NOAA Aurora Forecast: A Complete Guide to SWPC Products

The National Oceanic and Atmospheric Administration's Space Weather Prediction Center (NOAA SWPC), based in Boulder, Colorado, is the official U.S. government agency responsible for operational space weather forecasting. For aurora watchers worldwide, it is the single most important and authoritative source of geomagnetic activity predictions — and all its products are available free of charge.

SWPC is to space weather what the National Weather Service is to terrestrial weather: a center of professional human forecasters working 24/7, supported by a fleet of dedicated monitoring satellites and a suite of numerical models. Unlike commercial aurora apps that repackage NOAA data, SWPC is the original source — everything else ultimately derives from data they produce or collect.

SWPC's main operational inputs are the real-time solar wind measurements from the DSCOVR satellite (Deep Space Climate Observatory) and backup data from the older ACE satellite (Advanced Composition Explorer), both positioned at the L1 Lagrange point 1.5 million km toward the sun. From this vantage point, DSCOVR and ACE measure the solar wind's speed, density, temperature, and crucially, the magnetic field orientation (Bz) approximately 15–45 minutes before that solar wind reaches Earth's magnetosphere.

For aurora watchers, three SWPC products are immediately relevant: the 3-day geomagnetic forecast for trip planning, the 30-minute Ovation Prime model for real-time positioning, and the geomagnetic storm alerts and warnings for timely notification of major events. Understanding each of these is worth an investment of time — they are the foundation upon which every other aurora tool is built.

The Ovation Prime model is NOAA SWPC's near-real-time aurora oval prediction system and arguably the most practically useful aurora forecasting tool available anywhere. Developed from decades of satellite observations linking solar wind conditions to auroral emissions, the model ingests the latest DSCOVR solar wind measurements and computes where aurora is statistically expected to appear 30–40 minutes later — approximately the time it takes the measured solar wind to travel from the L1 point to Earth.

The model output is a polar projection map of the Northern Hemisphere (or Southern, for aurora australis). A colored ring or band overlaid on the map represents the predicted auroral oval, with intensity coded from green (very weak, visible only to sensitive cameras in complete darkness) through yellow and orange to red (bright, naked-eye visible even with some light pollution). The numbers shown at each point around the oval represent the energy flux in milliwatts per square meter — a direct measure of how much energy the aurora is depositing at each location.

How to use the Ovation map in practice:

• Locate your position on the map — the circular map is centered on the North Pole, with continents shown in gray. Find your approximate location.
• Check the oval's equatorward boundary — the southernmost edge of the colored ring is the equatorward limit of predicted aurora. If this boundary reaches or passes your location, aurora may be visible overhead or toward your northern horizon.
• Read the intensity color at your location — green means faint aurora (you may need to be fully dark-adapted and away from light pollution to see it); orange or red means bright aurora visible to the naked eye even from suburban locations.
• Refresh every 30 minutes during active conditions — the map updates every 30 minutes and can change dramatically as solar wind conditions evolve. A rapidly expanding oval during a southward Bz event is an immediate "go outside now" signal.

The key limitation: Ovation predicts where aurora should appear based on solar wind conditions, but it does not guarantee aurora below cloud cover, it does not predict sudden substorm brightening events perfectly, and it assumes a smooth response from the magnetosphere. Real aurora can be more patchy and dynamic than the smooth oval shown on the map. Use the Ovation map as a probability map, not a guarantee.

The NOAA 3-day geomagnetic forecast is the go-to product for planning aurora viewing over the next 72 hours. Published four times daily (at approximately 00:30, 06:30, 12:30, and 18:30 UTC), it is prepared by human space weather forecasters who combine automated model output with expert interpretation — the same methodology used for standard weather forecasting.

The forecast is structured as a table showing predicted KP index ranges for each of the next three days, divided into eight 3-hour windows per day (00–03, 03–06, 06–09 UTC, etc.). Each window is assigned a predicted maximum KP value and a general activity level label. The labels correspond to the G-scale:

• Quiet (KP 0–1): No significant activity. Aurora confined to latitudes above 68°N.
• Unsettled (KP 2): Slightly elevated but not stormy. Aurora still at high polar latitudes.
• Active (KP 3–4): Moderate activity — good conditions at 60–65°N. Northern Norway, Iceland, and northern Canada routinely see aurora at these levels.
• G1 Minor Storm (KP 5): First storm threshold — aurora can reach approximately 60°N. A meaningful event for mid-latitude European locations like Scotland or southern Scandinavia.
• G2 Moderate Storm (KP 6): Aurora reaches roughly 55°N — central and southern Scandinavia, Scotland, northern Germany. These events happen dozens of times per year near solar maximum.
• G3 Strong Storm (KP 7): Aurora can reach 50°N or lower — England, France, northern Germany, most of Canada, and the northern two-thirds of the United States. A major event.
• G4–G5 Severe/Extreme (KP 8–9): Rare but significant — aurora visible from 45°N or below, potentially covering southern Europe and much of the continental United States.

