Viewing archive of Wednesday, 20 December 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Dec 20 1230 UTC

SIDC Forecast

Valid from 1230 UTC, 20 Dec 2017 until 22 Dec 2017
Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

10cm fluxAp
20 Dec 2017070008
21 Dec 2017071016
22 Dec 2017071007

Bulletin

Solar activity was very low with only a couple of low level B class flares from the only region on disk Catania sunspotgroup 67. The region is still fairly simple but has shown quite some growth this morning. Flaring is expected to remain below C level. A filament eruption is seen off the North Eastern hemisphere around 3:00UT. Coronagraph data are not yet available to assess the extent of the likely associated CME. Proton flux values are at background levels and expected to remain so.

Solar wind has recovered to background conditions with Solar wind speed dropping to 450 km/s by around 2:00 UT this morning and remained stable since. Total magnetic field has been fluctuating around 3-4nT with a variable Bz. A possible arrival of the December 15 CME is no longer expected. A transition into a negative sector is expected within the next 24 hours with then also the influence of the negative polarity equatorial coronal hole possibly setting in. However, the leading part of the coronal hole which passed the central meridian on December 18 is not likely to bring any strong effects. A more significant high speed stream influence is only expected 3-4 days from now from the trailing part of the coronal hole which only now starts passing the central meridian. Geomagnetic conditions were quiet to unsettled (both local K Dourbes and NOAA Kp 1-3). Quiet to unsettled conditions are expected over the next days.

Today's estimated international sunspot number (ISN): 011, based on 06 stations.

Solar indices for 19 Dec 2017

Wolf number Catania011
10cm solar flux069
AK Chambon La Forêt012
AK Wingst006
Estimated Ap005
Estimated international sunspot number007 - Based on 19 stations

Noticeable events summary

DayBeginMaxEndLocStrengthOP10cmCatania/NOAARadio burst types
None

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

All times in UTC

<< Go to daily overview page

Latest news

Support SpaceWeatherLive.com!

A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!

Donate SpaceWeatherLive Pro
Support SpaceWeatherLive with our merchandise
Check out our merchandise

Latest alerts

Get instant alerts!

Space weather facts

Last X-flare2025/03/28X1.1
Last M-flare2025/04/01M5.6
Last geomagnetic storm2025/03/27Kp5 (G1)
Spotless days
Last spotless day2022/06/08
Monthly mean Sunspot Number
February 2025154.6 +17.6
Last 30 days128.5 -22.7

This day in history*

Solar flares
12001M7.89
22017M6.34
32001M5.75
42025M5.6
52024M3.9
DstG
11960-327G4
22001-228G2
31976-218G4
41973-211G4
51989-93G2
*since 1994

Social networks