Ten deadly Ten deadly weather signsweather signs

Martin BabakhanMartin Babakhan

MeteorologistMeteorologist

Proactive Decision-Support for Severe Weather

?

?

?

What products do I use in what situation?

BE WEATHER-WISEBE WEATHER-WISE

Understanding and Understanding and recognising the recognising the following weather clues following weather clues will assist flight safety!will assist flight safety!

Towering Cumulus Towering Cumulus cloud.cloud.

Cumulonimbus.Cumulonimbus.Microburst.Microburst.Mammatus cloud.Mammatus cloud.Lens shaped cloud.Lens shaped cloud.

Funnel shaped cloud.Funnel shaped cloud.Virga.Virga.Anvil cloud.Anvil cloud.Castellatus cloud.Castellatus cloud.Super cells.Super cells.

11

TOWERING TOWERING CUMULUS CUMULUS

22CUMULONIMBUSCUMULONIMBUS

TOWERING CUMULUSTOWERING CUMULUS

FLANKING LINE OF STORMS - FLANKING LINE OF STORMS - GLADSTONE QLD.GLADSTONE QLD.

CumulusCumulus CluesClues

Keep at least Keep at least five nautical miles five nautical miles away from away from developing Cumulus/ large Cumulus.developing Cumulus/ large Cumulus.

Keep as far away as possible from Keep as far away as possible from Cumulonimbus because of hazards eg:-Cumulonimbus because of hazards eg:-

turbulence; wind shear and gust fronts [which turbulence; wind shear and gust fronts [which may exist quite some distance from the edge of may exist quite some distance from the edge of the cloud], and the cloud], and

microbursts (a strong concentrated downburst of microbursts (a strong concentrated downburst of cold air).cold air).

Clumulus cluesClumulus clues

Never try to outclimb a towering CU Never try to outclimb a towering CU or developing CB. Their growth or developing CB. Their growth may exceed you climb rate and you may exceed you climb rate and you may end up inside a storm cloud.may end up inside a storm cloud.

Avoid flying under the clear area Avoid flying under the clear area below the anvil, because of the below the anvil, because of the dangers presented by hail falling dangers presented by hail falling from the anvil.from the anvil.

33DOWNBURST DOWNBURST

&&MICROBURSTMICROBURST

DOWNBURSTDOWNBURST & &

MICROBURSTMICROBURST Wind squalls may also be generated by Wind squalls may also be generated by

downbursts.downbursts. Concentrated, severe downdraughts are Concentrated, severe downdraughts are

usually accompanied by a descending usually accompanied by a descending deluge of precipitation.deluge of precipitation.

These induce an outward [horizontal] These induce an outward [horizontal] burst of damaging wind at the surface burst of damaging wind at the surface which on a smaller scale is known as a which on a smaller scale is known as a microburst.microburst.

Outwardly curved rain shafts Outwardly curved rain shafts are a good sign of strong are a good sign of strong

downburst or microburst downburst or microburst winds and the steeper the angle winds and the steeper the angle the stronger the flow.the stronger the flow.

In the next slide, the rain curtain In the next slide, the rain curtain has a “foot” close to the ground.has a “foot” close to the ground.

Also note the rising rain or dust Also note the rising rain or dust well to the rightwell to the right!!

RAIN CURTAIN & MICROBURSTRAIN CURTAIN & MICROBURST

RAIN CURTAINRAIN CURTAIN Other clues of storm severity can be found Other clues of storm severity can be found

in the rain curtain:-in the rain curtain:- If it is dark & smooth [as previous & next If it is dark & smooth [as previous & next

slide], very heavy rain is likely.slide], very heavy rain is likely. Rainfall in severe storms will become Rainfall in severe storms will become

progressively heavier & sometimes mixed progressively heavier & sometimes mixed with hail. Weaker storms have patchy with hail. Weaker storms have patchy rainfall or short downpours.rainfall or short downpours.

Severe storms have multiple lightning boltsSevere storms have multiple lightning bolts..

VERY HEAVY RAIN CURTAIN VERY HEAVY RAIN CURTAIN & LIGHTNING& LIGHTNING

44MAMMATUS MAMMATUS

CLOUDCLOUD

Mammatus Mammatus are rounded pouches are rounded pouches or bulges which indicate descending or bulges which indicate descending pockets of small droplets or ice pockets of small droplets or ice crystals from an anvil surface.crystals from an anvil surface.

