:Product: Weekly Highlights and Forecasts :Issued: 2026 Jun 08 0243 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # https://www.swpc.noaa.gov/content/subscription-services # # Weekly Highlights and Forecasts # Highlights of Solar and Geomagnetic Activity 01 - 07 June 2026 Solar activity reached high levels on 03 Jun when Region 4455 (N14, L=88, class/area=Dki/360 on 03 Jun) produced an M9.3/Sf flare (accompanied by Type-II (253 km/s) and Type-IV sweeps, and a 360 sfu Tenflare) at 03/0136 UTC, followed by an M7.7/1b flare (accompanied by Type-II (313 km/s) and Type-IV radio sweeps, and a 540 sfu Tenflare with Castelli-U signature) at 03/0700 UTC, and finally an X1.0/1n flare (accompanied by a Type-IV sweep and a 180 sfu Tenflare) at 03/1128 UTC. The CMEs associated with the three significant flares from AR4455 on 03 Jun arrived at Earth on 05 Jun. Other activity included an M1.8/2n (accompanied by Type-II (838 km/s) and 190 sfu Tenflare) flare at 06/1401 UTC from Region 4461 (S20, L=09, class/area=Dao/70 on 02 Jun). The resulting partial-halo CME, first visible in LASCO C2 imagery at 06/1401 UTC, is anticipated to arrive at Earth around midday on 08 Jun. The greater than 10 MeV proton flux became slightly enhanced after midday on 06 Jun following the M1.8/2n flare at 06/1401 UTC from Region 4461, but remained below event levels with a peak flux of 1.0 pfu observed at 06/1940 UTC. The greater than 10 MeV proton flux gradually returned to background levels on 07 Jun. The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels on 01-05 Jun, with high levels observed on 06-07 Jun. Geomagnetic field activity reached G1-G2 (Minor-Moderate) storm levels on 05 Jun, and active levels on 06 Jun, following the arrival and passage of the CMEs from 03 Jun. The shock arrival was observed beginning at around 05/0425 UTC, and in the hours following the total magnetic field strength (Bt) reached 20 nT, the Bz component reached as far southward as -17 nT, and solar wind speeds increased to a peak near 740 km/s. Quiet and quiet to unsettled levels under weak coronal hole high speed stream influences prevailed throughout the remainder of the period. Forecast of Solar and Geomagnetic Activity 08 June - 04 July 2026 Solar activity is expected to be at predominately low levels through 04 Jul, with M-class flare probabilities ranging from a chance to likely levels throughout the period. No proton events are expected at geosynchronous orbit, barring significant flare activity. The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on 09-10, 13-18 Jun and 04 Jul. Normal to moderate levels are expected to prevail throughout the remainder of the period. Geomagnetic field activity is likely to reach G1-G3 (Minor-Strong) storm levels on 08 Jun, with G1-G2 (Minor-Moderate) levels likely on 09 Jun, due to the anticipated arrival of the CME that left the Sun on 06 Jun. Periods of active conditions are likely on 23-26 Jun due to recurrent CH HSS influences. Quiet and quiet to unsettled levels are expected to prevail throughout the remainder of the period.