Viewing archive of Thursday, 21 January 2016

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2016 Jan 21 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
21 Jan 2016	102	026
22 Jan 2016	102	017
23 Jan 2016	103	009

Bulletin

Four C-class flares were recorded during the period, the strongest a C2.9 flare produced by NOAA 2487 at 01:45UT. This sunspot region continues its gradual growth and borders the top of a 20 degrees long north-south oriented filament. NOAA 2484, which rounded the west limb, and NOAA 2488 produced a C1 flare each. No earth-directed coronal mass ejections (CME) were observed.

Further C-class flaring is expected. . Intially, the Bz component of the solar wind remained at a steady -11 nT until about 18:00UT, when a gradual oscillation set in that displayed progressively stronger excursions. Values ranging from -20 nT to + 16 nT were recorded during the morning hours of 21 January. The start of this series of oscillations coincided with a gradual increase in solar wind speed from about 350 km/s to its current values near 500 km/s. Since about 08:00UT, the extremes of the Bz oscillations seem to be gradually damping out. Bt was at a steady 7 nT since 10:00UT. The Interplanetary Magnetic Field (IMF) is directed towards the Sun.

In response to the aforementioned solar wind variations, the geomagnetic field was strongly disturbed. Minor geomagnetic storming (Kp=5) was observed on 20 January during the 15-18UT and 18-21UT intervals, most likely in response to further effects from the coronal mass ejection (CME) that passed the Earth on 18 January. A moderate geomagnetic storm was observed (Kp=6) on 21 January during the 03-06UT interval, most likely in response to the compression zone ahead of the anticipated moderate speed stream from the southern polar coronal hole. During the entire period, only active conditions (3h intervals) were recorded at Dourbes.

Unsettled to active geomagnetic conditions are expected to prevail, with a small chance on a minor storming episode.

Today's estimated international sunspot number (ISN): 057, based on 14 stations.

Solar indices for 20 Jan 2016

Wolf number Catania	///
10cm solar flux	100
AK Chambon La Forêt	047
AK Wingst	024
Estimated Ap	025
Estimated international sunspot number	058 - Based on 18 stations

Noticeable events summary

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

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