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Weather 14th Annual Hot Air Balloon Safety Seminar PowerPoint PPT Presentation


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Weather 14th Annual Hot Air Balloon Safety Seminar. Rick Davis Senior Meteorologist National Weather Service - Tampa Bay Area. Observing the Weather. ASOS - Automated Surface Observing System. Wind Direction and Speed. Pressure measured at the Tower or other location nearby.

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Weather 14th annual hot air balloon safety seminar

Weather

14th Annual Hot Air Balloon Safety Seminar

Rick Davis

Senior Meteorologist

National Weather Service - Tampa Bay Area


Observing the weather

Observing the Weather

ASOS - Automated Surface Observing System

Wind Direction and Speed

Pressure measured at the Tower or other location nearby.

Precip type and intensity

Visibility

Temp & Dew Point

Data Unit

Rain


Weather 14th annual hot air balloon safety seminar

ASOS

Facts and Figures

  • 569 FAA sponsored sites

  • 313 NWS sponsored sites

  • Provides nonstop weather info, updating every minute if needed

  • Computer generated voice broadcasts gives pilots updates critical to safe landings

    • Using FAA VHF ground-to-air radio or appended to ATIS broadcast

  • Information is also available through the phone or on the internet


Weather 14th annual hot air balloon safety seminar

AWOS

Automated Weather Observing System

  • AWOSs cost about $94,000 and are much less expensive than ASOSs

  • Who owns them

    • Federal AWOSs are maintained by the FAA

    • Most AWOSs are owned and maintained by states, airports, or other local interest

  • There are three main types of AWOSs

    • AWOS I - temp, dew point, pressure, wind, density altitude

    • AWOS II - adds visibility

    • AWOS III - adds cloud information

      • AWOS IIIp - adds precipitation type sensor


Asos awos locations

ASOS/AWOS Locations

Florida


Decoding metars

Decoding METARs

Winter Observations

METAR KTPA 101955Z 33015G22KT 1/2SM FG VV002 19/19 A2955

RMK A02 PK WND 32035/1915 TWR VIS 3/4 SLP028 P0004 T01920188

Temp = 19.2 C

Dew = 18.8 C

00.04" rain in last hour

Sea level pressure 1002.8 MB

Tower visibility 3/4 mile

Peak wind northwest at 35kts at 1915Z

Automated precipitation reporting

Remarks


Aviation forecasts tafs twebs

Aviation ForecastsTafs/Twebs

From NWS in Ruskin

KFMY

KRSW


Decoding taf forecasts

Decoding TAF Forecasts

Some Insights

TAF AMD

KFMY 141542Z 141612 33030G40KT 2SM RA B KN010

TEMPO 1618 32035G44KT 3/4SM +TSRA SQ BKN008 OVC015CB

FM1800 32025G32KT P6SM BKN020

TEMPO 1821 ....

- Most detail is in first 12 hours, generalized outlook after 12 hours

- Issued four times a day at 06Z, 12Z, 18Z, and 00Z

- Format of each forecast group is wind, weather, clouds

- Naming of present weather has a strong French influence

- GR is hail >1/4 inch

- GS is hail < 1/4 inch

- FU is smoke


Weather balloons

Weather Balloons

The Radiosonde

  • Launched at the same time across the world (11Z & 23Z)

  • Rises 1000 feet per minute

  • Reaches 90,000 ft in 1.5 hours

  • Balloon expands to 35 feet before exploding

  • Measures:

    • Temperature

    • Dew Point

    • Wind direction and speed

    • Pressure


Radiosonde data

Radiosonde Data

Station Map and Data Plot


Doppler radar

Doppler Radar


Doppler vad wind profiles

Doppler VAD Wind Profiles

Velocity Azimuth Display


General winds

General Winds

  • Large-scale winds caused by the pressure patterns associated with high and low pressure areas.


Fronts instability

Fronts & Instability

IR satellite image overlaid with radar and fronts


Wind flow associated with pressure systems and fronts

Wind Flow Associated With Pressure Systems and Fronts

  • Wind direction ahead of an approaching low pressure system and cold front will generally be southerly. Wind Speed will normally increase ahead of approaching systems.

  • Wind direction behind a cold front and low pressure system will become northerly. Wind speed will normally be stronger just behind the front, then will slowly decrease.


Sources of lift

Sources of Lift

Fronts and Low Pressure Systems

L

H

70s

60s

80s

Cold air weighs more than warm air


Local winds

Local Winds

  • Smaller-scale winds caused by local temperature differences.


Seabreezes

Seabreezes

  • During a clear day. . . sunshine heats the land to a greater extent than the water.

  • Warm air over the land rises and is replaced by cooler, moister, marine air.


Sea breezes cont d

Sea Breezes (cont’d)

  • An area experiencing a sea breeze will see:

  • A temperature decrease 5-7o F.

  • An RH increase of 10-15 %.

  • A possible change in wind speed and direction.

  • Thunderstorms in unstable air.


Weather 14th annual hot air balloon safety seminar

Localized Thermals

cumulus cloud that

may form due to rising air reaching dewpoint

Cooler Sinking

Air

Bubble of

Warm Air


Air motion

Air Motion

Stability = Vertical Motion

Wind = Horizontal Motion


Wind shear

Wind Shear

  • Two Types of Wind Shear

  • Directional Shear - Wind direction varies with height.

  • Speed Shear – Wind speed significantly increases with height.

  • BOTH ARE IMPORTANT TO AVIATION!!!


