299
FXXX12 KWNP 031231
DAYDIS

:Product: Forecast Discussion
:Issued: 2026 Jun 03 1230 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity reached high levels with two R2 (Moderate) solar flares
and one R3 (Strong), all from Region 4455 (N14W20, Cki/beta-gamma): an
M9.3/sf at 03/0136 UTC, an M7.7/2B at 03/0700 UTC, and an X1.0 at
03/1128 UTC.

The M9.3 was accompanied by a Type IV radio sweep and a 10.7cm radio
burst peaking at 360 sfu. An associated CME became visible in LASCO C2
coronagraph imagery at approximately 03/0213 UTC. The structure is very
faint, but GOES/SUVI imagery suggests that the structure is a partial to
full halo, and triangulation with STEREO coronagraph imagery indicates
there is an Earth-directed component. Modeling is still ongoing.

The M7.7 was also accompanied by a 10.7cm radio burst, this one peaking
at 540 sfu, and a Type II radio burst with an estimated shock velocity
of 313 km/s. An associated CME became visible in LASCO C2 imagery at
approximately 03/0748 UTC; both coronagraph and GOES/SUVI imagery
suggest that the bulk of this eruption may have been deflected northward
due to the nearby coronal hole. Triangulation with STEREO also indicates
this CME has an Earth-directed component. Modeling is still ongoing.

The X1.0 also had a 10.7cm radio burst, this one lower than the two
M-flares, peaking at only 250 sfu. If a CME is associated with this
flare, it should become visible in coronagraph imagery in a few hours.

There was also an M3.3 flare at 02/1650 UTC (also from Region 4455) that

coincided with a large far-sided eruption whos CME became visible in
LASCO C2 at 02/1700 UTC. While localized coronal dimming seen in SUVI
195 near Region 4455 suggests a front-side eruption occurred with the
flare, a definitive CME signature is not clear in coronagraph data.
Modeling of this CME suggests there is no Earth-directed component.

Modeling of a large filament eruption from the SW from earlier in 02
June confirms no Earth-directed component; however its timing, source
location, and relatively slow velocity mean that it has a high
probability of interacting with the faster CMEs behind it and changing
their propagation into the near-Earth environment.

There are eight numbered regions on the visible disk, with Region 4449
(S08, L=137) having decayed to plage. Region 4455 remains
complex, displaying an anti-Hale configuration caused by a series of
small negative polarity spots developing south and west of its mature
positive spot; these spots exhibited continuous flux emergence, causing
a very mixed polarity area with substantial shear, likely the source of
the high level M-class flaring from that region. Regions 4458 (S05W08,
Dai/beta-gamma), 4459 (N14E35, Dai/beta-gamma), 4460 (S22W74, Dao/beta),
and 4461 (S20E57, Cai/beta-gamma) showed very rapid flux emergence
during the reporting period, leading to three of the regions developing
gamma magnetic configurations. However, these regions have been quiet
flare-wise. The remaining regions were stable or in decay.

.Forecast...
Solar activity is expected to be at moderate levels through 05
June with M-class (R1-R2/Minor-Moderate) flaring likely and a
slight chance for X-class (R3/Strong or greater) primarily due to
Regions 4455, 4458, 4461, and 4462.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at low
to moderate levels with a peak flux of 684 pfu observed at 02/1815 UTC.
The greater than 10 MeV proton flux at geosynchronous orbit remained at
background levels.

.Forecast...
The greater than 2 MeV electron flux is expected to remain at low to
moderate levels through 05 June. The greater than 10 MeV proton flux is
anticipated to continue at background levels through 05 June, as the
high-level M-class flares discussed above are not at a highly
geoeffective location for particle events.

Solar Wind

.24 hr Summary...
Solar wind parameters continued to reflect slightly elevated background
conditions. Total magnetic field (Bt) averaged near 6 nT during the
first half of the reporting period, then it gradually increased to a
peak of 10 nT until a solar sector boundary crossing (SSBC) at
approximately 03/0755 UTC. The North-South (Bz) component was variable,
with a maximum southward deflections of -6 nT at 02/1715 UTC and 03/0020
UTC. Solar wind speeds varied averaged just slightly less than 400 km/s
before the SSBC, afterwards averaging approximately 425 km/s. The phi
angle was largely in the negative (towards the Sun) sector.

.Forecast...
Solar wind parameters maybe become mildly enhanced on 03 June due to
low-confidence glancing influences from the slow 30 May CME. Late on 03
June or early on 04 June, more significant enhancements are expected
with the arrival of a co-rotating interaction region (CIR) preceding a
positive polarity coronal hole high-speed stream (+CH HSS). Elevated
conditions driven by the +CH HSS are expected to persist through 05
June.

Geospace

.24 hr Summary...
The geomagnetic field was quiet with an isolated period of unsettled
conditions.

.Forecast...
Geomagnetic field conditions are expected to be quiet to unsettled, with
a small chance for isolated active levels, due to on 03 June due to low
confidence 30 May CME influences and anticipated CIR effects. Unsettled
to active conditions, with a chance for isolated G1 (Minor) geomagnetic
storming periods, are anticipated on 04-05 June due to +CH HSS
influences. A chance for G1 (Minor) geomagnetic storming 4-5 June is
further heightened by the possibility of a transient arrival associated
with the M3.3 flare, whose signature may have been obscured in available
imagery.