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Daily bulletin on solar and geomagnetic activity from the SIDC

Випущено: 2023 Jul 18 1236 UTC

SIDC Forecast

Сонячні спалахи

M-class flares expected (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Сонячні протони

Proton event in progress (>10 MeV)

	10cm flux	Ap
18 Jul 2023	176	008
19 Jul 2023	170	022
20 Jul 2023	176	016

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours remained at moderate levels. NOAA AR 3363 produced two M-class flares within a period of 3 hours, the largest was an M5.7-flare, with peak time 00:06 UTC on July 18, associated with a wide CME and proton event. Another M1.5-flare, peak time 06:56 UTC, on July 18 was produced by a yet unnumbered active region, which has started to rotate unto the visible solar disk in the northern hemisphere. There are currently 8 numbered active regions on the visible disk. NOAA AR 3363, NOAA AR 3372 and NOAA AR 3373 are the largest and most complex regions. NOAA AR 3363 was the most active in the last 24 hours but has started to rotate off the visible disk. NOAA AR 3372 and NOAA AR 3373 have produced several C-class flares. NOAA AR 3372 is decaying while the number of sunspots of NOAA AR 3373 has increased. The remaining active regions were quiet and stable. The solar flaring activity is likely to remain at moderate levels over the coming days with a low chance for isolated X-class flaring.

Корональні викиди маси

A halo coronal mass ejection (CME) was observed in LASCO/C2 coronagraph data from 23:50 UTC on July 17, as an initial estimate the projected speed is over 1000 km/s. The CME is associated with the M5.7 originating from NOAA AR 3363 near the south west limb. Analysis of the CME is ongoing but, due to the location of the CME origin, a glancing blow at Earth may be possible from late on July 19.

Сонячний вітер

The solar wind speed fluctuated around 500 km/s. The magnetic field reached a peak value of 7 nT with an extended period of negative Bz between 16:00 UTC July 17 and 00:45 UTC July 18, reaching a minimum Bz of -6 nT. Further enhancements continue to be possible on July 18 and 19 from the expected ICME arrivals and a possible weak high speed stream arrival.

Geomagnetism

The geomagnetic conditions over the past 24 hours reached minor storm levels globally (NOAA KP = 5 minus, K-Bel =4) starting at 18:00 UTC July 17 ending at 03:00 UTC July 18, coinciding with the long period of negative Bz. Mostly unsettled to active geomagnetic conditions with isolated minor storm periods are expected over the next two days, due to the predicted weak high-speed stream and further glancing blow arrivals.

Proton flux levels

The greater than 10 MeV proton flux crossed the 10 pfu threshold on 18 July at 01:15 UTC and reached a maximum value of 620 at 06:15 UTC. This proton event was associated with the M5.7 flare and the halo CME. The proton flux is expected to remain above the threshold over the 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold, but has a small chance to exceed this level during the next 24 hours. The 24h electron fluence was at nominal levels and is expected to remain so.

Today's estimated international sunspot number (ISN): 164, based on 20 stations.

Solar indices for 17 Jul 2023

Wolf number Catania	163
10cm solar flux	180
AK Chambon La Forêt	026
AK Wingst	018
Estimated Ap	020
Estimated international sunspot number	159 - Based on 24 stations

Noticeable events summary

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

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