Checkride Oral Weather Questions: METAR, TAF, Advisories and the Go/No-Go

Weather is the part of the oral where examiners stop asking “what is” and start asking “so what.” The ACS task, PA.I.C Weather Information, lists the products you must understand (K2), the meteorology behind them (K3) and the risk you have to manage with them, starting with the go/no-go and continue/divert decisions (R1). Two notes in the task matter for your preparation: if the examiner selects K2 or K3, they must assess at least three sub-elements, and one of the skills is analyzing at least three of the K3 conditions using actual weather or weather they give you (FAA-S-ACS-6C, PA.I.C).

In practice, that means the examiner will put a real or printed report in front of you and ask you to read it aloud. DPE Larry Bothe describes the failure pattern precisely: he asks an applicant how they will know the weather at the destination when they get there hours from now, hears that they will consult the METARs, and concludes the applicant does not understand how to obtain and use weather information. So we will start where he starts, with the codes, and end where he ends, with the decision.

Read a METAR out loud

The report below is an invented example in the real format. Read it left to right, the way you would to the examiner, then check yourself against the notes.

• METAR KXYZ 141753Z: a routine report for the station, taken on the 14th at 1753 UTC. The “Z” is always UTC (FAA-H-8083-28B, Ch. 24).
• AUTO: fully automated, no human oversight. In the remarks, AO2 means the station has a precipitation discriminator (AO1 means it does not).
• 22012G22KT 180V250: wind from 220° at 12 knots, gusting 22, direction varying between 180° and 250°. METAR wind direction is referenced to true north; gusts are reported when peaks and lulls differ by 10 knots or more.
• 6SM -RA BR: visibility 6 statute miles in light rain and mist. BR is used for visibilities from 5/8 SM up to, but not including, 7 SM; below 5/8 SM the obscuration becomes fog (FG).
• BKN014 OVC025: broken at 1,400 feet, overcast at 2,500 feet, both above ground level. The ceiling is 1,400 feet: the lowest broken or overcast layer.
• 17/14 A2991: temperature 17 °C, dewpoint 14 °C, altimeter 29.91 inHg. A 3-degree spread is worth mentioning: it is narrowing weather, not good weather.
• RMK … SLP128 T01720139: sea-level pressure 1012.8 hPa, and the temperature and dewpoint to tenths (17.2 °C and 13.9 °C).

Then the SPECI arrives

A SPECI is an unscheduled report issued between the hourly METARs whenever specified criteria are met, such as a significant wind shift, a thunderstorm beginning or a ceiling or visibility change across set values. It contains every element of a METAR (FAA-H-8083-28B, Ch. 24).

Now the wind is 240 at 18 gusting 28, visibility 2 miles in a thunderstorm with heavy rain, and the ceiling is 800 feet broken with cumulonimbus. TSB16 in the remarks says the thunderstorm began at 16 minutes past the hour. If this is a towered airport with a surface area, there is no basic VFR here: 2 miles is below the 3 statute miles of ground visibility required to take off or land, and 800 feet is below the 1,000-foot ceiling (14 CFR 91.155(c)–(d)). The airspace guide walks through why.

Now the forecast: read the TAF

A TAF forecasts conditions within 5 statute miles of the center of the airport’s runway complex. Most cover 24 hours; some major airports get 30 hours. Scheduled TAFs are issued four times a day, at 0000, 0600, 1200 and 1800Z (FAA-H-8083-28B, Ch. 27).

• 1418/1518: valid from the 14th at 1800Z to the 15th at 1800Z.
• P6SM: visibility greater than 6 statute miles.
• TEMPO 1418/1421: temporary showers and a 3,000-foot broken layer between 18Z and 21Z. TEMPO means a greater than 50 percent probability, each occurrence lasting an hour or less, and in total covering less than half of the period. Only the elements that change are listed; the wind stays as forecast.
• FM142100: from 2100Z on the 14th, a complete new forecast that supersedes everything before it, which is why the wind appears again.
• PROB30 1422/1502: a 30 percent chance of thunderstorms with 2 miles and a 1,000-foot ceiling between 22Z and 02Z. PROB30 is the only probability group NWS TAFs use; PROB40 and BECMG appear in military and international TAFs.

