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| Warnings and Alerts | |
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Issue Time: 2026 Sep 21 1832 UTC
WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: Sep 22: None (Below G1) Sep 23: None (Below G1) Sep 24: G1 (Minor) THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT 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. Space Weather Scales |
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| Current Condition and Alerts | |
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Issued: 2026 Sep 24 1205 UTC
Prepared
by the US Dept. of Commerce, NOAA, Space Weather Prediction
Center
Geophysical Alert Message Solar-terrestrial indices for 23 September follow. Solar flux 121 and estimated planetary A-index 4. The estimated planetary K-index at 1200 UTC on 24 September was 4.33. No space weather storms were observed for the past 24 hours. Space weather for the next 24 hours is predicted to be minor. Geomagnetic storms reaching the G1 level are likely. Space Weather Scales |
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| Forecast Discussion | |
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Issued: 2026 Sep 24 1230 UTC
Prepared
by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction
Center
Solar Activity .24 hr Summary... Solar activity continued at low levels with occasional C-class flaring. The largest event of the period was a C1.5 flare at 24/0903 UTC from Region 4536 (N02W33, Dsi, beta). Eight numbered sunspot regions are present on the visible disk. Region 4535 (N12E29, Dso/beta) saw new flux emergence in its trailing spots. Region 4536 continued to grow, consolidating at both magnetic poles. Region 4537 (N07W47, Dao/beta) experienced growth and consolidation, primarily within its trailing portion. Region 4542 (S18E29, Bxo/beta) was numbered during the period. All other regions were stable or in a state of decay. A solar filament near S21E26 lifted off around 23/1600 UTC. While observations were partially hindered by data gaps in COR2 imagery, available coronagraph imagery indicates the material was reabsorbed. No Earth-directed CMEs were observed. .Forecast... Solar activity is likely to continue at low levels with isolated to occasional C-class flare activity, along with a slight chance for R1-R2 (Minor-Moderate) M-class flare events, through 26 Sep. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels, but crossed briefly crossed 1,000 pfu in an unsustained fashion at 23/1700 UTC. The greater than 10 MeV proton flux remained steady at background levels. .Forecast... The greater than 2 MeV electron flux is expected to cross into high levels above 1,000 pfu in geosynchronous orbit beginning on 24 Sep and remaining at high levels through 26 Sep. The greater than 10 MeV proton flux is expected to persist at background levels through 26 Sep. Solar Wind .24 hr Summary... Solar wind parameters reflected the ongoing onset and strengthening of positive polarity coronal hole high-speed stream (+CH HSS) influences. Total magnetic field strength (Bt) increased, ranging between 10 and 15 nT late in the period. The North-South (Bz) component experienced notable southward deflections, reaching a peak negative excursion near -13 nT around 24/0520 and 24/0815 UTC. Solar wind speeds steadily increased throughout the period, rising from early values near 280-290 km/s to 380-410 km/s late in the period. The phi angle shifted into a predominantly positive (away from the Sun) sector. .Forecast... Faster solar wind associated with the aforementioned positive polarity CH HSS is anticipated to arrive during the first half of 24 Sep. Enhanced conditions are expected to then persist through 25 Sep before beginning to slowly wane over the course of 26 Sep. Geospace .24 hr Summary... The geomagnetic field reached unsettled to active levels later in the reporting period under strengthening +CH HSS influences. .Forecast... Isolated periods of G1 (Minor) geomagnetic storms are likely on 24 Sep as +CH HSS influences strengthen. Isolated active levels are likely to persist into 25 and 26 Sep as disturbances continue, but gradually diminish. Space Weather Scales |
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| Three Day Forecast | |
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Issued: 2026 Sep 24 1230 UTC
Prepared
by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction
Center
A. NOAA Geomagnetic Activity Observation and Forecast The greatest observed 3 hr Kp over the past 24 hours was 4 (below NOAA Scale levels). The greatest expected 3 hr Kp for Sep 24-Sep 26 2026 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown Sep 24-Sep 26 2026 Sep 24 Sep 25 Sep 26 00-03UT 3.00 3.67 3.00 03-06UT 2.33 3.67 3.67 06-09UT 3.00 3.00 2.67 09-12UT 4.33 2.67 2.00 12-15UT 2.33 2.33 1.67 15-18UT 2.33 3.00 2.33 18-21UT 3.00 3.33 2.33 21-00UT 4.67 (G1) 3.00 2.67 Rationale: G1 (Minor) geomagnetic storming is likely on 24 Sep due to positive polarity CH HSS influences. Unsettled to active levels are expected to persist on 25 and 26 Sep as HSS effects gradually wane. B. NOAA Solar Radiation Activity Observation and Forecast Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was below S-scale storm level thresholds. Solar Radiation Storm Forecast for Sep 24-Sep 26 2026 Sep 24 Sep 25 Sep 26 S1 or greater 1% 1% 1% Rationale: No S1 (Minor) or greater solar radiation storms are expected. No significant active region activity favorable for radiation storm production is forecast. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Sep 24-Sep 26 2026 Sep 24 Sep 25 Sep 26 R1-R2 20% 20% 20% R3 or greater 1% 1% 1% Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio blackouts through 26 Sep primarily due to the flare potential of Active Regions 4536, 4538, and 4537. Space Weather Scales |
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| Weekly Highlights and Forecasts | |
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Issued: 2026 Sep 21 0317 UTC
Prepared
by the US Dept. of Commerce, NOAA, Space Weather Prediction
Center
