---
name: Jet Stream
slug: jet-stream
type: atmospheric-process
status: unstable
version: 0.0.666-alpha
released: "~11000 BCE (post-glacial reconfig)"
maintainer: "Hadley Cell Collective / nobody, really"
dependencies:
  - "[temperature differential](/temperature-differential)"
  - "[Coriolis effect](/coriolis-effect)"
  - "[solar radiation](/solar-radiation)"
  - "[pressure gradient](/pressure-gradient)"
  - "[jet fuel](/jet-fuel) (unrelated, but it keeps showing up in the logs)"
license: "GPL-3.0 (Geophysical Public Lorenz)"
tags:
  - atmosphere
  - wind
  - chaos
  - aviation
  - "please-stop"
  - meanders
  - grief
---

Jet Stream

What it actually is

A fast narrow river of air screaming around the planet at 30,000 feet, convinced it knows where it's going, which it does not.

How it works

Warm air and cold air meet at a boundary neither of them requested. The temperature contrast generates a pressure gradient. The Coriolis effect bends everything sideways because the planet is spinning and has opinions. The result is a band of wind moving 80 to 320 km/h in a roughly westerly direction.

"Roughly."

The stream develops waves. The waves are called Rossby waves and they are, technically, an error state that became a feature. When the waves amplify they meander. When they meander too far they pinch off. When they pinch off you get a blocking high pressure system and somewhere a continent stops receiving its weather in the correct order.

"It just sat there. For three weeks. The ridge just sat there." — every meteorologist, 2003, 2010, 2018, 2021, 2023

Features

Polar jet stream: Primary instance. Runs at 60°N/S. Responsible.
Subtropical jet stream: Secondary instance. Runs at 30°N/S. Less responsible.
Speed variance: 50% to 400% depending on season and how the polar vortex is doing
Undocumented behavior: occasionally runs backwards over Greenland; no patch currently planned
Aviation integration: tailwinds at altitude. Saves 1 to 3 hours transatlantic. The only thing it reliably does for humans.

Error Codes

ERR_POLAR_VORTEX_SPLIT       // chaos. cold air dispatched to wrong hemisphere sector
ERR_MERIDIONAL_FLOW_EXTREME  // wave amplitude exceeded. weather now arriving from wrong direction
ERR_BLOCKING_EVENT_PERSIST   // loop detected. heat dome installed. cannot interrupt
ERR_AMPLITUDE_RESONANCE      // the meander found itself. resonating. please wait
WARN_JET_DISPLACEMENT_NORTH  // Arctic warming faster than expected. jet weakening. this is fine
FATAL: ATTRIBUTION_REQUEST   // user asked "was this climate change?" — stack trace lost

Known Bugs

Weakens as Arctic sea ice declines, producing wider meanders and longer blocking events. This was not in the original spec.
Will sometimes split into two discrete jets with no warning and no documentation.
Mid-

Edge Cases

Sorry. Previous section encountered a blocking event.

Occasionally stalls directly over a mountain range and just. stays.
Interacts with El Niño in ways that are technically understood and practically impossible to predict more than two weeks out.
Has no official error handling for simultaneous northern and southern hemisphere disruption. The fallback is: weather becomes news.

Changelog

Version	Notes
Pre-1850	Stable. Boring.
1.4.2	Minor amplitude increase. Noted.
2.0.0-beta	Arctic differential narrowing. Behavior increasingly erratic.
0.0.666-alpha	Current. Versioning rolled back because forward numbering felt optimistic.

FAQ

Q: Can it be stopped? A: No.

Q: Can it be predicted? A: Yes. For about 10 days. Then the butterfly effect files a merge conflict.

Q: Is it getting worse? A: That depends on what you mean by worse.

drafting spec…