Detailed Information

Solar Activity

Solar activity in the past 24 hours was eruptive.

Four C-class flares occurred in the past 24 hours. The strongest was a C4.6 flare, which peaked at 22:42 UT from the east limb of the solar disk. Two type III solar radio bursts and seven CMEs were recorded during this period. The east-directed CMEs had the highest median velocity of 954 km/s and an angular width of 96°, while the west-directed CMEs had the highest median velocity of 766 km/s and an angular width of 88°. The latest SDO/HMI Intensitygram data show ten active regions (NOAA 14441, 14443, 14444, 14445, 14446, 14447, 14448, 14449, 14450, and 14451), while the latest BBSO H-alpha data reveal three plages (NOAA 14439, 14440, and 14442) on the solar disk. Farside data show one active regions expected to return from the solar eastern limb in the next 72 hours.

Based on today's conditions,
solar activity for 26 May, 04:00 UT–27 May, 03:59 UT is predicted to be eruptive;
solar activity for 27 May, 04:00 UT–28 May, 03:59 UT is predicted to be eruptive;
solar activity for 28 May, 04:00 UT–29 May, 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 increase from 270 km/s and 368 km/s, north-south component of interplanetary magnetic field fluctuate between -5.5 nT and 5.7 nT. There were geoeffective coronal holes at eastern equator and south-west, while the others at north-east and western equator were not geoeffective. CME on 25 May 2026 04:00 UT was mainly errupted toward north-west with speed of 339 km/s and angular width of 6°. The CME was geoeffective and is likely to have not impact until next 3 days.

Quiet level geomagnetic activity is expected for the next 24 hours.
Quiet level geomagnetic activity is expected for 27 May 2026 07UT - 28 May 2026 07UT
Quiet level geomagnetic activity is expected for 28 May 2026 07UT - 29 May 2026 07UT

 

Ionospheric Activity

Ionosphere was in quiet conditions for last 24 hours.

There was no depression of foF2 lower than 30% of its median value for the last 24 hours. There was  increment of fmin more than 30% of its median values for 120 minutes  for the last 24 hours. The Spread-F  not occurred for the last 24 hours. The Sporadic-E occurred in the night and daytime with foEs value exceeded the foF2 for several times for 960 minutes for the last 24 hours. The S4 index values was less than 0.5 (0.5<S4) and the maximum TEC index value was at 75.03, both over Pontianak for the last 24 hours.

 

The ionosphere activity on May 26th, 04:00 UT - May 27th, 03:59 UT is predicted on quiet level, due to previous of geomagnetic activity.

The ionosphere activity on May 27th, 04:00 UT - May 28th, 03:59 UT is predicted on quiet level, due to previous of geomagnetic activity.

The ionosphere activity on May 28th, 04:00 UT - May 29th, 03:59 UT is predicted on quiet level, due to previous of geomagnetic activity.

Navigation

Based on TEC and scintilation , the error of the single frequency GPS positioning for last 24 hours was in normal level.

 

Based on ionospheric scintilation and TEC variation, the probability of error positioning on May 26th, 04:00 UT - May 27th, 03:59 UT is predicted on normal level.

Based on ionospheric scintilation and TEC variation, the probability of error positioning on May 27th, 04:00 UT - May 28th, 03:59 UT is predicted on normal level.

Based on ionospheric scintilation and TEC variation, the probability of error positioning on May 28th, 04:00 UT - May 29th, 03:59 UT is predicted on normal level.

HF Radio Communication

MUF depression was in quiet condition and Short Wave Fadeout (SWF) was in moderate for last 24 hours.

 

The MUF depression on May 26th, 04:00 UT - May 27th, 03:59 UT is predicted on quiet level, due to previous of geomagnetic activity.

The MUF depression on May 27th, 04:00 UT - May 28th, 03:59 UT is predicted on quiet level, due to previous of geomagnetic activity.

The MUF depression on May 28th, 04:00 UT - May 29th, 03:59 UT is predicted on quiet level, due to previous of geomagnetic activity.

 

The SWF on May 26th, 04:00 UT - May 27th, 03:59 UT is predicted in quiet level due to the prediction of solar flare.

The SWF on May 27th, 04:00 UT - May 28th, 03:59 UT is predicted in quiet level due to the prediction of solar flare.

The SWF on May 28th, 04:00 UT - May 29th, 03:59 UT is predicted in quiet level due to the prediction of solar flare.

Satellites

The electron flux was on low level for the last 24 hours.

Low level of electron flux is expected for the next 24 hours.
Low level of electron flux is expected for 27 May 2026 07UT - 28 May 2026 07UT
Low level of electron flux is expected for 28 May 2026 07UT - 29 May 2026 07UT

The flux of high-energy protons in the past 24 hours was major proton event.

Based on today's condition,
the flux of high-energy proton for 26 May, 04:00 UT–27 May, 03:59 UT is predicted to be event in progress;
the flux of high-energy proton for 27 May, 04:00 UT–28 May, 03:59 UT is predicted to be quiet;
the flux of high-energy proton for 28 May, 04:00 UT–29 May, 03:59 UT is predicted to be quiet.