Viewing archive of Tuesday, 12 May 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 May 12 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

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

	10cm flux	Ap
12 May 2015	165	026
13 May 2015	165	034
14 May 2015	163	024

Bulletin

NOAA 2339 produced only low-level C-class flares, mainly over its mixed polarity trailing portion. The strongest flare was a C3.0 flare peaking at 11:51UT, with radio-bursts observed at Humain. A filament erupted at the west solar limb between 02:10 and 03:00UT. It was associated with a C2.6 flare peaking at 03:02UT. Probably in response to this event, the greater than 10 MeV proton flux started to increase shortly after 04:00UT, but did not reach event threshold (10 pfu), reaching a maximum of 6.2 pfu at 07:30UT. No earth-directed coronal mass ejections (CME) were observed over the period.

Further C-class flaring is expected, with a chance on an M-class flare.

Mostly quiet to unsettled geomagnetic conditions were observed, with an active interval at Dourbes (K = 4). Starting around 05:30UT, solar wind speed gradually picked up from 340 km/s to its current value of about 380 km/s. With temperature increasing and density slightly decreasing, this may herald the anticipated arrival of the high speed stream from the negative polarity coronal hole. Bz was mostly negative throughout the period, varying between -8 and + 4 nT.

Unsettled to minor storming conditions are expected.

Today's estimated international sunspot number (ISN): 121, based on 14 stations.

Solar indices for 11 May 2015

Wolf number Catania	180
10cm solar flux	163
AK Chambon La Forêt	019
AK Wingst	016
Estimated Ap	018
Estimated international sunspot number	114 - Based on 26 stations

Noticeable events summary

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

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