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NWS PocatelloAviation Forecast
Operations
Gary WicklundAviation Meteorologist
My 42 Year Forecast Method
Forecast Office Overview
• 5 Lead Forecasters• 5 Journey Forecasters• 3 Hydro-Met.Techs. / Intern
Our Responsibilities include:
• Public Forecasts and Warnings• Hydrologic• Wildfire and Land Management• Avalanche Guidance• Aviation Our Operational Staff includes:
Responsible for southeast Idaho
Aviation Operations Overview
Terminal Aerodrome Forecasts (TAFs)
Four times a day and updated as needed
Pocatello Idaho Falls Sun Valley Burley
What We Do…
Forecast Office Support, as needed, to:
Boise Salt Lake City
Weather FundamentalsCirculation: Earth’s orbit and axis tilt create our seasons
Weather FundamentalsAir rises higher at Equator than poles
Weather Fundamentals• Different air masses which affect North America, as well as
other continents, tend to be separated by frontal boundaries• Source regions of global air masses (cA, mP, etc.)
Weather Fundamentals
Clouds and stability– Stable air mass -- flat cloud development – Unstable air mass -- vertical growth
Weather Fundamentals
Cloud Classification
• Stratus: “layered”, “sheetlike”
• Cumulus: “puffy”, “heap”
• Nimbus: “rain cloud” or “violent rain”
• Cirrus: “wispy” type of cloud
Weather Fundamentals
Low Cloud Type - Cumulus
“Cotton ball” clouds
The top of the cloud generally denotes the limit of the rising air.
Clouds are “detached”, with blue sky between each cloud
Weather Fundamentals
Low Cloud Type – Fair Weather Cumulus
Weather Fundamentals
Low Cloud Type - Towering Cumulus
Weather Fundamentals
Mature Thunderstorm
Weather Fundamentals
Mature Thunderstorm Possibilities Dry Microburst / Tornado
Weather Fundamentals
Microburst Threat
Weather Fundamentals
Weather Fundamentals
Mt Shasta
Mt FujiMt Rainier
Teton Range
Lenticular CloudsWeather Fundamentals
Lenticular Clouds - Mountain WavesWeather Fundamentals
Danger? Vertical rises of over 15 Ft/sec with Mountain Waves
Cloud Type – Altocumulus
Weather Fundamentals
Cloud Type - High Clouds
Weather Fundamentals
Weather Fundamentals• Clouds can indicate the type of approaching front
X
• Cold air is approaching and clouds are very close to front
Cold Front
XObserver
Weather Fundamentals
Weather Fundamentals
Atmospheric Inversion
Fog
Horizontal Motion (Advection)– Moist air passes over a cool surface – Well known area is in the San Francisco Bay
Radiational Cooling– Moist air mass cools near the ground to the point of
condensation causing fog to form– Generally you need calm winds and clear skies
Weather Fundamentals
Weather Fundamentals
• How weather Fronts are Defined
Weather Fundamentals
Local Hazards
Dense Fog (especially Nov – Mar) Low Clouds and/or Visibility Mountain Obscurations
In the Winter months…In the Winter months…
In the Summer months… Thunderstorms, with hail and/or high winds
Local Hazards
Ice & SnowIce & Snow
Local Hazards
Strong WindsStrong Winds
Local Hazards
Mountain ObscurationsMountain Obscurations
Thunderstorms and LightningLocal Hazards
Low Level Wind ShearDanger? Stalls and abrupt landings
Vertical Wind Shear 10 knots or more per 100 feet in a layer at least 200 feet thick
Must be within 2000 feet of Ground
PIREP reporting non-convective wind shear causing an airspeed loss/gain of 20 knots (within 2000 feet of ground)
What Is It?
West winds at Sun Valley in gap to West of Tower
Likely with…
Terminal Aerodrome Forecast
A detailed weather forecast for the next 24 hours
Valid for a 5 mile radius from the center of any airport
Elements include Visibility, Cloud Heights, Winds, and Weather
Issued daily at 00Z, 06Z, 12Z, and 18Z
May include Low Level Wind Shear
What is a TAF?
