Central Region Technical Attachment 95-08 Examination of an Apparent
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A Study of Synoptic-Scale Tornado Regimes
Garner, J. M., 2013: A study of synoptic-scale tornado regimes. Electronic J. Severe Storms Meteor., 8 (3), 1–25. A Study of Synoptic-Scale Tornado Regimes JONATHAN M. GARNER NOAA/NWS/Storm Prediction Center, Norman, OK (Submitted 21 November 2012; in final form 06 August 2013) ABSTRACT The significant tornado parameter (STP) has been used by severe-thunderstorm forecasters since 2003 to identify environments favoring development of strong to violent tornadoes. The STP and its individual components of mixed-layer (ML) CAPE, 0–6-km bulk wind difference (BWD), 0–1-km storm-relative helicity (SRH), and ML lifted condensation level (LCL) have been calculated here using archived surface objective analysis data, and then examined during the period 2003−2010 over the central and eastern United States. These components then were compared and contrasted in order to distinguish between environmental characteristics analyzed for three different synoptic-cyclone regimes that produced significantly tornadic supercells: cold fronts, warm fronts, and drylines. Results show that MLCAPE contributes strongly to the dryline significant-tornado environment, while it was less pronounced in cold- frontal significant-tornado regimes. The 0–6-km BWD was found to contribute equally to all three significant tornado regimes, while 0–1-km SRH more strongly contributed to the cold-frontal significant- tornado environment than for the warm-frontal and dryline regimes. –––––––––––––––––––––––– 1. Background and motivation As detailed in Hobbs et al. (1996), synoptic- scale cyclones that foster tornado development Parameter-based and pattern-recognition evolve with time as they emerge over the central forecast techniques have been essential and eastern contiguous United States (hereafter, components of anticipating tornadoes in the CONUS). -
Tornadoes & Funnel Clouds Fake Tornado
NOAA’s National Weather Service Basic Concepts of Severe Storm Spotting 2009 – Rusty Kapela Milwaukee/Sullivan weather.gov/milwaukee Housekeeping Duties • How many new spotters? - if this is your first spotter class & you intend to be a spotter – please raise your hands. • A basic spotter class slide set & an advanced spotter slide set can be found on the Storm Spotter Page on the Milwaukee/Sullivan web site (handout). • Utilize search engines and You Tube to find storm videos and other material. Class Agenda • 1) Why we are here • 2) National Weather Service Structure & Role • 3) Role of Spotters • 4) Types of reports needed from spotters • 5) Thunderstorm structure • 6) Shelf clouds & rotating wall clouds • 7) You earn your “Learner’s Permit” Thunderstorm Structure Those two cloud features you were wondering about… Storm Movement Shelf Cloud Rotating Wall Cloud Rain, Hail, Downburst winds Tornadoes & Funnel Clouds Fake Tornado It’s not rotating & no damage! Let’s Get Started! Video Why are we here? Parsons Manufacturing 120-140 employees inside July 13, 2004 Roanoke, IL Storm shelters F4 Tornado – no injuries or deaths. They have trained spotters with 2-way radios Why Are We Here? National Weather Service’s role – Issue warnings & provide training Spotter’s role – Provide ground-truth reports and observations We need (more) spotters!! National Weather Service Structure & Role • Federal Government • Department of Commerce • National Oceanic & Atmospheric Administration • National Weather Service 122 Field Offices, 6 Regional, 13 River Forecast Centers, Headquarters, other specialty centers Mission – issue forecasts and warnings to minimize the loss of life & property National Weather Service Forecast Office - Milwaukee/Sullivan Watch/Warning responsibility for 20 counties in southeast and south- central Wisconsin. -
The Lagrange Torando During Vortex2. Part Ii: Photogrammetry Analysis of the Tornado Combined with Dual-Doppler Radar Data
