Viewing archive of Wednesday, 20 April 2016

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2016 Apr 20 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
20 Apr 2016	085	009
21 Apr 2016	082	007
22 Apr 2016	081	017

Bulletin

Solar activity was low with Catania group 54 producing the only C flare of the period. The C1.0 flare peaked at 23:02UT. Catania group 54 (NOAA 2529) will pass the West limb today representing a decrease in flaring probability, while a new fairly small and symmetric sunspot (Catania group 60) appeared over the East limb. C flares remain possible and even probable over the next 24 hours with only a slight and decreasing probability for M flaring. Proton events are not expected. No CMEs could be detected in available coronagraphic images. An extension of the Northern polar coronal hole, extending Southward over the equator will transit the central meridian during the next period. It is expected to influence Solar wind conditions in 2 to 3 days from now. Solar wind conditions were close to nominal. Solar wind speed saw a generally decreasing trend down to 330 km/s at present, while the total magnetic field strength increased steadily to close to 10 nT. After midnight, the North-South component turned steadily from Northward to Southward reaching values of -7.4nT after 6:00UT. It is currently again firmly directed Northward. The magnetic field phi angle was in the positive sector throughout the period. With no sign of the previously expected possible influence from the northern positive polarity coronal hole, close to nominal solar wind conditions are expected to continue. In the afternoon of April 22 the equatorial extension of the Northern polar coronal hole (transiting central meridian today) is expected to start enhancing solar wind conditions. The coronal hole appears as being larger than during its previous rotation when it caused a maximal solar wind speed of just 570 km/s. Geomagnetic conditions were essentially quiet (both local K Dourbes and NOAA Kp 0-2) with a short episode of unsettled conditions locally this morning associated to the negative Bz values. With no sign of the previously expected possible influence from the northern positive polarity coronal hole quiet to unsettled conditions are expected over the next days before increasing under the influence of the next coronal hole high speed stream.

Today's estimated international sunspot number (ISN): 025, based on 22 stations.

Solar indices for 19 Apr 2016

Wolf number Catania	033
10cm solar flux	089
AK Chambon La Forêt	005
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	029 - Based on 32 stations

Noticeable events summary

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

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