A TAF also leaves things out on purpose: the NWS TAF has no temperature, and it will not tell you what happens between airports. That is the opening for the next question.

Which product answers which question

The ACS lists the products you are expected to use (K2a to K2g). Examiners care less about the acronym than about whether you know if it tells you what is or what will be, and for where.

Two details examiners like: FB winds are not forecast within 1,500 feet of the station elevation and temperatures not within 2,500 feet, which is why the lowest levels are often blank, and the wind direction in the FB is true, like the METAR (FAA-H-8083-28B, Ch. 27). If a briefing is more than six hours before departure, the AIM calls it an outlook briefing; a standard briefing is for when you have not received a previous briefing, and an abbreviated one updates it (AIM 7-1-5).

AIRMETs, SIGMETs and Convective SIGMETs

This is the list most applicants half-know. AIRMETs are aimed at all pilots, especially VFR pilots and operators of sensitive aircraft; over the CONUS they are issued as graphics valid at snapshots no more than three hours apart, and scheduled four times a day (FAA-H-8083-28B, Ch. 26).

Four meteorology follow-ups

What makes a thunderstorm, and how long does a cell live?

Sufficient water vapor, unstable air and a lifting mechanism such as a front, upslope flow or converging winds. A cell goes through a towering cumulus stage marked by a strong updraft, a mature stage that begins when precipitation reaches the surface, and a dissipating stage dominated by downdrafts; the whole cycle typically lasts about 30 minutes. For avoidance, the AIM’s guidance is to stay at least 20 miles from any thunderstorm identified as severe or giving an intense radar echo, and not to use data-linked NEXRAD for tactical maneuvering, since it shows where the weather was (FAA-H-8083-28B, Ch. 22; AIM 7-1-27).

Which fog should worry you tonight?

Radiation fog forms over land when clear-night cooling brings the temperature to the dewpoint, and often does not burn off until after sunrise. Advection fog forms when moist air moves over a colder surface and can deepen with wind up to about 15 knots. Upslope fog forms when moist, stable air is cooled as it moves up rising terrain, and can form under cloudy skies. Frontal fog forms when rain falling from warm air above a front saturates the cold air below (FAA-H-8083-28B, Ch. 18). The narrow spread in our example METAR is the cue for this question.

What does freezing rain tell you about the air above you?

That there is warmer, above-freezing air aloft over a shallow below-freezing layer at the surface, a temperature inversion typical of a warm front. The rain falls into the cold layer and freezes on contact (FAA-H-8083-28B, Ch. 14). For a VFR private pilot, the answer that follows is not to be anywhere near it.

When does structural icing happen?

When supercooled water droplets strike the airframe and freeze. Clouds between 0 °C and −10 °C consist mainly of supercooled water, which is why “it’s below freezing, so it’s all ice crystals” is wrong (FAA-H-8083-28B, Ch. 20). For a VFR flight, visible moisture at or below freezing is simply a no.

The part that decides the grade: go or no-go

The risk-management elements of the task are where the oral is won: making the go/no-go and continue/divert decisions, including personal weather minimums and the circumstances that make a diversion prudent (PA.I.C.R1). The skill that closes the task is correlating weather information to make that decision (PA.I.C.S3). Before any flight away from the airport, 14 CFR 91.103 requires you to become familiar with weather reports and forecasts, fuel requirements and the alternatives available if the flight cannot be completed (91.103).

Put the examples together. The METAR shows a 1,400-foot ceiling with a 3-degree spread; the SPECI shows a thunderstorm on the field half an hour later; the TAF shows showers before 21Z, a new regime after that, and a 30 percent chance of thunderstorms from 22Z. A strong answer sounds like this: “Right now I’m at marginal VFR, which is below my personal minimums for a cross-country, and there’s convection building. I’d wait for the storm to pass, re-brief, and if the 22Z window still shows PROB30 thunderstorms along my route I’d move the flight to tomorrow morning, or plan a diversion airport on the west side with legal fuel reserves.” AIM 7-1-7 gives you the vocabulary: marginal VFR is a ceiling of 1,000 to 3,000 feet and/or visibility of 3 to 5 miles (AIM 7-1-7). Day VFR requires enough fuel to reach the first point of intended landing and fly 30 more minutes at normal cruise (91.151).

Quick answers