scientists are critical for the effective transfer of operationally relevant guidance, tools, and techniques to operational forecasters.

Forecast teams will work with a number of sets of advanced weather computer models, called ensembles, that can depict thunderstorms (4km grid or less) to create experimental severe weather hazard outlooks valid over shorter periods (1-hr and 4-hr periods) than current SPC operational products. The outlooks will define the probability of a hazard occurring, the confidence in its path, and adjust to trends in the threat level based on new observations. These activities are foundational to the emerging FACETs vision and designed to link with initial Warn on Forecast activities conducted by the Experimental Warning Program. In addition, the predictability of severe weather hazards into Days 2 and 3 will be explored using these ultra-high-resolution forecast systems.

The HWT experiments support the NOAA mission of Science, Service, and Stewardship, in addition to providing information that will help communities be more resilient. HWT research will improve the nation’s forecasting and numerical weather prediction capabilities through collaborative efforts between the academic community and NSSL. The effort is highly relevant to NOAA’s goal to evolve the National Weather Service.

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<![CDATA[2015 Spring Warning Project will look at new severe weather warning guidance]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=221http://www.nssl.noaa.gov/news/hotitems/display.php?id=221Tue, 21 Apr 15 00:00:00 -0500Several experiments to improve National Weather Service severe weather warnings will be conducted this spring in the NOAA Hazardous Weather Testbed (HWT) as part of the annual Experimental Warning Program, a joint project of the National Weather Service and NSSL/CIMMS to support NOAA’s goal to evolve the National Weather Service and build a Weather-Ready Nation. The EWP’s Spring Warning Project will run from May 4 through June 12, and provides a conceptual framework and a physical space to foster collaboration between research and operations to test and evaluate emerging technologies and science.

Forecasters will evaluate an updated Lightning Jump Algorithm (LJA), based on the GOES-R Geostationary Lightning Mapper, that was enhanced based on feedback from forecasters participating in the 2014 program. In severe storms, rapid increases in lightning flash rate, or “lightning jumps,” typically precede severe weather such as tornadoes, hail, and straight line winds at the surface by tens of minutes. These evaluations will help prepare for possible operational implementation in 2016 following the launch of GOES-R.

Earth Networks’ total lightning and total lightning derived products, including storm-based flash rates tracks, time-series, and three levels of thunderstorm alerts will be evaluated in real time, building upon the initial evaluation in 2014. The 2015 evaluation will test the feasibility of use and performance under the stress of real-time warning operations.

A new set of high-resolution Weather Research and Forecasting (WRF) models will serve as a prototype for developing the “Warn-on-Forecast” warning paradigm. Feedback from this project will go into developing new model tools capable of managing the large amounts of model information associated with future forecast systems.

During three weeks of the experiment, forecasters will assess a new tool using rapidly-updating high-resolution gridded Probabilistic Hazard Information (PHI) as the basis for next-generation severe weather warnings. This experiment is part of a broad effort to revitalize the NWS watch/warning paradigm known as Forecasting a Continuum of Environmental Threats (FACETs). The major emphasis of the HWT PHI experiment will be on initial testing of concepts related to human-computer interaction while generating short-fused high-impact Probabilistic Hazard Information for severe weather. The long-term goal of this effort is to migrate the refined concepts and methodologies that result from this experiment into Hazard Services, the next generation warning tool for the NWS, for further testing and evaluation in the HWT prior to operational deployment.

This year will mark the inaugural HWT Experiment with Emergency Managers. The EMs will be provide feedback on their interpretation of experimental probabilistic forecasts generated in the HWT from the PHI experiment and the Experimental Forecast Program (EFP). This feedback will be used in conjunction with feedback from forecasters to refine how the uncertainty information is generated and disseminated.

