Solar Activity Alerts

:Product: Forecast Discussion :Issued: 2026 Jun 23 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity returned to low levels, with the largest flare of the period being a C1.5 at 22/0456 UTC from just behind the SE limb. Due to decreased foreshortening effects, old Region 4473 was deemed to be two separate groups and was split: Region 4473 (S09E40, Dai/beta-gamma), the western-most group that produced the M6.8 at 21/1929 UTC, and Region 4475 (S09E51, Cao/beta-gamma), the eastern-most group. Regions 4472 (S14E28, Dao/beta)exhibited minor growth. Several eruptions were seen over 20-21 Jun associated with activity from Regions 4472 and 4473, such as the M6.8. Analysis of the coronagraph imagery suggests each eruption is quite slow (~250 km/s or less); however modeling of them all together indicates that they may interact with each other and an anticipated CIR, resulting in possible minor glancing blows to Earth late on 24 Jun and potentially 28 Jun. .Forecast... Solar activity is expected to continue at predominately low levels on 23-25 Jun, with a chance for M-class (R1-R2/Minor-Moderate) flares due primarily to the flare potential of Region 4473 and a region seen in Solar Orbiter data about to rotate onto the eastern limb. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 23-25 Jun. The greater than 10 MeV proton flux is expected to persist at background levels through 24 Jun. Solar Wind .24 hr Summary... Solar wind parameters were at background levels this period, with total magnetic field strength (Bt) at or below 6 nT, no significant periods of southward Bz, phi largely positive, and solar wind speeds averaging 350 km/s. At 22/1815 UTC, a solar sector boundary crossing produced a bump in Bt, peaking at 7 nT, but no appreciable change in other solar wind parameters. .Forecast... Background solar wind conditions are expected to prevail through 23 Jun. Enhanced conditions are expected 24-25 Jun due to the anticipated onset of negative polarity CH HSS influences and a potential minor glancing blow from a CME that left the Sun on 20 Jun. Geospace .24 hr Summary... The geomagnetic field was at quiet levels. .Forecast... The geomagnetic field is expected to continue at mostly quiet levels through 23 Jun. Periods of active conditions are likely 24-25 Jun due to the anticipated onset of negative polarity CH HSS and glancing blow influences.

:Product: Forecast Discussion :Issued: 2026 Jun 23 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity returned to low levels, with the largest flare of the period being a C1.5 at 22/0456 UTC from just behind the SE limb. Due to decreased foreshortening effects, old Region 4473 was deemed to be two separate groups and was split: Region 4473 (S09E40, Dai/beta-gamma), the western-most group that produced the M6.8 at 21/1929 UTC, and Region 4475 (S09E51, Cao/beta-gamma), the eastern-most group. Regions 4472 (S14E28, Dao/beta)exhibited minor growth. Several eruptions were seen over 20-21 Jun associated with activity from Regions 4472 and 4473, such as the M6.8. Analysis of the coronagraph imagery suggests each eruption is quite slow (~250 km/s or less); however modeling of them all together indicates that they may interact with each other and an anticipated CIR, resulting in possible minor glancing blows to Earth late on 24 Jun and potentially 28 Jun. .Forecast... Solar activity is expected to continue at predominately low levels on 23-25 Jun, with a chance for M-class (R1-R2/Minor-Moderate) flares due primarily to the flare potential of Region 4473 and a region seen in Solar Orbiter data about to rotate onto the eastern limb. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 23-25 Jun. The greater than 10 MeV proton flux is expected to persist at background levels through 24 Jun. Solar Wind .24 hr Summary... Solar wind parameters were at background levels this period, with total magnetic field strength (Bt) at or below 6 nT, no significant periods of southward Bz, phi largely positive, and solar wind speeds averaging 350 km/s. At 22/1815 UTC, a solar sector boundary crossing produced a bump in Bt, peaking at 7 nT, but no appreciable change in other solar wind parameters. .Forecast... Background solar wind conditions are expected to prevail through 23 Jun. Enhanced conditions are expected 24-25 Jun due to the anticipated onset of negative polarity CH HSS influences and a potential minor glancing blow from a CME that left the Sun on 20 Jun. Geospace .24 hr Summary... The geomagnetic field was at quiet levels. .Forecast... The geomagnetic field is expected to continue at mostly quiet levels through 23 Jun. Periods of active conditions are likely 24-25 Jun due to the anticipated onset of negative polarity CH HSS and glancing blow influences.

