How to Brief Aviation Weather Before a Flight

A good briefing works from the outside in. Before you look at a single METAR, ask what the atmosphere is doing today: where the fronts are, what the surface analysis and prog charts show for your window, and how the radar and satellite loops have been trending for the last few hours. Two minutes here frames everything that follows. A marginal ceiling ahead of a warm front is a very different problem from the same ceiling burning off behind a cold front.

Next, read the METARs and TAFs for departure, destination, and everything useful in between. Four things deserve most of your attention:

• Ceiling and visibility. These define your flight category (VFR, marginal VFR, IFR, low IFR) and your legal and personal minimums.
• Wind. Not just the number: the gust spread and the crosswind component at your runway. A 15G25 across a narrow strip is a different flight from 15 knots down the centerline.
• Temperature and dew-point spread. A closing spread is fog or low cloud waiting to happen, especially around sunset and dawn.
• The TAF's change groups. TEMPO and FM lines tell you when the picture flips. Brief the forecast for your actual arrival time, not for now.

Winds aloft change your groundspeed, your fuel plan, and sometimes your altitude choice entirely. Look for the altitude where the wind buys you the most, and for shear between levels, which hints at turbulence. Over high terrain, strong flow perpendicular to a ridge line means mountain wave and rotor; treat it with respect regardless of how smooth the valley METARs look.

AIRMETs (icing, turbulence, IFR conditions, mountain obscuration) describe broad areas and tell you what kind of day it is. SIGMETs and convective SIGMETs are the serious ones: severe turbulence, severe icing, thunderstorm complexes. And PIREPs are ground truth: an actual crew in an actual airplane telling you what the forecast got right or wrong. A fresh PIREP along your route is worth more than any model output. Read them, and file your own.

Decide what has to be true for the flight to work, and decide it on the ground: minimum ceiling and visibility, maximum crosswind, an escape route if the forecast is wrong, and fuel for the alternate plus a real reserve. Write your personal minimums down when you're calm. You will negotiate with yourself in the moment, and the written number wins. If the flight only works when the TAF is exactly right, it doesn't work.

A briefing is a snapshot; weather is a movie. Update METARs ahead of you while en route, re-check the radar trend before descending, and remember that datalink radar is strategic, not tactical. The mosaic you see can be several minutes old, which is an eternity next to a building cell. Use it to pick which side of the weather to be on, never to thread a gap.

A modern EFB collapses most of this workflow into one screen. Ascent assembles the route brief automatically: METARs and TAFs decoded in plain language, radar, winds aloft, PIREPs, AIRMETs and SIGMETs layered directly over your route, with a flag on whatever changed since you first planned. That speed is the point: the less friction a briefing has, the more often you'll actually do a thorough one.

Any EFB, Ascent included, is a supplemental aid to situational awareness. Cross-check official sources. A Flight Service standard briefing (1800wxbrief.com) remains the authoritative preflight brief, and the final go/no-go authority always rests with the pilot in command.