Viewing archive of Thursday, 25 July 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Jul 25 1302 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
25 Jul 2013	110	011
26 Jul 2013	112	015
27 Jul 2013	115	003

Bulletin

During the last 24 hours, Catania sunspot group 35 (NOAA AR 1800) produced three weak C-class flares, the strongest one being the C1.8 flare peaking at 21:43 UT yesterday. We expect more C-class flares in this group, but the probability for flaring at the M-level is low. A filament eruption at the solar central meridian (between Catania sunspot groups 35 and 44) starting around 02:00 UT today was accompanied by coronal dimmings and a post- eruption arcade, as shown by the SDO/AIA data. However, no corresponding CME was detected by SOHO/LASCO or STEREO/COR. The Earth is currently inside a slow (around 320 km/s) solar wind flow with average (around 5 nT) interplanetary magnetic field magnitude. We expect quiet geomagnetic conditions until the arrival of the interaction region between the slow and fast solar wind flows later today (followed by the fast flow from the equatorial coronal hole), which may result in active geomagnetic conditions.

Today's estimated international sunspot number (ISN): 058, based on 18 stations.

Solar indices for 24 Jul 2013

Wolf number Catania	090
10cm solar flux	108
AK Chambon La Forêt	007
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	047 - Based on 20 stations

Noticeable events summary

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

All times in UTC

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