The written "Discussion" text that accompanies the numerical forecast is particularly valuable. Human forecasters explain the solar drivers behind the prediction — whether a specific CME has been tracked from the sun, whether a coronal hole stream is responsible, and what the key uncertainties are. Reading the discussion tells you not just what is predicted but how confident the forecasters are. When they identify a specific Earth-directed CME by time and source region, confidence is high. When the prediction is based on uncertain model runs, the discussion will reflect that caveat.

NOAA classifies geomagnetic storms on the G-scale from G1 (minor) to G5 (extreme), directly paralleling the system used for solar flare classification. Each category corresponds to a KP index range and has measurable consequences for aurora visibility, radio communications, and satellite operations.

G1 (KP 5) — Minor: Aurora typically visible from latitudes above 60°N on clear nights. Power grid fluctuations possible at high latitudes. Migratory animals may experience navigation disruption. These events occur approximately 1,700 times per 11-year solar cycle — essentially routine in terms of space weather, but meaningful for aurora watchers already at high-latitude destinations.

G2 (KP 6) — Moderate: Aurora visible from latitudes above ~55°N. High-latitude power grid equipment may experience voltage alerts. HF radio communication can be interrupted. Approximately 600 events per solar cycle. For mid-latitude aurora watchers in Scotland, southern Norway, and the northern United States, a G2 alert is a genuine "go outside" signal if skies are clear.

G3 (KP 7) — Strong: Aurora can reach ~50°N, visible from England, France, Germany, Poland, southern Canada, and most of the northern United States. Intermittent satellite navigation errors. Some power systems experience current anomalies. Approximately 200 events per cycle. The May 2024 event that lit up social media across Europe and North America was a G4–G5 event reaching well below 50°N.

G4 (KP 8) — Severe: Aurora may extend to ~45°N — northern France, southern Germany, New England. Widespread voltage control problems in power systems. Possible surface charging effects on satellites. Very rare — roughly 100 events over a full solar cycle. These events generate mainstream news coverage and photographs from locations that rarely see aurora.

G5 (KP 9) — Extreme: The highest category. Aurora visible from ~40°N or below. Widespread power grid disruptions and possible blackouts. GPS and HF radio severely degraded. Historical examples: the March 1989 storm that caused a Quebec power blackout, the October 2003 Halloween storms, and the May 2024 event. Only a handful of G5 events occur per solar cycle. For most aurora enthusiasts, a G3 storm is a dream event — perspective matters.

NOAA issues Watches (3-day window), Warnings (within 3 hours of expected onset), and Alerts (real-time, when thresholds are crossed) for each G-level storm. Sign up for aurora alert notifications to be notified automatically when SWPC issues a G2+ watch or warning.

NOAA SWPC publishes over 50 different forecast products, but aurora watchers need only a handful. Here is a guide to the most relevant ones, with notes on how to find and interpret each.

Or let Borealis read them for you: our app takes these same SWPC feeds and turns them into one probability score for your location, plus alerts when the numbers line up. It is coming to the App Store soon — get notified at launch.

3-Day Geomagnetic Forecast (Product: SWPC 3-day forecast): Updated four times daily. Shows predicted KP by 3-hour window for 72 hours ahead. The narrative "Discussion" section explains the solar drivers. This is your primary trip-planning tool — check it daily once you are within a week of your aurora travel.

Geomagnetic Activity Observed and Predicted (Product: Geomag Activity): Shows actual observed KP values for the past 24 hours alongside the forecast. The bar chart gives immediate context for how active conditions have been today. Useful for the "what happened last night" question.

Aurora 30-Minute Forecast (Product: Ovation Prime): The polar map updated every 30 minutes showing aurora oval position and intensity. Available on the SWPC website under the "Aurora" section. During active events, bookmark this and refresh it every 30 minutes.

Real-Time Solar Wind (Product: ACE/DSCOVR data): Live charts of solar wind speed, density, Bz, and Bt from the L1 monitoring satellites. Available under "Satellite" on the SWPC site. The Bz chart is the most critical — watch for sustained southward dips.

Geomagnetic Alerts and Warnings: Issued as bulletins when geomagnetic storm thresholds are crossed or expected. These are the products that trigger push notifications in aurora apps. Available on the SWPC alerts page and via email subscription at the SWPC website — free to subscribe.

27-Day Space Weather Outlook: A rough extended outlook showing expected geomagnetic activity levels over the coming 27 days based on the sun's rotation pattern. Useful for trip planning — if an active coronal hole is visible on the sun right now, this product will show an elevated-activity window approximately 27 days later when that region returns to an Earth-facing orientation.

For a curated list of the best NOAA and third-party tools combined, see our complete aurora forecast tools guide.