Summer/Fall 1997 a Newsletter About the Employees and Activities of the National Severe Storms Laboratory
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NSSL Briefings Volume 2 No. 1 Summer/Fall 1997 A newsletter about the employees and activities of the National Severe Storms Laboratory Left box: Observed frontal location, modeled rainfall 0000 U TC 27 April during1991 the past hour (green), and observed severe reports (tornado as an inverted triangle; severe wind as a +; hail as a dot) Right box: Model parameters used 00 to determine likelihood of tornadic thunderstorms overlaid on a single figure. Region where tornadic 56 thunderstorms are most likely indicated by the color- filled sections in the right box that overlap where rainfall is simulated in the left box. 118 59 than the movement of the thunderstorm, the 39 raindrops produced in the storm updraft get blown 2 73 away from the storm, and the cooling effect of the 74 87 rain has little effect on the storm evolution. In 10 contrast, when the winds in the atmosphere are much slower than the movement of the thunder- storm, the raindrops all fall very close to the center of the storm, cooling the air near the ground and Forecasting producing very strong outflow. In between these two extremes, the winds in the atmosphere are tornadic roughly equal to the movement of the thunder- storm, and just the right amount of rainfall reaches the ground near the center of the storm. In this thunderstorms case, the cooling effect of the rain can be used to help generate rotation in the thunderstorm at levels by Dave Stensrud and Harold Brooks near the ground surface. This increases the likelihood of tornado formation. This conceptual perational forecasters are very good at model was developed by Brooks et al. (1994) by identifying days when severe weather examining numerical simulations of thunderstorms Ooccurs across large regions of the country. but also appears in our mesoscale model simula- In Brief..... It is more of a challenge, however, to determine tions of outbreak days. whether these days will be dominated by tornadic Three parameters are used to help determine State of NSSL 2 thunderstorms or non-tornadic thunderstorms. whether or not tornadic thunderstorms are pos- This difficulty is related to our general lack of sible. One is a measure of the positive buoyant Employees understanding of the processes that form torna- of the Year 3 energy available to a storm (Convective Available does. Potential Energy - CAPE), another is a parameter JMRF 4 The National Severe Storms Laboratory (NSSL) that has been used to forecast the rotational is exploring this operational forecast problem characteristics of thunderstorms (Storm-Relative Spotlight: using a mesoscale numerical weather prediction John Cortinas 6 Environmental Helicity - SREH), and the third a model. We have been examining hourly output measure of the wind shear over the lowest 6 km of FASTEX update 7 from a number of model simulations to determine the atmosphere (bulk Richardson number shear - whether or not any signal exists that would help BRNSHR), which is closely related to the storm- WDSS and AWIPS 8 forecasters determine whether or not tornadic relative wind. When these parameters all fall into Chaff suppression 9 thunderstorms are likely. a specified range, tornadic supercell thunderstorms Model results indicate that we can discriminate are more likely than non-tornadic supercell Glidersonde 10 between days with tornadic and non-tornadic thunderstorms (see figure). This conceptual model thunderstorms. The key parameter needed to Forecast evaluation 11 is presently being used by forecasters at the Storm answer this question is the storm-relative wind. Prediction Center (SPC) to help provide improved MRAD 12 When the winds in the atmosphere are much faster severe weather guidance to the nation. u Page 1 NSSL Briefings Summer/Fall 1997 On the state of NSSL by Jeff Kimpel, Director s promised in the last issue of NSSL Modernization serves us well. New national Briefings, I wish to take this opportunity priorities in natural hazards prediction, A to report on the health of NSSL and to reduction and mitigation offer excellent share with you my impressions of the strategic opportunities for the future. Historically, issues facing the Lab. I have been meeting weekly NSSL’s mission has been to conduct basic and with the NSSL Management Team, consulted with applied research focused on severe weather. many others, and believe this column reasonably Within that mission, major goals now include: reflects the consensus view. improved understanding of severe weather NSSL is a healthy organization. It has grown producing systems, improving and evaluating It is important rapidly in the last five years from a $7M, 90- mesoscale models, building and supporting employee laboratory to an $11M, 