Highlights of Solar and Geomagnetic Activity 14 - 20 September 2026 Solar activity was at very low levels on 14-18 Sep and increased to low levels on 19-20 Sep. Region 4535 (N12, L=353, class/area Hrx/020 on 20 Sep) produced a C1.1 flare at 20/0518 UTC, while Region 4534 (N11, L=074, class/area Dro/030 on 20 Sep) produced a C3.7/1f flare at 20/2234 UTC, the largest of the period. No Earth-directed CMEs were detected during the highlight period. No proton events were observed at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 14 Sep when a maximum flux of 4,650 pfu was observed at 14/1315 UTC. Low to moderate levels were observed on 15-20 Sep. Geomagnetic field activity reached unsettled levels on 14-17 Sep, with isolated active levels observed on 14 and 16 Sep. Unsettled to active levels were observed on 14 Sep due to a southern hemisphere filament eruption coupled with a SSBC. Unsettled levels were observed on 15-17 Sep, with an isolated active period early on 16 Sep, all due to negative polarity CH HSS effects. Quiet to isolated unsettled levels were observed on 18-20 Sep. Forecast of Solar and Geomagnetic Activity 21 September - 17 October 2026 Solar activity is expected to be at low levels, with a slight chance for moderate to high levels throughout the forecast period. </span> No proton events are expected at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 26-30 Sep, 01-03 Oct, and 05-11 Oct. Low to moderate levels are expected on 21-25 Sep, 04 Oct, and 12-17 Oct. Geomagnetic field activity is expected to reach active to G1 storm levels on 24-25 Sep due to positive polarity CH HSS effects. Unsettled to active levels are expected on 26-27 Sep and 04-08 Oct due to positive polarity CH HSS effects. Quiet to unsettled levels are expected on 11-14 Oct due to negative polarity CH HSS effects. Largely quiet levels are anticipated for all remaining dates in the forecast period. Space Weather Scales |
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| About AIA Images | |
| The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) is designed to provide an unprecedented view of the solar corona, taking images that span at least 1.3 solar diameters in multiple wavelengths nearly simultaneously, at a resolution of ~ 1 arcsec and at a cadence of 10 s or better. The primary goal of the AIA Science Investigation is to use these data, together with data from other SDO instruments and from other observatories, to significantly improve our understanding of the physics behind the activity displayed by the Sun's atmosphere, which drives space weather in the heliosphere and in planetary environments. The AIA will produce data required for quantitative studies of the evolving coronal magnetic field, and the plasma that it holds, both in quiescent phases and during flares and eruptions; the AIA science investigation aims to utilize these data in a comprehensive research program to provide new understanding of the observed processes Left Click Image for screen size, Right Click Image and open in new tab for full size. | |
| Daily Image AIA 171 | |
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| Daily Image AIA 171 PFSS Model | |
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| Daily Image AIA 193 | |
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| Daily Image AIA 304 | |
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| Daily Video AIA 171 | |
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| Daily Video AIA 171 PFSS Model | |
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| Daily Video AIA 193 | |
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| Daily Video AIA 304 | |
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| About the HMI Images | |
| (Helioseismic and Magnetic Imager) HMI is an instrument designed to study oscillations and the magnetic field at the solar surface, or photosphere. HMI is one of three instruments on the Solar Dynamics Observatory; together, the suite of instruments observes the Sun nearly continuously and takes a terabyte of data a day. HMI observes the full solar disk at 6173 Å with a resolution of 1 arcsecond. HMI is a successor to the Michelson Doppler Imager on the Solar and Heliospheric Observatory. This is very much how the Sun looks like in the visible range of the spectrum (for example, looking at it using special 'eclipse' glasses: Remember, do not ever look directly at the Sun!). The magnetogram image shows the magnetic field in the solar photosphere, with black and white indicating opposite polarities. Left Click Image for screen size, Right Click Image and open in new tab for full size. | |
| Daily Image HMI Continuum | |
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| Daily Image HMI Magnetogram | |
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| Daily Video HMI Continuum | |
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| Daily Video HMI Magnetogram | |
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| About LASCO Images | |
| LASCO (Large Angle Spectrometric Coronagraph) is able to take images of the solar corona by blocking the light coming directly from the Sun with an occulter disk, creating an artificial eclipse within the instrument itself. The position of the solar disk is indicated in the images by the white circle. The most prominent feature of the corona are usually the coronal streamers, those nearly radial bands that can be seen both in C2 and C3. Occasionally, a coronal mass ejection can be seen being expelled away from the Sun and crossing the fields of view of both coronagraphs. The shadow crossing from the lower left corner to the center of the image is the support for the occulter disk. C2 images show the inner solar corona up to 8.4 million kilometers (5.25 million miles) away from the Sun. C3 images have a larger field of view: They encompass 32 diameters of the Sun. To put this in perspective, the diameter of the images is 45 million kilometers (about 30 million miles) at the distance of the Sun, or half of the diameter of the orbit of Mercury. Many bright stars can be seen behind the Sun. Left Click Image for screen size, Right Click Image and open in new tab for full size. | |
| Combined C2 C3 and AIA 304 | |
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| Log Polar View C2 C3 and AIA 304 | |
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| Combined C2 C3 and AIA 304 Video | |
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| Log Polar View C2 C3 and AIA 304 Video | |
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| Space Weather Videos | |
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| Space Weather Information | |
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Demystifying Space Weather An article by Scientific Frontline Informative information and glossary about “Space Weather” Space weather has become increasingly important in our modern world due to our growing reliance on technology. It can impact various aspects of our daily lives, from communication and navigation systems to power grids and even astronaut safety. In this deep dive, we'll explore the intricacies of space weather, its causes, its effects, and why understanding it is crucial in our technology-dependent society. |