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<![CDATA[CIMMS/NSSL researchers work to get West Texas lightning data in AWIPS in time for severe weather]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=220http://www.nssl.noaa.gov/news/hotitems/display.php?id=220Mon, 20 Apr 15 00:00:00 -0500For the past few weeks, Darrel Kingfield and Dr. Kristin Calhoun from CIMMS/NSSL and Dr. Eric Bruning from Texas Tech University have been working alongside forecasters from the National Weather Service (NWS) Forecast Office in Lubbock, Texas, to generate and integrate real-time 1km lightning products into the Advanced Weather Interactive Processing System-2 (AWIPS-2). AWIPS-2 is the weather forecasting, display and analysis package currently being used by the NWS. The team pushed hard to get these products functional for potential severe weather on April 16 and were successful.

Two products -- Flash Extent Density and Flash Initiation Density -- are gridded visualizations of total lightning data from Lightning Mapping Arrays (LMA). There are several arrays across the U.S. that are able to map the three-dimensional shape, extent and development of branched lightning channels. These data are an essential component of modern lightning detection and physics studies, because they reliably map the extent of the in-cloud charge reservoirs tapped by each lightning flash. Both of these products have been successfully evaluated in the Hazardous Weather Testbed.

A third product, the experimental Flash Area product from Texas Tech University, was also integrated into AWIPS-2. Forecasters have seen in the LMA data that small, compact flashes are mostly associated with robust or developing convection. As thunderstorms mature and reach the subsequent dissipation stage, the flash area starts to increase. The transfer of these products to operations will provide the developers, researchers and forecasters with the opportunity to learn more about how total lightning products can be utilized in the forecast and warning decision process.

This work benefits operational forecasters, highlights research to operations transitions, and supports NOAA’s work to evolve the National Weather Service. It also supports NSSL’s Grand Scientific Challenge to predict useful warnings of lightning activity one hour in advance.

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<![CDATA[NSSL/CIMMS scientist to brief NWS forecasters]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=219http://www.nssl.noaa.gov/news/hotitems/display.php?id=219Mon, 30 Mar 15 00:00:00 -0500Kristin Calhoun (NSSL/CIMMS) will give an invited webinar to National Weather Service meteorologists and hydrologists on April 1, 2015, about current lightning prediction products in research and development at NSSL. Calhoun will also discuss the NOAA Hazardous Weather Testbed (HWT) and how forecaster feedback is used to evaluate and refine the products.The webinar is part of a monthly series for NWS Science Operations Officers and Development and Operations Hydrologists that benefits operational forecasters, highlights research to operations transitions, and supports NOAA’s work to evolve the National Weather Service.

It has long been theorized, and in limited studies demonstrated, that the use of total lightning detections and associated derivative products could have positive impacts on the warning process for thunderstorm events. Two total lightning algorithms to potentially improve short-term prediction and warnings of severe storms have been evaluated in the Hazardous Weather Testbed (HWT) in Norman, Oklahoma.

In severe storms, rapid increases in lightning flash rate, or “lightning jumps,” typically precede severe weather, such as tornadoes, hail and straight line winds, at the surface by tens of minutes. The GOES-R Geostationary Lightning Mapper (GLM) will allow the use of continuous total lightning observations and the lightning jump concept operationally throughout the United States. A total lightning jump algorithm (LJA) that can be used by NWS forecasters to enhance situational awareness and diagnose convective trends was evaluated in the HWT as part of the experimental warning program in 2014 and will be evaluated again in 2015.

Earth Networks (ENI), a private company that provides lightning data and products, has indicated the potential for their total lightning data and “Dangerous Thunderstorm Alerts” to increase lead-time over current National Weather Service (NWS) severe weather and tornado warnings, while maintaining a similar probability of detection and false alarm ratio. This project integrates the ENI total lightning data and products into the NWS operational software and tests the feasibility of use and performance under the stress of real time warning operations.

