Alerts:
none
Solar-terrestrial indices for 25 April follow.
Solar flux 148 and estimated planetary A-index 9.
The estimated planetary K-index at 0300 UTC on 26 April was 2.67.
Space weather for the past 24 hours has been minor.
Radio blackouts reaching the R1 level occurred.
Space weather for the next 24 hours is predicted to be moderate.
Geomagnetic storms reaching the G1 level are likely.
Radio blackouts reaching the R2 level are likely.
Geo Magnetic Forecast:
NOAA Ap Index Forecast
Observed Ap 24 Apr 009
Estimated Ap 25 Apr 014
Predicted Ap 26 Apr-28 Apr 020-014-008
NOAA Geomagnetic Activity Probabilities 26 Apr-28 Apr
Active 30/45/20
Minor storm 45/10/01
Moderate storm 05/01/01
Strong-Extreme storm 01/01/01
NOAA Kp index forecast 26 Apr - 28 Apr
Apr 26 Apr 27 Apr 28
00-03UT 4.67 3.67 2.33
03-06UT 4.33 3.00 2.00
06-09UT 3.33 2.67 2.00
09-12UT 3.33 2.33 2.00
12-15UT 2.33 2.00 2.33
15-18UT 2.33 2.33 2.00
18-21UT 3.00 3.33 2.00
21-00UT 3.33 3.33 2.00
Extended Three Day Forecast:
A. NOAA Geomagnetic Activity Observation and Forecast
The greatest observed 3 hr Kp over the past 24 hours was 3 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Apr 26-Apr 28 2026 is 4.67 (NOAA Scale
G1).
NOAA Kp index breakdown Apr 26-Apr 28 2026
Apr 26 Apr 27 Apr 28
00-03UT 4.67 (G1) 3.67 2.33
03-06UT 4.33 3.00 2.00
06-09UT 3.33 2.67 2.00
09-12UT 3.33 2.33 2.00
12-15UT 2.33 2.00 2.33
15-18UT 2.33 2.33 2.00
18-21UT 3.00 3.33 2.00
21-00UT 3.33 3.33 2.00
Rationale: Isolated G1-G2 (Minor-Moderate) geomagnetic storming
conditions are possible (G1 likely with a chance for G2)early 26 Apr in
response to the arrival of the glancing CMEs.
B. NOAA Solar Radiation Activity Observation and Forecast
Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
below S-scale storm level thresholds.
Solar Radiation Storm Forecast for Apr 26-Apr 28 2026
Apr 26 Apr 27 Apr 28
S1 or greater 10% 10% 10%
Rationale: There is a chance to exceed the S1 (Minor) solar radiation
storm thresholds due to the flare potential of Region 4419 further
beyond the western limb, and Region 4420 near the central solar
meridian.
C. NOAA Radio Blackout Activity and Forecast
Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Apr 25 2026 0759 UTC.
Radio Blackout Forecast for Apr 26-Apr 28 2026
Apr 26 Apr 27 Apr 28
R1-R2 55% 55% 55%
R3 or greater 15% 15% 15%
Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely, with a
slight chance for R3 (Strong or greater) events through 28 Apr,
primarily driven by the complexity of Regions 4420, 4423, and 4425.
Extended Space Weather Discussion:
Solar Activity
.24 hr Summary...
Solar activity was at moderate levels during the reporting period. The
largest events were an M1.3/Sf flare at 25/0759 UTC from Region 4423
(S05E18, Dai/beta-gamma-delta) and an impulsive M1.1/Sf flare at 25/1430
UTC from Region 4425 (N05E66, Eac/beta-gamma). While Regions 4423 and
4425 were the primary drivers of activity, isolated C-class flares were
observed from Regions 4420 (N16W01, Fki/beta-gamma-delta) and 4424
(N16E33, Dsi/beta). A bright and partially obscured C3.8 flare was
observed from Region 4419 (N17, L=316) as it rotated over the western
limb.
There are currently eight numbered regions on the visible disk. Region
4419 rotated beyond the western limb during the period. Region 4420
showed flux emergence in its intermediary spots, increased shear in the
trailing portion, and growth in overall area. Region 4423 showed
consolidation in both the leader and trailer spots and became less
fragmented. Region 4424 showed growth in its intermediate spots,
alongside consolidation in the trailing spot. Region 4425 rotated
further into view, though limb proximity continues to hinder full
characterization of its extent and magnetic complexity. Region 4426
(N12W37, Axx/alpha) lost its trailing spot and became a unipolar group,
and Region 4427 (S30E67, Axx/alpha) was numbered during the period as an
unremarkable unipolar group. All other regions were stable or in slight
decay.
