Viewing archive of Saturday, 15 July 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Jul 15 1327 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
15 Jul 2023	185	020
16 Jul 2023	184	017
17 Jul 2023	182	006

Solar Active Regions and flaring

Solar flaring activity was at moderate levels with three low M-class flares over the past 24 hours. The strongest activity was an M2.9-flare, peak time 07:41 UTC on July 15th, produced by NOAA AR 3363 (beta-gamma-delta), which retained its magnetic complexity and produced multiple low C-class flaring. The remaining M-flares were produced close to 10:00 UTC on July 15th by NOAA AR 3372 (beta-gamma-delta), which has shown some slight decay, but remains the second largest active region after NOAA AR 3363. The other magnetically complex active region, NOAA 3361, has now rotated behind the west limb. The newly numbered regions in the east limb, NOAA AR 3373 (beta) and NOAA AR 3374 (alpha) have remained quiet. Some mid to high C-class flaring was observed from behind the west limb, possibly from NOAA AR 3368. The solar flaring activity is expected to remain at moderate levels over the coming days with likely M-class flaring and some chances for isolated X-class flaring.

Coronal mass ejections

Two partial halo coronal mass ejections (CMEs) were observed in LASCO/C2 coronagraph data on July 14th, a north-eastward and south-westward one. The second one appears related to a filament eruption close to the west limb. These CMEs are estimated to miss Earth with no expect impact. Another partial halo CME was observed in LASCO/C2 coronagraph imagery at 19:10 UTC. The CME is associated to an on disc filament eruption related to a C8.8-flare, peak time 18:44 UTC on July 14th, from plage region NOAA AR 3370. The CME is currently being analysed, but overlapping with previous partial halo from the east limb and lack of STEREO data for this interval makes analysis harder. Based on the source location and SDO/AIA 304 images the eruption is likely to have an impact on Earth. Expected arrival times will be presented later. No other Earth- directed CMEs have been detected in the available coronagraph imagery.

Coronal holes

A narrow positive polarity coronal hole is currently crossing on the central meridian and might cause enhanced solar wind conditions at Earth for a couple fo days as early as late UTC July 18th.

Solar wind

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) registered signatures of a weak ICME arrival, possibly marking the expected glancing blow from the southward partial halo CME which lifted off the solar surface around 19:24 UTC on July 11th. A fast forward shock was observed in the solar wind parameters at 15:25 UTC on July 14th. The solar wind velocity increased from 386 km/s to 441 km/s. The interplanetary magnetic field jumped from 8 nT to 14 nT and further increased up to 18 nT later. The minimum Bz reached -12 nT. The solar wind density jumped from 9 ppc to 16 ppc and reached almost 36 ppc over the next hours. The current solar wind speed is close to 500 km/s with B field values around 9 nT. The orientation of the interplanetary magnetic field has switched to the negative sector (directed towards the Sun). A high speed stream arrival from a negative polarity coronal hole was expected to reach Earth by now and its signatures could be mixed within the ongoing glancing blow. Slightly elevated solar wind conditions are expected to continue throughout July 16th and start easing up on July 17th pending no new ICME arrivals.

Geomagnetism

The geomagnetic conditions over the past 24 hours were globally quiet to active with two minor storm intervals observed over Belgium between 19:00 and 21:00 UTC on July 14th. Mostly quiet to active geomagnetic conditions with chances for isolated minor storms are expected for the next 24h. Quiet to active conditions are expected on July 16th and mostly quiet conditions on July 17th, pending no new ICME arrivals.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to continue so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measured by GOES 16 and GOES 18 was well below the 1000 pfu threshold. The greater than 2 MeV electron flux is expected to be below the 1000 pfu threshold in the upcoming days. The 24h electron fluence was at nominal levels and is expected to remain so over the next days.

Today's estimated international sunspot number (ISN): 130, based on 15 stations.

Solar indices for 14 Jul 2023

Wolf number Catania	180
10cm solar flux	181
AK Chambon La Forêt	029
AK Wingst	025
Estimated Ap	024
Estimated international sunspot number	152 - Based on 24 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page