Solar activity reached high levels. Region 1402 (N28W36) produced a long-duration M8/2b flare at 23/0359Z. Associated with this event were multi-frequency radio emissions spanning 25 MHz through 15.4 GHz including a 5100 sfu Tenflare. SOHO/LASCO observed an asymmetric, full-halo CME, first observed in C2 imagery at 27/0412Z as a bright halo over the northern hemisphere. Model output suggests potential Earth impact midday on 24 January. Region 1402 showed some umbral separation in the large leader spot. Region 1401 (N16W39) produced a C1/Sf at 23/2011Z. The remainder of the disk was quiet and stable.

Solar activity is expected to be low during the period (24 - 26 January) with M-class activity likely from Regions 1401 and 1402.

The geomagnetic field ranged from quiet to minor storms levels. The period began with active to minor storm conditions as the field was under the influence of the 19 January CME. By 23/0600Z, the field became mostly quiet to unsettled. Solar wind speeds began the period at about 450 km/s while the Bz component of the interplanetary magnetic field (IMF) was at about -10 nT. By about 0630Z, wind speeds dropped sharply to near 300 km/s, density dropped to near 0 p/cc and IMF Bz turned northward. These signatures were consistent with a possible reverse shock at the back end of the CME. The greater than 10 MeV proton flux at greater than or equal to 10 pfu and the greater than 100 MeV proton flux at greater than or equal to 1 pfu at geosynchronous orbit were above threshold during the period. The 10 MeV event began at 23/0530Z and reached at maximum of 3100 pfu at 23/1940Z. The 100 MeV event began at 23/0445Z and reached a maximum of 2.3 pfu at 23/0750Z. Both events were still in progress at the time of this report.

The geomagnetic field is expected to range from quiet to isolated severe storm levels on day one (24 January). Mostly quiet levels are expected through midday on 24 January when the anticipated arrival of the 23 January CME is expected to affect the field. Active to major storm levels, with isolated severe storm periods, are expected for the remainder of day one. By day two (25 January), field activity is expected to decrease to unsettled to active levels, with isolated minor storm periods, as effects from the CME wane. Day three (26 January) should see a return to mostly quiet conditions.

  Observé       23 Jan 144
  Prévisionnel   24 Jan-26 Jan  145/145/145
  Moyenne des 90 derniers jours        23 Jan 143

  Observé Afr/Ap 22 Jan  022/024
  Estimé     Afr/Ap 23 Jan  008/009
  Prévisionnel    Afr/Ap 24 Jan-26 Jan  022/042-018/020-005/005