Understanding TS SE-SW: how thunderstorms are encoded relative to the observation point in LAWRS observations

Outline in a nutshell

• Set the scene: thunderstorms on a weather map and why direction matters in aviation reports

• The coding basics: what TS means, and how location is described using origin-to-extent wording

• The key example: why TS SE-SW is correct and what the others imply

• Why pilots and dispatchers care: safety, routing, and real-world use

• Common gotchas and quick tips for decoding on the fly

• A friendly wrap-up with a few practical takeaways

Let’s talk about thunderstorm cues that actually help a pilot chart a safer course. When you’re cruising through the aviation weather map, a tiny set of letters can tell you a lot about what’s happening up ahead. The goal? Reliable, precise information that you can act on quickly. The way thunderstorms are described in Limited Aviation Weather Reporting System (LAWRS) observations follows a simple but strict rule: specify where the weather is coming from and how far it stretches. It’s a compass for your cockpit, not just a line on a chart.

What the code means, in plain language

• TS is shorthand for thunderstorm. It’s the big headline you’ll see in a METAR-like observation when storms are present.

• The letters that follow aren’t a random add-on. They describe the storm’s location relative to the observer, using a directional footprint.

• The format typically reads as a starting direction and an ending direction, separated by a dash. The phrase tells you where the storm activity originates and how broad the area is around the observer.

Think of it like describing a storm’s footprint on a map: “It starts to the [direction] and extends to [direction].” The origin matters because weather moves, and knowing the starting point helps you estimate where the storm might travel next. If you’re thinking in terms of a storm’s path, the direction tells you not only where it’s located now, but where the next edge might be.

Let’s unpack the example you’ll often see in LAWRS observations: TS SE-SW

• This denotes thunderstorm activity that is located toward the southeast of the observer and extends to the southwest. In other words, if you stand at the observation point, the storm is in the SE quadrant and spans toward the SW, giving you a sort of diagonal footprint in that quadrant.

• Why SE-SW rather than SW-SE or another ordering? The convention is grounded in where the weather originates and where its extent lies. Starting from SE and tracing toward SW communicates a southeast-origin with a broad reach toward the southwest. It’s precise enough to guide flight planning and avoidance.

Why the others don’t fit as well

• TS SW-SE would imply the storm’s footprint runs from southwest to southeast, which suggests a different orientation and could mislead you about the edge of the activity.

• TS E-SW would place the storm more toward the east with an unusual extension to the southwest, potentially underrepresenting the actual spread.

• TS S-SE would shrink the footprint to a more limited, southern-to-southeastern spread, giving a picture that’s too narrow for many routing decisions.

So, TS SE-SW is the clear, correct way to express a storm system whose origins sit to the southeast and extend toward the southwest. It’s not arbitrary—it's about giving you a concise, navigable snapshot you can act on, even when the weather is shifting by the hour.

Why this matters in real life—beyond the paper codes

• For pilots, precise direction and extent help with flight planning, especially when choosing detours or re-routing to minimize turbulence, lightning risk, and wind shear. It’s not just about avoiding a storm; it’s about anticipating how the weather might evolve as you approach the area.

• For air traffic controllers and dispatchers, clear directional encoding reduces ambiguity. In busy airspace, a small misread can ripple into a late turn or a change in altitude that affects fuel and timing.

• For weather enthusiasts and students, understanding this logic builds a foundation for reading METARs, TAFs, and other aviation weather products. You begin to see the pattern: weather isn’t random; it’s directional, trackable, and forecastable to a workable degree.

A quick tour of the tools you’ll meet

• METARs and LX observations: The shorthand used in these reports relies on compact phrases that tell you what’s happening, where it is relative to the observer, and how it’s changing.

• AWOS/ASOS: Automated weather systems provide frequent, location-specific data that pilots can cross-check with the verbal or coded reports.

• NOTAMs and SIGMETs: When thunderstorms show up in reports, they often trigger broader advisories. Understanding the location language helps you connect the dots between a single observation and the bigger picture.

