Solar Report - July 19th, 2016
:Product: Forecast Discussion :Issued: 2016 Jul 19 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity (24 hr Summary) ------------------------------ Solar activity was at low levels due to a C4 flare from Region 2565 (N05W21, Cko/beta) at 18/0823 UTC. This region also produced a B6 flare at 18/1839 UTC, which was the only other notable flare during the period. Both Regions 2565 and 2567 (N05W11, Dki/beta) experienced slight growth in the peripheral spots, while Region 2569 exhibited slight growth in both the leader and trailer spots. Region 2566 (N10W25, Axx/alpha) had spots reemerge during the period, but remained a magnetically simple spot group. . Analysis from the faint, asymmetric halo CME from 17 July suggested a possible impact from the slow moving plasma cloud sometime early on 21 Jul. Speeds analyzed indicated a relatively slow moving CME, approximately 450 km/s, with anticipated timing to coincide with the arrival of the coronal hole high speed stream (CH HSS). No new Earth-directed CMEs were detected in available coronagraph imagery. . Forecast Solar activity is likely to reach low levels through the period (19-21 Jul) with a chance for M-class flares (R1-R2/Minor-Moderate) due to flare potential from Regions 2565 and 2567, as well as the continued growth of Region 2569. . Energetic Particle (24 hr Summary) ---------------------------------- The greater than 2 MeV electron flux was at moderate to high levels with a peak flux of 6,229 pfu observed at 18/1605 UTC. The greater than 10 MeV proton flux continued at background levels. . Forecast The greater than 2 MeV electron flux is expected to be at moderate to high levels on day one and early on day two (19-20 Jul) in response to elevated wind speeds from CH HSS activity. On day two, electron flux levels are expected to return to normal levels following a redistribution of particles due to the arrival of the anticipated CME. The greater than 10 MeV proton flux is expected to continue at background levels for the forecast period (19-21 Jul). . Solar Wind (24 hr Summary) -------------------------- Solar wind parameters, as measured by the ACE spacecraft, reflected a return to ambient conditions. Solar wind speeds gradually decreased through the period from about 460 km/s to near 360 km/s. Total magnetic field strength ranged between 2-5 nT, while the Bz component fluctuated between +/-3 nT. The phi angle was in a predominately positive sector throughout the period. . Forecast Solar wind parameters are expected to remain at ambient levels on day one and early on day two (19-20 Jul). Enhanced conditions are expected early on day two and into day three (21 Jul) as a negative polarity CH HSS moves into a geoeffective position, as well as the anticipated arrival of the 17 Jul CME. . Geospace (24 hr Summary) ------------------------ The geomagnetic field was at quiet levels. . Forecast The geomagnetic field is expected to be at mostly quiet levels through the end of day one (19 Jul). Quiet to unsettled conditions are then expected, with active periods likely on day two (20 Jul), due to effects from a recurrent negative polarity CH HSS. Active levels, with a slight chance for G1 (minor) storm conditions are possible early on day three (21 Jul) with the arrival of the anticipated CME, combined with the CH HSS effects, before beginning to taper off near the end of the period.