Weather monitoring for outdoor events is the single most consequential environmental signal SignalGuard tracks. According to FEMA's after-action reviews of US mass-gathering incidents, severe weather is the leading cause of fatal stage collapses, mass-evacuation calls, and unplanned show stops at outdoor festivals — the 2011 Indiana State Fair stage collapse and 2018 Pemberton Festival heat emergency are reference cases security ops teams still drill against. SignalGuard fuses live forecasts and active alerts at the venue's exact coordinates so your incident command knows what's actually coming, not what was forecast at 6 a.m.
What this signal monitors
The Weather signal tells you what the atmosphere is doing at the venue right now and what it will be doing through the event window. It covers temperature and RealFeel extremes, sustained wind and gust speed, precipitation probability, lightning proximity, and every active National Weather Service alert (tornado warning, severe thunderstorm, flood, heat advisory, wind advisory, winter storm, dense fog) whose polygon intersects your venue point.
Data sources
The default source is the US National Weather Service public API at api.weather.gov. NWS is free, requires no key, and is the authoritative US government forecast — the same data feed local TV stations and emergency managers consume. SignalGuard's weatherClient.js calls three NWS endpoints per scan: /points/{lat},{lon} to resolve your venue to a forecast zone and county warning area (CWA), the returned forecast URL for 7-day day/night periods, and /alerts/active?point={lat},{lon} for live watches and warnings. Venue coordinates come from OpenStreetMap Nominatim, which resolves both addresses and named venues like "Madison Square Garden."
NWS coverage is US-only. International venues automatically route to the premium AccuWeather provider when configured (see Premium upgrade path).
How SignalGuard scores severity
Every NWS alert carries a native severity (Extreme, Severe, Moderate, Minor, Unknown). SignalGuard maps these to our five-level scale: Extreme becomes critical, Severe becomes high, Moderate becomes medium. When NWS marks severity Unknown, the client falls back to event-name token matching — tornado, hurricane, flash flood, excessive heat, blizzard, and ice storm escalate to high; severe thunderstorm, flood warning, heat advisory, and high wind to medium. Forecast text for the event-day period is then re-scanned for the same tokens so a "thunderstorms likely" line in the detailed forecast can still raise the level even when no alert is yet active. The overall threat level is the maximum across all signals — a single tornado warning anywhere over the venue's coordinates trips the whole card to critical regardless of how clean the rest of the forecast looks.
Use cases for event security
- Heat-emergency staging. When the NWS issues an Excessive Heat Warning for the venue's county and the event-day RealFeel forecast exceeds 105°F, security pre-stages cooling stations, briefs medical, and validates radio comms for a possible ingress hold.
- Lightning hold protocol. When the forecast period flags isolated thunderstorms and active alerts include a severe thunderstorm watch, the production team enacts the 30/30 rule (suspend show 30 minutes after the last strike within 6 miles) without waiting for visual confirmation.
- Wind-driven structural risk. Sustained winds above 35 mph or gusts above 50 mph trigger pre-show LED-wall and rigging inspections; sub-cards on the SignalGuard weather widget surface exactly that wind reading from the forecast period covering your show window.
Pairs well with
- Severe-weather outlooks (SPC) — tomorrow's convective risk envelope when today's forecast is still clean.
- Air quality monitoring — wildfire smoke and ozone events that the weather card alone won't surface.
- Wildfire smoke monitoring — proximate hotspots that explain why AQI is rising.
Premium upgrade path
The default NWS source is US-only. For global venues, BYOK an AccuWeather API key on the Integrations page — SignalGuard's accuweatherClient.js adds MinuteCast (minute-by-minute precip for the next 2 hours), RealFeel temperature, and global severe-alert coverage with 5-day daily forecasts. AccuWeather Lightning Imminent Strikes (separate subscription) escalates the level to critical when a strike lands inside 5 miles of the venue. Alternative paid providers SignalGuard supports via BYOK include Tomorrow.io, IBM Environmental Intelligence (formerly The Weather Company), and DTN's MetService Pro feeds.
Frequently asked questions
Does SignalGuard monitor severe weather for outdoor events outside the US?
The free NWS path is US-only. Connect an AccuWeather, Tomorrow.io, or IBM Environmental Intelligence key on /integrations for global coverage at the same severity scale.
How often does the weather signal refresh? NWS forecasts update every hour and alerts within 60 seconds of issuance. SignalGuard rescans on every load of the event view and surfaces a "stale" indicator if the upstream call fails.
What weather conditions trigger a critical threat level? Any NWS alert marked Extreme severity (typical for tornado emergencies, hurricane warnings, or hazardous materials releases) escalates the level to critical. AccuWeather Lightning strikes within 5 miles also reach critical.
Does the weather card include lightning data? Only via the AccuWeather premium upgrade. The free NWS feed publishes thunderstorm forecasts and severe thunderstorm warnings but not real-time strike geometry.
Can I get hourly forecasts instead of 12-hour periods? Yes — when AccuWeather is connected, the hourly forecast and MinuteCast supersede the NWS day/night period model. See the Integrations page and SignalGuard docs hub.
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