6.3 THE LAGRANGE TORANDO DURING VORTEX2. PART II: PHOTOGRAMMETRY ANALYSIS OF THE TORNADO COMBINED WITH DUAL-DOPPLER RADAR DATA Nolan T. Atkins*, Roger M. Wakimoto#, Anthony McGee*, Rachel Ducharme*, and Joshua Wurman+ *Lyndon State College #National Center for Atmospheric Research +Center for Severe Weather Research Lyndonville, VT 05851 Boulder, CO 80305 Boulder, CO 80305 1. INTRODUCTION studies, however, that have related the velocity and reflectivity features observed in the radar data to Over the years, mobile ground-based and air- the visual characteristics of the condensation fun- borne Doppler radars have collected high-resolu- nel, debris cloud, and attendant surface damage tion data within the hook region of supercell (e.g., Bluestein et al. 1993, 1197, 204, 2007a&b; thunderstorms (e.g., Bluestein et al. 1993, 1997, Wakimoto et al. 2003; Rasmussen and Straka 2004, 2007a&b; Wurman and Gill 2000; Alexander 2007). and Wurman 2005; Wurman et al. 2007b&c). This paper is the second in a series that pre- These studies have revealed details of the low- sents analyses of a tornado that formed near level winds in and around tornadoes along with LaGrange, WY on 5 June 2009 during the Verifica- radar reflectivity features such as weak echo holes tion on the Origins of Rotation in Tornadoes Exper- and multiple high-reflectivity rings. There are few iment (VORTEX 2). VORTEX 2 (Wurman et al. 5 June, 2009 KCYS 88D 2002 UTC 2102 UTC 2202 UTC dBZ - 0.5° 100 Chugwater 100 50 75 Chugwater 75 330° 25 Goshen Co. 25 km 300° 50 Goshen Co. 25 60° KCYS 30° 30° 50 80 270° 10 25 40 55 dBZ 70 -45 -30 -15 0 15 30 45 ms-1 Fig. -
Art Directable Tornadoes
ART DIRECTABLE TORNADOES A Thesis by RAVINDRA DWIVEDI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2011 Major Subject: Visualization Art Directable Tornadoes Copyright 2011 Ravindra Dwivedi ART DIRECTABLE TORNADOES A Thesis by RAVINDRA DWIVEDI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Vinod Srinivasan Committee Members, John Keyser Wei Yan Head of Department, Tim McLaughlin May 2011 Major Subject: Visualization iii ABSTRACT Art Directable Tornadoes. (May 2011) Ravindra Dwivedi, B.E., Rajiv Gandhi Proudyogiki Vishwavidyalaya Chair of Advisory Committee: Dr. Vinod Srinivasan Tornado simulations in the visual effects industry have always been an interesting problem. Developing tools to provide more control over such effects is an important and challenging task. Current methods to achieve these effects use either particle systems or fluid simulation. Particle systems give a lot of control over the simulation but do not take into account the fluid characteristics of tornadoes. The other method which involves fluid simulation models the fluid behavior accurately but does not give control over the simulation. In this thesis, a novel method to model tornado behavior is presented. A tool based on this method was also created. The method proposed in this thesis uses a hybrid approach that combines the flexibility of particle systems while producing interesting swirling motions inherent in the fluids. The main focus of the research is on providing easy-to-use controls for art directors to help them achieve the desired look of the simulation effectively. -
June 18, 2017 Landspout Tornadoes
June 18, 2017 Landspout Tornadoes During the evening hours of Sunday, June 18, thunderstorms developed in the vicinity of a cold front over Reagan and Upton Counties.As a result of intense heating and an incredible amount of instability along this boundary, three EF0 landspout* (see definitionat bottom of report) tornadoes touched down in Reagan and southeast Upton Counties between 7 and 8 pm CDT. These tornadoes occurred in open country and no damage was reported. Tornado #1 – EF0: Southwest Reagan County to Southeast Upton County (~7:05-7:13 pm CDT) The first thunderstorm developed around 6:00 pm near Big Lake, TX and slowly moved west along and near US Hwy 67. Law enforcement officersand folks in the area viewed and took images of a tornado that developed 1-2 miles south of US Hwy 67 roughly 14 miles east of Big Lake and continued westward through open fields insouth east portions of Upton County. The tornado was narrow, perhaps 50-75 yards in width and no damage was reported with this tornado. Photo by Maybell Carrasco Photo by Greg Romero Tornado #2 – EF0: Central Reagan Photo by Shanna Gibson County (~8:00 pm CDT) Another thunderstorm moving west, entered eastern Reagan County around 7:30 pm. As this storm approached Big Lake, a second tornado was spotted around 8 pm roughly 6-7 miles northeast of Big Lake, 2-3 miles east of SH 137. This tornado was very short-lived and went undetected on radar. It occurred in open country and no damage was reported. Tornado #3 – EF0: Northeast Reagan County – approximately 20-25 miles north of Big Lake. -
