:Product: Forecast Discussion :Issued: 2026 Apr 16 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached low levels with only B and C-class flaring from Region 4419 (N13E36, Eki/beta-gamma). Moderate growth occurred in Region 4419 along with consolidation of its leading spots. Slight decay was observed in Region 4416 (N20W57, Dao/beta). Other activity included two CMEs on the NE and SE quadrants. The first was associated with a long-duration B7.9 flare that started at 15/0730 UTC from Region 4419. A likely associated CME was observed off the NE limb at 15/0748 UTC. The second was an approximate 35 degree filament eruption, centered near S30E20, at 15/0940 UTC. An associated CME was observed off the SE limb at 15/1036 UTC. Initial modelling indicated no Earth-directed component. A partial halo CME was observed with the bulk off the NW limb beginning at 15/1148 UTC. That CME was determined to be backsided. An additional CME was observed off the West limb starting in C2 imagery near 16/0000 UTC. This CME was also determined to originate from the far side of the disk. .Forecast... Solar activity is expected to be low with a chance for M-class (R1-R2, Minor-Moderate) flare on 16-18 Apr primarily due to the flare potential of Region 4419. Energetic Particle .24 hr Summary... Electrons greater than 2 MeV at geosynchronous orbit reached high levels with a peak of 3,248 pfu observed at 15/1820 UTC. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to reach high levels on 16-17 Apr. A brief drop to moderate levels is expected on 18 Apr with the arrival of a negative polarity CH HSS. The greater than 10 MeV proton flux is expected to continue at background levels on 16-18 Apr. Solar Wind .24 hr Summary... Solar wind parameters were at nominal levels with solar wind speed ranging from 324-381 km/s. Total field ranged from 2-6 nT while the Bz component was between +4/-5 nT. Phi angle was predominantly positive. .Forecast... Solar wind parameters are expected to become enhanced by mid to late on 17 Apr with the arrival of a co-rotating interaction region followed by negative polarity CH HSS activity. Solar wind speed ranging from 600-700 km/s are likely based on recurrent values. Enhanced conditions are expected to persist through 18 Apr. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... The geomagnetic field is expected to be quiet to unsettled on 16 Apr. By mid to late on 17 Apr, CH HSS activity is expected to cause unsettled to active periods with G1-G2 (Minor-Moderate) geomagnetic storming likely. Unsettled to G2 (Moderate) levels are expected to continue through 18 Apr as HSS effects persist.