120-employee observational facilities for field studies that we laboratory. This was accomplished while our true (Doppler radars, mobile laboratories), maintain our base funding and federal workforce declined. developing applications and systems, and niche and Thus, recent growth can be attributed to NSSL’s transferring that technology to the NWS and continuously ability to capitalize on opportunities to attract one- other operational environments. Future adjust as time and project-oriented funding for basic initiatives under the NOAA and natural research, applications, and technology transfer hazards umbrella may include: present work. This trend is likely to continue in the lhydrometeorology as a follow-on to initiatives foreseeable future, and NSSL is in an excellent dual-polarization radar, conclude and position in terms of niche. lcross-mesoscale model evaluation and new Given the uncertainty in the external environ- ensemble forecasting, opportunities ment, it is important that we maintain our niche l making the Joint Mobile Research and continuously adjust as present initiatives Facility a national resource, arise conclude and new opportunities arise. In recent lexploring socio-economic and health years NSSL has successfully expanded its research aspects of severe weather including heat and development efforts to include severe winter and cold waves, weather and weather in complex terrain. To l transferring technology into the private improve our responsiveness in this new environ- sector via systems and tool kits, and ment we must: lmitigating weather hazards. l retain and recruit an excellent workforce, The strength of NSSL lies in its people. l further develop our infrastructure, including Their willingness to seek new opportunities, state-of-the-art telecommunication, network collaborate with others in joint ventures, and and computer resources, and field observing emphasize customer service while enduring facilities, less-than- adequate workspace is extraordi- l diversify our funding sources, and nary. This “can do” attitude is responsible for l form alliances with other organizations. the reinvention of NSSL over the last decade NOAA's strategic goal of advancing short-term and the success it enjoys presently. NSSL is warnings and forecasts coupled with the NWS healthy. Its future is bright. u OAR Employees of the Year very year the Oceanic and Atmospheric Program, and the Environmental Research Research (OAR) Committee presents its Laboratories (ERL). This year, two of the recipi- EEmployee of the Year Awards to recognize ents are from NSSL. They were honored in a OAR employees for "significant contributions to ceremony in Washington D.C., and are pictured on OAR programs and exceptional and sustained the next page with Elbert W. "Joe" Friday, assistant effort towards accomplishment of the OAR administrator for OAR (pictured left) and Alan mission." The programs and laboratories under Thomas, deputy assistant administrator (pictured the OAR umbrella include: the National Undersea right). Research Program, the National Sea Grant College (continued on next page) Page 2 Summer/Fall 1997 NSSL Briefings Doug Forsyth, Deputy Director, has NSSL News Briefs been honored with the Employee of the Year OAR Outstanding Scientific Award for his service as Paper award recognizes NSSL Assistant and Deputy scientists Director (1990-present), Harold Brooks and Chuck Doswell were temporary Acting awarded the "Outstanding Scientific Paper" Director (late 1996-early Award for "The Role of Midtropospheric 1997), and ex-officio Winds in the Evolution and Maintenance of Director of NSSL for Low-Level Mesocyclones," Monthly four and one-half years Weather Review (1994) 17 December 1996. due to medical emergencies affecting the permanent Director and his family. Bob Davies-Jones and Harold Brooks were Doug's nominating letter stated, "Mr. Forsyth's dedication to the employees of also recognized with the 1996 ERL Outstand- NSSL and to the ERL/OAR mission during this extended period of time, often ing Scientific Paper Award for "Meso- at great personal sacrifice, is nothing short of heroic." Doug's skilled leader- cyclogenesis from a Theoretical Perspective," ship contributed greatly in helping NSSL advance in many ways over the past Geophysical Monograph (1993). seven years. A few of these accomplishments included: the start-up of the $1.6M re-host project for the WSR-88D Radar Product Generator and Radar Data Acquisition System, the move of the SPC into the NSSL facility and the Scientists make first dual- establishment of a close working relationship with the SPC, the planning and Doppler tornado intercept execution of the very successful VORTEX field program, and increased A team of NSSL, Cooperative Institute for interaction with NSSL's primary customer, the NWS. Also, during this period, Mesoscale