911
FXXX12 KWNP 040031
DAYDIS

:Product: Forecast Discussion
:Issued: 2026 Jun 04 0030 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
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#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity remained at high levels. Activity was dominated by Region
4455 (N14W21, Dki/beta-gamma-delta), which produced frequent C-class
flares alongside three significant flare events: an M9.3/Sf at 03/0136
UTC, an M7.7/1b at 03/0700 UTC, and an X1.0/1n at 03/1128 UTC.

There are eight numbered regions on the visible disk. Region 4455
remains complex, maintaining its anti-Hale configuration and displaying
a newly developed delta structure. Continuous flux emergence and spot
growth with penumbral development were observed just ahead of its
mature, positive polarity lead spot. Regions 4458 (S05W08, Dai/beta) and
4459 (N14E36, Dai/beta-gamma) both showed growth and consolidation, with
Region 4459 showing rapid spot development in its trailing area and
gaining a mixed-polarity gamma configuration. Region 4461 (S21E59,
Cai/beta-gamma) also showed flux emergence driving a gamma
configuration, though extreme foreshortening near the limb limits
high-confidence analysis of its overall complexity. Region 4462 (N17E60,
Dao/beta) consolidated and showed increased separation between its
poles. The remaining regions were stable or in decline.

Several eruptive events occurred during the reporting period: The
M9.3/Sf flare at 03/0136 UTC was accompanied by wideband radio
emissions, including a Type IV radio sweep, a Type II sweep with an
estimated shock velocity of 253 km/s, and a 10.7cm radio burst peaking
at 360 sfu. An associated CME became visible in LASCO C2 imagery at
approximately 03/0213 UTC and GOES CCOR1 at 03/0215 UTC. While faint in
coronagraph imagery, GOES/SUVI imagery implies a partial to full halo
profile, and COR2 triangulation confirms an Earth-directed component.
Modeling indicates this event is the most Earth-directed CME of the
periods events.

The M7.7/1B flare at 03/0700 UTC was accompanied by by wideband radio
emissions, including a Type IV sweep, a Type II sweep with an estimated
shock velocity of 313 km/s, and a prominent three-minute 10.7cm radio
burst peaking at 540 sfu with a Castelli-U signature. The associated CME
was first seen in LASCO C2 at 03/0748 UTC and CCOR1 at 03/0745 UTC.
GOES/SUVI 304 imagery shows much of the ejecta was deflected
significantly northward by an adjacent positive polarity coronal hole.
STEREO COR2 imagery and modeling shows that though that while it retains
an Earth-directed glancing component, it is the least directly targeted
event of the period.

The X1.0/1N flare at 03/1128 UTC was accompanied by wideband radio
emissions, including a Type IV sweep and a 10.7cm radio burst peaking at
180 sfu. An associated CME was observed in CCOR1 imagery at 03/1200 UTC.
GOES/SUVI 304 imagery suggests that the ejecta was deflected both
eastward and northward. Triangulation with COR2 and modeling confirm an
Earth-directed component. Together, these three eruptions are
anticipated to arrive at Earth mid- to late on 04 June.

.Forecast...
Solar activity is expected to be at moderate to high levels through 06
June. M-class (R1-R2/Minor-Moderate) flaring remains likely, with a
slight chance for X-class (R3/Strong or greater) events, primarily due
to the eruptive capabilities of Regions 4455, 4458, and 4459.

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 400 pfu observed at 03/1755 UTC.
The greater than 10 MeV proton flux at geosynchronous orbit remained at
baseline background levels.

.Forecast...
The greater than 2 MeV electron flux at geosynchronous orbit is
anticipated to rise to high levels on 04 June in response to CME
effects, remaining high through 06 June. While the greater than 10 MeV
proton flux is expected to remain below the S1 threshold, proton
enhancements are possible on 04 June due to CME shock front
interactions.

Solar Wind

.24 hr Summary...
Solar wind parameters continued to be slightly elevated with conditions
reflecting possible embedded transient influences. Total magnetic field
(Bt) averaged near 8 nT during the first half of the reporting period
before dropping sharply around 03/0800 UTC. Following this, Bt was
variable and reached as low at 0.5 nT during one of several solar sector
boundary crossings around 1845 UTC. After this crossing, Bt steadily
increased ending the period around 10 nT. The North-South (Bz) component
was mostly northward, but turned south later in the period after 1845
UTC and reached a maximum deflection of -6 nT. Wind speeds held steady
near 400 km/s for most of the period before a distinct increase to near
450 km/s late in the period. The phi angle showed a distinct transition
into the positive (away from the Sun) sector late in the period.

.Forecast...
Mild enhancements are expected early on 04 June under the initial onset
of positive polarity high-speed stream (+CH HSS) influences. Conditions
will escalate dramatically mid- to late on 04 June with the arrival of
the multiple 03 June CMEs. These significant enhancements are expected
to persist through 05 June with elevated conditions persisting through
06 June.

Geospace

.24 hr Summary...
The geomagnetic field was quiet to unsettled.

.Forecast...
Geomagnetic field conditions are expected to escalate rapidly from quiet
to active, reaching up to G3 (Strong) geomagnetic storming levels mid-
to late on 04 June and persisting into 05 June in response to the
multiple CME arrivals. There is a chance for isolated periods of G4
(Severe) geomagnetic storming during the peak of the multi-CME passage
over 04-05 June. Conditions are expected to drop to active levels, with
a remaining chance for isolated G1 (Minor) storming thresholds, on 06
June as CME effects gradually wane.