They can also be seen below middle They can also be seen below middle level cloud.level cloud.

They are associated with They are associated with severe severe turbulence.turbulence.

MAMMATUSMAMMATUS

55LENS LENS

SHAPED SHAPED CLOUDCLOUD

LENS SHAPED LENS SHAPED CLOUDSCLOUDS

When observed to the When observed to the leelee of a mountain of a mountain range they indicate mountain wave activity range they indicate mountain wave activity and and possible severe turbulence possible severe turbulence [especially [especially below the cloud].below the cloud].

StrongStrong wind flow over ranges gives rise to wind flow over ranges gives rise to downstream lee wave action.downstream lee wave action.

Mountain waves can also occur without lens Mountain waves can also occur without lens shaped clouds being present [shaped clouds being present [in dry air].in dry air].

66FUNNEL FUNNEL SHAPEDSHAPEDCLOUDCLOUD

TORNADOTORNADO The typical funnel shape of a The typical funnel shape of a

tornado is formed when tornado is formed when moist air moist air condenses condenses within the lower pressure within the lower pressure of the rotating column of air.of the rotating column of air.

Under Under relatively dry conditionsrelatively dry conditions, it , it may not form and the only evidence may not form and the only evidence of a tornado at the surface may be of a tornado at the surface may be indicated by a mass of debris [eg indicated by a mass of debris [eg dust].dust].

TYPICALTYPICAL

FUNNEL FUNNEL

SHAPESHAPEOF TORNADO.OF TORNADO.

NORTHAM W.A NORTHAM W.A

A A waterspoutwaterspout looks like a tornado, looks like a tornado, but occurs over water when cool but occurs over water when cool unstable air passes over warmer unstable air passes over warmer waters.waters.

Local topography etc allows Local topography etc allows local local convergence convergence of the air flow, which of the air flow, which results in vigorous updraughts results in vigorous updraughts “tightening up” into spinning columns.“tightening up” into spinning columns.

They mostly occur in late Summer & They mostly occur in late Summer & Autumn.Autumn.

WATERSPOUTSWATERSPOUTS

A A landspout landspout is formed when is formed when relatively cool air passes over relatively cool air passes over hot ground.hot ground.

In In the next slidethe next slide, note the , note the lack of anvil lack of anvil and the absence and the absence of any wall cloud associated of any wall cloud associated with the large cumulus cloud.with the large cumulus cloud.

LANDSPOUT - CLEVE S.ALANDSPOUT - CLEVE S.A

WALL CLOUDWALL CLOUD

A small cloud feature, particularly A small cloud feature, particularly valuable is assessing a storms severe valuable is assessing a storms severe potential, potential, beneath a rain free beneath a rain free cloud base cloud base can be found toward the rear of the can be found toward the rear of the storm.storm.

This localised cloud base lowering This localised cloud base lowering occurs at the site of the occurs at the site of the main, focused main, focused updraught updraught into the system.into the system.

WALL CLOUD WALL CLOUD BENEATH RAIN FREE STORMBENEATH RAIN FREE STORM

WALL CLOUDWALL CLOUD As a storm becomes As a storm becomes strongerstronger and and

develops an develops an organised infloworganised inflow, its main , its main updraught may begin to rotate slightly.updraught may begin to rotate slightly.

This can be seen as broad rotation of the This can be seen as broad rotation of the cloud base beneath the main updraught cloud base beneath the main updraught or in the circular nature of the wall or in the circular nature of the wall cloud.cloud.

In the Southern hemisphere viewed from In the Southern hemisphere viewed from a distance the rotation will be a distance the rotation will be clockwise.clockwise.

WALL CLOUD - ADELAIDEWALL CLOUD - ADELAIDE[ROTATING CLOUD BASE][ROTATING CLOUD BASE]

77VIRGAVIRGA

Virga, Virga, or rain which evaporates or rain which evaporates before reaching the ground, before reaching the ground, often looks like dark, tapered often looks like dark, tapered extensions below a cloud.extensions below a cloud.

It is diffuse and soft-edged.It is diffuse and soft-edged.

Be aware of possible Be aware of possible downdraughts.downdraughts.

