Solar activity was high. Region 484 (N06E54) produced an X1/1n flare starting at 1629 UTC, with maximum at 1650 UTC and ending at 1704 UTC. The flare was accompanied by strong radio bursts, a type II radio sweep, and was associated with a coronal mass ejection. The CME was observed in LASCO-C2 off the northeast limb beginning at 1708 UTC with a plane-of-sky speed of about 500 km/s. Region 484 also produced two M1 flares: one at 0626 UTC, the other at 1926 UTC. The region also produced a C6/1f at 18/2218 UTC that was associated with a CME off the southeast limb around 18/2230 UTC. Neither of these CMEs appear to have any earthward directed component. Region 484 grew dramatically during the past 24 hours from 240 millionths at the start of the day to just over 1000 millionths by forecast issue time. This remarkable emergence of new flux led to the formation of a strong delta configuration across a northeast-to-southwest polarity inversion line which was also the location of the most intense emission from the X1 flare event.

Solar activity is expected to be predominantly moderate for the next three days, with Region 484 as the dominant source of activity. There is a chance for more major flare activity from Region 484, especially if it continues to grow.

The geomagnetic field ranged from unsettled to minor storm levels during the past 24 hours. A jump in solar wind velocity from 540 km/s to 600 km/s was observed around 2200 UTC. However, the solar wind signatures continue to be consistent with a high-speed coronal driven wind stream. The Bz component of the interplanetary magnetic field continues to oscillate around an average value of about -5 nT. The greater than 2 MeV electron fluxes continue to be at high levels.

The geomagnetic field is expected to be unsettled to active for the next 24 hours, increasing to mostly active with minor storm periods on the second day, and returning back to unsettled to active for the third day. The increase on day two is expected as a response to the particular morphology of a coronal hole rotating across the western part of the solar disk. A glancing blow from the partial-halo CME of 18/1554 UTC may also contribute to activity on day two.

  Observé       19 Oct 120
  Prévisionnel   20 Oct-22 Oct  125/130/130
  Moyenne des 90 derniers jours        19 Oct 115

  Observé Afr/Ap 18 Oct  015/027
  Estimé     Afr/Ap 19 Oct  015/025
  Prévisionnel    Afr/Ap 20 Oct-22 Oct  012/020-020/030-015/025