CAP‑Warn

NOAA / NWS Weather Alerts for ASL3 and AllStar — Modern Skywarn Replacement

**© 2023–2026 KJ5MZL / WRXB288 — la2way.com • lagmrs.com — All Rights Reserved.**

Read the CAP‑Warn Release Blog Post

Software made in loUiSiAna — it’s just better.
No more manually installing on ASL3. All my programs now include an installer and an update repository.

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About CAP‑Warn

CAP‑Warn is a 100% new not based on any other code, actively maintained weather alert system for Linux hosts.
It monitors National Weather Service (NWS) CAP alerts, generates automated audio warnings, and includes high‑temperature monitoring for Raspberry Pi systems.

This repository contains the APT repository files used for installation and updates.
If you want to install CAP‑Warn on a supported Linux system, use the one‑line installer below.

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Installation (One‑Line Installer)

For Debian‑based systems:

curl -fsSL https://raw.githubusercontent.com/tmastersmart/cap-warn/main/install_capwarn.sh | sudo bash

You may also view the installer online if you wish.

The installer will:

• Install the CAP‑Warn APT signing key
• Add the CAP‑Warn APT repository
• Update your package list
• Install the cap-warn package

You may want to read the blog first:
Visit the CAP‑Warn Blog

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VoiceRSS API Key (Optional)

CAP‑Warn supports VoiceRSS Text‑To‑Speech for higher‑quality audio output.
You can obtain a free API key here:

VoiceRSS Website

If you do not provide a key, CAP‑Warn will fall back to the built‑in ASL3 TTS system.

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Automatic Updates

Once installed, CAP‑Warn updates automatically through APT.

To manually update:

sudo apt update sudo apt upgrade cap-warn

No more manual installs — CAP‑Warn now updates with your normal system packages.

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Features

• Automatic GPS‑Based Alert Targeting
  CAP‑Warn uses your latitude and longitude to automatically determine your forecast zone, county/parish zone, and fire weather zone. No UGC codes or manual configuration required.

• NWS CAP Alert Monitoring
  Continuously monitors the National Weather Service CAP feed for watches, warnings, advisories, and special weather statements relevant to your exact location.

• Hurricane & Tropical Cyclone Tracking
  Automatically fetches National Hurricane Center (NHC) cyclone advisories and announces only new advisories, with distance filtering to avoid irrelevant storms.

• High‑Quality Text‑to‑Speech
  Supports VoiceRSS for natural‑sounding speech, with fallback to ASL3’s built‑in TTS if no API key is provided.

• Automatic APT Updates
  CAP‑Warn installs as a Debian package and updates through your normal apt upgrade process — no more manual installs or script replacements.

• Smart Cron Scheduling
  Runs on a safe, offset schedule that avoids the top‑of‑hour NWS/NHC update storm and system clock sync events.

• Zone + Point Alert Merging
  Combines point‑based alerts with zone‑level alerts to ensure complete coverage, including polygon warnings and county‑wide advisories.

• Pi Temperature Monitoring
  Monitors Raspberry Pi CPU temperature and issues alerts if overheating is detected.

• Installer + Setup Wizard
  One‑line installer, automatic repo setup, and a guided setup script that configures everything without requiring technical knowledge.

• Actively Maintained
  100% original code written in PHP — not based on Skywarn, SkywarnPlus, or any legacy scripts. Fully maintained and updated.

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Goals

1. Create a modern replacement for Skywarn/SkywarnPlus
   No Perl, no reused code — CAP‑Warn is 100% new and written entirely in PHP.

2. Make installation and updates effortless
   Everything installs via APT and updates automatically.
   No zone codes, no UGC lists — just enter your latitude and longitude.

3. Provide hurricane monitoring for coastal users
   CAP‑Warn tracks active cyclones and reports new advisories as they are released by the National Hurricane Center.

4. Provide a light weight utility that wont overload the cpu. Overloading the CPU is a major problem on HUBs and pis so we need to keep the package light and exit when done.

Why I Use Cron Instead of a System Service

CAP‑Warn is designed to run as a lightweight polling script, not a full‑time daemon. It wakes up, checks for new alerts, processes them, and exits. Because of this design, using cron is the most efficient and reliable choice. Cron allows users to choose how often CAP‑Warn runs, supports safe offset scheduling to avoid the top‑of‑hour NWS/NHC update surge, and keeps the system simple without requiring a persistent background service. A systemd service is ideal for programs that must run continuously or restart automatically, but CAP‑Warn doesn’t need that overhead. Cron provides predictable timing, low resource usage, and easy user configuration — making it the right tool for this job. And keeping with goal 4 above.

(c)2023/2026 All rights reserved. I wrote it.