CH.14 Thunderstorms, Tornadoes
PP מזוודות P
Thunderstorms testimated 45,000 storms develop each day. til milion a year. Emost develop in Hopical regions tmast in southeastern states in U.S. thighest frequency in Florida Life cycle of ordinary storm sé i Cumulus Stage a 2. Mature Stage 3. Dissipating stage o cumulus Stage tinitial developing) stage Honly updrafts exist. tin flux of cool, dry air surrounding the cloud
We also discuss several other topics like Who founded the oxygen theory of combustion?
called entrainment takes place tentrainment intensifies the docendrafts
Mature stage tintense stageof the storm + begins when precipaton starts totall tuparats belime oiganized and strong Hupdrafts and downdrafts exist side by side If you want to learn more check out Who is the mathematician assistant of tycho brahe?
We also discuss several other topics like In common, how many girls will present in the beginning?
osissipation stages tupdrafts begin to weaken and collapse
Ilater, doundrafis dominate the cloud de caso types of thunderstorms
1. Ordinary Cell Thunderstorms 2. Multicell Thunderstorms
- Mesoscale Convective complexes (MCCs) 6- Squall-Line Thunderstorms
3. Supercell Thunderstorms
Stues soup We also discuss several other topics like Who is the daughter of epimetheus and pandora?
o Ordinary cell Thunderstorms Hair mass thunderstorms - widely scattered summerstorms short-lived, does not produce severe weather o serere thunderstorms produce one or more Don't forget about the age old question of What do you call a different form of a gene, a variation?
of the following: a thau llinch in diameter or larger) ttornadoes twind gusts (68mph or greater) + Filted-updrafts downdrafts + gust front- boundary between dense, cold downdrafts and warm updrafts... -strong localized doundrafts are called downbursts. Adounburst sless than 4 km 12. miles) wide beneath an intense thunderstorm are called microbursts. Lo greater than 4 km are called macrobursts tmost severe storms are associated with Cold fronts and hurricanes. If you want to learn more check out What kind of disorder is very critical to others but very sensitive to criticism?
• Multicell thunderstorms - thunderstorms that consist of multiple Convective cells, each one in different stage of development torganized in clusters are called mesoscale
connective complexes (MCCS) - Mesoscale complexes
- large, circular convective system -1000 times larger than ordinary cell. can cover entire state (Fig.14.19)
- Squall Line thunderstorms - a line of intense thunderstorms that form
alonga coid front or out ahead of it (Fig. 14.13)
Supercell Thunderstorms talarge, long lasting thunderstorm with a
singie violenty rotating updraft. (Fig.14.21) tproduce
Theavy rain large hail high surface winds highly damaging tornadoes
extreme downbursts. bronditionsleading to formation of supercell
thunderstorms. (Fig 14-23)
December 4, 2015 Tornadoes talso called twisters -offsprings of thunderstorms
typical tornadoes 300-
20ooft. in diameter average length of a tornado path. 4 miles Tornado occurrence tus; highest frequency (see handout) d Conditions leading to formation of tornadoes
i. Warm, moist air on surface 2. Cold, dry air at about 10,000 ft. 3. Approaching cold front bo tornado Alley for tornado belt
Region of most tornado frequency (Fig.14.4 Tornado Alley Region in us F Central Plains region Hover Mississippi and the Alabama i called
Dixie Alley thighest frequency: (oklonoma)
• Tornadoes in us toccor each month +75% occur March - July -highest occurrence : May
oTornado Development -begins with development of a mesocyclone -"vertical column(updraft) of air that rotates within a severe thinderstorm" o stages in Tornado Formation
1. First mesocyclone is wider, shorter, rotating slowly 2. Mesócucione stretches vertically and narrows 13. Mesocyclone stretches downwards to cloud bar
- "Resembles a sink full of water as it accelerate When it spirals down a drain
4. wall cioud develops lan area that protrudes beneatha cloud base) ti Tornado watch is issued when wall cloud is spotted." 5. wall cloud develops into a funnel cloud - A tornado warning is issued when a
funnel cloud is spotted ...
