Aviation/Turbulence Forecasting

Aviation Weather Center (AWC)

• National Weather Service office

• Turbulence, flight rules, upper level progs

SIGWXCharts (High-level)

Streamlinesat 36,000 ft.(other levelsavailable)

ConvectiveSIGMETS

Forecasting Aviation Turbulence

• Complicated– Topography– Convection– Mechanical forcing– Microscale

• Cannot be resolved by NWP models

• Approach: Analyze synoptic patterns that create or allow turbulence

Graphical Turbulence Guidance (GTG)

• Developed by National Center for Atmospheric Research (NCAR)

• Uses RUC (Rapid Update Cycle) 20 km grids and observations of turbulence/lightning

• Combines 11 different turbulence forecasting tools through a weighting function

• Produces upper-level clear-air turbulence (CAT) prediction

• Output is a number from 0-1

This value is used in coordination with other observations to produce a 3,6,9, and 12 hour forecast of turbulence

Turbulence Guidance

How Good is GTG?

Kelsch et al., 2004, AMS

Terminal Aviation (Aerodrome) Forecasts (TAFs)

• Surface forecast for hundreds of airport terminals around the country– Use METAR code– Produced by a human (not always at the

reporting site)– Can be more accurate than NWP models

• Local effects

TAF KAVL 021120Z 021212 34010G20KT P6SM SCT025 BKN250

FM1500 35008KT P6SM SCT040 BKN100

FM0000 VRB04KT P6SM BKN035

FM0800 16005KT P6SM BKN025

StationReport issued 2nd day of themonth (April 2) at 1120Z

Valid for 12Z today thru 12Z tomorrow

Forecast Wind at12Z today

6+ milesvisibility

Sky Conditionat 12Z

15Z forecast today

00Z forecast tomorrow

08Z forecast tomorrow

Line that begins with “TEMPO” indicates temporary or occasional conditions(e.g. fog, visibility) within a time period specified

TEMPO 0912 2SM BR OVC 010

Flight Path Tool

http://adds.aviationweather.gov/flight_path/