Aviation Weather: Terminal Aerodrome Forecasts (TAF)

I wrote about an aviation weather product known as a METARs the other day. Today I am going to focus on the Terminal Aerodrome Forecast (TAF) that uses the same coding that the METAR uses.

TAFs are issued four times a day by the National Weather Service. As its name suggests, the TAF is a weather forecast of particular interest to aviation interests. A TAF is written for a specific airport, usually a larger airport, extending out to five statute miles from the center of the airport. They are updated four times a day, covering a 30 hour time period. When the forecaster determines that the forecast is no longer valid, an amended TAF will be issue superseding  the earlier forecast. A 30 hour TAF is often broken down into specific time periods reflecting a forecast of changing weather conditions.

Before going on a scenic flight, I try to check for TAFs for airports that are near or the route of the flight. Depending on where we are going, there might be two TAF for two airports. For example, late last summer, I flew to the NJ shore on one of my scenic rides. Two of the larger airports along the route had TAFs, Trenton (KTTN) and McGuire Air Force Base in Wrightstown NJ (KWRI), so I looked at TAFs for KTTN and KWRI. An added benefitis that when a TAF is issued for a specific airport, there is usually a METAR. So I will know the hourly weather report as well as a forecast.

You can get a TAF and a METAR for airports in the U.S. by going to one webpage from the National Weather Service (NWS) Aviation Digital Data Service (ADDS): go here to get a TAF. Enter the four digit code (will start with the letter "K") for your nearest international airport in the little box, select TAF, highlight the translate button and then select get TAF. If you aren't sure what the four letter code is for the nearest international airport in your State, you might find your code in this list of Class B airports in the US or this list of Class C airports.

At 1 PM EST (6 PM UTC) on March 2, I went to the NWS ADDS TAF page and got the latest TAF for Newark Liberty International Airport in Newark NJ (KEWR), note that if you try this you will probably get a different TAF. If you want to translate universal or greenwich mean time (UTC) into your time, go here, look for United Kingdom - England - London to get UTC time.

You will see in the TAF below the forecast passage of low pressure system through Newark later today into tomorrow with a low cloud deck and rain. Also note the forecasted change in wind direction and speed.

Forecast for: KEWR (NEWARK , NJ, US)

TAF (coded): KEWR 021723Z 0218/0324 14008KT P6SM BKN015 OVC025
Forecast period: 1800 to 2200 UTC 02 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the SE (140 degrees) at 9 MPH (8 knots; 4.2 m/s)
Visibility: 6 or more miles (10+ km)
Ceiling: 1500 feet AGL
Clouds: broken clouds at 1500 feet AGL
overcast cloud deck at 2500 feet AGL
Weather: no significant weather forecast for this period

TAF (coded): FM022200 13010KT P6SM BKN015 OVC025
Forecast period: 2200 UTC 02 March 2012 to 0200 UTC 03 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the SE (130 degrees) at 12 MPH (10 knots; 5.2 m/s)
Visibility: 6 or more miles (10+ km)
Ceiling: 1500 feet AGL
Clouds: broken clouds at 1500 feet AGL
overcast cloud deck at 2500 feet AGL
Weather: no significant weather forecast for this period

TAF (coded): FM030200 11014KT 4SM -RA BKN009 OVC015
Forecast period: 0200 to 0400 UTC 03 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the ESE (110 degrees) at 16 MPH (14 knots; 7.3 m/s)
Visibility: 4 miles (6 km)
Ceiling: 900 feet AGL Clouds: broken clouds at 900 feet AGL
overcast cloud deck at 1500 feet AGL
Weather: -RA  (light rain)

TAF (coded): FM030400 08010KT 1SM -RA BR OVC004
Forecast period: 0400 to 1000 UTC 03 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the E (80 degrees) at 12 MPH (10 knots; 5.2 m/s)
Visibility: 1.00 miles (1.61 km)
Ceiling: 400 feet AGL
Clouds: overcast cloud deck at 400 feet AGL
Weather: -RA BR  (light rain, mist)

TAF (coded): FM031000 VRB06KT 1SM -RA BR OVC004
Forecast period: 1000 to 1400 UTC 03 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: variable direction winds at 7 MPH (6 knots; 3.1 m/s)
Visibility: 1.00 miles (1.61 km)
Ceiling: 400 feet AGL
Clouds: overcast cloud deck at 400 feet AGL
Weather: -RA BR  (light rain, mist)

TAF (coded): FM031400 28012KT P6SM BKN012 BKN050
Forecast period: 1400 to 1700 UTC 03 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the W (280 degrees) at 14 MPH (12 knots; 6.2 m/s)
Visibility: 6 or more miles (10+ km)
Ceiling: 1200 feet AGL
Clouds: broken clouds at 1200 feet AGL
broken clouds at 5000 feet AGL
Weather: no significant weather forecast for this period

TAF (coded): FM031700 28013G20KT P6SM BKN050
Forecast period: 1700 to 2000 UTC 03 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the W (280 degrees) at 15 MPH (13 knots; 6.8 m/s)
gusting to 23 MPH (20 knots; 10.4 m/s)
Visibility: 6 or more miles (10+ km)
Ceiling: 5000 feet AGL
Clouds: broken clouds at 5000 feet AGL
Weather: no significant weather forecast for this period

TAF (coded): FM032000 26015G25KT P6SM SCT250
Forecast period: 2000 UTC 03 March 2012 to 0000 UTC 04 March 2012
Forecast type: FROM: standard forecast or significant change
Winds: from the W (260 degrees) at 17 MPH (15 knots; 7.8 m/s)
gusting to 29 MPH (25 knots; 13.0 m/s)
Visibility: 6 or more miles (10+ km)
Clouds: scattered clouds at 25000 feet AGL
Weather: no significant weather forecast for this period

For now, this wraps up my articles on aviation weather products. I will be revisiting aviation weather topics from time to time.

June 13, 2014: Someone asked me why the weather products are coded. I don't really know the answer to this question at this time. I just know that when I was learning about various aviation weather reports that I learned about the codes. Fortunately, in the link to the NWS digital aviation weather service that I provided above you can select a button to get a translated TAF. I'll try to find an answer to this question and when I do, I'll post another update.

June 27, 2014: I posted a response to the question of why TAF and METAR weather products are coded in an article that I posted on June 27, 2014 called "Why are METARs and TAFs coded?".

References
U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service. Pilots Handbook of Aeronautical Knowledge (2008), pp 12-10 to 12-11 obtained from this page on the FAA website where individual chapters may be downloaded. Chapter 12 is devoted to Aviation Weather Services.

U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Weather Service. U.S. Department of Transportation, Federal Aviation Administration. Aviation Weather Services, Advisory Circular AC 00-45G (2011) obtained from the FAA, pp. 7-19 to 7-35.