Weather and its ImpactWeather and its Impact on Aviation Operations on Aviation Operations

National Weather Service National Weather Service Hastings, Nebraska Hastings, Nebraska

Kearney Explorers Club

November 21, 2006

High and Low High and Low Pressure SystemsPressure Systems

Cold and Cold and Warm FrontsWarm Fronts

Density AltitudeDensity Altitude

Wind ShearWind Shear

Wind ShearWind ShearChange in wind speed and direction as you

go higher in the atmosphere– Changes are sometimes very abrupt

Low level wind shear – Horizontal winds– Vertical winds

Aircraft IcingAircraft Icing

Aircraft IcingAircraft IcingDisrupts smooth flow of air over wing

surfaces and around airplane parts that stick out– Decreases lift– Adds weight to aircraft

Icing prevention– On the ground

De-icing procedure

– In the air Avoiding clouds with temperatures and humidities

which lead to ice buildups

ThunderstormsThunderstorms

Thunderstorm HazardsThunderstorm HazardsDownburst windsHailReduced visibilities

Terminal AerodromeTerminal AerodromeForecastsForecasts

Terminal Aerodrome ForecastsTerminal Aerodrome Forecasts

Airport specific forecasts within 5 miles of the center of the airport for a 24-hour period

Weather elements– Wind and wind shear– Cloud levels– Precipitation / fog / dust / sand– Visibility– Probability of precipitation toward the end of

the forecast

Terminal Aerodrome ForecastsTerminal Aerodrome Forecasts

TAF GRI 191128Z 191212 25006KT P6SM SKC

FM1600 30010KT P6SM SKC

FM1900 33013KT P6SM SKC

FM0000 32006KT P6SM FEW250

FM0400 VRB03KT P6SM SCT250

Regional AirportsRegional Airports

NWS Hastings TAF SiteNWS Hastings TAF Site

Grand Island (KGRI)

– Located 2 miles east-northeast of Grand Island

– Elevation: 1846 ft. MSL

NWS Hastings TAF SiteNWS Hastings TAF Site

Grand Island (KGRI)– Airport is serviced by an ASOS

Augmentation of observations is performed by Grand Island Control Tower personnel from 0600 to 2200 local time

Occurrences of precipitation or thunderstorms are manually appended to observations as a remark

NWS Hastings TAF SiteNWS Hastings TAF Site Grand Island (KGRI)

– Main forecast considerations Diurnal pressure gradient winds Thunderstorm intensities during convective season

Low ceilings/visibilities during stratiform precipitation events

Radiation Fog

Transcribed WeatherTranscribed WeatherBroadcastsBroadcasts

Transcribed Weather BroadcastsTranscribed Weather Broadcasts

Weather forecasts for expected conditions 25 miles on either side of specified routes of flight (50 mile-wide corridor)

12-hour forecast

Regional AirportsRegional Airports

TWEB 261 KOMA-KGRI-KLBF

TWEB 261 KOMA-KGRI-KLBF TWEB 261 KOMA-KGRI-KLBF

Combines regional surface observations (METARs) and terminal forecasts (TAFs)– METARs: Omaha, Offutt AFB, Council Bluffs (IA),

Millard, Fremont, Lincoln, Columbus, York, Aurora, Grand Island, Hastings, Kearney, Broken Bow, Lexington, North Platte

– TAFs: Omaha, Lincoln, Grand Island, North Plattte

TWEB 261 KOMA-KGRI-KLBFTWEB 261 KOMA-KGRI-KLBFPrevailing conditions defined for entire

route or portions of the route– Logical separation of meteorological

occurrencesPre-frontal conditionsPost-frontal conditionsAirmass thunderstormsSurface gradient winds > 25 knotsLow level wind shear

Questions?Questions?

The End The End