A few practical tips for decoding

• Start with the origin: If you see TS SE-SW, picture a storm that originates toward the southeast. That gives you the starting point of the storm’s footprint.

• Check the extent: The second direction (SW) shows how far the storm’s influence reaches. If the range is long, you’ll want to treat it as a broader hazard area.

• Cross-verify with nearby reports: Look at other observations along your likely route. If neighboring stations report similar directions, you’ve got a more confident picture of the storm’s position and movement.

• Relate it to your route: If your path passes near SE or SW of you, you’ll want to plan alternate altitudes, hold patterns, or course changes to avoid the core activity.

• Remember the dynamic nature: Storms aren’t static. Treat the direction and extent as current guidance rather than a guaranteed forecast. Updates come in quickly, so stay tuned to new reports and weather advisories.

Common pitfalls—and how to sidestep them

• Confusing origin with the edge: It’s easy to think the first direction is where you’ll encounter the storm. Instead, use it as a cue for where the storm starts relative to you, then look at the extent to gauge how far it covers.

• Ignoring motion: The direction tells you where the storm sits now, but motion matters too. A storm drifting toward your path can become a bigger hazard if you don’t you adjust in time.

• Overgeneralizing: A broad SE-SW footprint is a good warning, but you still need to check wind, visibility, and lightning potential inside the footprint. Layer the data sources for a safer plan.

• Skipping cross-checks: One report is a clue, not a map. Compare with radar updates when available, and consider pilot reports and NOTAMs to confirm the live situation.

A natural, real-world rhythm

If you’ve ever stood on a runway edge waiting for clearance, you know the air is a living thing. The clouds shift, the wind changes, and the weather decoding you learned in a classroom suddenly becomes a practical tool you lean on to stay safe. That’s the essence of these directional codes: they compress a lot of situational detail into a compact, readable line so you can make quick, confident decisions in a real cockpit.

How to cultivate a mental shorthand that travels well

• Connect letters to a mental map: TS means thunderstorm; SE-SW translates into a SE-origin footprint extending to the SW. The more you link the letters to a picture, the quicker you’ll interpret them in flight.

• Practice with real-world examples: Look at senior pilots’ notes, aviation weather apps, or flight planning manuals that show how these codes translate into route changes. A little daily exposure builds a strong memory.

• Use simple mnemonics sparingly: A quick rhyme like “Thunder starts SE, stretches to SW” can help you recall the pattern without turning it into a crutch.

A gentle reminder about the bigger picture

The aviation weather reporting system exists to keep people safe—pilots, crew, passengers, and those on the ground who rely on predictable air traffic flow. The way thunderstorm locations are encoded isn’t about clever abbreviations; it’s about giving a precise, actionable picture in seconds. That precision helps you anticipate the storm’s path, plan a safer route, and keep everything moving smoothly up there where the sky is your working document.

Final thoughts you can carry into your next flight or study session

• Direction is more than a compass point. It’s a map of risk and a guide for decision-making.

• The SE-SW notation is not arbitrary; it’s a standardized way to describe where the storm sits now and how wide its influence travels.

• When in doubt, cross-check with other data sources, stay updated, and keep your eye on the process: a moving target calls for flexible planning.

• Practice makes comfortable. The more you read and interpret these codes in real-world settings, the quicker you’ll translate them into safe, efficient flight decisions.

If you’re curious, the next time you tune into aviation weather updates, pause for a moment at the thunderstorm note and picture that footprint. It’s a small paragraph that carries a big amount of guidance. And in the fast-paced world of aviation, that clarity can be the difference between a smooth ride and a hard decision in the clouds.

In short: TS SE-SW is the clean, correct way to express a thunderstorm’s position relative to the observer—starting in the southeast and stretching toward the southwest. It’s a prime example of how weather language, when used well, becomes a practical tool pilots rely on to navigate safely through a stormy sky.

Wouldn’t you like every weather note you read to feel like a clear, direct map? That’s the aim of this kind of encoding: a simple shortcut that keeps the flight deck calm, the route efficient, and the sky safer for everyone.