In 2014, 18 NWS forecasters visited the HWT during a period of six weeks, 21 July-29 August, for a full product evaluation. The forecasters completed a series of six two hour weather-warning simulations of marginally severe storms to high-impact tornadic events throughout the United States. The 2015 HWT experiment will build upon the initial evaluation in 2014, including enhancements based on forecaster feedback.

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<![CDATA[Impacts of Phased Array Radar Data on Forecaster Performance during Severe Hail and Wind Events (Weather and Forecasting)]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=218http://www.nssl.noaa.gov/news/hotitems/display.php?id=218Tue, 17 Feb 15 00:00:00 -0600Early online release 1/13/15

Katie A. Bowden,1 Pamela L. Heinselman,2 Darrel M. Kingfield,1,2 and Rick P. Thomas3

Summary: Twelve National Weather Service (NWS) forecasters participated in the Phased Array Innovative Sensing Experiment (PARISE) 2013 and were assigned to either a control (5-min radar data updates) or experimental (1-min radar data updates) group. Each group worked a marginally severe hail event and a severe hail and wind event in simulated real-time. While working each event, participants made warning decisions regarding the detection, identification, and re-indentification of severe weather, now known as “the compound warning decision process.”

Important conclusions: The experimental group's performance exceeded that of the control group's, as demonstrated through their significantly longer median warning lead time, as well as superior probability of detection and false alarm ratio scores. The experimental group also had a larger proportion of mastery decisions (i.e., confident and correct) than the control group, possibly because of their enhanced ability to observe and track individual storm characteristics through the use of 1-min updates.

Significance: This work furthers efforts that have already been made to understand the impact of higher-temporal resolution radar data, as provided by PAR, on the warning decision process of NWS forecasters. The research questions, methodology, and analysis presented in this paper build upon the findings presented from earlier PARISE work, while also sharing findings that are of a new nature.

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<![CDATA[Multiple-Radar Multiple Sensor system developed at NSSL goes into NWS operations]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=216http://www.nssl.noaa.gov/news/hotitems/display.php?id=216Thu, 16 Oct 14 00:00:00 -0500Weather forecasters rely on an incredibly large amount of information when they make forecasts and issue warnings. A new system, activated by NOAA’s National Weather Service last week, quickly harnesses the tremendous amount of weather data from multiple sources, intelligently integrates the information, and provides a detailed picture of the current weather.

The Multiple Radar Multiple Sensor (MRMS) system combines data streams from multiple radars, satellites, surface observations, upper air observations, lightning reports, rain gauges and numerical weather prediction models to produce a suite of decision-support products every two minutes. Because it provides better depictions of high-impact weather events such as heavy rain, snow, hail, tornadoes, and other threats, forecasters can quickly diagnose severe weather and issue more accurate and earlier forecasts and warnings.

“MRMS uses a holistic approach to merging multiple data sources, allowing forecasters to better analyze data and potentially make better predictions,” said Ken Howard, a research meteorologist at NOAA’s National Severe Storms Laboratory who helped design MRMS. “It was developed in collaboration with NOAA’s National Weather Service hydrologists and forecasters who tested experimental versions and provided valuable input and feedback.”

Researchers at NOAA’s National Severe Storms Laboratory designed the MRMS system to improve decision making within NOAA and other agencies – marking another NOAA research to operations success. Implementation of the system into NWS operations was funded in part by the Disaster Relief Appropriations Act of 2013.

MRMS will improve the ability of forecasters to issue public warnings and advisories for severe weather such as tornadoes, hail and flash floods, and will help improve forecasts for safety of air traffic.

NSSL’s experimental version of the MRMS system has been available at various National Weather Service offices, but now that it is becoming operational, NOAA researchers plan to continue their collaboration with NOAA partners such as developers, trainers and forecasters to collect best practices and case studies. The system is designed so that new techniques and products can be added, increasing its capabilities.

