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Here is the current forecast discussion on space weather and geophysical activity, issued 2015 Dec 18 1230 UTC.

Solar Activity

24 hr Summary: Solar activity continued at low levels. Region 2468 (S17W33, Axx/alpha) changed little and produced two B-class flares. Region 2469 (N18W07, Axx/alpha) exhibited slight decay, but managed to produce the largest flare of the period, a C4/1f at 18/0509 UTC. Region 2470 (N15E12, Eko/beta) remained stable through the period and produced one C1/Sf.

No Earth-directed coronal mass ejections (CME) were observed during the period.

Forecast: Solar activity is likely to continue at low levels with a slight chance for M-class flares (R1-R2/Minor-Moderate radio blackouts) all three days (18-20 Dec). These probabilities are mainly due to the flare potential from Region 2470.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux was at moderate levels. The greater than 10 MeV proton flux continued at background levels.

Forecast: The greater than 2 MeV electron flux may increase to moderate to high levels on day one (18 Dec) in response to the higher speed winds associated with recent coronal hole high speed stream (CH HSS) activity. The electron flux is likely to drop to normal levels on day two (19 Dec) due to electron redistribution associated with expected CME arrival. Day three (20 Dec) is expected to see the electron flux at moderate to high levels as CME impacts wane. The greater than 10 MeV proton flux is expected to continue at background levels.

Solar Wind

24 hr Summary: Solar wind parameters, as measured at the ACE spacecraft, were indicative of a waning coronal hole high speed stream. Solar wind speed decreased steadily from early measurements near 475 km/s to about 400 km/s by periods end. Total field strength was variable and ranged between 2 to 7 nT. The Bz component was also variable and ranged from +3/-7 nT. The phi angle was predominantly negative (towards the Sun).

Forecast: The solar wind environment is expected to continue at nominal levels for the remainder of day one (18 Dec). Early on day two (19 Dec) solar winds and the IMF are both expected to become elevated as the CMEs from 16 Dec arrive, and are expected to remain enhanced through much of day two. Day three (20 Dec) is expected to see solar wind speeds and IMF strength decrease as CME effects wane.

Geospace

24 hr Summary: The geomagnetic field was at mostly quiet with an isolated period of active levels due to a period of sustained southward Bz.

Forecast: Mid-day to late on day one (18 Dec), the geomagnetic field is expected to be predominantly quiet to unsettled, with an isolated period of G1 (Minor) storming conditions due to CME effects. Day two is likely to experience the majority of the CME impacts and storming conditions are likely to reach major (G2-Moderate) levels. Day three (20 Dec) is expected to see periods of unsettled to active conditions as CME effects wane.

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Live data: SunSpotWatch.com

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