Viewing archive of Friday, 16 May 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 May 16 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Solar protons

Quiet

	10cm flux	Ap
16 May 2025	122	017
17 May 2025	124	024
18 May 2025	125	020

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with one M-class flare and a few C-class flares. The strongest flare was a M2.1 flare (SIDC Flare 4395) peaking at 17:21 UTC on May 15, associated with SIDC Sunspot Group 496 (NOAA Active Region 4087, magnetic type beta-delta). There are currently five numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 496 (NOAA Active Region 4087). SIDC Sunspot Group 492 (NOAA Active Region 4082) has rotated behind the west limb. The solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares expected, a chance for M-class flares and a small chance for X-class flares.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CMEs) were observed in the available coronagraph imagery in the last 24 hours.

Coronal holes

An elongated, mid-latitude, positive polarity coronal hole (SIDC Coronal Hole 104) continues to cross the central meridian since May 15. An associated high-speed stream may arrive at Earth starting from May 18.

Solar wind

The solar wind conditions (ACE and DSCOVR) are gradually returning to the slow solar wind regime, under the waning influence of the high-speed stream from the equatorial, negative polarity coronal hole (SIDC Coronal Hole 114). Speed values ranged between 360 km/s and 470 km/s. The interplanetary magnetic field values were between 1 nT and 8 nT. The Bz component varied between -6 nT and 4 nT. The interplanetary magnetic field angle phi was in the negative sector until 03:00 UTC on May 16, when it flipped to the positive sector. Enhanced solar wind conditions are expected over the next 24 hours, due to the expected arrival of the ICME associated with the Coronal Mass Ejection (CME) observed around 23:00 UTC on May 12.

Geomagnetism

Geomagnetic conditions globally were mostly at quiet to unsettled levels (NOAA Kp 2 to 3). Geomagnetic conditions locally were mostly at quiet to unsettled levels (K BEL 2 to 3). Minor storm conditions (NOAA Kp 5, K BEL 5), with possible isolated moderate storm conditions (NOAA Kp 6, K BEL 6), are expected over the next 24 hours due to the expected arrival of the ICME associated with the Coronal Mass Ejection (CME) observed around 23:00 UTC on May 12.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold level over the past 24 hours. It is expected to remain below the threshold level over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 was below the 1000 pfu threshold in the last 24 hours and is expected to remain so over the next 24 hours. The 24-hour electron fluence is presently at normal levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 067, based on 26 stations.

Solar indices for 15 May 2025

Wolf number Catania	///
10cm solar flux	119
AK Chambon La Forêt	018
AK Wingst	015
Estimated Ap	016
Estimated international sunspot number	046 - Based on 29 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

All times in UTC

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