Viewing archive of Thursday, 1 October 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Oct 01 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
01 Oct 2015	120	011
02 Oct 2015	110	011
03 Oct 2015	110	006

Bulletin

Solar flaring activity is gradually decreasing, with only one M1 (with peak at 13:20 UT) and eight C-class flares, mainly from NOAA active region 2422. NOAA 2422 is slightly decaying but still retains a complex magnetic configuration. NOAA 2427 has slightly grown, but did produce much activity. A series of CMEs were launched on September 30 of which at least two were related to a prominence eruption at the southwest limb. SDO/AIA and PROBA2/SWAP data indicate that solar material starts to lift late September 29/early morning September 30 and part of it falls back south and another part falls to the north. The southern part produces a CME with first measurement in LASCO/C2 at 10:00 UT and shortly after that the NW part produces a CME as well. These two CMEs visually merge later on. They mainly propagate to the West with a speed of 330 km/s (CACTus estimate), but it is not excluded that a glancing arrives at Earth late October 4. The CME activity did cause a rise in the proton flux (at >10MeV) to about 1pfu, though the flux values have not reached the event threshold. Proton flux values are gradually decreasing again. More C-class flares are expected, with a 25% chance for M-class flares.

The slow wind speed was low (with values around 300 km/s) till around 11 UT when the speed slightly increased to about 330 km/s. The phi angle has been varying from negative (towards) to positive (away) orientation. At 11 UT, the interplanetary magnetic field magnitude reached a peak of 10 nT. The geomagnetic conditions are quiet (K<3) to unsettled (K=3) and are mainly expected to remain so. There is a some chance for isolated time slots of active conditions (K=4).

Today's estimated international sunspot number (ISN): 092, based on 20 stations.

Solar indices for 30 Sep 2015

Wolf number Catania	///
10cm solar flux	131
AK Chambon La Forêt	006
AK Wingst	003
Estimated Ap	002
Estimated international sunspot number	/// - Based on /// stations

Noticeable events summary

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

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