Employing the WSR-88D for Waterspout Forecasting
Employing the WSR-88D for Waterspout Forecasting Scott M. Spratt LT (jg) Barry K. Choy, NOAA Corps National Weather Service Melbourne, Florida 1. Introduction Waterspouts and weak coastal tornadoes or "landspouts" (hereafter referred to collectively as "spouts") account for much of Florida's severe weather during the "wet season" (Schmocker et al. 1990). The Melbourne NEXRAD Weather Service Office (NWSO) County Warning Area (CWA) includes 160 miles of coastline along the east central Florida peninsula. Within this area, spouts are most frequent from June through September (Fig. 1). In the past, warnings were issued for spouts only after reports of visual sightings were received. This delay was likely due to the seemingly benign atmospheric conditions in which spouts develop, combined with a lack of pronounced severe weather signatures on conventional radars. However, recent research utilizing the NWSO MLB WSR- 88D may now help forecasters warn for spouts prior to receiving visual reports. A preliminary forecast strategy was developed based on post analyses of archived WSR- 88D products and regional upper-air data from reported spout days (Choy and Spratt 1994). This strategy has proved useful by providing additional lead time for spout events. This paper will identify specific atmospheric conditions which have been observed to precede spout generations along the east central Florida coast. A unique WSR-88D Routine Product Set (RPS) list will be shown which can be implemented once these conditions become satisfied. Finally, case studies of two recent events will be illustrated to help familiarize WSR-88D users with the environmental conditions and radar signatures often evident prior to and during spout events. -
Observed Cyclone–Anticyclone Tropopause Vortex Asymmetries
JANUARY 2005 H A K I M A N D CANAVAN 231 Observed Cyclone–Anticyclone Tropopause Vortex Asymmetries GREGORY J. HAKIM AND AMELIA K. CANAVAN University of Washington, Seattle, Washington (Manuscript received 30 September 2003, in final form 28 June 2004) ABSTRACT Relatively little is known about coherent vortices near the extratropical tropopause, even with regard to basic facts about their frequency of occurrence, longevity, and structure. This study addresses these issues through an objective census of observed tropopause vortices. The authors test a hypothesis regarding vortex-merger asymmetry where cyclone pairs are repelled and anticyclone pairs are attracted by divergent flow due to frontogenesis. Emphasis is placed on arctic vortices, where jet stream influences are weaker, in order to facilitate comparisons with earlier idealized numerical simulations. Results show that arctic cyclones are more numerous, persistent, and stronger than arctic anticyclones. An average of 15 cyclonic vortices and 11 anticyclonic vortices are observed per month, with maximum frequency of occurrence for cyclones (anticyclones) during winter (summer). There are are about 47% more cyclones than anticyclones that survive at least 4 days, and for longer lifetimes, 1-day survival probabilities are nearly constant at 65% for cyclones, and 55% for anticyclones. Mean tropopause potential-temperature amplitude is 13 K for cyclones and 11 K for anticyclones, with cyclones exhibiting a greater tail toward larger values. An analysis of close-proximity vortex pairs reveals divergence between cyclones and convergence be- tween anticyclones. This result agrees qualitatively with previous idealized numerical simulations, although it is unclear to what extent the divergent circulations regulate vortex asymmetries. -
The Unnamed Atlantic Tropical Storms of 1970