• Modified (FF) Fujita scale tenhanced fupitaintensity scale. Scale MI/HR
Thunderstorms: Self-Extinguishing vs. Self-Propagating
Developing (cumulus) stage
Figure 11-4 The cumulus (a), mature (b), and dissipative (C) stages of an air mass thunderstorm. [Adapted from Gedzelman, The Science and Wonders of the Atmosphere, © 1980, Wiley, Inc., New York, NY]
November 30, 2015
Thunderstorms: Self-Extinguishing vs. Self-Propagating
0 20 40
Figure 11-9 Squall line thunderstorms require the presence of wind shear. The arrows in (a) represent the wind speeds with respect to the movement of the storm. The movement of the air within the cumulonimbus is shown in (b). The upper part of the cloud is pushed forward more rapidly than the lower part, which helps to draw in warm, moist air. Note the gust front near the ground ahead of the rain shaft. [Adapted from Wallace and Hobbs, Atmospheric Science, An Introductory Survey, © 1977, Academic Press, New York, NY]
X Tornadoes Per Year Per 10,000 Square Miles
0.9 2.0) 0.67
8 0.8/1.53 2.6
5.2 13.934 2.1 2.6 S
7.5 Į 39 LT
Figure 10.2. (a) Black dots mark the regions of the world that typically experience at least several tornadoes a year. The number listed beside some countries represents the annual frequency of tornadoes per 10,000 mi?; (b) A state-by state breakdown of the reported annual frequency of tornadoes per 10,000 mi?, based on data from 1953–90 (courtesy of Greg Forbes).
75.0/4.2 | 3.4
THE TORNADO-THUNDERSTORM CONNECTION
FIGURE 14.5 Features of a severe thunderstorm that spawns a tornado. [From J. T. Snow, “The Tornado,” Scien tific American 250, No. 4 (1984):91. George V. Kelvin Sci ence Graphics; copyright © 1984 by Scientific American, Inc. All rights reserved.]
December 2, 2015
CHAPTER 11 Lightning, Thunder, and Tornadoes
Tropic of Cancer
Tropic of Capricom
· FIGURE 11-34 Tornadoes Around the Globe. The areas of greatest dot concentration correspond to those of greatest tornado frequency
GEO 211 EARTH'S DYNAMIC WEATHER STUDY GUIDE - EXAM 5 (FINAL).
Chapter 11. Air Masses and Fronts. What is an Air Mass? Know air masses that affect weather in North America. Know their source and their characteristics.
What are Fronts? How do they form? What weather characteristics are associated with each front? Review Tables 11. 2, 11.3, and 11. 4. Review Figures associated with air masses and fronts.
Chapter 12. Middle-Latitude Cyclones. Where do Mid-Latitude Cyclones Tend to form? Review the idealized life cycle of a Mid-Latitude Cyclone in the
Chapter 15. Tropical Cyclones. What are Tropical Cyclones? Where do they Form? How do they compare with Mid-Latitude Cyclones? How do Tropical Cyclones Form? Describe stages of development of Tropical Cyclones. Describe the Anatomy of Tropical Cyclones. What the damage-potential scale of Tropical Cyclones?
Chapter 14. Thunderstorms and Tornadoes. What atmospheric conditions lead to the formation of thunderstorms? Where does the highest frequency of thunderstorms occur in US? Why
there? Describe stages of development of ordinary thunderstorms. Describe types of thunderstorms and their weather characteristics. Describe atmospheric conditions at the surface and aloft necessary for the
development of most supercell thunderstorms. How do Tornadoes form? What are stages in their development? Know the tornado occurrence and distribution in US and world wide. Why is the central part of the United States more susceptible to tornadoes? How does tornado watch differ from a tornado warning? What is the “Tornado Ally”? Know the scale for damaging tornado winds.
REVIEW ALL WE HAVE COVERED IN CLASS.
EXAM DATE: TUESDAY, DECEMBER 8, 2015.
7:50 AM - 9:50 AM.