Viewing archive of Sunday, 20 December 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Dec 20 1242 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
20 Dec 2015	126	035
21 Dec 2015	126	011
22 Dec 2015	126	007

Bulletin

The Sun produced nine C flares in the past 24 hours. The brightest flare was a C4.5 flare by both a new unnumbered region near the East limb and NOAA AR 2469, peaking at 22:28 UT on December 19. C flares are expected within the next 24 hours, with a chance (30%) for an M flare, especially from this unnumbered region near the East limb. The C1.7 flare released by this region near the East limb and peaking at 13:26 UT on December 19 was accompanied by a Type II burst observed at Humain and Sagamore Hill. It was observed as a bright flare by EUVI A. LASCO and COR2 A imagery showed an associated bright CME towards the East, first observed in LASCO C2 at 13:25 UT. Due to its easterly position, this CME is not expected to be Earthbound. ACE registered a shock in the solar wind at 15:27 UT on December 19. Solar wind speed jumped from 360 to 470 km/s, while the magnitude of the Interplanetary Magnetic Field jumped from 5.5 to 16 nT. This was probably the arrival of the December 16 CMEs. After the arrival of the shock, the solar wind speed increased from 470 to 500 km/s, and then decreased to current values of 400 km/s. Meanwhile the magnitude of the Interplanetary Magnetic Field increased from 16 to 18 nT and then decreased to current values of 11 nT. Bz has been below -10 nT between 2:30 and 7:00 UT on December 20. A NOAA Kp value of 6 (moderate geomagnetic storm) was observed on 3h, and a value of 5 (minor geomagnetic storm) on 6h and 9h UT on December 20, preceded by Kp values of 4 (active conditions) since 15h UT on December 19. Active geomagnetic levels (K Dourbes = 4) were mostly registered since 18h UT on December 19, with minor geomagnetic storm (K Dourbes = 5) at 0h and from 6h till 9h UT on December 20. Unsettled to minorm storm geomagnetic levels (K Dourbes = 3-5) are expected on December 20. Quiet to unsettled geomagnetic conditions (K Dourbes < 4) are expected on December 21 and 22, with a chance for active excursions (K Dourbes = 4) on December 21.

Today's estimated international sunspot number (ISN): 019, based on 16 stations.

Solar indices for 19 Dec 2015

Wolf number Catania	///
10cm solar flux	119
AK Chambon La Forêt	035
AK Wingst	015
Estimated Ap	014
Estimated international sunspot number	043 - Based on 19 stations

Noticeable events summary

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

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