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| Warnings and Alerts | |
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Issue Time: 2026 Sep 28 0500 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1,000pfu Continuation of Serial Number: 3746 Begin Time: 2026 Sep 26 1535 UTC Yesterday Maximum 2MeV Flux: 3060 pfu Max time: 2026 Sep 27 1720 UTC Space Weather Scales |
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| Current Condition and Alerts | |
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Issued: 2026 Sep 28 1205 UTC
Prepared
by the US Dept. of Commerce, NOAA, Space Weather Prediction
Center
Geophysical Alert Message Solar-terrestrial indices for 27 September follow. Solar flux 97 and estimated planetary A-index 8. The estimated planetary K-index at 1200 UTC on 28 September was 1.33. No space weather storms were observed for the past 24 hours. No space weather storms are predicted for the next 24 hours. Space Weather Scales |
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| Forecast Discussion | |
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Issued: 2026 Sep 28 1230 UTC
Prepared
by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction
Center
Solar Activity .24 hr Summary... Solar activity remained at low levels with C1 flares observed from Region 4535 (N12W31, Bxi/beta-gamma), which developed additional spots this period while the remaining regions were either stable or in decay. No Earth-directed CMEs were detected in available coronagraph imagery. .Forecast... Solar activity is likely to reach low levels with a slight chance for an M-flare (R1-R2/Minor-Moderate) on 28 Sep. Solar activity is expected to be very low over 29-30 Sep. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels, with a peak of 3,060 pfu at 27/1720 UTC. The greater than 10 MeV proton flux was steady at background levels. .Forecast... The greater than 2 MeV electron flux is expected to reach high levels on 28-30 Sep. The greater than 10 MeV proton flux is expected to persist at background levels through 30 Sep. Solar Wind .24 hr Summary... Solar wind parameters showed diminishing CH HSS influences and the return of ambient-like solar wind conditions. Total magnetic field strength was less than 5 nT throughout the reporting period, and the Bz component varied between +1/-2 nT. Solar wind speeds gradually decreased from 400 km/s at the beginning of the period to 350 km/s by the end. The phi angle was positive. .Forecast... Ambient solar wind conditions are expected to prevail over 28-30 Sep. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... The geomagnetic field is expected to be mostly quiet over 28-30 Sep. Space Weather Scales |
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| Three Day Forecast | |
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Issued: 2026 Sep 28 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 2 (below NOAA Scale levels). The greatest expected 3 hr Kp for Sep 28-Sep 30 2026 is 2.00 (below NOAA Scale levels). NOAA Kp index breakdown Sep 28-Sep 30 2026 Sep 28 Sep 29 Sep 30 00-03UT 0.67 1.67 1.67 03-06UT 1.67 2.00 1.67 06-09UT 1.00 1.67 1.67 09-12UT 1.67 1.00 1.33 12-15UT 1.67 1.00 1.33 15-18UT 0.67 1.00 1.00 18-21UT 0.67 1.67 1.00 21-00UT 1.67 1.67 1.67 Rationale: No G1 (Minor) or greater geomagnetic storms are expected. No significant transient or recurrent solar wind features are forecast. 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 28-Sep 30 2026 Sep 28 Sep 29 Sep 30 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 28-Sep 30 2026 Sep 28 Sep 29 Sep 30 R1-R2 5% 1% 1% R3 or greater 1% 1% 1% Rationale: No R1 (Minor) or greater radio blackouts are expected. No significant active region flare activity is forecast. Space Weather Scales |
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| Weekly Highlights and Forecasts | |
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Issued: 2026 Sep 28 0221 UTC
Prepared
by the US Dept. of Commerce, NOAA, Space Weather Prediction
Center
Highlights of Solar and Geomagnetic Activity 21 - 27 September 2026 Solar activity was at low levels throughout the summary period. Region 4534 (N11, L=075, class/area=Dai/050 on 22 Sep) produced the strongest flare of the period, an impulsive C3.1 flare at 26/1655 UTC. There were 13 other numbered active regions recorded on the visible disk this week but they all remained relatively simple and absent of any significant activity. No Earth-directed CMEs were observed in available coronagraph imagery. No proton events were observed at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 23 Sep, and 26-27 Sep due to influence from a positive polarity CH HSS. Geomagnetic field activity was at quiet levels from 21-23 Sep. A CIR ahead of a positive polarity CH HSS caused active levels over 24-27 Sep. Total magnetic field strength reached 15 nT during the CIR on 24 Sep, with the Bz component rotating as far south as -12 nT. Solar wind speeds steadily increased from below 300 km/s on 23 Sep to a peak of ~525 km/s by 25 Sep. Both total magnetic field strength and solar wind speeds gradually declined during the waning phase of the coronal hole HSS over 26-27 Sep. Forecast of Solar and Geomagnetic Activity 28 September - 24 October 2026 Solar activity is likely to continue at very low to low levels throughout the outlook period. 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 from 28 Sep-03 Oct, 05 Oct-11 Oct, and 23-24 Oct due to anticipated influence from multiple, recurrent, CH HSSs. Moderate levels are likely over the remainder of the outlook period. Geomagnetic field activity is likely to reach G1 (Minor) geomagnetic storm levels on 22 Oct. Active conditions are likely over 04-06 Oct, 21 Oct, and 23-24 Oct. Unsettled conditions are likely over 07-08 Oct and 11-14 Oct. All increases in geomagnetic activity are associated with anticipated influence from multiple, recurrent, coronal hole HSSs. The remainder of the outlook period is likely to be at mostly quiet levels. 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. |