A narrow eruption likely associated with the M1.1 flare from Region 4425
was observed off the eastern limb. Modeling indicates the ejecta will
pass well behind Earth. No other CMEs were observed in available
coronagraph imagery.
.Forecast...
Solar activity is expected to be at low levels, with M-class flares
(R1-R2-Moderate) likely, and a chance for X-class (R3/Strong or greater)
flares through 28 Apr, primarily driven by the complexity of Regions
4420, 4423, and 4425.
Energetic Particle
.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at low
to moderate levels with a peak of 403 pfu at 25/1910 UTC. The greater
than 10 MeV proton flux at geosynchronous orbit was slightly elevated,
but remained near background levels.
.Forecast...
The greater than 2 MeV electron flux is expected to be at moderate to
high levels through 28 Apr. The greater than 10 MeV proton flux is
expected to remain at background levels, though there is a decreasing
chance for levels to exceed S1 (Minor) solar radiation storm thresholds
due to the flare activity of now-departed Region 4419 and Region 4420 as
it approaches central solar meridian.
Solar Wind
.24 hr Summary...
Solar wind parameters were marginally enhanced through the period, with
speeds initially near 450 km/s before trending toward 350 km/s.
Conditions became increasingly perturbed late in the period, signaling
the passage of a transient structure that is possibly the glancing
influence of the 23 Apr CME. Total magnetic field (Bt) averaged near 8
nT before peaking at 12 nT near the end of the UT day. This peak in Bt
coincided with a southward deflection of the Bz component to -9 nT and
an increase in solar wind speed to 450 km/s. This disturbance was
characterized by a distinct density enhancement and a transient rotation
in the phi angle, which was otherwise predominantly positive throughout
the period.
.Forecast...
Further enhancements in the solar wind environment are anticipated 26-27
Apr due to anticipated arrival of further glancing influences from
the 23 Apr and 24 Apr CMEs.
Geospace
.24 hr Summary...
The geomagnetic field was quiet to unsettled.
.Forecast...
Isolated G1 (Minor) geomagnetic storming conditions are possible late on
early 26 Apr in response to the arrival of the glancing CMEs. Quiet to
unsettled conditions are then anticipated 27-28 Apr as CME influences
subside.
27 Day Forecast:
Date | Radio Flux | Planetary A Index | Largest Kp Index
2026 Apr 20 105 18 4
2026 Apr 21 110 15 4
2026 Apr 22 120 8 3
2026 Apr 23 125 5 2
2026 Apr 24 120 8 3
2026 Apr 25 115 8 3
2026 Apr 26 120 5 2
2026 Apr 27 125 5 2
2026 Apr 28 125 5 2
2026 Apr 29 125 20 5
2026 Apr 30 125 18 5
2026 May 01 125 12 4
2026 May 02 125 10 4
2026 May 03 115 8 3
2026 May 04 108 8 3
2026 May 05 105 5 2
2026 May 06 100 5 2
2026 May 07 95 20 5
2026 May 08 90 15 4
2026 May 09 90 8 3
2026 May 10 95 5 2
2026 May 11 100 5 2
2026 May 12 105 5 2
2026 May 13 110 5 2
2026 May 14 110 5 2
2026 May 15 105 25 5
2026 May 16 105 20 5
v4.16b
v4.X Release 17th Dec 2020)
Fixed New GOES and HPI inputs from noaa for Json (17/12/20).
Addded the ability to add 2 custom Magnetometers in settings (comming soon) (18/10/19).
Improved Hobart Magnetometer code. (18/18/19)
Move all presets into their own pop out side menu. (19/06/19)
Added Composite weather maps (TAS, VIC and SA), thanks to Oz forecast! (19/06/19)
UI Upgrades, Name, Logo and Website Site Changes.
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v3.8x
Various Updates, New AF Index Algo. (8/12/18)
v3.6x
Added more Presets. Disabled Presets overwriting graph views (6/7/18)
Added GeoSpace Kp Model Prediction. (3/7/18)
Added SWPC Kp Forecast + Observation. (2/7/18)
Removed WingKP and USKp. :( No longer Avaliable. (2/7/18)
Removed feed from www.dunedinaurora.nz (Unreliable). (2/7/18)
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Added Macquarie Island MAG feed.
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Added Brendan's experemental MAG feed (Hobart).
Fixed cookie bug, One Alert is enough for landscape mode.
> v1.0 (Started 20/10/2014)
Mawson and Macquarie Island data is copyright Commonwealth of Australia (Geoscience Australia), and redistributed under Creative Commons v4.
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