SIDC Ursigram

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

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Latest issue 

:Issued: 2024 Apr 23 1241 UTC
:Product: documentation at http://www.sidc.be/products/meu
#--------------------------------------------------------------------#
# DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC     #
# (RWC Belgium)                                                      #
#--------------------------------------------------------------------#
SIDC URSIGRAM 40423
SIDC SOLAR BULLETIN 23 Apr 2024, 1240UT
SIDC FORECAST 
SOLAR FLARES  : M-class flares expected (probability >=50%)
GEOMAGNETISM  : Quiet (A<20 and K<4)
SOLAR PROTONS : Warning condition (activity levels expected to increase,
but no numeric forecast given)
PREDICTIONS FOR 23 Apr 2024  10CM FLUX: 210 / AP: 003
PREDICTIONS FOR 24 Apr 2024  10CM FLUX: 207 / AP: 004
PREDICTIONS FOR 25 Apr 2024  10CM FLUX: 204 / AP: 006

Solar Active Regions and flaring: Solar flaring activity remained at
moderate levels in the past 24 hours with multiple low M-class flares.
There are 18 numbered and several unnumbered active regions on the visible
solar disc with NOAA AR 3645 (beta-gamma) being the largest one, followed
by NOAA AR 3647 (beta-gamma) and NOAA AR 3639 (beta-gamma). The strongest
activity was M3.6 flare, start time 03:06 UTC, end time 03:37 UTC, peak
time 03:19 UTC on April 23rd produced by NOAA AR 3654 (beta). This region
was responsible for another M3.0-flare, peak time 08:21 UTC on April 23rd
and continuous to be actively flaring. Isolated low M-class flaring was
produced by regions NOAA 3645 and NOAA 3638. Other regions which
contributed to the flaring activity are NOAA AR 3649 (beta), NOAA AR 3656
(beta) and NOAA AR 3646 (beta). The remaining active regions are relatively
simple simple (magnetic type alpha or beta) and did not show significant
flaring activity. The solar flaring activity is expected to remain at
moderate levels over the next days with likely further M-class flaring and
increased chances for isolated X-class flaring.

Coronal mass ejections: No Earth-directed coronal mass ejections (CMEs)
have been detected in the available coronagraph imagery over the past 24
hours. A small filament eruption was observed to the south of the central
meridian starting around 1:40 UTC on April 23rd. A related chain of flaring
activity was observed from regions NOAA 3654 (M3.4 flare, peak time 03:19
UTC on April 23rd) and region NOAA AR 3638 (C-class flaring, peaking at
01:22 UTC and 07:04 UTC on April 23rd) with an eastward and series of
south-west CMEs detected by LASCO/C2 around 03:48 UTC and 07:36 UTC.
Current analysis is ongoing to determine any potential Earth-directed
components related to these eruptions.

Solar wind: Over the past 24 hours the solar wind parameters (ACE and
DSCOVR) were indicative of background slow solar wind regime. The solar
wind velocity was in the range of 335 km/s to 456 km/s. The interplanetary
magnetic field was weak with a maximum value of 3.36 nT and a minimum Bz of
-5.06 nT. The B field phi angle was predominantly in the negative sector
(directed towards the Sun). The solar wind conditions are expected to
remain at slow solar wind conditions in the next hours with possible mild
elevations due to possible high speed stream arrival from a positive
polarity coronal hole on April 25th - April 26th.

Geomagnetism: The geomagnetic conditions over the past 24 hours were
globally quiet and locally in Belgium quiet to unsettled. Mostly quiet to
unsettled geomagnetic conditions are expected throughout April 23rd and
24th. Quiet to active conditions with chances for isolated minor storms are
anticipated for late April 25th-April 26th.

Proton flux levels: Over the past 24 hours the greater than 10 MeV GOES
proton flux was at background levels and is expected to continue so over
the next days, pending any fast eruptive solar activity.


Electron fluxes at GEO: The greater than 2 MeV GOES 16 electron flux as
measured by GOES 16 was below the 1000 pfu threshold and might reach the
1000 pfu threshold over the next 24h. The greater than 2 MeV electron flux
as measured by GOES 18 briefly exceeded 1000 pfu threshold around 17 UTC
and midnight UTC on April 22nd and is expected to cross the 1000 pfu
threshold again in the late afternoon on April 23rd. The 24h electron
fluence was at nominal level and is expected to remain so.


TODAY'S ESTIMATED ISN  : 279, BASED ON 12 STATIONS.

SOLAR INDICES FOR 22 Apr 2024
WOLF NUMBER CATANIA    : ///
10CM SOLAR FLUX        : ///
AK CHAMBON LA FORET    : ///
AK WINGST              : ///
ESTIMATED AP           : ///
ESTIMATED ISN          : 278, BASED ON 19 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
22  1313  1335 1417 S10W39 M1.6 1N       60/3645      VI/2 
22  1446  1455 1508 N23E07 M1.1 1F       60/3645      
22  1508  1519 1532 N23E07 M1.6 1F       64/3646      
22  1541  1550 1558 S11E67 M2.8 SN       ///3656      III/3 
22  1626  1630 1636 ////// M1.0          ///3656      III/2 
22  2105  2116 2124 S17W48 M1.5 1N       59/3638      VI/1III/3II/3 
23  0306  0319 0335 ////// M3.6          ///3654      III/1 
23  0807  0821 0829 S05E41 M3.0 1B       ///3654      VI/1 
END

BT
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Details

The SIDC ursigram starts with the code SIDC URSIGRAM YMMDD, where
Y is the last digit of the year number,
MM is the number of the month,
DD is the day of the month.

A forecast is given on:
the global flare probability,
geomagnetic disturbances,
solar proton events.
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
COMMENT
ESTIMATED ISN : xxx, based on xx stations.
where ISN stands for International Sunspot Number.
OBSERVED SOLAR INDICES FOR THE DAY BEFORE
SUNSPOT INDEX : xxx, the Wolf number observed by Catania
10CM SOLAR FLUX : xxx,
AK CHAMBON LA FORET : xxx,
AK WINGST : xxx,
ESTIMATED AP : xxx,
ESTIMATED ISN : xxx, based on xx stations.
NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX END LOC XRAY OP 10CM TYPE Catania NOAA NOTE

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.