Viewing archive of Friday, 27 December 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Dec 27 1242 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
27 Dec 2013	125	003
28 Dec 2013	130	007
29 Dec 2013	133	007

Bulletin

There were four C flares on the Sun during the past 24 hours. The brightest one was a C4.4 flare peaking at 12:13 UT on December 27, for which the source region is still unknown at this moment. Since AR 11934 and 11936 are showing fast flux emergence, the probability for C flares over the next 48 hours is high (around 75%) and for M flares around 25%. The > 10 MeV proton flux as observed by GOES13 has stabilized around 2 pfu and is not expected to exceed the threshold level of 10 pfu in the next 48 hours. STEREO COR2 B observed a full halo CME at 3:12 UT on December 26, which was detected as a partial halo CME on LASCO C2 by CACTUS. This CME is related to a backsided event. Another CME was observed by LASCO C2 at 7:36 UT on December 26 and by STEREO COR2 A at 7:54 UT. This CME is probably related to the C2.2 flare released by AR 11931 which peaked at 7:02 UT. There is a slight chance that this CME will deliver a glancing blow in the first half of December 30. Around 3h UT on December 27, the solar wind speed as observed by ACE increased quickly from about 265 to about 310 km/s. Over the past 24 hours, the magnitude of the Interplanetary Magnetic Field has increased from about 3 to about 7 nT. These observations may be the effect of a weak coronal hole high speed stream arriving at Earth. Geomagnetic activity has been quiet over the past 24 hours (K Dourbes between 0 and 2; NOAA Kp between 1 and 2). Quiet geomagnetic conditions (K Dourbes < 4) are expected on December 27, 28, and 29.

Today's estimated international sunspot number (ISN): 075, based on 07 stations.

Solar indices for 26 Dec 2013

Wolf number Catania	///
10cm solar flux	125
AK Chambon La Forêt	003
AK Wingst	002
Estimated Ap	001
Estimated international sunspot number	068 - Based on 18 stations

Noticeable events summary

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

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