GEOALERT SIDC

3-day-forecast of solar and geomagnetic activity.
Source SIDC (RWC-Belgium)
Frequency Daily
Format Encoded data (ISES)
Mail header GEOALERT SIDC
SIDC code xut

Latest issue

:Issued: 2021 Apr 20 1250 UTC
:Product: documentation at http://www.sidc.be/products/xut
#--------------------------------------------------------------------#
# GEOALERT message from the SIDC (RWC-Belgium)                       #
#--------------------------------------------------------------------#
GEOALERT BRU110
UGEOA 30512 10420 1250/ 9930/ 
10202 20202 30202 
99999
PLAIN
NOTE: the above forecasts are valid from 1230UT, 20 Apr 2021 until 22 Apr
2021
PREDICTIONS FOR 20 Apr 2021  10CM FLUX: 083 / AP: 011
PREDICTIONS FOR 21 Apr 2021  10CM FLUX: 080 / AP: 010
PREDICTIONS FOR 22 Apr 2021  10CM FLUX: 078 / AP: 008
COMMENT: Two, out of several, sunspot groups observed on the visible side
of the solar disc have during last 24 hours increased the complexity of
their photospheric magnetic field configuration. Catania sunspot groups 87
and 86 (NOAA ARs 2816 and 2817) have presently beta configuration of their
photospheric magnetic field.
During last 24 hours 17 B-class and one M-class flare were reported,
majority of them originating from the Catania sunspot group 86 (NOAA AR
2817). The M1.1 flare observed on April 19 (peaked at 23:42 UT), have
originated from the Catania sunspot group 87 (NOAA AR 2816) which is
presently still increasing the area and sunspot numbers. During coming
hours we can expect B-class flares, and isolated C-class flares. The
M-class flares are still possible but not very probable.
The M 1.1 flare was associated with the EUV wave, coronal dimming, type II
radio burst (indicating presence of a shock wave), and a rather diffuse
CME. The CME had angular width of about 100 degrees and projected line of
the sight speed of about 500 km/s (as reported by CACTUS software).
Although the CME is not very wide, its source region is situated close to
the solar disc center and the glancing blow still might be expected at
Earth on April 23, although this is not very probable.
During last 24 hours the proton flux levels remained at background values.

The greater than 2MeV electron flux still remains above the 1000 pfu
threshold, and it is expected to remain above the threshold for long
periods throughout April 20. The 24h electron fluence is at moderate levels
and is expected to be in the range of moderate to high levels in the next
24 hours.

Earth is still inside the fast solar wind with the speed of about 590 km/s.
The interplanetary magnetic field magnitude is 4 nT.
Small, negative polarity equatorial coronal hole has reached central
meridian this morning. The associated fast solar wind can be expected at
Earth on April 23.
Due to longer interval of the negative value of the Bz component of the
interplanetary magnetic field, active geomagnetic conditions were reported
in the evening of April 19 (from about 19 until 23 UT). The local station
at Dourbe reported Kp=4 and NOAA reported K=4.
Presently the geomagnetic conditions are quiet and we expect them to stay
so in the coming hours.

TODAY'S ESTIMATED ISN  : 055, BASED ON 23 STATIONS.
99999
UGEOI 30512 10420 1250/ 19/// 
10032 20860 3018/ 4//// 80202 90120 
99999

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
19  2319  2342 2359 S24E25 M1.1 SN       87/2816      II/2III/2IV/1 
END

UGEOR 30512 10420 1250/ 20/07 20104 
10087 2//// 3//// 4422/ 50100 60010 21724 03100 
10086 2//// 3//// 4422/ 50080 60013 45218 01000 
10088 2//// 3//// 410// 50010 60001 43714 00000 
10089 2//// 3//// 472// 50020 60001 27517 00000 
99999
USSPS 31405 20075 06532 86008 45218 24413 87010 21724 25410 88001 43714
0/101 89002 27517 2/801
USSPS 32404 18137 01622 24005 23925 21406
USSPS 81202 19018 03532 29003 43218 01205 27008 23326 24210
UMAGF 30503 10420 1004/ 19062 1/028 23333 34332
UMAGF 31523 10420 0000/ 19004 1/018 23333 33344
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Details

The Geoalert message starts with the code GEOALERT BRUXXX, where xxx is the day-of-the-year number.
Besides the ISES codes like UGEOA, UGEOI, UGEOR and USSPS, this message contains the following information:
PLAIN
PREDICTIONS FOR "today" : 10CM FLUX: xxx / AP: xxx
PREDICTIONS FOR "today+1": 10CM FLUX: xxx / AP: xxx
PREDICTIONS FOR "today+2": 10CM FLUX: xxx / AP: xxx
99999
This gives the predicted 10.7 cm radioflux and the predicted Ap index for 3 days starting on the date of the message
NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX END LOC XRAY OP 10CM TYPE Catania NOAA NOTE

This is the header of a table that lists all major events.
DAY gives the day-of-the-month.
BEGIN, MAX and END give the UT time of the different phases of the X-ray output of the event.
LOC gives the location of the event in heliographic coordinates.
XRAY gives the GOES X-ray class of the event.
OP lists the optical flare class.
10cm gives the 10.7 cm radioflux output of the event.
TYPE specifies the type of radiobursts observed.
Catania gives the Catania sunspot group number where the event happened.
NOAA is the corresponding NOAA active region number.
NOTE is the header of any other type of information, e.g. if a CME was observed associated with the event.


Check the ISES code book for information on ISES codes.