Solar activity is currently at relatively low levels with numerous C-Class flares detected around sprawling sunspot 1861. The active region continues to evolve magnetically as it rotates towards the west limb. There will remain a chance for an isolated M-Class event within the next 24 hours. All other regions, including formerly active sunspot 1865 remain stable. A new sunspot is forming quickly in the southeast quadrant and should be monitored for further growth. Old sunspot 1850 rotated back into view off the east limb and appears to be stable at this time.
Solar activity was low. Region 1865 (S22W37, Dso/beta-delta) and Region
1861 (S10W57, Dhc/beta-gamma) were responsible for multiple C-class
flares. Region 1861 produced a C1/Sf flare at 16/0920 UTC with
associated weak types II (est. shock speed 548 km/s) and IV radio
sweeps. After analysis, the associated CME was determined to have a
narrow south-western trajectory unlikely to be geoeffective.
.Forecast...
Solar activity is expected to be low with a chance for an M-class (R1-R2
Minor to Moderate) flare for the forecast period (17-19 Oct). The most
likely regions for M-class flare activity continue to be Regions 1861
and 1865.
Energetic Particle
.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels. The greater than 10 MeV proton flux at
geosynchronous orbit was at background levels.
.Forecast...
The greater than 2 MeV electron flux at geosynchronous orbit is expected
to be at moderate to high levels for the forecast period (17-19 Oct).
The greater than 10 MeV proton flux at geosynchronous orbit is expected
to remain at background levels.
Solar Wind
.24 hr Summary...
Solar wind parameters, measured at the ACE spacecraft, indicated the
remnant presence of a coronal hole high-speed stream (CH HSS). Speed
decreased from near 550 km/s at the beginning of the period to just over
460 km/s by the end of the period. IMF total field held steady at
around 4 nT, while IMF Bz intermittently dipped southward briefly
as low as -4 nT. Phi angle remained in a positive (Away) orientation
throughout the period.
.Forecast...
Enhanced solar wind variability is expected to persist for the next two
days (17-18 Oct) from combined effects of residual CH HSS and the
anticipated arrival of the CME from 13 Oct, now expected early on day
one (17 Oct). A return to ambient conditions is forecast for day three
(19 Oct).
Geospace
.24 hr Summary...
The geomagnetic field was quiet to unsettled with an isolated active
period at 16/00-03 UTC due to residual CH HSS effects.
.Forecast...
The geomagnetic field is expected to be unsettled to active with a
slight chance for minor storm (G1-minor) levels late on day one (17 Oct)
with the anticipated arrival of the weak CME from 13 October. Day two
(18 Oct) should expect a decrease, with quiet to unsettled periods
expected as CH HSS and CME effects wane. A return to mostly quiet
conditions is forecast for day three (19 Oct).