:Product: Forecast Discussion :Issued: 2026 Jun 22 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached high levels. Region 4473 (S08E52, Fai/beta-gamma) produced an M6.8/2b flare (R2-Moderate) at 21/1929 UTC, with an associated Type-II radio sweep (est. 380 km/s); the strongest of the period. Regions 4472 (S13E34, Dao/beta) and 4473 exhibited minor growth, and new Region 4474 (N03W70, Cao/beta) was numbered. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to continue at predominately low levels on 22-24 Jun, with a chance for M-class (R1-R2/Minor-Moderate) flares due primarily to the flare potential of Region 4473. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 22-24 Jun. The greater than 10 MeV proton flux is expected to persist at background levels through 24 Jun. Solar Wind .24 hr Summary... Solar wind parameters were at background levels this period. Total magnetic field strength was at or below 6 nT. No significant periods of southward Bz were observed. Solar wind speeds varied between ~390-330 km/s. .Forecast... Background solar wind conditions are expected to prevail over 22-23 Jun. Enhanced conditions are expected on 24 Jun due to the anticipated onset of negative polarity CH HSS influences. Geospace .24 hr Summary... The geomagnetic field was at quiet levels. .Forecast... The geomagnetic field is expected to continue at mostly quiet levels over 22-23 Jun. Periods of active conditions are likely on 24 Jun due to the anticipated onset of negative polarity CH HSS influences.

:Product: Forecast Discussion :Issued: 2026 Jun 22 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached high levels. Region 4473 (S08E56, Eai/beta-gamma) produced an M2.6 flare at 21/0246 UTC, followed by an M6.8/2b flare (R2-Moderate) at 21/1929 UTC; the strongest of the period. A Type II radio sweep (est. 380 km/s) was associated with the second event. Further coronagraph imagery is need to determine if an Earth-directed CME was produced. The regions leader spots continued to develop over the past 24 hours. The other two spotted active regions on the disk only exhibited minor changes. .Forecast... Solar activity is expected to continue at predominately low levels on 22-24 Jun, with an increasing chance for M-class (R1-R2/Minor-Moderate) flares due primarily to the flare potential of Region 4473. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 22-24 Jun. The greater than 10 MeV proton flux is expected to persist at background levels through 24 Jun. Solar Wind .24 hr Summary... Solar wind parameters were at background levels this period. Total magnetic field strength was at or below 6 nT. No significant periods of southward Bz were observed. Solar wind speeds varied between ~390-330 km/s. Phi angle was oriented in a positive solar sector. .Forecast... Background solar wind conditions are expected to prevail over 22-23 Jun. Enhanced conditions are expected on 24 Jun due to the anticipated onset of negative polarity CH HSS influences. Geospace .24 hr Summary... The geomagnetic field was at quiet levels. .Forecast... The geomagnetic field is expected to continue at mostly quiet levels over 22-23 Jun. Periods of active conditions are likely on 24 Jun due to the anticipated onset of negative polarity CH HSS influences.

Space Weather Message Code: ALTTP2 Serial Number: 1507 Issue Time: 2026 Jun 21 1951 UTC ALERT: Type II Radio Emission Begin Time: 2026 Jun 21 1932 UTC Estimate Velocity: 380 km/s Comment:

Space Weather Message Code: SUMXM5 Serial Number: 319 Issue Time: 2026 Jun 21 1948 UTC SUMMARY: X-ray Event exceeded M5 Begin Time: 2026 Jun 21 1917 UTC Maximum Time: 2026 Jun 21 1929 UTC End Time: 2026 Jun 22 1935 UTC Xray Class: M6.8 Optical Class: 2b Location: S07E55 Noaa Scale: R2 - Moderate Comment: NOAA Scale: R2 - Moderate NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact centered primarily on sub-solar point on the sunlit side of Earth. Radio - Limited blackout of HF (high frequency) radio communication for tens of minutes.

Space Weather Message Code: ALTXMF Serial Number: 532 Issue Time: 2026 Jun 21 1930 UTC ALERT: X-Ray Flux exceeded M5 Threshold Reached: 2026 Jun 21 1927 UTC Noaa Scale: R2 - Moderate Comment: NOAA Scale: R2 - Moderate NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact centered on sub-solar point on the sunlit side of Earth. Extent of blackout of HF (high frequency) radio communication dependent upon current X-ray Flux intensity. For real-time information on affected area and expected duration please see http://www.swpc.noaa.gov/products/d-region-absorption-predictions-d-rap.

:Product: Forecast Discussion :Issued: 2026 Jun 21 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached moderate levels. Region 4473 (S08E63, Eao/beta) produced most of the flare activity this period, including an M2.6 flare (R1-Minor) at 21/0246 UTC; the strongest of the period. Regions 4472 (S14E49, Dao/beta) and 4473 underwent minor development, while the remaining regions were in decay. No Earth-directed CMEs were detected in available coronagraph imagery. .Forecast... Solar activity is expected to continue at predominately low levels on 21-23 Jun, with a chance for M-class (R1-R2/Minor-Moderate) flares. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 21-23 Jun. The greater than 10 MeV proton flux is expected to persist at background levels through 23 Jun. Solar Wind .24 hr Summary... Solar wind parameters returned to background levels this period. Total magnetic field strength reached 7 nT, and the Bz component ranged between +/-5 nT. Solar wind speeds were steady between 350-400 km/s, and the phi angle was predominately positive throughout the period. .Forecast... Background solar wind conditions are expected to prevail over 21-22 Jun. Enhanced conditions are expected on 23 Jun due to the anticipated onset of negative polarity CH HSS influences. Geospace .24 hr Summary... The geomagnetic field was at quiet levels. .Forecast... The geomagnetic field is expected to continue at mostly quiet levels over 21-22 Jun. Periods of active conditions are likely on 23 Jun due to the anticipated onset of negative polarity CH HSS influences.

