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Here is the current forecast discussion on space weather and geophysical activity, issued 2015 Dec 10 1230 UTC.

Solar Activity

24 hr Summary: Solar activity was at low levels. Newly numbered region 2468 ((S15E71, Cao/beta) was responsible for several B-class flares as well as a C3/Sf flare, the largest of the period, at 10/0750 UTC. Due to its proximity to the solar limb, accurate analysis of its magnetic structure is hindered at this time. The only other region to produce measurable flare activity was Region 2466 (S13W02, Dai/beta), which produced a C1 flare at 09/1212 UTC. Region 2466 exhibited penumbral consolidation in its leader spots and overall decay in its intermediate and trailer spots. Region 2467 (S05E08, Cao/beta) lost its trailer spots and remained inactive. Region 2465 (S05E17, Dao/beta) underwent decay in its trailer spots and was also predominantly inactive. Region 2463 (S08W13, Hsx/alpha) remained relatively unchanged.

No Earth-directed coronal mass ejections (CME) were observed in the available, but very limited, coronagraph imagery.

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 (10-12 Dec). The increase in activity is due to the increased flare potential of Region 2466 and the newly numbered active Region 2468 as it continues to rotate onto the visible disk.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux was at high levels with a maximum flux of 10,717 pfu at 09/1455 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 moderate to high levels on all three days (10-12 Dec) as wind speeds are expected to remain elevated due to coronal hole high speed stream (CH HSS) effects. The greater than 10 MeV proton flux is expected to remain at background levels.

Solar Wind

24 hr Summary: The solar wind and interplanetary magnetic field (IMF) parameters reflected a slightly disturbed, but mostly stable solar wind environment through the first half of the period. Shortly after 09/2200 UTC, the Earths magnetosphere began to respond to a co-rotating interaction region (CIR), as forecast. Wind speeds began to climb from around 450 km/s to over 560 km/s over an approximately 10 hour period. The IMF total field strength (Bt) began to fluctuate between 3 nT and 11 nT, while the Bz component saw values reach 10 nT and experienced southward deflections as low as -9 nT. Phi angle remained in a mostly positive (away from the Sun) orientation.

Forecast: The solar wind environment is expected to remain enhanced on day one (10 Dec) due to effects from the CIR, followed by another positive polarity CH HSS. Wind speeds are expected to reach around 600 km/s as the CH HSS connects with Earth. Day two (11 Dec) is expected see continued higher wind speeds as Earth remains in the open field lines of the CH HSS. Day three (12 Dec) is expected to see the wind speeds begin to decline as the CH HSS begins to rotate out of geoeffective position.

Geospace

24 hr Summary: The geomagnetic field began the period at quiet to unsettled levels. Around 09/220 UTC, the anticipated CIR ahead of the expected positive polarity CH HSS appeared to have arrived at Earths magnetometer, prompting an increase to G1-Minor storm levels by 10/0435 UTC.

Forecast: Periods of minor (G1-Minor) geomagnetic storming are expected on day one (10 Dec) in response to the aforementioned CIR. Subsequent solar wind speed increases and a disturbed IMF are also expected to follow, due to connection with the CH HSS. Day two (11 Dec) is likely to see CH HSS effects continue, producing occasional periods of G1 storming. CH HSS effects are expected to persist on day three (12 Dec), but waning conditions should only contribute to unsettled to active conditions.

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