Subject: Weekly Highlights of Solar and Geomagnetic Activity, 11 - 17 March 2024

:Product: Weekly Highlights and Forecasts
:Issued: 2024 Mar 18 0617 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
11 - 17 March 2024

Solar activity ranged from low to moderate levels. Moderate levels
were reached on 14 Mar due to an M1.0/sf flare at 14/0604 UTC from
Region 3599 (S12, L=065, class/area Dao/230 on 12 Mar). On 16 Mar,
Moderate levels were once again seen as an M3.5 and an M1.1 occurred
at 16/1635 UTC and 16/2155 UTC from a region just beyond the SE
limb. Region 3599 was also responsible for a series of CMEs just
beyond the SW limb which occurred at 15/0210 UTC and 15/0328 UTC.
Modelling of the event indicated no Earth-directed component,
however, an associated minor solar radiation storm (S1) was
observed. Other activity included an approximate 35 degree filament
channel eruption centered near S28W25 beginning at 17/0100 UTC. Two
subsequent CMEs were observed in SOHO/LASCO C2 imagery off the SSE
and SW limbs at 17/0312 UTC and 17/0336 UTC, respectively. Modelling
indicated possible glancing blows late on 20 Mar to early on 21 Mar.

A greater than 10 MeV proton event above the 10 pfu (S1/Minor)
threshold as a result of activity from Region 3599 beyond the SW
limb early on 15 Mar. The event began at 15/2050 UTC, reached a peak
flux of 16.7 pfu at 16/0635 UTC, and ended at 16/1505 UTC.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 11 Mar due to CH HSS influence. A peak of 1,420 pfu
was observed at 11/1605 UTC.

Geomagnetic field activity ranged from quiet to active levels. Solar
wind speed decreased on 11 Mar as weak negative polarity CH HSS
influence diminished. A solar sector boundary crossing was observed
midday on 11 Mar followed by another mild increase in solar wind
speed and total field on 12-13 Mar. Solar wind speed reached a
maximum around 484 km/s by 14/1350 UTC with total field near 9 nT
early on 14 Mar due to positive polarity CH HSS influence. The
geomagnetic field responded with unsettled periods on 12 and 14 Mar
and an isolated active period early on 15 Mar. Solar wind speed
slowly decreased around 290 km/s with total field values below 5 nT
by the end of the period.

Forecast of Solar and Geomagnetic Activity
18 March - 13 April 2024

There is a chance for moderate (R1-R2/Minor-Moderate) levels through
31 Mar, mainly due to the flare potential of Region 3614 (N16,
L=223, class/area Hax/080 on 17 Mar) and an unnumbered region
rotating onto the SE limb. Low levels with a slight chance of
M-class flares are likely on 01-13 Apr.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 07-08 Apr due to recurrent CH HSS
influence.

Geomagnetic field activity is expected to be at unsettled to active
levels, with G1 (Minor) storming likely, on 20-21 Mar due to
activity from the 17 Mar CMEs. Unsettled levels are expected on
28-29 Mar, 03-05 Apr, and 09-11 Apr due to recurrent CH HSS
activity.


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