“The nationally consistent products available from the MRMS are another important step toward NOAA’s goal of building a Weather Ready Nation by providing better analyses and forecasts to a wide range of decision makers,” said Louis Uccellini, Ph.D., director of NOAA’s National Weather Service. “This is another tool to help ensure communities are better prepared and more resilient in the face of high-impact weather events.”

MRMS data are also an input into the newly operational High-Resolution Rapid Refresh weather model, which will improve the quality of forecasts and warnings for severe weather events.

NOAA researchers developed the MRMS system in cooperation with The University of Oklahoma’s Cooperative Institute for Mesoscale Meteorological Studies.

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<![CDATA[NOAA study shows pattern of fewer days with tornadoes, but more tornadoes on those days]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=217http://www.nssl.noaa.gov/news/hotitems/display.php?id=217Thu, 16 Oct 14 00:00:00 -0500Are tornadoes increasing? Not really, the number has remained relatively constant. What is changing is that there are fewer days with tornadoes each year, but on those days there are more tornadoes, according to a NOAA report published today in the journal Science.

NOAA researchers looked at records of all but the weakest tornadoes in the United States from 1954 to 2013 for the study, “Increased variability of tornado occurrence in the United States.” They found that although there are fewer days with tornadoes, when a tornado does occur, there is increased likelihood there will be multiple tornadoes on that day. A consequence of this is that communities should expect an increased number of catastrophes, said lead author Harold Brooks, research meteorologist with the NOAA National Severe Storms Laboratory.

“Concentrating tornado damage on fewer days, but increasing the total damage on those days, has implications for people who respond, such as emergency managers and insurance interests,” Brooks said. “More resources will be needed to respond, but they won’t be used as often.”

Why tornadoes are concentrating on fewer days is still an open question, Brooks said. The pattern may be connected to changes in weather and climate. More research involving climate and tornado scientists is needed.

The study also showed there is greater variability in the starting date of spring tornado season, with more early starts and late starts in recent years. From 1954 to 1997, 95 percent of the time tornado season started between March 1 and April 20. But in the last 17 years, this happened only 41 percent of the time.

Researchers note tornadoes differ from tropical cyclones or hurricanes in the North Atlantic because tornadoes can occur year round. In fact, tornadoes have occurred in the U.S. on every calendar day at some point during the past 60 years.

Recent experience illustrates the study’s findings of variability. The study looked at tornadoes rated EF1 or higher on the Enhanced Fujita Scale, a measure of the damage caused by tornadoes with categories from EF0 to EF5. From June 2010 to May 2011, there were 1,050 EF1 and stronger tornadoes, the most in any 12-month period on record. Shortly after that, the U.S. saw the fewest in a 12-month period, only 236 EF1 and stronger tornadoes occurred from May 2012 to April 2013. November of 2012 had no EF1 tornadoes, but November of 2013 had the sixth most on record, with 66. There have been a relative low number of tornadoes to date in 2014, with an estimated 800 tornadoes of all intensities reported through September, almost 400 tornadoes below what is considered a normal year.

The study’s results are a first step toward understanding the relationship between changing tornado activity and a changing climate. The next step will be for climate scientists and tornado researchers to work together to identify what specific large scale pattern variations in climate may cause, or are related to, clustering of tornado activity.

Co-authors of the study are Gregory Carbin and Patrick Marsh with the NOAA’s National Weather Service Storm Prediction Center.

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<![CDATA[NSSL to host Unmanned Aerial Systems expert]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=215http://www.nssl.noaa.gov/news/hotitems/display.php?id=215Tue, 09 Sep 14 00:00:00 -0500Dr. Brian Argrow, Professor of Aerospace Engineering Sciences at the University of Colorado and an expert in Unmanned Aerial Systems (UAS), will temporarily join NSSL to conduct collaborative research and help advance NOAA and NSSL observational and research capabilities. The six-month sabbatical begins Sept. 15 and extends through December 2014.

