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Here is the current forecast discussion on space weather and geophysical activity, issued 2015 Oct 21 1230 UTC.

Solar Activity

24 hr Summary: Solar activity was low. Region 2434 (N07E26, Eki/beta-gamma) produced the largest flare of the period, an impulsive C6/1f at 21/0434 UTC. The region saw slight growth spots near the leader and produced a few small intermediate spots. 2435 (S15E11, Cro/beta) developed a few small trailer spots. All other regions were relatively stable throughout the past 24 hours.

A filament centered near N18E18 began erupting around 20/2010 UTC in SDO 304 imagery. Further analysis is being conducted to determine if an Earth-directed component is present.

Forecast: Solar activity is expected to be low with a chance for M-class, R1-R2 (Minor-Moderate) radio blackouts over the next three days (21-23 Oct).

Energetic Particles

24 hr Summary: The greater than 2 MeV electron flux was at moderate to high levels, reaching a peak flux of 1,254 pfu at 20/1540 UTC. The greater than 10 MeV proton flux was at background levels during the period.

Forecast: The greater than 2 MeV electron flux is expected to be at normal to high levels on day one (21 Oct). Days two and three (22-23 Oct) should see a drop to normal to moderate levels after particle redistribution due to the anticipated arrival of a coronal hole high-speed stream (CH HSS). The greater than 10 MeV proton flux is expected to remain at background levels throughout the forecast period.

Solar Wind

24 hr Summary: Solar wind parameters, measured by the ACE spacecraft, suggested the onset of the anticipated negative polarity coronal hole high speed stream. Solar wind speeds began the period around 370 km/s. Wind speeds remained steady until after 21/0800 UTC, when they began to trend upwards of 450 km/s and climbing by the end of the period. Temperatures paralleled the increase in wind speeds while density exhibited a pronounced decline coinciding with rise in wind speeds. Total magnetic field strength (Bt) rose to a peak of 12 nT at 21/0936 UTC. Bz began the period mostly southward until a transitioned to a more northward component after 20/1635 UTC. Following the increase in wind speeds after 21/0800 UTC, the Bz component has remained predominantly north. Phi began the period in the positive (away) sector and transitioned to a predominantly negative sector (towards) until around 21/0700 UTC, when oscillations between the sectors were observed.

Forecast: Solar wind parameters are likely to exhibit enhancement in wind speeds from the negative polarity CH HSS over the next two days (21-22 Oct). Day three (23 Oct) is expected to see the decay of the CH HSS influence with solar wind speeds trending back to nominal conditions.

Geospace

24 hr Summary: The geomagnetic field was mostly quiet to unsettled. An isolated period of active was observed late in the period due to the onset of the CH HSS.

Forecast: Geomagnetic field activity is expected to be mostly quiet for the beginning of day one (21 Oct) with quiet to active levels expected later in the day due to the onset of a negative polarity CH HSS. Day two (22 Oct) should continue quiet to unsettled conditions as CH HSS influence begins to subside. A return to mostly quiet conditions is expected on day three (23 Oct).

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