Introduction to Mesoscale Meteorology Overview
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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). -
Tornado Safety Q & A
TORNADO SAFETY Q & A The Prosper Fire Department Office of Emergency Management’s highest priority is ensuring the safety of all Prosper residents during a state of emergency. A tornado is one of the most violent storms that can rip through an area, striking quickly with little to no warning at all. Because the aftermath of a tornado can be devastating, preparing ahead of time is the best way to ensure you and your family’s safety. Please read the following questions about tornado safety, answered by Prosper Emergency Management Coordinator Kent Bauer. Q: During s evere weather, what does the Prosper Fire Department do? A: We monitor the weather alerts sent out by the National Weather Service. Because we are not meteorologists, we do not interpret any sort of storms or any sort of warnings. Instead, we pass along the information we receive from the National Weather Service to our residents through social media, storm sirens and Smart911 Rave weather warnings. Q: What does a Tornado Watch mean? A: Tornadoes are possible. Remain alert for approaching storms. Watch the sky and stay tuned to NOAA Weather Radio, commercial radio or television for information. Q: What does a Tornado Warning mean? A: A tornado has been sighted or indicated by weather radar and you need to take shelter immediately. Q: What is the reason for setting off the Outdoor Storm Sirens? A: To alert those who are outdoors that there is a tornado or another major storm event headed Prosper’s way, so seek shelter immediately. I f you are outside and you hear the sirens go off, do not call 9-1-1 to ask questions about the warning. -
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. -
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. -
Mesoscale Convective Vortex That Causes Tornado-Like Vortices Over the Sea: a Potential Risk to Maritime Traffic
JUNE 2019 T O C H I M O T O E T A L . 1989 Mesoscale Convective Vortex that Causes Tornado-Like Vortices over the Sea: A Potential Risk to Maritime Traffic EIGO TOCHIMOTO Atmosphere and Ocean Research Institute, The University of Tokyo, Tokyo, Japan SHO YOKOTA Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan HIROSHI NIINO Atmosphere and Ocean Research Institute, The University of Tokyo, Tokyo, Japan WATARU YANASE Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan (Manuscript received 24 August 2018, in final form 28 January 2019) ABSTRACT Strong gusty winds in a weak maritime extratropical cyclone (EC) over the Tsushima Strait in the south- western Sea of Japan capsized several fishing boats on 1 September 2015. A C-band Doppler radar recorded a spiral-shaped reflectivity pattern associated with a convective system and a Doppler velocity pattern of a vortex with a diameter of 30 km [meso-b-scale vortex (MBV)] near the location of the wreck. A high- resolution numerical simulation with horizontal grid interval of 50 m successfully reproduced the spiral- shaped precipitation pattern associated with the MBV and tornado-like strong vortices that had a maximum 2 wind speed exceeding 50 m s 1 and repeatedly developed in the MBV. The simulated MBV had a strong cyclonic circulation comparable to a mesocyclone in a supercell storm. Unlike mesocyclones associated with a supercell storm, however, its vorticity was largest near the surface and decreased monotonically with in- creasing height. The strong vorticity of the MBV near the surface originated from a horizontal shear line in the EC. -
Coniglio Et Al. (2006)
P1.30 FORECASTING THE SPEED AND LONGEVITY OF SEVERE MESOSCALE CONVECTIVE SYSTEMS Michael C. Coniglio∗1 and Stephen F. Corfidi2 1NOAA/National Severe Storms Laboratory, Norman, OK 2NOAA/Storm Prediction Center, Norman, OK 1. INTRODUCTION b. MCS maintenance Forecasting the details of mesoscale convective Predicting MCS maintenance is fraught with systems (MCSs) (Zipser 1982) continues to be a difficult challenges such as understanding how deep convection problem. Recent advances in numerical weather is sustained through system/environment interactions prediction models and computing power have allowed (Weisman and Rotunno 2004, Coniglio et al. 2004b, for explicit real-time prediction of MCSs over the past Coniglio et al. 2005), how pre-existing mesoscale few years, some of which have supported field features influence the system (Fritsch and Forbes 2001, programs (Davis et al. 2004) and collaborative Trier and Davis 2005), and how the disturbances experiments between researchers and forecasters at generated by the system itself can alter the system the Storm Prediction Center (SPC) (Kain et al. 2005). structure and longevity (Parker and Johnson 2004c). While these numerical forecasts of MCSs are promising, the utility of these forecasts and how to best use the From an observational perspective, Evans and capabilities of the high-resolution models in support of Doswell (2001) suggest that the strength of the mean operations is unclear, especially from the perspective of wind (0-6 km) and its effects on cold pool development the Storm Prediction Center (SPC) (Kain et al. 2005). and MCS motion play a significant role in sustaining Therefore, refining our knowledge of the interactions of long-lived forward-propagating MCSs that produce MCSs with their environment remains central to damaging surface winds (derechos) through modifying advancing our near-term ability to forecast MCSs. -
Morning Tornado / Waterspout Guide (1950-2020) (For North Central and Northeast Wisconsin)
MORNING TORNADO / WATERSPOUT GUIDE (1950-2020) (FOR NORTH CENTRAL AND NORTHEAST WISCONSIN) MORNING TORNADOES (MIDNIGHT TO NOON CST) UPDATED: 2/1/21 1 MORNING TORNADO / WATERSPOUT GUIDE (1950-2020) (FOR NORTH CENTRAL AND NORTHEAST WISCONSIN) MORNING TORNADOES (MIDNIGHT TO NOON CST) Event EF Date Time TOR in GRB Service Area # Rank Month Date Year (CST) Start / End Location County or Counties 1 2 6 20 1954 02:30-02:40 Rothschild - 6 NE Mosinee Marathon 2 2 6 20 1954 04:00 Brothertown Calumet 3 1 5 4 1959 10:30 Wausau Marathon 4 1 5 4 1959 11:45 Deerbrook Langlade 5 2 5 6 1959 03:20 Symco - 3 SE Clintonville Outagamie - Waupaca 6 2 9 3 1961 00:10 Fenwood Marathon 7 1 9 3 1961 01:00 Athens Marathon 8 1 7 1 1967 00:45 3 E Kiel Manitowoc 9 2 6 30 1968 04:00 3 NW Cavour Forest 10 1 6 30 1968 04:45 3 S Pembine Marinette 11 1 12 1 1970 07:00 Hull Portage 12 2 12 1 1970 09:00 12 SE Marshfield Wood 13 2 12 1 1970 09:45-10:30 4 NW Iola - Pella Shawano - Langlade - Oconto 14 3 12 1 1970 10:10-1045 near Medina - Rose Lawn Outagamie - Shawano 15 1 7 8 1971 02:00 Wisconsin Rapids Wood 16 0 7 30 1971 07:00 4 E Oshkosh (waterspout) Winnebago 17 1 3 11 1973 10:30 2 E Calumetville Calumet 18 1 6 18 1973 11:00 2 W Athens Marathon 19 1 7 12 1973 03:00 Boulder Junction - Sayner Vilas 20 1 7 12 1973 07:30 Jacksonport Door 21 1 7 12 1973 08:00 4 W Freedom Outagamie 22 2 6 16 1979 09:30 Oconto Falls - 2 NE Lena Oconto 23 1 8 4 1979 10:00 Manitowoc Manitowoc 24 2 6 7 1980 00:20 Valders Manitowoc 25 1 7 5 1980 00:30 Valders Manitowoc 26 2 4 4 1981 00:35 4 W Kiel -
ESSENTIALS of METEOROLOGY (7Th Ed.) GLOSSARY
ESSENTIALS OF METEOROLOGY (7th ed.) GLOSSARY Chapter 1 Aerosols Tiny suspended solid particles (dust, smoke, etc.) or liquid droplets that enter the atmosphere from either natural or human (anthropogenic) sources, such as the burning of fossil fuels. Sulfur-containing fossil fuels, such as coal, produce sulfate aerosols. Air density The ratio of the mass of a substance to the volume occupied by it. Air density is usually expressed as g/cm3 or kg/m3. Also See Density. Air pressure The pressure exerted by the mass of air above a given point, usually expressed in millibars (mb), inches of (atmospheric mercury (Hg) or in hectopascals (hPa). pressure) Atmosphere The envelope of gases that surround a planet and are held to it by the planet's gravitational attraction. The earth's atmosphere is mainly nitrogen and oxygen. Carbon dioxide (CO2) A colorless, odorless gas whose concentration is about 0.039 percent (390 ppm) in a volume of air near sea level. It is a selective absorber of infrared radiation and, consequently, it is important in the earth's atmospheric greenhouse effect. Solid CO2 is called dry ice. Climate The accumulation of daily and seasonal weather events over a long period of time. Front The transition zone between two distinct air masses. Hurricane A tropical cyclone having winds in excess of 64 knots (74 mi/hr). Ionosphere An electrified region of the upper atmosphere where fairly large concentrations of ions and free electrons exist. Lapse rate The rate at which an atmospheric variable (usually temperature) decreases with height. (See Environmental lapse rate.) Mesosphere The atmospheric layer between the stratosphere and the thermosphere. -
Tornadogenesis in a Simulated Mesovortex Within a Mesoscale Convective System