Argrow’s University of Colorado and University of Nebraska-Lincoln research team was the first to intercept supercells with a UAS. The team successfully probed the rear-flank downdraft of a tornadic supercell in northeast Colorado during the second Verification of the Origins of Rotation in Tornadoes Experiment in 2009. With NSSL support, in June 2013, a CU/UNL/NSSL team supported by NSSL flew a UAS in coordination with an NSSL mobile mesonet (vehicle with atmospheric instruments) to sample outflows from several supercells in northeast Colorado. The data collected during the week-long Airdata Verification and Integration Airborne Tempest Experiment (AVIATE) identified needs for follow-on research in a number of areas.

Argrow plans to refine the measurement of inertial winds from a small UAS (sUAS) optimized for low cost and to return high-quality thermodynamic and wind data. He also hopes to explore deployment strategies for coordinated sUAS-Mobile Mesonet deployments, and revisit the Mobile Mesonet design, specifically to better characterize how the vehicle induces velocities in the local wind field.

Because of their adaptability, potential ease of deployment, and potential low cost, sUAS are becoming increasingly important as instrument platforms for remote and in-situ observations in the lower troposphere for NOAA’s mission “To understand and predict changes in climate, weather, oceans, and coasts….”

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<![CDATA[NSSL researcher lends expertise to Joplin tornado report]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=214http://www.nssl.noaa.gov/news/hotitems/display.php?id=214Fri, 05 Sep 14 00:00:00 -0500NSSL’s David Jorgensen was a member of the National Institute of Standards and Technology (NIST) study team that investigated the effects of the May 22, 2011 tornado in Joplin, Missouri. It was the first comprehensive study of tornado impacts under the auspices of the National Construction Safety Team Act, a law giving NIST the same powers to investigate building collapses as at the NTSB has with aircraft accidents.

The report describes the wind field of the tornado and how the wind pressures and windborne debris damaged and destroyed thousands of buildings; the emergency communications before and during the tornado and how the public responded; the influence of tornado hazards and public response and building and designated shelter area performance on survival and injury; and areas of current building and emergency communications codes, standards and practices that warrant revision.

The report outlines 47 findings and concludes with a list of 16 recommendations for action in areas of improved measurement and characterization of tornado hazards, new methods for tornado resistant design of buildings, enhanced guidance for community tornado sheltering, and improved and standardized emergency communications.

This work supports NOAA’s Weather-Ready Nation Goal: “Society is prepared for and responds to weather-related events,” and the Weather-Ready Nation Objective: “Reduced loss of life, property, and disruption from high-impact events.”

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<![CDATA[NSSL/CIMMS researchers to share cutting-edge radar research in Europe]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=213http://www.nssl.noaa.gov/news/hotitems/display.php?id=213Wed, 03 Sep 14 00:00:00 -0500Researchers from NSSL/CIMMS will share the latest radar research at the 8th European Conference on Radar in Meteorology and Hydrology September 1-5 in Garmisch-Partenkirchen, Germany.

Some of the topics to be presented include:

New techniques and algorithms that use output from a high-resolution weather model to predict precipitation types at the ground, and to identify the layer in the atmosphere where melting occurs

Observations made by a dual-pol data quality team during and after the dual-pol deployment process including observations of tornado debris, the descent of the snow level in Arizona, a smoke plume, and the interface of shallow and deep water over the ocean.

A new technique was demonstrated for WSR-88D and weather Phased Array Radar (PAR) that transmits a few radar pulses into different directions and simultaneously receives returns to shorten update time from 1 minute to 15 seconds

Whether super-resolution data produced by range-oversampling techniques help or hurt NEXRAD’s ability to detect tornadoes.

