Viewing archive of Wednesday, 20 May 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 May 20 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
20 May 2026	107	007
21 May 2026	105	007
22 May 2026	103	007

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with five C-class flares identified. SIDC Sunspot Group (SG) 825 (NOAA Active Region [AR] 4436, Beta magnetic configuration) produced three of these flares. The brightest flare was SIDC flare 7734, a C2, that peaked on 19 May at 20:00 UTC. The back-sided SIDC SG 853 produced a C1 flare (SIDC flare 7738) on 20 May at 04:43 UTC. Another C1 flare (SIDC flare 7739) was emitted by SIDC SG 869 (NOAA AR 4439, Beta magnetic configuration) on 20 May at 10:09 UTC. More C-class flaring activity is expected in the next 24 hours, mostly from SIDC SG 825 and 853.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CME) were observed in the last 24 hours.

Coronal holes

SIDC Coronal Hole (CH) 164 is a southern, high-latitude, very elongated, positive polarity structure. Although It started crossing the solar central meridian in the last 24 hours, it not expected to produce a geo-effective High Speed Stream (HSS) due to its shape and position.

Solar wind

The glancing blow that arrived at Earth on 19 May subsided in the past 24 hours and the Solar Wind (SW) conditions have now returned to a slow SW regime. The SW speed dropped from 640 to 460 km/s, the interplanetary magnetic field (B) ranged between 3 and 8 nT, and its North- South component (Bz) varied from -7 to 5 nT. The SW conditions are expected to remain at the current levels in the next 24 hours.

Geomagnetism

The geomagnetic conditions of the past 24 hours reach active levels both globally and locally (NOAA Kp 4 on 19 May from 12:00 to 18:00 UTC and K BEL 4 on 19 May at 15:00-18:00 UTC). The remaining time both global and local levels ranged between unsettle and quiet conditions (NOAA Kp 1 to 3 and K BEL 2 to 3). In the next 24 hours it is likely that they will decrease to unsettled to quiet levels, as the effects of the glancing blow have now subsided.

Proton flux levels

The greater than 10 MeV proton flux, as measured by the GOES-19 satellite, was at nominal levels over the past 24 hours and is likely to remain so in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as, measured by GOES 19, was around the 1000 pfu alert threshold for past 24 hours. It reached a peak value of 2900 pfu on 20 May at 04:50 UTC. It is expected to marginally drop in the next 24 hours and possibly stay below the alert threshold. The electron fluence was at moderate levels in the past 24 hours and it is expected to drop to normal levels at some point in the next 24 hours.

Today's estimated international sunspot number (ISN): 077, based on 14 stations.

Solar indices for 19 May 2026

Wolf number Catania	///
10cm solar flux	106
AK Chambon La Forêt	028
AK Wingst	018
Estimated Ap	019
Estimated international sunspot number	075 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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