Example:
KSUN 131741Z 1318/1418 10013KT P6SM OVC060 FM140100 10012KT P6SM SCT040 OVC070 TEMPO 1402/1406 -RA FM140600 17014KT P6SM -RA BKN040 OVC070 FM141200 21005KT P6SM SCT025 BKN045=
Current METAR for KPIH reported at: Apr 7 2010, 8:53 am MDT
KPIH: 071453Z 22009KT 10SM CLR 02/M04 A3037 RMK AO2 SLP300
T00171039 53009
TAF: KPIH 071120Z 0712/0812 22007KT P6SM SKC
FM071800 24012G18KT P6SM SCT200
FM080200 VRB05KT P6SM SCT200
Metar Observation
Pilot Reports
Forecasters!
Fellow Pilots!
Anyone with a flying interest
PIREPs often are the first sign of trouble, or weather to affect routes/airport terminals
REMEMBER, your PIREP is extremely valuable.
Who Needs Them?
Example:GEG UA /OV GEG 180008 /TM 2246 /FL 150 /TP PAY2 /SK OVC-TOP012/OVC160 /TA M07 /WV 23040KT /TB LGT OCNL MOD
AIRMET TANGO UPDT 2 FOR TURB VALIDUNTIL 082100 AIRMET TURB...NV OR CA AND CSTL WTRS FROM50NW LKV TO BAM TO 30W LAS TO 20E MZB TO 220SWMZB TO 140WSW FOT TO 150NW FOT TO 50NW LKV MOD TURB BTN FL230 AND FL410. CONDS CONTG BYD 21Z THRU 03Z. OTLK VALID 2100-0300Z AREA 1...TURB NV CA AND CSTL WTRS BOUNDED BY 20ENE BAM-20E OAL-40NW RZS-150WSW RZS-140SW PYE-SNS- 20ENE BAM MODTURB BLW 140. CONDS CONTG THRU 03Z.AREA 2...TURB NV UT AZ OR CA BOUNDED BY 50NW LKV-20NNW REO-20ESE ILC-80WSW TUS-BZA-20ESE MZB- 30W LAS-BAM-50NW LKV MOD TURB BTN FL230 AND FL410. CONDS CONTG THRU 03Z.
AIRMETs
Areas of Moderate Turbulence
Areas of Moderate Icing and freezing levels
Areas of IFR Conditions and mountain obscurations
Strong Convective Areas
Volcanic Ash Tracks
Issued at 13Z, 19Z, 01Z, & 07Z -- Updated as needed
Issued by National Aviation Center in KCMO
SIGMETs
Thunderstorms greater than (33 dBZ) affecting 40% or more of a 3000 square mile area Line(s) of Thunderstorms
Isolated Severe Thunderstorms (3/4” hail and/or 50 knot winds)
Tornadoes
Embedded Thunderstorms
Volcanic Ash
Issued when needed
WSUS31 KKCI 081955SIGECONVECTIVE SIGMET...NONEOUTLOOK VALID 082155-090155TS ARE NOT EXPD.
Issued by National Aviation Center in KCMO
Upper Air Winds
Where to get Weather Information
• Information Sources- Pilot Weather Briefings @ 1-800-WEATHER
- Internet
-- ADDS – Aviation Weather
-- DUATS
-- Salt Lake City Center Weather Service Unit
-- Weather Forecast Office, Pocatello
-- AIM
-- AOPA
Where to get Weather Informationadds.aviationweather.gov
Where to get Weather informationwww.wrh.noaa.gov/zlc
www.weather.gov/pocatello
ForecastsActivity PlannerSoutheast IdahoDiscussionAviationFire WeatherHydrologyAvalancheRecreationGraphicalOutlooks
Where to get Weather information
Weather and Accidents
Source: NTSB chairman, Jim Hall’s testimony before the Committee on Transportation and Subcommittee on Aviation (22 July 1999)
National Transportation Safety Board Statistics… 33% of all FATAL accidents are weather related
Of these, 40% occur within the TAF area of the airport
Low Ceilings and/or Visibilities
Icing
Thunderstorms, Lightning and/or Hail
Low Level Wind Shear
Main Weather with these Crashes…
Weather Forecast Office Pocatello
Questions?
Thank You.
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