944 MONTHLY WEATHER REVIEW Vol. 99, No. 12 UDC 551.515.23:661.507.35!2:551.607.362.2(261) “1970.08-.lo” THE UNNAMED ATLANTIC TROPICAL STORMS OF 1970 DAVID B. SPIEGLER Allied Research Associates, Inc., Concord, Mass. ABSTRACT A detailed analysis of conventional and aircraft reconnaissance data and satellite pictures for two unnamed Atlantic Ocean cyclones during 1970 indicates that the stqrms were of tropical nature and were probably of at least minimal hurricane intensity for part of their life history. Prior to becoming a hurricane, one of the storms exhibited characteristics not typical of any of the recognized classical cyclone types [i.e., tropical, extratropical, and subtropical (Kona)]. The implications of this are discussed and the concept of semitropical cyclones as a separate cyclone category is advanced. 6. INTRODUCTION ing recognition of hybrid-type storms provides additional support for the recommendation. During the 1970 tropical cyclone season, tn7o storms occurred that were not given names at the time. The 2. UNNAMED STORM NO. I-AUG. Q3-$8, 6970 National Hurricane Center (NHC) monitored their prog- ress and issued bulletins throughout their life history but A mell-organized tropical disturbance noted on satellite they mere not officially recognized as tropical cyclones of pictures during August 8, south of the Cape Verde Islands tropical storm or hurricane intensity. In their annual post- in the far eastern tropical Atlantic, intensified to ti strong season summary of the hurricane season, NHC discusses depression as it moved westmarcl. On Thursday, August 13, these storms in some detail (Simpson and Pelissier 1971) some further intensification of the system appeared to be but thej- are not presently included in the official list of taking place while the depression was about 250 mi 1970 tropical storms. -
Skip Talbot Photography by Jennifer Brindley
STORM SPOTTING Skip Talbot SECRETS Photography by Jennifer Brindley Ubl and others Topics • Supercell Visualization • Radar Presentation • Structure Identification • Storm Properties • Walk Through Disclaimers • Attend spotter training • Your safety is more important than spotting, photos, video, or tornado reports Supercell Visualization Lemon and Doswell 1979 Supercell Visualization Supercell Visualization Photo: Chris Gullikson Supercell Visualization Photo: Chris Gullikson Anvil Anvil Backshear Mammatus Cumulonimbus Flanking Line Cloud Base Striations Precipitation Wall Cloud Precipitation-free Base Supercell Visualization Radar Presentation Classic Hook Echo Radar Presentation Android / iOS Android Windows GrLevel3 / GrLevel2 Radar Presentation Classic Hook Echo Radar Presentation Radar Presentation Radar Presentation Radar Presentation Storm Spotting Zoo • Bear’s Cage • Whale’s Mouth • Beaver Tail • Horseshoe • Ghost Train Base (Updraft Base) (Rain Free Base or RFB) Base (Updraft Base) (Rain Free Base or RFB) Base (Updraft Base) (Rain Free Base or RFB) Base (Updraft Base) (Rain Free Base or RFB) Base (Updraft Base) (Rain Free Base or RFB) Base (Updraft Base) (Rain Free Base or RFB) Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe Horseshoe - Cyclical supercell with multiple tornadoes HorseshoeHorseshoe HorseshoeHorseshoe Horseshoe Horseshoe – Anticyclonic Funnel Horseshoe Horseshoe – Anticyclonic Funnel Horseshoe - No Wall Cloud Horseshoe - No Wall Cloud -
Meteorology – Lecture 19
Meteorology – Lecture 19 Robert Fovell [email protected] 1 Important notes • These slides show some figures and videos prepared by Robert G. Fovell (RGF) for his “Meteorology” course, published by The Great Courses (TGC). Unless otherwise identified, they were created by RGF. • In some cases, the figures employed in the course video are different from what I present here, but these were the figures I provided to TGC at the time the course was taped. • These figures are intended to supplement the videos, in order to facilitate understanding of the concepts discussed in the course. These slide shows cannot, and are not intended to, replace the course itself and are not expected to be understandable in isolation. • Accordingly, these presentations do not represent a summary of each lecture, and neither do they contain each lecture’s full content. 