Viewing archive of Friday, 26 July 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Jul 26 1235 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
26 Jul 2013	109	017
27 Jul 2013	111	005
28 Jul 2013	114	003

Bulletin

Catania sunspot group 35 (NOAA AR 1800) kept the beta-gamma configuration of its photospheric magnetic field and exhibited a slight growth during the last 24 hours. It produced a C2.1 flare peaking at 22:44 UT yesterday, which is the strongest flare since the beginning of the week. We expect more C-class flares from this active region, with M-flares being very unlikely. Yesterday the Earth entered the interaction region between the slow and fast solar wind flows (with the fast flow produced by the equatorial coronal hole currently situated in the western hemisphere). The interplanetary sector boundary was crossed early yesterday afternoon, and the interplanetary magnetic field (IMF) magnitude reached 15 nT, with several intervals of southward IMF. As a result, the K-index reported by Dourbes, IZMIRAN, and NOAA reached 4 (active geomagnetic conditions). The peak speed of the fast stream was around 600 km/s (reached this morning). Currently the Earth is still inside the fast solar wind stream, with the speed around 550 km/s. As the IMF magnitude already decreased to 5-7 nT, we expect unsettled to quiet geomagnetic conditions in the coming hours. Active geomagnetic conditions are nevertheless possible, although not very likely.

Today's estimated international sunspot number (ISN): 051, based on 10 stations.

Solar indices for 25 Jul 2013

Wolf number Catania	096
10cm solar flux	107
AK Chambon La Forêt	029
AK Wingst	016
Estimated Ap	015
Estimated international sunspot number	056 - 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