Space Weather Forecast - Discussion

Issued: 2025 Aug 15 0030 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center and processed by SpaceWeatherLive.com

Solar activity

24 h Summary

Solar activity has been at low levels with only C-class flares observed. There are 13 regions on the disk with most being simple in magnetic complexity. Region 4172 (N09W59, Dai/beta-gamma) continued to decay with its magnetic field decreasing in complexity. Region 4178 (N09W90, Dso/beta) looks to be decreasing in its complexity but due to the limb effect, analysis has become difficult. No Earth-directed CMEs were observed in available coronagraph imagery.

Forecast

Solar activity is likely to continue at low levels through 17 August. Despite their decreasing activity, Regions 4172 & 4178 will help maintain a slight chance (35%) for isolated M-class flares (R1-2/Minor-Moderate radio blackouts) in the forecast through 15 Aug. Chances decrease to 30% as the regions move beyond the western limb.

Energetic Particles

24 h Summary

Persistent high speed stream (HSS) influence from the large, positive polarity CH in the southern hemisphere caused the greater than 2 MeV electron flux to surpass - for the fifth day in a row - the 1,000 particle flux units (pfu) on both GOES satellites. The GOES-19 satellite observed a peak of 3,820 pfu at 14/0500 UTC. The greater than 10 MeV proton flux remained at background.

Forecast

Waning influences from the CH HSS will steadily decrease the flux of 2 MeV electrons, but concentrations at geostationary orbit will remain high most likely through 17 Aug. Last rotation, electrons remained significantly above the 1,000 pfu threshold for seven days with diurnal maximas above threshold for 11 days. The greater than 10 MeV proton flux is expected to remain at background levels through 17 August. There remains a very slight chance (5%) for radiation storming levels to reach the S1 threshold based on the potential for significant flaring from Regions 4172 and/or 4178 as they approach the western limb.

Solar Wind

24 h Summary

Solar wind parameters, as measured at Lagrange point 1 (L1) by the ACE spacecraft, reflected a continued, but weakening positive polarity CH HSS regime. Total field (Bt) remained around 5 nT with the north-south (Bz) component oscillating between +/-5 nT. Solar wind speeds gradually declined from about 500 km/s to around 450 km/s. Phi was predominantly in the positive (away from the Sun) solar sector with a few excursions into negative orientation.

Forecast

Waning influences from the CH HSS are expected through 16 August. Solar wind analyses project wind speeds to be down towards 370 km/s by the close of 16 August indicating a more nominal wind speed environment thereafter.

Geospace

24 h Summary

The geomagnetic field has been at quiet to unsettled levels.

Forecast

As CH HSS influences wane, mostly quiet to unsettled conditions are expected to persist through 17 Aug. There remains a slight chance for an isolated period of active conditions on 15 Aug. -Bri