Alerting Authority & NWWS OI

Alerting Authority & NWWS-OI 📡

SPCBot's primary mission is delivering severe weather information with the lowest possible latency. To achieve this, it utilizes a tiered hierarchy of data sources.

🥇 Gold Standard: NWWS-OI (XMPP)

The National Weather Service Weather Wire Service Open Interface is a satellite-sourced XMPP push feed.

• Latency: Near-zero. Products often arrive in Discord before they appear on the NWS API or IEM.
• Reliability: By connecting directly to nwws-oi.weather.gov, the bot receives raw text products as they are issued.
• Usage: Primarily used for TOR, SVR, and FFW warnings, as well as SVS updates and PNS damage surveys.

🥈 Silver Standard: IEMBot (XMPP/JSON)

The Iowa Environmental Mesonet (IEM) provides a robust real-time feed of NWS products via their iembot service.

• Latency: Low (1–5s).
• Fallback: Acts as the primary source for Mesoscale Discussions (MDs) and a redundant path for warnings if NWWS-OI is unreachable.
• Formatting: SPCBot leverages IEM's pre-parsed product text and autoplot maps for warnings.

🥉 Bronze Standard: NWS API & SPC Polling

Traditional polling via the NWS API (api.weather.gov) and spc.noaa.gov.

• Latency: Moderate (30–60s+).
• Role: Used for "Aggressive Checking" during Moderate/High risk days and for rehydrating state at startup.
• Persistence: ETag and Last-Modified headers are used to minimize bandwidth and detect updates efficiently.

🛡️ Circuit Breakers & Resilience

SPCBot implements Circuit Breakers for all upstream HTTP endpoints.

• If an endpoint (e.g., SPC website) fails multiple times, the bot "opens the circuit," stopping requests for a cooldown period to prevent loop starvation.
• Graceful Degradation: If the SPC website is down, the bot will attempt to serve cached MD images or fall back to text-only summaries from IEM.
• Watchdog: A background loop monitors feed health and proactively alerts administrators if both NWWS and IEM paths are down.