Viewing archive of Monday, 28 September 2020

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2020 Sep 28 1230 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
28 Sep 2020	073	028
29 Sep 2020	072	020
30 Sep 2020	072	009

Bulletin

The solar activity was at very low levels with no significant flares. There are no sunspots on the solar disk and no significant flares are expected over the next 24 hours.

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

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours, and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux was oscillating at moderate levels, exceeding the 10^3 pfu threshold between 07:55 and 10:00 UT today. The electron flux is expected to remain elevated over the next 24 hours.

Over the past 24 hours the solar wind conditions were elevated due to the arrival of a high-speed stream, associated with a positive polarity northern coronal hole, which crossed the central meridian on Sept 26th. According to ACE and DSCOVR data, the total interplanetary magnetic field varied between 1 nT and 10 nT. The north-south Bz component fluctuated between -9 nT and 8 nT, with highest absolute value around 19:00 UT on Sept 27th. The Phi angle was predominantly positive reflecting the influence of the positive-polarity coronal hole. In the past 24 hours the solar wind speed was enhanced with values between 433 km/s and 660 km/s. A prolonged period of fast stream with speed exceeding 600 km/s was observed around 18:30 UT on Sept 27th and continues at present. The solar wind conditions are expected to remain enhanced over the next 24 hours.

Over the past 24 hours the geomagnetic conditions have globally reached moderate storm levels with planetary index Kp equal to 6 between 21:00 UT and midnight on Sept 27th, and locally minor storm levels with K Dourbes equal to 5. We are currently under the influence of the fast solar wind stream originating from the positive-polarity low-latitude large-area coronal hole which is now connected to the northern polar coronal hole and partially still residing on the central meridian. This influence is expected to continue in the following 2 to 3 days. Over the next 48 hours we expect active conditions with periods of minor geomagnetic storms. Isolated periods of moderate storms remain possible.

Today's estimated international sunspot number (ISN): 000, based on 10 stations.

Solar indices for 27 Sep 2020

Wolf number Catania	///
10cm solar flux	074
AK Chambon La Forêt	042
AK Wingst	021
Estimated Ap	024
Estimated international sunspot number	000 - Based on 21 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