SIDC URSIGRAM 31026
SIDC SOLAR BULLETIN 26 Oct 2003, 1230UT
SIDC FORECAST (valid from 1230UT, 26 Oct 2003 until 28 Oct 2003)
SOLAR FLARES  : Major flares expected (X-class flares expected, probability >= 50%)
GEOMAGNETISM  : Minor geomagnetic storm expected (A>=30 or K=5)
SOLAR PROTONS : Warning condition
PREDICTIONS FOR 26 Oct 2003  10CM FLUX: 235 / AP: 021
PREDICTIONS FOR 27 Oct 2003  10CM FLUX: 235 / AP: 037
PREDICTIONS FOR 28 Oct 2003  10CM FLUX: 230 / AP: 070
COMMENT: The solar disk again showed a large flaring activity, concentrated
around NOAA 0484 and 0486 (Cat 65 and 70). However, region 0486 is the most
active one, and still capable of producing strong flares (M and X). EIT reported
an X1.3 flare between 05:00 and 08:00 UT, peaking at 06:52 UT, in this region. A
new solar region has rotated around the east limb and at this stage seems to
have a relatively simple bipolar magnetic configuration, although proximity to
limb makes assessment difficult. A CME is visible in LASCO C2 & C3 images. It is
first visible in C2 at about 01:31 UT this morning (26 Oct) and at about 03:18
UT in C3. It is most likely to be related to a large filament (prominence)
eruption clearly visible in all EIT images (e.g. in 284 at 01:06 UT, in 304 at
01:19 UT). The filament is situated South-West the NOAA 0484 (Catania 70). Since
the eruption occurred at a geoeffective position, it is likely to arrive on
Earth, early on 28 October. Solar wind speed decreased from 600 to 500km/sec
over the UT day. The north-south component of the interplanetary magnetic field
was predominately northward for most of the UT day, a state that decreases the
geoeffectivness of the solar wind. At 07:49 UT today, a shock occurred in the
solar wind speed, roughly jumping from 360 to 550 km/s. The solar wind density
shows an enhancement by a factor 10. Currently the solar wind speed is 600 km/s.
Since the IMF is still pointing North, geomagnetic activity stays at quiet
level. A new coronal hole is entering the geoeffective position on the solar
disk. This means the solar wind speed will enhance gradually.

SOLAR INDICES FOR 25 Oct 2003
SUNSPOT INDEX       : 118
10CM SOLAR FLUX     : 222
AK CHAMBON LA FORET : 032
AK WINGST           : ///
ESTIMATED AP        : 020

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC   XRAY OP 10CM     TYPE          Catania NOAA NOTE
26  0555 0652 0800 S15E43 X1.3                                70  0486 EIT derived loc     
END
BT