Instability

Instability

Parcel Theory

  • A parcel is a small bag of air (size of cubic foot)

  • Acts like a hot air balloon

    • Doesn’t let air in or out

    • The bag will rise if it is warmer than the surrounding air

    • The bag will sink if it is colder than the surrounding air


Parcel theory

Parcel Theory

Parcels act like bags of air

50̍ at 10,000 ft

70̍ at 5000 ft

90̍ at surface

A

I

r

T

e

m

p

e

r

a

t

u

r

e

70̍̍

Will this parcel rise or sink?

The parcel will rise because the air inside the parcel > air outside

(70̍ > 60̍)

Will this parcel rise or sink?

70̍̍

The parcel will sink because the air inside the parcel < air outside

(70̍ < 80̍)


Instability1

Instability

Relating to Temperature Inversions

50̍

60̍

85̍

80̍

90̍̍

10,000 feet

Stable Layer

82̍̍

92̍̍

Surface

What happens when temperatures warm with height?

(a temperature inversion)


Instability2

Instability

Sea Breeze and Outflow Boundaries

50̍

60̍

80̍

88̍̍

50̍

60̍

70̍

85̍

80̍

90̍̍

10,000 feet

55̍̍

63̍̍

72̍̍

Stable Layer

82̍̍

Sea Breeze

92̍̍

Surface

Need lifting mechanism to get parcel above inversion


Weather 14th annual hot air balloon safety seminar

Unstable Atmosphere


Weather 14th annual hot air balloon safety seminar

Stable Atmosphere


Unstable but no storms

Unstable, But No Storms?

Why is that?

Stable Layer

Need additional lift to get thunderstorms to develop


Atmospheric stability

Atmospheric Stability

  • Stability is a measure of the equilibrium of the atmosphere to vertical motion.

  • Stable Air - Resists Vertical Motion

  • Unstable Air - Encourages Vertical Motion


Stability continued

Stability Continued

  • Paramount to the concept of stability is:

    • Relative to the surrounding environment: hot air rises and cold air sinks.


Weather 14th annual hot air balloon safety seminar

Remember that indicators of stable and unstable atmospheres are instantaneous indicators. Changes in stability can be extremely rapid.


Stability is a function of the lapse rate

Stability is a function of the Lapse Rate

  • Change in temperature with height


Average lapse rate

Average Lapse Rate

Decrease of

3.5 degrees F per

1000 feet of

altitude

66.6o

1,000’

H

70o

T


Weather 14th annual hot air balloon safety seminar

Lapse Rate and Stability

  • If the measured lapse rate is greater than 5.5° F per 1000 ft, the atmosphere is unstable.

  • If the measured lapse rate is less than 5.5° F per 1000 ft, the atmosphere is stable.

  • If the measured lapse rate is equal to 5.5° F per 1000 ft, the atmosphere is neutral.


Inversions

Inversions

Layer of air in which the temperature rises with height.

3 Types

Radiation or Nighttime Inversion

Marine Inversion

Subsidence


Temperature inversions

Temperature Inversions

  • As you go aloft, temperature normally decreases at a rate of 5.5° F. per 1000 feet.

  • Temperature inversion occurs when the temperature increases with height instead of decreasing.


Temperature inversions1

Temperature Inversions

Dewpoint

Temperature


Inversions1

Inversions

  • Inversions normally dissipate as the surface temperature rises and mixing of the atmosphere begins, unless inversion is strong.

  • Inversions frequently occur near the center of high pressure systems where winds are light and skies are clear.


Mixing height

Mixing Height

  • The height below which relatively vigorous mixing in the atmosphere is taking place

  • Winter Daytime 2- 4 Thousand Feet

  • Summer Daytime 4-6 Thousand Feet

  • Nighttime/early morning 100-500 feet when stable to 1000 feet in unstable


Transport winds

Transport Winds

  • Average horizontal wind speed and direction between the surface and the mixing height.

  • Determines the rate of horizontal movement.


Dispersion index

Dispersion Index

  • A forecast tool used to estimate daytime and nighttime stability.

  • Incorporates the stability, transport winds and mixing heights.

  • Daytime DI: 50-75 = unstable

  • Nighttime DI: 1-4 = stable


Thunderstorms

Thunderstorms

  • Thunderstorms significantly effect the local environment

  • Gusty erratic winds

  • Cooler temps/Higher RH

  • Rain - Possible Hail/Tornadoes

  • Lightning as far as 10 miles from the storm


Safety above all else

Safety Above All Else

Lightning Safety

  • #1 Florida weather killer

  • Average 10 fatalities and 40 injuries each year

  • Can strike over 10 miles away from the storm


When is lightning most dangerous

When is Lightning Most Dangerous?

June through September


Noaa weather radio

NOAA Weather Radio

Automated All-Hazards Warning Information

  • Warns of natural and man made hazards

  • Alerts you even when you’re sleeping

  • New radios can be programmed just for your county


Visit us on the web

Visit Us on the Web!

http://weather.gov


Local nws office

Local NWS Office


Aviation weather center

Aviation Weather Center

http://aviationweather.gov

  • AIRMETs, SIGMETs, SIGWX Progs, etc.

  • Aviation Digital Data Service

  • Standard unofficial briefing

  • Experimental products

  • Training


Useful web sites

Useful Web Sites

  • www.srh.noaa.gov/tbw -- National Weather Service, Tampa Bay, Florida

  • www.srh.noaa.gov -- National Weather Service, Southern Region Headquarters, Ft. Worth, TX

  • www.aviationweather.gov -- Aviation Weather Center, Kansas City, Missouri

  • www.weather.gov -- National Weather Service Headquarters, Washington, D.C.

  • www.spc.noaa.gov – Storm Prediction Center, Norman, OK


Questions and or comments

QUESTIONS AND/OR COMMENTS???


Weather 14th annual hot air balloon safety seminar

THE END!

Norman, OK 06/28/99 (Todd Lindley)


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