Solar Activity

» 24 hr Summary: Solar activity was at low levels with only C-class flares, mostly from new Region 4312 (N17E62, Hax/alpha). Region 4307 (S15W81, Dao/beta) showed slight growth and consolidation as it neared the SW limb. Slight decay and separation was observed in Region 4311 (N03W05, Cso/beta). The rest of the spotted regions were either stable or in decay.

Beginning at approximately 17/1230 UTC, an approximate 13 degree filament eruption, centered near N37E12, was observed in SUVI 304 imagery. CME analysis is ongoing for this event. No other potentially Earth-directed CMEs were observed.

» Forecast: Solar activity is expected to be low with a slight chance for M-class flares (R1-R2, Minor-Moderate) on 18-20 Dec.

Energetic Particle

» 24 hr Summary: The greater than 2 MeV electron flux briefly reached high levels with a peak flux of 1,630 pfu observed at 17/1440 UTC. The greater than 10 MeV proton flux remained steady at background levels during the period.

» Forecast: The greater than 2 MeV electron flux is expected to remain at moderate to high levels through 18 Dec with a chance for high levels on 19 Dec due to HSS influences. The greater than 10 MeV proton flux is expected to persist at background levels over 17-19 Dec.

Solar Wind

» 24 hr Summary: Solar wind parameters continued under the influence of a negative polarity CH HSS. Solar wind speed was mostly in the 550-650 km/s range. Total field ranged from 1-9 nT while the Bz component was between +/-7 nT. Phi angle was mostly negative.

» Forecast: Solar wind parameters are expected to continue to be enhanced through 18 Dec under negative polarity CH HSS influence. HSS influences are expected to gradually diminish over 19-20 Dec.

Geospace

» 24 hr Summary: The geomagnetic field was at quiet to G1 (Minor) geomagnetic storming levels due to persistent CH HSS activity.

» Forecast: The geomagnetic field is expected to be at unsettled to G1 (Minor) storm levels through 18 Dec as HSS activity persists. Quiet to unsettled levels are expected on 19-20 Dec as HSS activity gradually wanes.


Prepared by:
The U.S. Dept. of Commerce, NOAA, SWPC