:Product: Forecast Discussion :Issued: 2026 Jul 31 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 4492 (N15W82, Hax/alpha) produced a long-duration M1.9/Sf (R1-Minor) flare at 30/1700 UTC. Coinciding with the flare was an approximately eight-degree-long filament eruption, centered near N20W67. Additionally, two Type II radio sweeps were observed: the first at 30/1627 UTC (est.853 km/s), and the second at 30/1645 UTC (est. 1,681 km/s). Other radio events included a Type IV sweep at 30/1631 UTC, and a 17-minute-long Tenflare (190 sfu) that peaked at 30/1643 UTC. A partial-halo CME was observed in GOES CCOR2 coronagraph imagery, beginning at 30/1715 UTC, as well as a full-halo signature in STEREO COR2 coronagraph imagery at 30/1653 UTC. Results from WSA-Enlil runs suggested possible arrival at Earth early on 02 Aug. Regions 4500 (N18E35, Dao/beta), 4498 (N14E29, Dai/beta0gamma), 4499 (N05W02, Dao/beta-gamma-delta), and 4496 (N05W31, Cao/beta) all exhibited growth over the past 24 hours. Only minor changes were observed in the remaining numbered active regions on the visible disk. .Forecast... Solar activity is expected to be low with a chance for M-class flares (R1-R2, Minor-Moderate) over 31 Jul - 02 August. 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 reached S1 (Minor) storm levels at 30/1845 UTC, peaked at 18 pfu at 30/2055 and fell below S1 after 30/0715 UTC. Additionally, the greater than 100 MeV proton flux briefly exceeded 1 pfu at 30/1825 UTC. All proton flux enhancements were likely associated with the M1.9/Sf flare from Region 4492 mentioned above. .Forecast... The greater than 2 MeV electron flux is likely to remain at normal to moderate levels over the next three days. There remains a chance for the greater than 10 MeV proton flux to reach S1 levels over 31 Jul and 01 Aug. Solar Wind .24 hr Summary... Solar wind parameters were at nominal levels. Total magnetic field strength was below 5 nT. Solar wind speeds were mostly between ~300-330 km/s. Phi angle was predominantly oriented in the positive solar sector. .Forecast... There is a diminishing chance for a disturbed solar wind environment on 31 July as the CMEs from 26 and 27 July may yet graze the Earth. An additional disturbance is possible on 01 August with the arrival of an additional CME that left the Sun late on 27 July combined with weak CH HSS influence. A more pronounced enhancement in solar wind parameters is likely early on 02 Aug as the CME that left the Sun on 30 Jul passes by Earth. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... Quiet to unsettled conditions, with a chance for isolated active periods, are still possible on 31 Jul, persisting through 01 August due to weak positive polarity CH HSS influences and a combination of either glancing or relatively weak CME effects from events that left the Sun over the course of 26 and 27 July. G1-G2 (Minor-Moderate) storm levels are likely on 02 Aug due to the arrival of a CME that left the Sun on 30 Jul.