:Issued: 2004 Dec 04 1259 UTC :Product: documentation at http://sidc.oma.be/products/meu #------------------------------------------------------------------------------# # DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC (RWC-Belgium) # #------------------------------------------------------------------------------# SIDC URSIGRAM 41204 SIDC SOLAR BULLETIN 04 Dec 2004, 1155UT SIDC FORECAST (valid from 1230UT, 04 Dec 2004 until 06 Dec 2004) SOLAR FLARES : Eruptive (C-class flares expected, probability >= 50%) GEOMAGNETISM : Major geomagnetic storm expected (A>=50 or K>=6) SOLAR PROTONS : Proton event expected (10 pfu at >10 MeV) PREDICTIONS FOR 04 Dec 2004 10CM FLUX: 099 / AP: 012 PREDICTIONS FOR 05 Dec 2004 10CM FLUX: 095 / AP: 068 PREDICTIONS FOR 06 Dec 2004 10CM FLUX: 092 / AP: 020 COMMENT: The solar wind has now a very low speed (320km/s) and very low density, and it carries a weak interplanetary magnetic field <4nT. As a consequence, the geomagnetic conditions are currently particularly quiet. However, the arrival of a first CME disturbance is expected in the second part of the day, while a second stronger disturbance should arrive tomorrow, Dec.5. Those transients are expected to trigger a geomagnetic storm later today. This storm should first be minor to moderate, but may amplify tomorrow Dec. 5, with the arrival of the second CME, then becoming a major storm. Since Dec.3 around 12:00UT, the >10MeV proton flux is slightly enhanced (1 pfu), although it remains below event trershold. This slight excess is probably associated with the M1.5 flare and resulting CME shock. The proton flux may increase further when the shock will reach the Earth in the coming hours. The solar activity is currently very low. All active regions are stable or decaying. We thus forecast only C flares, although a new isolated M flare from active region 79 is not entirely excluded. SOLAR INDICES FOR 3 Dec 2004 SUNSPOT INDEX : 059 10CM SOLAR FLUX : 101 AK CHAMBON LA FORET : 006 AK WINGST : /// ESTIMATED AP : 003 NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM RADIO BURST TYPES Catania NOAA NOTE NONE END BT #------------------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # Fax : 32 (0) 2 373 0 224 # # Tel.: 32 (0) 2 373 0 491 # # # # For more information, see http://sidc.oma.be. Please do not reply directly # # to this message, but send comments and suggestions to 'sidctech@oma.be'. # # If you are unable to use that address, use 'rvdlinden@spd.aas.org' instead. # #------------------------------------------------------------------------------#