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1
HAZARDS
Wind shear Turbulence Icing Lightning Hail
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WIND SHEARTURBULENCE
CATBLOWOFF
ROLL CLOUD
WIND SHEARTURBULENCE
FIRSTGUST
TURBULENCE and WIND SHEAR
55-10 mi(8-16 km)
HEIGHT, (Ft)
HEIGHT, (km)
GUST FRONT
DOWNBURST
APPROACH PROFILE
RUNWAY
GUST FRONT
Cb
Cb
STORM DIRECTION
ROLL CLOUD
Clear or possibly wind blown dust within turbulent air.
Up to 10 miles.
First gust, windshear turbulence, and rapid wind changes up to about 6000’ A.G. L.
Up to 100 Kts 150 ft. A.G.L.
LIGHTNING STRIKE
Copyright Robert A. Prentice, 1992
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Low and Mid Level Moisture
High Humidity
Unstable Heat rises Moisture Condenses
into clouds as air rises Common with Low
Pressure Systems Stable
Air sinks Commons with High
Pressure Systems
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Warm /Cold Fronts Thunderstorm Outflow Boundaries
Lake Breezes
Varying degrees of the 3 main elements will affect strength of thunderstorms
Additional ingredients that affect strength of thunderstorms include Wind Shear Location of Jet Streams Large Scale Weather Pattern
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Cumulus Mature Dissipation
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Rising currents of air are referred to as an Updraft. When combined with sufficient moisture, towering cumulus clouds develop.
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19Copyright Charles A. Doswell, III
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Photo courtesy of Michael BathAustraliasevereweather.com
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Photo courtesy of Michael BathAustraliaweather.com
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Photo courtesy of Jimmy DeguaraAustraliasevereweather.com
Fair Weather Cumulus – Not Enough Instability or Lift to Generate Thunderstorms
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Photo courtesy of Jimmy DeguaraAustraliasevereweather.com
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Photo courtesy of Jimmy DeguaraAustraliasevereweather.com
Moisture will condense out of the cloud causing rain, thunder, and lightning. This marks the Mature Stage of the thunderstorms when the updraft and downdraft co-exist together.
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27Copyright Marty Feely, 1990
The updraft will eventually overcome the downdraft, causing the thunderstorm to weaken. The thunderstorm is now in the Dissipation Stage.
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Single Cell Multicell Cluster Linear Multicel (Squall Line) Supercell
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SINGLE CELL
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Multi Cell Cluster
38Copyright Alan R. Moller
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Multi Cell Linear
DRY AIR INFLOW
MOTION OF STORM
GUST FRONTWARM AIR INFLOW
COLD AIR OUTFLOW
FAST-MOVING CELLS
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Multicell line: shelf cloudMulticell line: shelf cloud
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SUPERCELL THUNDERSTORM
SWSW NENEPRECIPITATION-FREE BASEPRECIPITATION-FREE BASE WALL CLOUDWALL CLOUD PRECIPITATIONPRECIPITATION
CLOUD BASE STRIATIONSSHELF CLOUD
CUMULONIMBUS
MAMMATUSCLOUD
ANVIL
OVERSHOOTINGTOP
FLANKING LINE
SOUTHWEST WEST NORTHWEST
Super Cell
VERTICAL WIND SHEARS
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Supercells – upper level featuresSupercells – upper level features
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Supercells – mid level featuresSupercells – mid level features
Main storm tower
Flanking line
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Low Level Jet
N SStable
Unstable
Occur to the north of a surface warm front.
Most common type of thunderstorms from late fall through the winter.
Common at night during the spring and summer.
Biggest hazards are heavy rainfall and hail.
Strong wind gusts are usually infrequent due to the stable layer near the ground.
Typically occur in multi cell clusters. Widespread flooding events are usually
caused by these systems.
National Convective Weather Forecast Radar CCFP (Collaborative Convective Forecast
Product) 2, 4, 6 hour forecasts
Center Weather Advisories and Meteorological Impact Statements
Watch/Warning Map Severe Weather Products
Mesoscale Discussions Day 1, 2 and 3 convective outlooks
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THE END