Detailed Information

Solar Activity

Solar activity over the past 24 hours was eruptive. Three C-class flares were observed, with no M-class or X-class flares reported. The most significant event was a C1.7 flare originating from NOAA 14419, peaking at 12:25UT. Associated with this activity, seven Type III solar radio bursts were detected, while no Type II or Type IV radio bursts were observed. Furthermore, no coronal mass ejections were observed during this period.

On the visible disk, three active regions were identified by SDO/HMI: NOAA 14415, NOAA 14416, and NOAA 14419. Additionally, BBSO H-alpha observations revealed two plages, NOAA 14414 and NOAA 14418. Looking at the farside, three regions are due to return between 16 April and 18 April.

Based on today's condition, solar activity for:

April 17th, 2026 04:00 UT - April 18th, 2026 03:59 UT is predicted to be active.
April 18th, 2026 04:00 UT - April 19th, 2026 03:59 UT is predicted to be active.
April 19th, 2026 04:00 UT - April 20th, 2026 03:59 UT is predicted to be eruptive.

 

Geomagnetic Activity

The geomagnetic activity was on quiet level for the last 24 hours.

The solar wind speed decreased from 375 km/s to 309 km/s, and the north-south component of the interplanetary magnetic field fluctuated between -5.3 nT and 4.5 nT. There was a geoeffective coronal hole at the eastern equator, while the others at the southeast, south pole, and southwest were not geoeffective.

Quiet level geomagnetic activity is expected for the next 24 hours.
Active level geomagnetic activity is expected for 18 April 2026 07UT - 19 April 2026 07UT
Active level geomagnetic activity is expected for 19 April 2026 07UT - 20 April 2026 07UT

 

 

Ionospheric Activity

Ionosphere was in minor conditions for the last 24 hours.

There was depression of foF2 lower than 30% of its median value for 60 minutes. There was increment of fmin more than 30% of its median values for 45 minutes.  The Spread-F occured for the last 24 hours for 450 minutes. The Sporadic-E occurred in the night and daytime with foEs value exceeded the foF2 for several times for 1350 minutes. The S4 index values (condition of ionospheric scintillation ) was over than 0.8 and the maximum TEC index value was at 76.77 both over Pontianak for the last 24 hours.

The ionosphere activity is predicted to be quiet level on April 17th 2026, 04:00 UT - April 18th 2026 03:59 UT.

The ionosphere activity is predicted to be minor level on April 18th 2026, 04:00 UT - April 19th 2026 03:59 UT.

The ionosphere activity is predicted to be minor level on April 198th 2026, 04:00 UT - April 20th 2026 03:59 UT.

Navigation

The error of the single frequency GPS positioning for the last 24 hours was on slight level,

based on ionospheric scintilation and TEC variation.

 

Based on ionospheric scintilation and TEC variation, the probability of error positioning for

April 17th 2026, 04:00 UT - April 18th 2026 03:59 UT is predicted to be on slight level.

Based on ionospheric scintilation and TEC variation, the probability of error positioning for

April 18th 2026, 04:00 UT - April 19th 2026 03:59 UT is predicted to be on slight level.

Based on ionospheric scintilation and TEC variation, the probability of error positioning for

April 19th 2026, 04:00 UT - April 20th 2026 03:59 UT is predicted to be on slight level.

 

HF Radio Communication

Maximum Usable Frequency (MUF) Depression was in moderate condition and the Short Wave Fadeout (SWF) was in moderate for the last 24 hours.

 

The MUF depression for April 17th 2026, 04:00 UT - April 18th 2026 03:59 UT is predicted at a quiet

level, due to previous geomagnetic activity.

The MUF depression for April 18th 2026, 04:00 UT - April 19th 2026 03:59 UT is predicted at a minor

level, due to predicted geomagnetic activity.

The MUF depression for April 19th 2026, 04:00 UT - April 20th 2026 03:59 UT is predicted at a minor

level, due to predicted geomagnetic activity.

 

The SWF for April 17th 2026, 04:00 UT - April 18th 2026 03:59 UT is predicted at a minor level due to

the prediction of a solar flare.

The SWF for April 18th 2026, 04:00 UT - April 19th 2026 03:59 UT  is predicted at a minor level due to

the prediction of a solar flare.

The SWF for April 19th 2026, 04:00 UT - Fe April 20th 2026 03:59 UT is predicted at a quiet level due to

the prediction of a solar flare.

Satellites

The electron flux was at a high level for the last 24 hours.

A high level of electron flux is expected for the next 24 hours.
High level of electron flux is expected for 18 April 2026 07UT - 19 April 2026 07UT.
High level of electron flux is expected for 19 April 2026 07UT - 20 April 2026 07UT.

The 10 MeV proton flux remained quiet over the past 24 hours.

Based on today's conditions, the flux of high-energy protons for :

April 17th, 2026 04:00 UT - April 18th, 2026 03:59 UT is predicted to be quiet.
April 18th, 2026 04:00 UT - April 19th, 2026 03:59 UT is predicted to be quiet.
April 19th, 2026 04:00 UT - April 20th, 2026 03:59 UT is predicted to be quiet.