VIRGAVIRGA

Supercell Visual CluesSupercell Visual Clues

Visual characteristics can be used to determine supercellsVisual characteristics can be used to determine supercells Anvils can indicate where the storm is moving and Anvils can indicate where the storm is moving and

possible the strength of the updraftpossible the strength of the updraft The direction of cirrues is being blown off is the general The direction of cirrues is being blown off is the general

direction of movementdirection of movement If the top is small, chance are the storm will be short-If the top is small, chance are the storm will be short-

lived.lived. If the top appears dome-like and lasts for a fairly long If the top appears dome-like and lasts for a fairly long

period of time, the supercell is more than likely severeperiod of time, the supercell is more than likely severe

88ANVILANVILCLOUDCLOUD

AN ANVILAN ANVIL Is the top of a thunderstorm cloud;Is the top of a thunderstorm cloud; It can reach up to a height of 10-16 It can reach up to a height of 10-16

kilometres [approx 32 - 52,000 ft];kilometres [approx 32 - 52,000 ft]; May appear to be “boiling” ,but more often May appear to be “boiling” ,but more often

has a fibrous, frozen appearance;has a fibrous, frozen appearance; It is primarily composed of It is primarily composed of ice crystals;ice crystals; The next slide The next slide shows a shows a crisp thunderstorm crisp thunderstorm

anvil anvil which is a good indicator of a which is a good indicator of a strong strong updraught updraught !!

THUNDERSTORM - ANVILTHUNDERSTORM - ANVIL

THE ANVILTHE ANVIL The anvil can indicate the age, The anvil can indicate the age,

strength & organisation of the strength & organisation of the thunderstorm.thunderstorm.

UnevennessUnevenness on the top indicates on the top indicates erratic growth, erratic growth, whilewhile

A A diffuse edge diffuse edge suggests suggests weak weak updraughts updraughts [a weaker system].[a weaker system].

TheThe next slide next slide is an example of a is an example of a weak, fibrous anvil from a non weak, fibrous anvil from a non severe storm.severe storm.

FIBROUS ANVILFIBROUS ANVIL

The top of the anvil is normally The top of the anvil is normally restricted by the restricted by the tropopausetropopause and and blown forward blown forward on strong winds on strong winds aloft .aloft .

When the main updraught is When the main updraught is very strong very strong a portion of the anvil a portion of the anvil may push upward above the may push upward above the general level into the general level into the stratosphere. This feature is stratosphere. This feature is known as an known as an overshooting top. overshooting top.

OVERSHOOTING ANVIL OVERSHOOTING ANVIL & BACK-SHEARED& BACK-SHEARED

SEVERE STORM ANVILSEVERE STORM ANVILWITH “NOTCHES” & WITH “NOTCHES” & OVERSHOOTING TOP.OVERSHOOTING TOP.

99CASTELLATUSCASTELLATUS

CLOUDCLOUD

Altocumulus Altocumulus castellatus:- an indicator castellatus:- an indicator of of instabilityinstability..

[[Note the separate Note the separate towers.towers.]]

ALTOCUMULUS CASTELLATUSALTOCUMULUS CASTELLATUS

1010SUPERSUPERCELLSCELLS

A SUPERCELLA SUPERCELLMaintains an Maintains an intenseintense steady state steady state

for many hours.for many hours.Is a Is a dangerousdangerous cloud complex cloud complex

and accounts for most of the and accounts for most of the seriousserious thunderstorm events. thunderstorm events.

NOTE the high, crisp anvil in NOTE the high, crisp anvil in the next slide, which indicates a the next slide, which indicates a very strong , sustained updraughtvery strong , sustained updraught

SUPERCELL STORMSUPERCELL STORMFISKVILLE VIC.FISKVILLE VIC.

Characteristics of severe storms

An An overshooting top overshooting top that is prominent and that is prominent and lasts for longer than several minutes.lasts for longer than several minutes.

a high anvil with a a high anvil with a crisp crisp edge; edge; a steep, almost vertical mass of a steep, almost vertical mass of boiling boiling

towers towers at the rear of the storm;at the rear of the storm; a tendency for the anvil toa tendency for the anvil to push back push back

against the prevailing winds [a back-against the prevailing winds [a back-sheared anvil].sheared anvil].

ISOLATED SEVERE STORM ISOLATED SEVERE STORM POINT LOOKOUT N.S.WPOINT LOOKOUT N.S.W

1111SUPERSUPERCELLSCELLS

FINALLYFINALLYREMEMBER TO CHECK FOR REMEMBER TO CHECK FOR

SEVERE SEVERE WEATHERWARNINGS.WEATHERWARNINGS.

The EndThe End