Routine Space Environment Product (Daily)
Issued by NWS
Issued by NWS
393 FXXX12 KWNP 181231 DAYDIS :Product: Forecast Discussion :Issued: 2026 Aug 18 1230 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # http://www.swpc.noaa.gov/wwire.html # # Forecast Discussion # Solar Activity .24 hr Summary... Solar activity remained at low levels with 4 active regions on the visible disk. The majority of the C-class activity was originated from Region 4510 (N12W74, Dai/beta), including a C2.0 flare at 17/1653 UTC that was associated with a Type II radio sweep (825 km/s). Region 4507 (N04W48, Ekc/beta-gamma-delta) continued to develop and was responsible for the largest flare of the period: a C3.9/Sf at 18/0643 UTC. Region 4506 (N12W65, Dao/beta-gamma) showed a slight development while Region 4508 (N08W16, Cao/beta) remained mostly stable during the day. The narrow CME observed off the NW limb at 17/1845 UTC was analyzed and no associated impact near-Earth is anticipated. No other Earth-directed CME was observed during the period. .Forecast... Solar activity is expected to continue at low levels on 18-20 Aug, with a high chance for M-class flares (R1-R2, Minor-Moderate) and a slight chance for X-class (R3, Strong) events. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux at geosynchronous orbit remained at normal to moderate levels. The greater than 10 MeV proton flux at geosynchronous orbit remained at background levels. .Forecast... The greater than 2 MeV electron flux is likely to remain at low to moderate levels through 19 Aug, reaching high levels on 20 Aug due to upcoming HSS influences. The greater than 10 MeV proton flux is expected to remain at background levels through 20 Aug. Solar Wind .24 hr Summary... Solar wind parameters became enhanced after 17/1720 UTC, possibly due to flanking influences from the 14 Aug CME and/or a CIR preceding a negative polarity CH HSS. Total field strength increased from 6 to 16 nT while the Bz component reached as south as -12 nT. Bz remained positive from 18/0430 UTC until the end of the period. Solar wind speed increased from approximately 300 km/s to near 400 km/s. Phi angle was variable. .Forecast... CME and/or CIR influences are expected to continue until late 18 Aug, when a transition into a negative polarity CH HSS is anticipated. HSS conditions are expected to then continue through 20 Aug. Geospace .24 hr Summary... The geomagnetic field was at quiet to G1 (Minor) storm levels, due to the presence of solar wind transients near Earth, associated with the CME that left the Sun on 14 Aug and/or the onset of the CIR ahead of the anticipated -CH HSS. .Forecast... Unsettled to active levels are expected through 20 Aug, with a remaining chance for G1 (Minor) storm conditions on 18 Aug as possible CME and/or CIR onset activity persists. Periods of G1 storms are likely on 19 Aug due to increased -CH HSS influences.