3372 JOURNAL OF THE ATMOSPHERIC SCIENCES VOLUME 69 Tornadogenesis in a Simulated Mesovortex within a Mesoscale Convective System ALEXANDER D. SCHENKMAN,MING XUE, AND ALAN SHAPIRO Center for Analysis and Prediction of Storms, and School of Meteorology, University of Oklahoma, Norman, Oklahoma (Manuscript received 3 February 2012, in final form 23 April 2012) ABSTRACT The Advanced Regional Prediction System (ARPS) is used to simulate a tornadic mesovortex with the aim of understanding the associated tornadogenesis processes. The mesovortex was one of two tornadic meso- vortices spawned by a mesoscale convective system (MCS) that traversed southwestern and central Okla- homa on 8–9 May 2007. The simulation used 100-m horizontal grid spacing, and is nested within two outer grids with 400-m and 2-km grid spacing, respectively. Both outer grids assimilate radar, upper-air, and surface observations via 5-min three-dimensional variational data assimilation (3DVAR) cycles. The 100-m grid is initialized from a 40-min forecast on the 400-m grid. Results from the 100-m simulation provide a detailed picture of the development of a mesovortex that produces a submesovortex-scale tornado-like vortex (TLV). Closer examination of the genesis of the TLV suggests that a strong low-level updraft is critical in converging and amplifying vertical vorticity associated with the mesovortex. Vertical cross sections and backward trajectory analyses from this low-level updraft reveal that the updraft is the upward branch of a strong rotor that forms just northwest of the simulated TLV. The horizontal vorticity in this rotor originates in the near-surface inflow and is caused by surface friction. -
Central Region Technical Attachment 95-08 Examination of an Apparent
CRH SSD APRIL 1995 CENTRAL REGION TECHNICAL ATTACHMENT 95-08 EXAMINATION OF AN APPARENT LANDSPOUT IN THE EASTERN BLACK HILLS OF WESTERN SOUTH DAKOTA David L. Hintz1 and Matthew J. Bunkers National Weather Service Office Rapid City, South Dakota 1. Abstract On June 29, 1994, an apparent landspout occurred in the Black Hills of South Dakota. This landspout exhibited most of the features characteristic of traditional landspouts documented in eastern Colorado. The landspout lasted 3 to 8 minutes, had a width of less than 20 m and a path of 1 to 3 km, produced estimated wind speeds of Fl intensity (33 to 50 m s1), and emanated from a towering cumulus (TCU) cloud located along a quasi-stationary convergencq/cyclonic shear zone. No radar echo was observed with this event; however, a supercell thunderstorm was located 80-100 km to the east. National Weather Service meteorologists surveyed the “very localized” damage area and ruled out the possibility of the landspout being related to microburst, gustnado, or dust devil activity, as winds away from the landspout were less than 3 m s1. The landspout apparently “detached” from the parent TCU and damaged a farm which resulted in $1,000 dollars in expenses. 2. Introduction During the late 1980’s and early 1990’s researchers documented a phe nomenon with subtle differences from traditional tornadoes and waterspouts, herein referred to as the landspout (Seargent 1994; Brady and Szoke 1988, 1989; Bluestein 1985). The term “landspout” was actually coined by Bluestein (I985)(in the formal literature) when he observed this type of vortex along an Oklahoma squall line. -
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. -
Quasi-Linear Convective System Mesovorticies and Tornadoes
Quasi-Linear Convective System Mesovorticies and Tornadoes RYAN ALLISS & MATT HOFFMAN Meteorology Program, Iowa State University, Ames ABSTRACT Quasi-linear convective system are a common occurance in the spring and summer months and with them come the risk of them producing mesovorticies. These mesovorticies are small and compact and can cause isolated and concentrated areas of damage from high winds and in some cases can produce weak tornadoes. This paper analyzes how and when QLCSs and mesovorticies develop, how to identify a mesovortex using various tools from radar, and finally a look at how common is it for a QLCS to put spawn a tornado across the United States. 1. Introduction Quasi-linear convective systems, or squall lines, are a line of thunderstorms that are Supercells have always been most feared oriented linearly. Sometimes, these lines of when it has come to tornadoes and as they intense thunderstorms can feature a bowed out should be. However, quasi-linear convective systems can also cause tornadoes. Squall lines and bow echoes are also known to cause tornadoes as well as other forms of severe weather such as high winds, hail, and microbursts. These are powerful systems that can travel for hours and hundreds of miles, but the worst part is tornadoes in QLCSs are hard to forecast and can be highly dangerous for the public. Often times the supercells within the QLCS cause tornadoes to become rain wrapped, which are tornadoes that are surrounded by rain making them hard to see with the naked eye. This is why understanding QLCSs and how they can produce mesovortices that are capable of producing tornadoes is essential to forecasting these tornadic events that can be highly dangerous.