Issued: 2004 Aug 19 1236 UTC
DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC (RWC-Belgium)
SIDC URSIGRAM 40819
SIDC SOLAR BULLETIN 19 Aug 2004, 1223 UTC
SIDC FORECAST (valid from 1230UT, 19 Aug 2004 until 21 Aug 2004)
SOLAR FLARES : Active (M-class flares expected, probability >= 50%)
GEOMAGNETISM : Active conditions expected (A>=20 or K=4)
SOLAR PROTONS : Quiet
PREDICTIONS FOR 19 Aug 2004 10CM FLUX: 135 / AP: 012
PREDICTIONS FOR 20 Aug 2004 10CM FLUX: 130 / AP: 015
PREDICTIONS FOR 21 Aug 2004 10CM FLUX: 126 / AP: 011
COMMENT: The arrival of a shock wave driven by the CME detected by CACTUS at
18:06 UT on August 18 is possible early on August 22. However, this CME was not
particularly fast, so we expect it to produce only a weak geomagnetic
disturbance. A fast flow from the low-latitude coronal hole may still arrive.
An X1.8 flare occurred yesterday in NOAA AR 0696, Catania sunspot group 90,
peaking at 17:40 UT. A partial halo CME was associated with this event, first
observed in C2 field of view at 18:06 UT. Its speed estimated by CACTUS is 511
km/s. As the CME source region was situated right at the Western limb, we
expect that only the CME-driven shock will arrive to the Earth at the most,
probably early on August 22. It may produce a moderate geomagnetic disturbance.
NOAA AR 0661 produced yesterday two eruptions observed by EIT, the first around
10:48 UT, the second around 18:24 UT. It appears that only the second one was
associated with a (narrow) CME observed by LASCO, at 17:06 UT. Although the
source region is situated relatively close to the solar disc center, we do not
expect this CME to be geoeffective as the eruption was directed rather towards
the Eastern limb.
SOLAR INDICES FOR 18 Aug 2004
SUNSPOT INDEX : 066
10CM SOLAR FLUX : 140
AK CHAMBON LA FORET : 017
AK WINGST : ///
ESTIMATED AP : 012
NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM TYPE Catania NOAA
NOTE
18 1729 1740 1754 S12W83 X1.8 SF 150 II/2 90 0656
19 0635 0701 0718 S12W88 M3.0 90 0656 GOES-12/SXI derived location, AR is
behind the W limb
73,
Thomas F. Giella, KN4LF
Plant City, FL, USA
Grid Square EL87WX
Lat & Long 27 58 31 44N 82 09 51 98W
kn4lf@arrl.net
KN4LF Solar Space Weather & Geomagnetic Data Archive:
http://www.kn4lf.com/kn4lf5.htm
KN4LF Amateur & SWL Radio History: http://www.kn4lf.com
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