A dual-pol product that could aid in the detection of developing and evolving deep moist convection by locating and tracking thunderstorm updrafts

A range-based volume coverage pattern algorithm developed to improve vertical spatial resolution without sacrificing scan update times

Results from a study that asked a NWS forecaster, who issued warnings for a violent tornado event in central Oklahoma using WSR-88D data, to evaluate the same event using rapid-scanning Phased Array Radar data. The forecaster found PAR data proved most advantageous in instances of rapid storm organization, sudden mesocyclone intensification, and abrupt, short-term changes in tornado motion.

Overview of the NSSL Research to Operations (R2O) process, past scientific and engineering contributions, as well as current R2O activities in signal processing and polarimetric techniques.

The mission of ERAD2014 is to provide a platform for exchange between students, research scientists, radar operators, and end users of weather radar. It also provides an opportunity to transfer knowledge from research into operational use (and vice versa) of weather radar. The first ERAD conference was in Bologna, Italy in 2000.

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<![CDATA[Scientists study storm electricity in Florida]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=212http://www.nssl.noaa.gov/news/hotitems/display.php?id=212Wed, 06 Aug 14 00:00:00 -0500NSSL is wrapping up a three-week project to provide the first ever simultaneous measurements of the vertical structures of microphysics, electrical charge, and electric fields in Florida storms. The project is a collaboration with the International Center for Lightning Research and Testing (ICLRT) and the University of Oklahoma, funded by the Defense Advanced Research Projects Agency (DARPA) and the GOES-R program office.

During the project, NSSL is launching two balloon-borne instruments simultaneously into each targeted storm; one to measure in situ electric fields and one to measure the number, size, and type of precipitation particles along a vertical profile through the storm. The microphysics data from both balloons will be used to improve the microphysics schemes used in weather forecast models. Using OU’s mobile polarimetric radar, scientists are collecting additional data on the same storms to help evaluate and refine schemes for determining precipitation type from polarimetric radar measurements.

The microphysics measurements from the balloon-borne instruments will also be combined with lightning mapping and extensive ground-based triggered lightning measurements at the ICLRT to improve understanding of the storm processes that produce lightning.

These data will aid development of applications of lightning data from existing detection networks and from the planned GOES-R Geosynchronous Lightning Mapper.

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<![CDATA[Forecasters to test experimental lightning data]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=211http://www.nssl.noaa.gov/news/hotitems/display.php?id=211Thu, 17 Jul 14 00:00:00 -0500NOAA National Weather Service (NWS) forecasters will test how lightning data impacts the warning process during convective events in the NOAA Hazardous Weather Testbed from July 21-August 29. The project is a collaboration between NSSL and Earth Networks, Inc., a private weather company.

Earth Networks has indicated the potential for its continental scale total lightning network (ENTLN) data and associated “Dangerous Thunderstorm Alerts” (DTAs) to increase forecaster situational awareness and lead times. Prior limited studies have shown the use of total lightning detections and associated derivative products could have positive impacts on the warning process.

During the tests, Earth Networks lightning data and its DTA products will be implemented into NWS operational software (AWIPS2) in the NOAA Hazardous Weather Testbed. Forecasters will complete a series of weather-warning scenarios in displaced real time, ranging from marginally severe to high-impact tornadic events for a variety of geographic locations.

These tests will evaluate the feasibility of using this data in warning operations, as well as the impact on warnings issued by NWS forecasters. The final outcome of this project is to make recommendations on possible product improvements, and determine whether Earth Networks products should become part of the operational product suites available to NWS offices nationally.

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<![CDATA[NSSL researchers lead project to evaluate experimental flash flood products]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=210http://www.nssl.noaa.gov/news/hotitems/display.php?id=210Wed, 18 Jun 14 00:00:00 -0500A research team from NSSL is leading the NOAA Hazardous Weather Testbed - Hydro 2014 (HWT-hydro) project from July 7 - Aug. 1 to evaluate and improve experimental products used by the NOAA National Weather Service to issue flash flood watches and warnings. Participants include NOAA scientists, technology developers, and operational forecasters.

