Solar Activity

» 24 hr Summary: Solar activity reached moderate levels. Region 3932 (S17E54, Ekc/beta) produced an impulsive M1.9 flare at 21/0038 UTC; the largest event of the period. Region 3927 (S08E25, Hsx/alpha) was split this period, with the lead spot maintaining the 3927 designation, and following intermediate and trailer spots being named new Region 3933 (S08E34, Dao/beta). Minor to moderate growth was observed in Regions 3928 (S14E34, Dai/beta), 3930 (S22W49, Cai/beta), 3932, and 3933.

A CME, first visible in C2 off the NNE at 20/2324 UTC, associated with flaring from the vicinity of N22E08 at around 20/2230 UTC. Analysis and modelling suggested a glancing blow is possible on 24 Dec. A filament centered near N35W53 began lifting off at around 21/1000 UTC. Subsequent coronagraph imagery suggested most of the material was reabsorbed.

Other activity included a Type IV and Type II (est. 1,314 km/s) radio sweep associated with an eruption just behind the NE limb. No Earth-directed ejecta is suspected with this event.

» Forecast: R1-R2 (Minor-Moderate) events are likely, with a slight chance for R3 (Strong) or greater events, over 22-24 Dec.

Energetic Particle

» 24 hr Summary: The greater than 10 MeV proton flux was elevated around 4 pfu, but remained below S1 (Minor) levels. The greater than 2 MeV electron flux was at normal to moderate levels. .Forecast: The greater than 10 MeV proton flux is expected to remain below S1 (Minor) levels over 22-24 Dec. The greater than 2 MeV electron flux is expected to continue at normal to moderate levels through 24 Dec.

Solar Wind

» 24 hr Summary: Solar wind parameters were mildly enhanced this period. Total field strength reached 9 nT and the Bz component varied between +/-8 nT. Solar wind speeds ranged between 450-560 km/s. Phi angle was predominantly oriented in the negative sector.

» Forecast: Enhanced solar wind conditions are likely to continue through 24 Dec due to negative polarity CH HSS influence, with additional influence of a weak CME possible on 24 Dec.

Geospace

» 24 hr Summary: The geomagnetic field ranged from quiet to active.

» Forecast: The geomagnetic field is expected to be quiet and unsettled, with a chance for isolated active periods, over 22-24 Dec due to anticipated influence of a negative polarity CH HSS. Additional enhancements from a weak CME are possible over 24 Dec.


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