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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