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: 2021 Apr 20 1251 UTC :Product: documentation at http://www.sidc.be/products/meu #--------------------------------------------------------------------# # DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC # # (RWC Belgium) # #--------------------------------------------------------------------# SIDC URSIGRAM 10420 SIDC SOLAR BULLETIN 20 Apr 2021, 1250UT SIDC FORECAST (valid from 1230UT, 20 Apr 2021 until 22 Apr 2021) SOLAR FLARES : Quiet conditions (<50% probability of C-class flares) GEOMAGNETISM : Quiet (A<20 and K<4) SOLAR PROTONS : Quiet 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. SOLAR INDICES FOR 19 Apr 2021 WOLF NUMBER CATANIA : 032 10CM SOLAR FLUX : 086 AK CHAMBON LA FORET : 028 AK WINGST : 018 ESTIMATED AP : 021 ESTIMATED ISN : 035, BASED ON 27 STATIONS. 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 BT #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # # # Website http://www.sidc.be. # # E-mail sidc-support@oma.be # # To unsubscribe http://www.sidc.be/registration/unsub.php # # # # Legal notices: # # - Intellectual Property Rights: # # http://www.astro.oma.be/common/internet/en/data-policy-en.pdf # # - Liability Disclaimer: # # http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf # # - Use and processing of your personal information: # # http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf # #--------------------------------------------------------------------#
Details
The SIDC ursigram starts with the code SIDC URSIGRAM YMMDD, whereY 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.