Preflight Weather Briefing Basics

Every good flight is planned twice — once on paper and once in the air, matching what you briefed against what you're actually seeing out the windscreen. The gap between those two is where most weather-related incidents live. A solid preflight weather briefing isn't about memorizing symbols; it's about building a mental model of the sky you're about to fly through, so nothing out there surprises you.

Start with the big picture before the small print

Don't open a METAR first. Open a surface analysis or prog chart first, so you understand why the weather is doing what it's doing. A single station's current conditions tell you almost nothing about whether they'll hold for the next three hours. Look for fronts, pressure gradients, and the general flow pattern along your route. A stationary front sitting across your destination matters more than any individual ceiling number, because it tells you the whole system is stuck rather than moving through.

Once you have the pattern, work outward to inward: departure, en route, destination, and at least one alternate. Weather that looks fine at both ends of your route can still be hiding something ugly in the middle, especially over higher terrain or open water where reporting stations are sparse.

Read METARs and TAFs as a story, not a checklist

A METAR is a snapshot; a TAF is a forecast narrative. Read the TAF's change groups (FM, BECMG, TEMPO) in order and ask what's driving each transition. A TEMPO group for reduced visibility during a specific window is different from a sustained BECMG shift — one is a chance of turbulence in your plan, the other is a near-certainty you need to route around.

• Compare the current METAR against the TAF's earliest period. If they already disagree, treat the forecast with extra suspicion for the rest of the flight.
• Pay attention to the observation time relative to now. A METAR that's 50 minutes old at a station with rapidly changing conditions is closer to a guess than a fact.
• Note the wind direction and speed trend across the TAF, not just the current report — a building crosswind at your destination's ETA changes the runway math even if today's number looks tame.

Ceilings and visibility aren't just personal minimums

Treat published ceiling and visibility numbers as the floor of what's reported, not a guarantee of what you'll see. Broken versus overcast changes your options for climbing through or staying below; scattered layers can still obscure terrain in mountainous areas even though they don't legally count as a ceiling.

Check the things that don't show up in a routine METAR

AIRMETs, SIGMETs, and PIREPs cover the hazards that a station report can't capture — turbulence, icing, mountain wave, and convective activity between reporting points. A route that looks clean on paper can still cross an AIRMET Tango for moderate turbulence that no single airport's METAR would ever mention. PIREPs are especially valuable because they're the only weather product describing what pilots actually experienced, not what a model predicted.

Winds aloft matter even on a short VFR hop — not just for groundspeed and fuel planning, but because a stronger-than-forecast wind at pattern altitude often means mechanical turbulence and gusty crosswinds you didn't plan for at the runway.

Never treat a briefing as a one-time event. Conditions that were forecast marginal in the morning can still deteriorate faster than the TAF predicted — build a personal recheck point before you commit to the final leg, and have a real turnaround decision already made before you need it.

Build your own go/no-go picture

Numbers alone don't make the decision — your currency, the airplane's capability, and the terrain you're flying over do. Write down your personal minimums before you ever look at a forecast, so the numbers you read later get compared against a standard you set with a clear head, not one you're inventing in the moment under pressure. A ceiling that's perfectly legal can still be a bad idea for the airplane, the route, or the pilot flying it that day.

Finally, brief your alternate with the same rigor as your destination. An alternate you picked in five seconds because the regulations required one is not a real backup plan — it's a box you checked. Give it the same look at ceilings, winds, and approach options you gave your primary field, because it's the airport you'll actually need if things go sideways.