2 Animations linked in the PowerPoint version of these slides may also be found here: http://people.atmos.ucla.edu/fovell/meteo/ 3 Mesoscale convective systems (MCSs) and drylines 4 This map shows a dryline that formed in Texas during April 2000. The dryline is indicated by unfilled half-circles in orange, pointing at the more moist air. We see little T contrast but very large TD change. Dew points drop from 68F to 29F -- huge decrease in humidity 5 Animation 6 Supercell thunderstorms 7 The secret ingredient for supercells is large amounts of vertical wind shear. CAPE is necessary but sufficient shear is essential. It is shear that makes the difference between an ordinary multicellular thunderstorm and the rotating supercell. The shear implies rotation. -
Doppler Radar Observations of Anticyclonic Tornadoes in Cyclonically Rotating, Right-Moving Supercells
APRIL 2016 B L U E S T E I N E T A L . 1591 Doppler Radar Observations of Anticyclonic Tornadoes in Cyclonically Rotating, Right-Moving Supercells HOWARD B. BLUESTEIN School of Meteorology, University of Oklahoma, Norman, Oklahoma MICHAEL M. FRENCH School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York JEFFREY C. SNYDER Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, and NOAA/OAR National Severe Storms Laboratory, Norman, Oklahoma JANA B. HOUSER Department of Geography, Ohio University, Athens, Ohio (Manuscript received 31 August 2015, in final form 27 January 2016) ABSTRACT Supercells dominated by mesocyclones, which tend to propagate to the right of the tropospheric pressure- weighted mean wind, on rare occasions produce anticyclonic tornadoes at the trailing end of the rear-flank gust front. More frequently, mesoanticyclones are found at this location, most of which do not spawn any tornadoes. In this paper, four cases are discussed in which the formation of anticyclonic tornadoes was documented in the plains by mobile or fixed-site Doppler radars. These brief case studies include the analysis of Doppler radar data for tornadoes at the following dates and locations: 1) 24 April 2006, near El Reno, Oklahoma; 2) 23 May 2008, near Ellis, Kansas; 3) 18 March 2012, near Willow, Oklahoma; and 4) 31 May 2013, near El Reno, Oklahoma. Three of these tornadoes were also documented photographically. In all of these cases, a strong mesocyclone (i.e., vortex signature characterized by azimuthal shear in excess of ;5 3 2 2 2 10 3 s 1 or a 20 m s 1 change in Doppler velocity over 5 km) or tornado was observed ;10 km away from the anticyclonic tornado. -
Severe Weather Forecasting Tip Sheet: WFO Louisville
Severe Weather Forecasting Tip Sheet: WFO Louisville Vertical Wind Shear & SRH Tornadic Supercells 0-6 km bulk shear > 40 kts – supercells Unstable warm sector air mass, with well-defined warm and cold fronts (i.e., strong extratropical cyclone) 0-6 km bulk shear 20-35 kts – organized multicells Strong mid and upper-level jet observed to dive southward into upper-level shortwave trough, then 0-6 km bulk shear < 10-20 kts – disorganized multicells rapidly exit the trough and cross into the warm sector air mass. 0-8 km bulk shear > 52 kts – long-lived supercells Pronounced upper-level divergence occurs on the nose and exit region of the jet. 0-3 km bulk shear > 30-40 kts – bowing thunderstorms A low-level jet forms in response to upper-level jet, which increases northward flux of moisture. SRH Intense northwest-southwest upper-level flow/strong southerly low-level flow creates a wind profile which 0-3 km SRH > 150 m2 s-2 = updraft rotation becomes more likely 2 -2 is very conducive for supercell development. Storms often exhibit rapid development along cold front, 0-3 km SRH > 300-400 m s = rotating updrafts and supercell development likely dryline, or pre-frontal convergence axis, and then move east into warm sector. BOTH 2 -2 Most intense tornadic supercells often occur in close proximity to where upper-level jet intersects low- 0-6 km shear < 35 kts with 0-3 km SRH > 150 m s – brief rotation but not persistent level jet, although tornadic supercells can occur north and south of upper jet as well.