Subject: Weekly Highlights of Solar and Geomagnetic Activity, 17 - 23 March 2025

:Product: Weekly Highlights and Forecasts
:Issued: 2025 Mar 24 0202 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
17 - 23 March 2025

Solar activity was at moderate levels (R1-Minor) on 17, 19 and 21
March. Region 4033 (N24, L=122, class/area Bxo/010 on 15 Mar)
produced an M1.0/1f at 17/1933 UTC. This event produced a northerly
vector CME with a possible weak Earth impact. Region 4031 (N16,
L=165, class/area Eai/120 on 19 Mar) produced an M1.5/1n at 19/2040
UTC. Region 4028 (S17, L=141, class/area Dai/240 on 15 Mar) produced
an M1.2/1n at 21/1558 UTC/ Associated with this event was a Type II
sweep with an estimated velocity of 504 km/s. At about the same time
as this flare, a fast shock signature CME off the SE appeared to
have originated from the vicinity of Region 4034 (S12, L=112,
class/area Cso/020 on 20 Mar).

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels on 17 and 18 March with a peak flux of 6,680 pfu at
17/1600 UTC. Low to moderate levels were observed on 19-23 March.

Geomagnetic field activity was at quiet to unsettled levels on 17-18
March and quiet to minor storm (G1-Minor) levels on 19 March. This
activity was attributed to negative polarity CH HSS combined with
CME effects. Quiet levels were observed on 20 March. Activity levels
increased to unsettled to minor and moderate (G1-G2/Minor-Moderate)
storm levels on 21-22 March. This activity was attributed to the 17
March CME and negative polarity CH HSS effects. Quiet to active
levels were observed on 21 March due to waning CME effects.

During the highlight period, Bt peaked at 40 nT and Bz dipped south
to -17 nT late on 21 March. Solar wind speeds generally peaked to
525 km/s mid to late on 19 March and again late on 22 March to early
on 23 March.

Forecast of Solar and Geomagnetic Activity
24 March - 19 April 2025

Solar activity is expected to be at a chance for R1-R2
(Minor-Moderate) levels through the outlook period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels on 27-31 March and 06-14 April. Low to
moderate levels are expected on 24-26 March, 01-05 April and 15-19
April.

Geomagnetic field activity is expected to be at active to G1-Minor
levels on 24 March due to CME effects. G1-G2 (Minor-Moderate) levels
on 25-26 March and unsettled to active levels on 27-29 March are
forecasted due to positive polarity CH HSS influence. A combination
of unsettled to G1-Minor levels are forecasted for 04-19 April due
to negative polarity CH HSS influence.


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* Origin: NOAA Space Weather Prediction Center (3:633/280.2@fidonet)