SIDC ursigram

:Issued: 2021 Apr 18 1230 UTC
:Product: documentation at http://www.sidc.be/products/uge
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# DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC     #
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SIDC URSIGRAM 10418
GEOALERT BRU108
UGEOA 30512 10418 1230/ 9930/ 
10182 21182 30182 
99999
PLAIN
NOTE: the above forecasts are valid from 1230UT, 18 Apr 2021 until 20 Apr
2021
COMMENT: Solar activity remained at very low levels over the last 24 hours.
The visible active regions NOAA 2814 (Catania 86, magnetic type Beta), NOAA
2815 (not classified) and NOAA 2016 (magnetic type Beta) remained at very
low levels of activity. A B9.7 class-flare (peak time 17:17 UTC) was
produced on April 17th by an active region behind the east limb and
resulted in a type II radio emission. The flaring activity within the next
24 hours is expected at very low to low levels with 40% chance for a
C-class flare.

A CME associated with the B9.7 class-flare was detected to leave the east
limb around 16:36 UTC on April 17th. It will not impact the Earth. No other
Earth-directed coronal mass ejections (CMEs) were detected in the available
coronagraph imagery at the moment.

The greater than 10 MeV proton flux was at nominal levels in the past 24
hours and is expected to remain so in the next 24 hours. The greater than
2MeV electron flux crossed the 1000 pfu threshold several times and is
expected to remain above the threshold for long periods throughout April
18th. The 24h electron fluence reached moderate levels and is expected to
remain at moderate levels in the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) remained
elevated from the high speed stream (HSS) currently affecting the Earth.
The total magnetic field registered a maximum magnitude of 10 nT with a
minimum Bz of -10 nT. The solar wind speed varied between 570 km/s and 670
km/s. The solar wind speed is expected to remain elevated throughout April
18th.

Unsettled to active geomagnetic conditions were registered over the past 24
hours under the influence of the HSS. Unsettled to active geomagnetic
conditions are expected for the next 24 hours. Isolated periods of minor
geomagnetic storms remain possible in case of prolonged intervals with
negative Bz.


TODAY'S ESTIMATED ISN  : 016, BASED ON 17 STATIONS.
UGEOI 30512 10418 1230/ 17/// 
1//// 20750 3031/ 4//// 8//// 9//// 
99999
UGEOR 30512 10418 1230/ 14/07 18101 
10085 2//// 3//// 4201/ 50030 60011 30822 00000 
99999
UMAGF 30503 10418 1004/ 17066 1/031 23344 33332
UMAGF 31523 10418 0000/ 17004 1/031 25443 34544
BT
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