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IR0EQ > DX 01.11.21 18:59l 83 Lines 4175 Bytes #999 (0) @ WW
BID : 58514IR0EQ
Read: GUEST
Subj: Weekly Highlights of Solar and Geomagnetic Activity, 25 - 31
Path: IZ3LSV<IR1UAW<IW2OHX<IW0QNL<VE2PKT<I0OJJ
Sent: 211101/1756z @:I0OJJ.ITA.EU [Rome] $:58514IR0EQ
:Product: Weekly Highlights and Forecasts
:Issued: 2021 Nov 01 0509 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# https://www.swpc.noaa.gov/content/subscription-services
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# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
25 - 31 October 2021
Solar activity ranged from low to high levels. Low levels occurred
on 25, 27, and 30-31 Oct. Moderate levels were reached on 26 and 29
Oct as Region 2891 (N17, L=212, class/area Dki/350 on 29 Oct)
produced M1 flare activity at 26/0247 UTC, 26/1557, and 29/0242 UTC.
High levels were reached on 28 Oct as Region 2887 (S25, L=278,
class/area Dki/440 on 24 Oct) produced an M1/1n flare at 28/0740
UTC, an M2/1f flare at 28/1028 UTC, and an X1/2n flare at 28/1535
UTC. Two CMEs were modelled during the period. The first was a CME
off the SE limb beginning at 26/2024 UTC although the source region
was unclear. It was speculated to come from Region 2887. WSA ENLIL
modeling showed a potential glancing arrival late on 30 Oct. The
second CME was associated with the X1 flare on 28 Oct. Type II (1457
km/s) and IV radio emissions were observed coinciding with the flare
and WSA ENLIL modeling of the event showed an arrival of mid to late
on 30 Oct as well, although parameterization of the event was
difficult.
Coinciding with the X1 flare on 28 Oct was a greater than 10 MeV and
100 MeV proton event. The greater than 10 MeV event began at 28/1740
UTC, reached a peak flux of 29 pfu (S1-Minor) at 29/0250 UTC and
ended at 30/1610 UTC. S1 thresholds were crossed once again
beginning at 30/2100 UTC, reaching a peak flux of 11pfu at 30/2105
UTC and ending at 30/2130 UTC due to an enhancement from the 26 Oct
CME. The greater than 100 MeV proton event began at 28/1635 UTC,
reached a peak flux of 7.3 pfu at 28/1815 UTC and ended at 30/0440
UTC. The greater than 10 MeV proton flux continued to decline
towards background levels on 31 Oct - 01 Nov.
The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels throughout with a peak flux of 348 pfu
observed at 25/1700 UTC
Geomagnetic field activity was at quiet levels on 25 Oct through
late on 30 Oct under a nominal solar wind environment. Around
30/1800 UTC, a weak discontinuity was observed that was believed to
be the arrival of the 26 Oct CME. Total field increased to 11 nT
while the Bz component deflected southward to a maximum of -10 nT at
30/2045 UTC. Solar wind speed slowly increased to 400 km/s. A weak
shock was observed beginning at 31/0914 UTC which is believed to be
the arrival of a glancing blow from the 28 Oct CME. Total field
increased from 4 nT to 13 nT while the Bz component briefly reached
a maximum southward deflection of -11 nT at 31/1124 UTC. Solar wind
speed continued to rise to a peak of 465 km/s at 31/1905 UTC. By
31/1500 UTC, total field had calmed to between 5-8 nT and remained
there through the end of the period. The geomagnetic field responded
with an isolated active period late on 30 Oct followed by unsettled
to G1 (Minor) storming on 31 Oct.
Forecast of Solar and Geomagnetic Activity
01 November - 27 November 2021
Solar activity is expected to be at low levels with a chance for
further M-class flare activity (R1-R2, Minor-Moderate) on 01-08 Nov
as Regions 2887 and 2891 transit across the visible disk. Very low
to low levels are expected on 09-15 Nov. Low levels with a chance
for M-class flares are likely again on 16-27 Nov as Regions 2887 and
2891 return to the visible disk on 16 Nov and 21 Nov, respectively.
No proton events are expected at geosynchronous orbit as Regions
2887 and 2891 decay and simplify magnetically.
The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal to moderate levels with a chance for high
levels on 02-03 Nov due to CME influence.
Geomagnetic field activity is expected to reach active levels on 01
Nov followed by quiet to unsettled levels on 02 Nov as CME effects
diminish. Unsettled levels are expected once again on 04-05 Nov and
15-16 Nov due to recurrent CH HSS activity.
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