:Product: Forecast Discussion :Issued: 2026 Jun 21 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached moderate levels. Region 4472 (S14E54, Dao/beta) produced an M1.3 flare (R1-Minor) at 20/0451 UTC, the strongest of the period. Newly numbered Region 4473 (S08E69, Eko/beta) added an M1.0/Sf (R1) at 20/1500 UTC, as well as a C4.8/Sf flare at 20/2205 UTC. Growth was observed in Region 4473 as it rotated further on to the visible disk. Multiple areas of pores were observed in the western hemisphere but most decayed before becoming sunspots. The remaining numbered active regions were either stable or in gradual decay. A CME associated with the M1.3 flare at 20/0151 UTC, and first visible in LASCO C2 imagery off the E at 20/0212 UTC, is expected to miss Earth. Another CME, first visible in C2 imagery at 20/0312 UTC, was associated with activity on the far side and is not Earth-directed. .Forecast... Solar activity is expected to continue at low levels on 21-23 Jun, with a chance for M-class (R1-Minor) flares due to the increased magnetic complexity of Regions 4472 and 4473. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached moderate levels. The greater than 10 MeV proton flux remained at background values. .Forecast... The greater than 2 MeV electron flux is expected to remain at moderate levels over 21-23 Jun. The greater than 10 MeV proton flux is expected to remain at background levels through 23 Jun. Solar Wind .24 hr Summary... Solar wind parameters remained mildly enhanced. Total magnetic field strength was between 5-7 nT. The Bz component was briefly observed as far south as -7 nT. Solar wind speeds were between 360-419 km/s. Phi angle was oriented in a positive solar sector. .Forecast... Solar wind parameters are expected to transition to background levels over 21 Jun. Background levels are expected to persist through 23 Jun. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels under waning CH HSS influences. .Forecast... The geomagnetic field is expected to continue at quiet to unsettled levels on 21 Jun as CH HSS influences diminish. Mostly quiet conditions are expected to prevail over 22-23 Jun.

:Product: Forecast Discussion :Issued: 2026 Jun 20 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached moderate levels when Region 4472 (S14E61, Cao/beta) produced an M1.3 flare (R1-Minor) at 20/0151 UTC; the strongest of the period. Region 4470 (N08E21, Dao/beta) exhibited minor growth this period and produced a C1.4 flare at 20/0307 UTC that was accompanied by a Type-II radio sweep (~300 km/s). The remaining regions were either stable or in decay. New spots were observed rotating into view on the E limb near S08, but these remain unnumbered pending additional observational data. A CME associated with the M1.3 flare at 20/0151 UTC, and first visible in LASCO C2 imagery off the E at 20/0212 UTC, is expected to miss Earth. Another CME, first visible in C2 imagery at 20/0312 UTC, was associated with activity on the far side and is not Earth-directed. .Forecast... Solar activity is expected to continue at low levels on 20-22 Jun, with a slight chance for M-class (R1-Minor) flares. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached moderate levels. The greater than 10 MeV proton flux remained at background values. .Forecast... The greater than 2 MeV electron flux is expected to reach moderate levels over 20-22 Jun. The greater than 10 MeV proton flux is expected to remain at background levels through 22 Jun. Solar Wind .24 hr Summary... Solar wind parameters remained mildly enhanced under positive polarity CH HSS influences. Total magnetic field strength reached 10 nT, and the Bz component was observed as far south as -7 nT. Solar wind speeds ranged between ~360-460 km/s. Phi angle was primarily oriented in a positive solar sector. .Forecast... Solar wind parameters are expected to remain slightly enhanced through 21 Jun due to CH HSS influences. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels under waning CH HSS influences. .Forecast... The geomagnetic field is expected to continue at quiet to unsettled levels on 20-21 Jun as CH HSS influences diminish. Mostly quiet conditions are expected to prevail on 22 Jun.

Space Weather Message Code: ALTTP2 Serial Number: 1506 Issue Time: 2026 Jun 20 0407 UTC ALERT: Type II Radio Emission Begin Time: 2026 Jun 20 0407 UTC Estimate Velocity: 300 km/s Comment:

Space Weather Message Code: ALTTP2 Serial Number: 1505 Issue Time: 2026 Jun 20 0406 UTC CANCEL ALERT: Type II Radio Emission Cancel Serial Number: 1504 Original Issue Time: 2026 Jun 20 0403 UTC Cancelling duplicate Type-II Alert Cancelling duplicate Type-II Alert

Space Weather Message Code: ALTTP2 Serial Number: 1504 Issue Time: 2026 Jun 20 0403 UTC ALERT: Type II Radio Emission Begin Time: 2026 Jun 20 0300 UTC Estimate Velocity: 300 km/s Comment: