Highlights of Solar and Geomagnetic Activity
09 - 15 September 2024

Solar activity ranged from low to strong levels. Low levels were
observed on 15 Sep, R1 (Minor) levels observed on 09-14 Sep, R2
(Moderate) levels observed on 11-13 Sep and R3 (Strong) levels
observed on 12 Sep and 14 Sep. Region 3824 (S04, L=071, class/area
Eso/200 on 07 Sep) produced an X1.3/Sf at 12/3824 UTC with no
apparent CME observed. The largest event of the period was an
X4.5/2b flare at 14/1529 UTC from Region 3825 (S18, L=013,
class/area Dac/240 on 14 Sep). This event produced an Earth-directed
CME expected to hit Earth midday on 16 Sep. 

Numerous R1-R2 (Minor-Moderate) flares were observed from Region
3811 (S09, L=179, class/area Ehi/290 on 06 Sep) including an M1/1f
flare at 10/0028 UTC that produced an Earth-directed CME. Region
3814 (N15, L=116, class/area Dhi/300 on 11 Sep) produced a few R1
(Minor) flares during the period. Overall, 33 M-class flares and 2
X-class flares were observed this period. 

No proton events were observed at geosynchronous orbit. However,
proton flux levels became enhanced on 14-15 Sep, reaching a maximum
flux of 6.18 pfu at 15/1455 UTC, likely associated with the X4.5
flare on the 14th. 

The greater than 2 MeV electron flux at geosynchronous orbit was at
moderate levels on 09-12 Sep and 14 Sep. High levels were reached on
13 and 15 Sep with a peak flux of 1,690 pfu observed on 15/1605 UTC. 

Geomagnetic field activity ranged from quiet to R3 (G3-Strong)
levels. Quiet to unsettled levels were observed on 09 Sep to early
12 Sep. Early on 12 Sep, activity levels increased to active to G3
(Strong) levels when the 09-10 CME impacted Earth. Levels remained
enhanced to active to G2 (Moderate) levels on 13 Sep due to
continued CME effects. Quiet to active levels were observed on 14
Sep due to continued weak CME effects coupled with positive polarity
CH HSS influence. Quiet to active levels continued on 15 Sep due to
continued CH HSS effects. 

During the CME influence, total field Bt peaked at about 30 nT, Bz
reached a southward extent to about 27 nT and wind speeds peaked at
near 610 km/s midday on the 12th. 

Forecast of Solar and Geomagnetic Activity
16 September - 12 October 2024

Solar activity is likely to be at moderate levels
(R1-R2/Minor-Moderate), with a slight chance for x-class events
(R3-Strong), throughout the outlook period. This is due to complex
regions on the visible disk, as well as the anticipated return of
complex regions. 

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal to moderate levels. 

Geomagnetic field activity is expected to range from quiet to G3
(Strong) storm levels. Enhanced activity to G1-G3 (Minor-Strong)
storm levels are likely on 16-17 Sep due to anticipated CME
activity. Unsettled to G1 (Minor) storm activity is likely on 26-29
Sep, 05-06 Oct and 10-12 Oct due to recurrent, positive polarity CH
HSS occurence. Mostly quiet levels are expected on 20-26 Sep, 30
Sep, 01-04 Oct and 07-09 Oct. 

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