SpaceWeatherTracker · NOAA sources
G3 Geomagnetic Storm: Strong
G3 is NOAA’s strong geomagnetic storm category, associated with Kp 7. It describes global magnetic disturbance, not a guarantee of local damage or visible aurora.
Latest geomagnetic reading
Kp 3.0
Below geomagnetic storm threshold
NOAA interval begins
Kp summarizes a three-hour interval. The page checks sources every five minutes; that is not NOAA's observation cadence.
Possible impacts
Power systems may require voltage corrections. Satellite navigation and low-frequency radio navigation can experience interruptions. NOAA’s scale lists possible effects, not a prediction that all of them will occur in each event.
Aurora during this storm level
Stronger storms can expand auroral activity toward lower magnetic latitudes. Your sky must still be dark and clear; local magnetic latitude and the event’s timing matter. Do not use a storm category as a precise city viewing boundary.
Is this level happening now?
Use the latest reporting interval and official NOAA notices below. This explainer remains useful outside a storm; its title does not claim an event is underway.
How to prepare
Aurora viewers should choose a safe, legal observing place and check local weather. Infrastructure operators should follow their established procedures and official warnings.
Recent NOAA notices
All notices and validity detailswarning
Kp 4 Geomagnetic Activity Warning
Issued
NOAA product text
Space Weather Message Code: WARK04 Serial Number: 5435 Issue Time: 2026 Oct 13 2058 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 5434 Valid From: 2026 Oct 13 0115 UTC Now Valid Until: 2026 Oct 14 1200 UTC Warning Condition: Persistence NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.
warning
Kp 4 Geomagnetic Activity Warning
Issued
NOAA product text
Space Weather Message Code: WARK04 Serial Number: 5434 Issue Time: 2026 Oct 13 1431 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 5433 Valid From: 2026 Oct 13 0115 UTC Now Valid Until: 2026 Oct 13 2100 UTC Warning Condition: Persistence NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.
warning
Kp 4 Geomagnetic Activity Warning
Issued · Valid to 2026-10-13T15:00:00.000Z
NOAA product text
Space Weather Message Code: WARK04 Serial Number: 5433 Issue Time: 2026 Oct 13 0115 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2026 Oct 13 0115 UTC Valid To: 2026 Oct 13 1500 UTC Warning Conditions: Onset Comment: NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.
watch · G1
G1 Geomagnetic Storm Watch
Issued
NOAA product text
Space Weather Message Code: WATA20 Serial Number: 1129 Issue Time: 2026 Oct 11 1911 UTC WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: Oct 12: None (Below G1) Oct 13: G1 (Minor) Oct 14: None (Below G1) THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT Comment: NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.
cancelled · G2
G2 Geomagnetic Storm Cancelled
Issued
NOAA product text
Space Weather Message Code: WATA30 Serial Number: 286 Issue Time: 2026 Oct 11 1702 UTC CANCEL WATCH: Geomagnetic Storm Category G2 Predicted Cancel Serial Number: 285 Original Issue Time: 2026 Oct 09 1636 UTC Cancelled Level Predicted: Oct 11 : None (Below G1) Conditions no longer warrant a G2 Watch. NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude. Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. Radio - HF (high frequency) radio propagation can fade at higher latitudes. Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.
Recent products can include expired, superseded or cancelled notices. Read the original product before treating it as an active warning.
Sources and limitations
Independent interpretation by SpaceWeatherTracker; official measurements and notices are attributed to NOAA. Not for safety-of-life or operational decisions.