[Propagation+Space Weather] Today's Space Weather Forecast Discussion on 2015 Aug 25 1230 UTC

[nw7us@sunspotwatch.com]

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Here is the current forecast discussion on space weather and geophysical activity, issued 2015 Aug 25 1230 UTC.

Solar Activity

24 hr Summary: Solar activity reached moderate levels during the period. Region 2403 (S15W24, Fkc/beta-gamma-delta) produced multiple C-class flares and an M-class flare, a M1/Sf flare at 24/1746 UTC. Region 2403 continued to grow as it gained area and developed a new mix of opposite polarity spots adjacent to, and just east of, the large trailing penumbra. This area of tighter magnetic field gradient and shear, along with another area of lingering shear along the southern periphery of the spot group, are likely contributors to the high level of activity from this region. Region 2404 (N14W37, Cro/beta) decayed during the period and did not provide any noteworthy activity.

No Earth-directed CMEs were seen in available LASCO coronagraph imagery during the period.

Forecast: Solar activity is expected to be at low levels, with M-class flares (R1-R2, Minor-Moderate) likely, and a slight chance for X-class flares (R3, Strong or greater) on days one through three (25-27 Aug), due to the continued instability and magnetic complexity of Region 2403.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux reached high levels this period with a peak flux of 1700 pfu at 24/1800 UTC. The greater than 10 MeV proton flux remained at background levels.

Forecast: The greater than 2 MeV electron flux is expected to be at normal to high levels for day one (25 Aug) and decrease down to normal to moderate levels for days two and three (26-27 Aug). The greater than 10 MeV proton flux is expected to remain at background levels all three days, but with a slight chance for an S1 (Minor) solar radiation storm due to the more magnetically conducive positioning of Region 2403.

Solar Wind

24 hr Summary: Solar wind parameters as measured by the ACE spacecraft indicated a return towards a more ambient space weather environment as solar wind velocities steadily decreased from near 460 km/s at the start of the period down to under 380 km/s by periods end. The total interplanetary magnetic field (IMF) strength remained fairly steady between 4-6 nT with a variable -Bz component. The phi angle remained primarily in a positive (away) orientation.

Forecast: Solar wind and IMF parameters are expected to remain near ambient levels on days one and two (25-26 Aug) due to the waning effects of the positive polarity coronal hole high speed stream (CH HSS). Solar wind velocity and IMF strength is expected to increase as the trans-equatorial, negative polarity CH HSS rotates into a geoeffective position later on day three (27 Aug).

Geospace

24 hr Summary: The geomagnetic field was at quiet to unsettled levels.

Forecast: Quiet to unsettled conditions are expected on days one and two (25-26 Aug) due to waning CH HSS effects. Quiet to unsettled levels are expected the first half of day three (27 Aug), before reaching active levels due to the negative polarity CH HSS and potential CIR.

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