HWT-hydro will coordinate operations with the 2nd annual Flash Flood and Intense Rainfall experiment (FFaIR) at the NOAA/NWS Weather Prediction Center (WPC) to simulate the collaboration that occurs between the National Weather Service’s national centers, river forecast centers, and local forecast offices during flash flood events.

HWT-hydro and FFaIR will simulate the real-time workflow from WPC 6-24 hour forecast and guidance products to experimental flash flood watches and warnings issued in the 0-6 hour period. The HWT-hydro team will shift its area of responsibility on a daily basis to where heavy precipitation events and associated flash flooding is anticipated.

The specific goals of HWT-hydro 2014 are:
- Evaluate the operational utility of experimental observations of flash flooding from local storm reports, mPING (meteorological Phenomena Identification Near the Ground) citizen scientist reports, Severe Hazards Analysis and Verification Experiment (SHAVE) targeted observations from the public, and USGS streamflow observations for product validation
- Evaluate the relative skill of experimental flash flood monitoring and short-term prediction tools from NSSL’s Multiple Radar - Multiple Sensor (MRMS) system, and Flooded Locations And Simulated Hydrographs (FLASH) modeling network
- Determine the benefit of increasing lead time (vs. potential loss in spatial accuracy and magnitude) through the use of the High Resolution Rapid Refresh (HRRR) 0-6 hr precip forecasts as input to FLASH
- Explore the utility of experimental flash flood watches and warnings that communicate the probability of occurrence and the magnitude of the event
- Employ human factors research methods to determine “best practices” for using flash flood prediction tools in experimental watches/warning and optimizing their displays in AWIPS2
- Enhance collaboration across testbeds, and between the operational forecasting, research, and academic communities on the forecast challenges associated with short-term flash flood forecasting.

Researchers will collect feedback from NWS operational forecasters through comments during their shifts, live blogging, electronic surveys, and de-briefings. NWS feedback is critical for future development and eventual implementation of new applications, displays, and product concepts into AWIPS2 and other operational systems.

HWT-hydro 2014 provides a real-time environment to rapidly test the latest observational and modeling capabilities so they may be improved and optimized for transition to operational decision-making in the National Weather Service.

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<![CDATA[Lightning Experts from Around the World to Meet in Norman June 15-20]]>http://www.nssl.noaa.gov/news/hotitems/display.php?id=209http://www.nssl.noaa.gov/news/hotitems/display.php?id=209Fri, 13 Jun 14 00:00:00 -0500NORMAN, OKLA. – More than 200 national and international lightning experts have gathered this week in Norman, Oklahoma, for what organizers have called “the most important international conference on atmospheric electricity in the world.” Held every four years, the 2014 International Conference on Atmospheric Electricity is co-hosted by the NOAA National Severe Storms Laboratory and the University of Oklahoma’s College of Atmospheric and Geographic Sciences and features the latest research on lightning and other electrical phenomena in the atmosphere. NSSL researchers Don MacGorman and Ted Mansell are co-chairs of the event.

The conference, scheduled for June 15 through 20 at the National Center for Employee Development Conference Center, is supported by the International Union of Geodesy and Geophysics and the International Association of Meteorology and Atmospheric Sciences.

Research about a new instrument to be launched on the next weather satellite will be presented. This instrument will map where lightning occurs over both land and ocean in much of the hemisphere, including over the United States. Scientists are investigating how these new data can be used to improve the NOAA National Weather Service’s warnings and forecasts of hazardous weather.

Additional topics to be discussed include how thunderstorms become electrified; how storms initiate lightning flashes; what controls where lightning channels go; what influences which objects are struck by lightning; what processes affect the various kinds of discharges observed above storms, such as sprites, blue jets, and elves; and what causes the electric current that constantly flows through the atmosphere in fair weather.

Lightning experts have traveled from countries including England, France, Brazil, China, Russia, Poland and Japan. The last time the U.S. hosted was in 1999.

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