Viewing archive of Tuesday, 29 December 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Dec 29 1230 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Major magstorm expected (A>=50 or K>=6)

Solar protons

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

	10cm flux	Ap
29 Dec 2015	112	006
30 Dec 2015	115	047
31 Dec 2015	115	063

Bulletin

NOAA AR 2473 produced a long duration M1.8 flare at the start of the period peaking at 12:45UT as well as a C6.9 flare peaking at 10:32UT and several other C flares in the tail of the long duration flare. NOAA AR 2473 remains capable of strong flaring so flaring at M level is expected with also a slight chance for an X flare. The long duration M1.8 flare was associated with a partial halo CME first visible in SoHO/LASCO C2 field of view at 12:12UT. It had an angular width of close to 250 degrees with primary angle to the South-West off the Sun- Earth line. Projected speeds were in the order of 600 km/s with a slightly faster component towards the South-East. An impact at Earth can be expected in the afternoon of December 30 (around 21:00 UT). This CME initiation was also the likely source of a slight and gradual increase of the >10MeV proton flux. It reached a peak just below 4 pfu after midnight and has been decreasing since. With AR 2473 on the Western hemisphere and reamaining capable of strong flaring, a warning condition for proton events is issued. Solar wind conditions were nominal, with speed dropping to 400 km/s early in the period and remaining stable in the 380-420 km/s range. Total magnetic field started very low but was later mainly in the 4.5-6.5 nT range. Bz was variable though mostly negative in the later part of the period but essentially remained above -3nT. The magnetic field phi angle settled in the positive (outward) direction. Solar wind conditions will remain nominal until the expected arrival of the December 28 CME, due in the late afternoon of December 30. Geomagnetic conditions have been essentially quiet (NOAA Kp 1-2) with only an isolated unsettled period locally (K Dourbes 0-3). Quiet to unsettled conditions are expected to continue until the arrival of the December 28 CME which may bring moderate to major geomagnetic storm conditions in the late afternoon of December 30, through to December 31.

Today's estimated international sunspot number (ISN): 055, based on 13 stations.

Solar indices for 28 Dec 2015

Wolf number Catania	///
10cm solar flux	112
AK Chambon La Forêt	009
AK Wingst	005
Estimated Ap	004
Estimated international sunspot number	065 - Based on 24 stations

Noticeable events summary

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

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